RX-8 Owners Club 2020 Annual Meet weekend
Saturday 29th February - Sunday 1st March

Club exclusive trackday at the Three Sisters Circuit | Evening Dinner | AGM




Castle Combe Circuit's Japanese Car Show
Saturday 6th June 2020

Club Displays | Drifting Demos | Tracktime | and more

Modifying for Performance & Style

Place for discussions about the RX-8
User avatar
warpc0il
Spin Doctor
Spin Doctor
Posts: 22769
Joined: Sat Sep 06, 2008 10:56 pm
RX-8: 231
Colour: Lightning Yellow
Location: Groomsport, Co Down, NI
Has thanked: 324 times
Been thanked: 1214 times
Contact:

Modifying for Performance & Style

Post by warpc0il » Mon Sep 17, 2018 6:09 pm

WARNING: This post is long, really long, and doesn’t even have any pictures.

I've been active on this forum for ten years now and this is all based on my personal experience owning and working on RX8s, talking to owners, information gleaned and distilled from forum posts and PMs, working for Ford (who owned Mazda at the time) plus my own research. Most of the information provided is fact, while I’ve tried to differentiate that from opinion.

It was originally intended to post in the FAQ section but as that would make it difficult for members to add their own comments and experiences, I have posted in the General RX8 Discussion area, which is also open to non-members (prospective owners).

Background

Before you consider changing anything you should consider why the car is how it is.

The RX8 was launched in 2003, so the fundamental design was produced in the last century and the details were pretty much locked-down by 2001. This means that the technologies available were limited to those of 20 years ago and the world was very different than today, in so many ways.

In the UK, the RX8 was marketed at the same demographic that was buying the Audi TT – a mainstream “sporty” car with a recognisable style. This was far from the last rendition of the RX7, which had been aimed at potential Porsche buyers.

It’s the input from Mazda UK Marketing we have to thank for all our cars coming with Sports Suspension, Twin Oil Coolers, Air Conditioning, 18” Alloys with big front brakes, Bose audio, and HIDs on the 231. None of which were standard in most other markets and only available as expensive options (if at all).

Our UK 192 is a bit of a parts-bin special, taking the 4-port engine from the JDM/US automatic and the gearbox from the RX7. This was in response to Audi offering a low-power version of the TT, with all the same style but a lower purchase price and cheaper insurance, especially for young drivers. At this time it was determined that a “sports car” with an automatic ‘box wouldn’t sell in the UK – how times have changed…

Modifying for Performance

The first question you need to ask yourself when looking at modifying is “Why didn’t Mazda do it this way in the first place?

If a $10 bolt-on would add 30bhp or 20% better fuel consumption then Mazda would have done it, unless;
- the technology didn’t exist at the time
- it would make the car significantly less reliable or drivable
- it would mean that the car would fail regulatory requirements, e.g. noise or emissions
- it’s actually BS and the product claims are fictional.

Let’s look at some areas that could be considered for modification and review the Pros & Cons…

Engine internals

The Renesis Side-Port engine was developed to address the emissions of the peripheral port engine, with a recognition that this would also compromise maximum power. Power delivery was determined by the timing of the ports and the adoption of the complicated intake system and a state-of-the-art Powertrain Control Module.

A popular modification is to adjust the porting, anything from a mild Street Port up to a wild Bridge Port. Any change in the porting is a compromise and has downsides that have to be considered against the potential benefits. The details of these are documented elsewhere but it’s sufficient to point out that it would have cost Mazda nothing to make the ports a different shape and, after spending millions on R&D, they choose the shape that we have.

Oil pressure management can also be modified and here we find an external influence that may have pushed Mazda in a wrong direction. In the late 1990’s Mazda were working closely with Texaco, who were developing a new range of engine oils, aimed at assisting manufacturers meet emissions requirements by reducing the parasitic drag associated with pumping the oil around and the stickiness in the bearing. These new oils had a lower viscosity and higher shear strength, protecting bearings even at lower system pressure. This resulted in Mazda recommending 5W30 oils for all their petrol cars and engineering the Renesis to run at a lower system pressure than the RX7.

However, it’s now clear that Texaco (and all the oil companies at the time) were over-selling the capabilities of their products and that laboratory results weren’t being reflected in the real world.

By far the cheapest modification that you can make is to switch to a 10W40 engine oil, which really has no downside, while providing better protection for your engine. Some rebuilders specify the ongoing use of 10W40 oil as part of their warranty requirements.

If you’re having an engine rebuilt, then most specialists will also recommend modifying the oil pressure management to increase the flow to the bearings. This again has no known downsides and is likely to be what the Mazda engineers would have done, if Texaco had been more honest. Mazda changed the R3 to run at a similar oil pressure to the RX7.

While we’re talking about oil, the powertrain engineers have specified the maximum time between engine oil changes, while under pressure from Marketing to make the Service Intervals as long as possible and based on the (mis)information from Texaco. Those engineers were also not to know that Marketing would specify twin coolers in some markets (including the UK), such that an oil change only replaces ~60% of the total capacity.

So another modification you can make with no downside is to replace the oil twice, when you first get the car, and then every 6 months or 4k miles thereafter. The fact that the Renesis uses nice cheap mineral oil, rather than expensive synthetic, makes this very cost effective. For convenience, I use a suction pump through the dipstick hole for every other change and only replace the filter when I drain from the sump.

Those twin coolers are also a mixed blessing. Rotary engines are renowned for having heat management issues and this was particularly the case with twin-turbo RX7s. The RX8 engineers made provision for twin oil coolers as an option, expected to be taken by those that live in tropical climates and/or planning to take their cars Tōuge racing. Pre-production testing identified that even with a single oil cooler, the RX8 was over-cooled and it was necessary to block-off the engine bay intake below the front numberplate, to avoid chilling of the engine casing causing internal condensation.

Marketing then chose to give us, in the UK, twin oil coolers as standard, either because it was “more sporty” or “because they thought that UK cars would be driven harder” - depending which story you believe. Either way our oil is constantly being chilled by these coolers, in our temperate climate. While they might be of value in the occasional heatwave and they do provide some benefit on a trackday, the rest of the time they’re just cooling the oil way below its optimum operating temperature. In subzero ambient the chill of the air under the sump is more than sufficient and under any normal conditions, one cooler is able to keep the oil temperature right – at around 105-110C.

Blocking the oil flow through the coolers could be fraught with issues but blocking the airflow is easy – see the Mouse Mat Mod.

The pipework to the oil coolers can corrode and leak. This was a recognised issue even when the cars were under warranty and is becoming even more common as the cars get older. I often wonder if the low temperatures of the circulating oil could be a factor here as, with both coolers open, it often doesn’t get above the 100C required to boil away water that has splashed onto the pipework.

Aftermarket replacement oil cooler pipes are available while some owners have reported good results having pipes made by their local Pirtek outlet.

The position of the oil coolers also makes them vulnerable to impact damage, so aftermarket or home-made protection grills are a recommended modification.

While considering the engine oil system we should also include the element that is unique to the rotary - the Oil Metering Pump and its associated injectors. The Renesis engine is designed to consume oil, which is injected into the engine housings by the OMP at a rate determined by the PCM, dependant on the engine revs and load. Oil consumption is minimal pottering about around town and can increase dramatically when thrashing around a track.

The RX8 gained a reputation for massive oil consumption. Partially based on the 2003 pre-launch press fleet having incorrect settings in the PCM, such that they really did go through a lot of oil. The motoring press also like to drive cars hard and then assume that both the fuel and oil consumption they see is representative of normal driving.

Anyway, the Renesis engine does consume oil and, in standard form, this is the same oil that is circulating around the engine and sump. This means that you have to keep an eye on the oil level, topping up as required, while making sure not to overfill, as this can be worse than being slightly down. It also means that you shouldn’t use an engine oil that could create hard carbon deposits when burnt (e.g. many synthetic oils) and if you don’t keep your engine oil clean then it’s dirty oil having to squeeze through the tiny hole into the OMP reservoir, through the pump and injected into the engine.

Given the choice, I’m sure that the Mazda powertrain engineers would much rather have provided the OMP with its own dedicated supply of clean oil, designed to burn, and thus also allowing a greater choice of engine oils.

However, such a solution, with its separate oil tank, was a step too far for Mazda Marketing, who seemed happy enough to expect owners to manage their varying engine oil level but not to keep a tank topped-up – which in reality is much easier (and very similar to modern diesels having to AdBlue)

We have the US Experimental Aircraft community to thank for making this obvious solution a reality. Richard Sohn developed an adapter that now bears his name. Originally for the 13B (RX7) and later for the Renesis engine, to improve reliability. Ryan Rotary have since taken that basic design and produced their own version, with improvements, and the option of a complete kit including all pipework and tanks – the COFS (Clean Oil Feed System).

Going back to the intake system, changing the original airbox for a Cold Air Intake is often the starting point for anyone “tuning” their family car or hot hatch, so why not for the RX8?

So far no one has managed to produce a replacement for the Mazda airbox that produces any significant increase in power, while all but two are recognised as killing power and drivability. Most will increase intake noise, which is an easy way to fool you into thinking that you have more power. Many will create huge dips in the power curve, which may make you think that you have more power as the smooth delivery is replaced by a hesitation and finally a surge as the engine finally gets an AFR that it can work with.

The K&N Typhoon is the most common of the problem intakes, as this both messes with the airflow to the MAF and takes hot air from within the engine bay, rather than cool air from outside – so actually the opposite to a CAI - and much the same for most aftermarket "CAI" offerings for the RX8.

Which two systems got it right? Those would be the Racing Beat Revi and the AEM.

The Revi has two components, a replacement airbox and the Revi Duct, that takes ram air from below the numberplate area. Ram air is interesting and worth an article of its own. All manufactures, including Mazda, have experimented with ram air and recognise the benefits. Some bikes make use of ram air for both low-pressure intake and cooling, but no mass-production cars. Why is that? The answer is simple and is mainly because the testing conditions required for emissions type-approval are all on rolling roads without representative air-flows. If you design a car to take advantage of ram-air in the real world then you immediately compromise its performance in the artificial environments dictated for type-approval. There’s also a real-world downside of exploiting ram-air, as it’s not available in all driving conditions. For example, get close enough behind a truck to feel the advantage of its slipstream and you’ve lost the high-pressure air on the nose, that would have been feeding that ram. Manufacturers don’t want people claiming that there was drop in power (even though it would only be down to the non-ram level) just as they went for an overtake. The trick is to accelerate and move out of the slipstream from further back.

The Revi system does deliver ram air benefits, with a slight increase in intake noise, which some people like, and with no downside, other than that noted above, and the purchase price.

If you’re not chasing more intake noise and/or you’re running the car on a budget, then the Revi Ram Scoop works just as well with the Mazda OEM airbox as it does with the Revi box – as many of us have found.

Changing the air filter panel for a quality brand (e.g. K&N, Pipercross, Mahle, etc), may help the engine breathe but it’s more important to just to make sure whichever panel filter you use is clean and dry. No debris or “oil burp” evidence.

If you're buying a replacement filter for the engine, also but a pair for the cabin air. These are often forgotten and don't even need tools to replace, just drop the glovebox right down, and can make as huge difference to a/c performance and screen demisting, when you remove all the accumulated debris.

Back to engine breathing, if you actually want more intake noise then the answer is the AEM CAI intake. This replaces the entire intake, outboard of the throttle body, with a set of aluminium pipes and silicone junctions, mounting a cone air filter behind the bumper, with a sock to resist water splashes.

The AEM won’t increase power (at least not on its own) and may even reduce power slightly, as it can cause lean running under some conditions.

Mazda USA sold a CAI under the Mazdaspeed brand, which was actually developed for them by AEM and there’s no functional difference between the Mazdaspeed and AEM branded systems.

AEM clones are now also available though the quality can be a bit hit-n-miss. Some members have resolved poor running issues by replacing their AEM clone with the real AEM product.

Still looking at the intake, Mazda chose to warm the throttle body with coolant circulation. The heat transfer to the intake air charge is almost non-existent, especially above idle and with the huge volumes of air that the rotary ingests. The reason that Mazda do this is to ensure that the low-pressure area directly behind the butterfly can’t create local freezing conditions, even in normal ambient temperatures. Icing can cause the throttle to stick, which would at best compromise performance and, at worse, could be dangerous.

Some people are under the impression that there is power to be gained by deleting this throttle body warming. I’ve not seen any evidence that supports this, the physics is against it and the downsides are real and potentially serious.

While we’re looking at engine breathing, what about the exhaust?

The OEM exhaust manifold is cast iron, both heavier and less smooth than a fabricated tubular manifold. Why, and does it make any difference?

The why is easy. Cast manifolds are much easier and cheaper to manufacture for volume vehicles. They are also much more reliable. There are no reported instances of an original manifold cracking or leaking at the joints – both of which are common problems with aftermarket fabricated replacements. The original manifold also incorporates a heat-shield, which both keeps the exhaust charge hot for the cat (not that that’s really an issue with a rotary) and also protects the adjacent engine mount and (on rhd cars) the steering column UJ from some of the radiated heat.

While it’s possible to wrap or spray insulate a fabricated manifold to reduce the heat radiation, that then can increase the risk of material failure and cracking.

There has been no proven power gains from direct replacement fabricated manifolds, i.e. those that fit with the original cat. Manifolds with longer, balanced-length headers, can provide some benefits but have implications downstream.

I know that the Mazda engineers would have preferred to run the Renesis without a catalytic converter, but the regulators had other ideas. The Mazda cat is large, heavy and expensive @ around £1,300 to replace. Why did Mazda take that route rather than a “high-performance” option?

The rotary engine stresses a cat more that just about any other road car, with it’s combination of high gas flows and temperatures. Despite this, and what you may have heard to the contrary, the original cat is among the most reliable fitted to any sports car. Unlike all aftermarket replacements, it’s a 3-way platinum-palladium-rhodium core with a 3L capacity.

While original cat failure isn’t that uncommon, it’s nearly always associated with either persistent flooding events, or more commonly, ignition system failures.

My 2004 RX8 is still running with the original cat and that’s despite one of the trailing plugs rotting away within 600 miles of a Mazda Dealer servicing the car back in 2007, and charging an additional £200 to supply and fit new plugs – which was clearly a lie.

Generic aftermarket cats have been reported to fail within weeks or months of fitting, due to the excess demands of the 8.

Some “sports cats” can be marginal in passing or failing MOT emissions testing and despite the nice throaty note that they can give to the exhaust, there’s no evidence that a cheap sports cat gives any power advantage compared to a fully functioning original.

There are quality replacement cats available from our specialist suppliers that can cope with the demands, while not breaking the bank.

Removing the cat (aka decats) are totally illegal on road cars, other than in the Republic of Ireland. At the moment, across the UK, Police roadside checks with the support of VOSA (Vehicle & Operator Services Agency) are still fairly rare and mainly focused on commercial vehicles. However, such checkpoints have been targeted around known custom car meeting points and action taken against drivers with dark tinted windows, aftermarket lights and other obviously illegal modifications. There is evidence that decats have also come onto their radar and there is going to be increased attention in the future. The insurance position is also pretty black-n-white; tell your insurer that your car is decatted and you’re telling them that it’s illegal to drive on the road – don’t tell them that the car is decatted and that’s an undeclared modification and your insurance is void anyway.

It’s impossible to pass an MOT emissions test with a decat. You might find a "friendly" MOT tester (not in Northern Ireland) that will fudge the result for you, or you will have to refit a cat, just for the test every year.

The exhaust system beyond the cat, known as the “cat back” is also quite heavy and makes the exhaust sound fairly muted. This is because Mazda chose to fit the same system to all 8’s in all markets, some of which have even more restrictive “drive-by” noise requirements than the UK.

This does mean that the catback is a prime candidate for modification, especially as Mazda didn’t choose to make the original from stainless steel, which means you have the perfect excuse to replace the old rotting system with something nice and shiny, with a bit more character. Options here run from the Toyosport/Japspeed offering, through those from Racing Beat, and other brands, up to the remote controlled system from Ryan Rotary. There’s plenty to read about your choices in other threads, though the one thing I would advise against is having a one-off system created by your local pipe bender, who is unlikely to have any idea as to the unique challenges of a rotary engine. You should tell you insurance company that you have replaced your exhaust with a "corrosion-resistant replacement" not "a performance system", as the latter would just be an excuse to bump your premiums and any power gains claims from the supplier are bogus anyway.

When fitting a replacement catback, just make sure that the joint at the back of the cat is both gas-tight and able to swivel as designed. Exhaust leaks can set fire to the underside while making this joint rigid will transmit all the exhaust movement to the powertrain, making the car feel nasty and damaging the engine mounts.

Ah, engine mounts

Mazda openly admit that they initially got these wrong. The design was fine and very sophisticated, being almost solid laterally – where you don’t want the engine to move – while allowing controlled movement vertically – perfect.

What wasn’t perfect was the original materials specification or the quality control. It took Mazda five iterations to get the mounts right, mainly due to the heat from the exhaust manifold cooking the right-hand mount and then the excess forces being transmitted to the left-hand. One of their iterations included an additional heatshield but this was dropped when they finally got the component optimised, around 2007.

In the meantime and since, aftermarket alternative options have been produced. Some are no longer available, while new ones are still being developed. The challenge that all of these face is to limit the horizontal movement while allowing sufficient vertical movement to not transmit powertrain vibrations to the bodyshell and cabin. Not easy if you’re just using a block of synthetic rubber rather than the sophisticated membrane and oil-damper construction of the originals.

This leads on to the other alternative for replacement engine mounts, which is to take a failed original, drill-out the insides and fill with synthetic rubber. While this works, in that it should hold the engine in place, give or take, depending on which grade of rubber was used, there’s a very good reason why Mazda went to the expense of their design and stuck with it.

A refilled mount or any simple replacement will never be able to manage the ratio between hard horizontal and soft vertical movement; it will always be too soft horizontally and/or too hard vertically. If you’re building a track weapon or you don’t care about such things as vibration, then this might not matter to you, but it still helps to understand.

This leads me to a neat segue into suspension, as Mazda went to the great expense of fitting most of the suspension bushes with a similar technology to the engine mounts. While not oil-filled, these suspension bushes also have great stiffness in one plane with compliance in the other, achieved by using a tough membrane sandwiched within the “rubber” bush.

Replacing these original bushes with “performance” one-piece parts will always mean that the direction that was designed to be compliant, now isn’t, while the direction that should be almost solidly supported can now move. The result being a harder ride, more road vibration and poorer wheel location.

Go firm enough and you might get the wheel location better than an old set of the original bushes but for a significant compromise in NVH (Noise, Vibration and Harshness).

Again, this might be a step that you’re willing to take for a track car, but you might not want it for your daily or even your weekend toy.

While we’re talking about suspension, it’s worth mentioning the Anti-Roll Bars (ARBs). The ARBs fitted by Mazda are quite conservative and they weren’t uprated when opting for Sports rather than Standard suspension. This means that, even with the Sports suspension, the car exhibits more body roll than some people would prefer, especially when driving near the limit. However, it does allow the suspension to deal with potholes etc without transmitting too much movement to the cabin.

Aftermarket ARBs, offered by the likes of Racing Beat, are stiffer and help the car corner flatter, at the expense of less asymmetric compliance. I ran unmodified Sports Suspension with RB ARBs for a couple of years and appreciated the difference.

The original ARB mounting bushes aren’t anything special and when worn these can be replaced with “polybush” without compromise, just make sure you get the correct replacements, as there are two different types (long and short).

The original ARB drop links were designed with a plastic insert to aid in the isolation of high-frequency vibration from the wheel movements. However, this makes them quite weak and breakage is a common cause of strange handling, suspension noises and MOT failures.

They can break from old age, pothole impact or just the stress of jacking one side of the car much higher than the other, when working on it.

A visual inspection of the original droplinks should show a pattern of four blue plastic rivet heads on the back of each end. Any less than four and the link is about to break.

Aftermarket ARB droplink replacements with solid metal “rose bush” inserts are fairly cheap and readily available. These tend to last much longer and any increase in transmitted vibration is unnoticeable, in my experience.

The suspension units themselves are already “coil-overs”, though not adjustable or rebuildable.

Most aftermarket “lowering springs” will say something like “30mm lower” on the listing. Note that this will be in comparison to Mazda Standard Suspension, which was the OEM fit in the US, JDM etc. We all got Mazda Sports Suspension, so ours is already lower and the drop will therefore be much less. The Mazda springs are progressively wound, so they start soft and get harder the more they’re compressed, so that you have compliance over ripples in the road but they don’t bottom out on big bumps. Some aftermarket springs are just hard and crash from bump to bump. This isn’t just uncomfortable for the occupants, and puts much more impact load on the bodyshell, but it also significantly reduces traction for cornering, braking and accelerating on anything other than a smooth surface.

Before we move on from the suspension I’d just like to mention a discussion I had with a “hot hatch” petrolhead at a show. He insisted that “The RX8 wasn’t a real sports car because you couldn’t buy aftermarket suspension components to allow you to adjust the camber”.

I pointed-out that there wasn’t a demand for such aftermarket components for the RX8, as these adjustments were available as standard – “Because the RX8 Is A Real Sports Car”.

This is a reminder that having your suspension (4-wheel) alignment checked and, if necessary, adjusted, by someone with the right equipment, who knows what they’re doing and is using the correct “Sports Suspension” table against your ride-height, could have more positive impact on the handling of your car than any aftermarket upgrade. Note that many garages and tyre fitters that offer "wheel alignment" can only check and adjust the front wheel tracking (toe in/out) as that's the only adjustment that most normal cars have anyway. As our cars get older some of the adjustment bolts may have seized and it could cost you more in labour costs to get these shifted than the actual adjustment itself. It pays to give them a good soak in release spray (e.g. Plusgas) a couple of days before.

Wheel alignment gets me neatly to the wheels and tyres.

The 18” alloys that all our cars came with take some beating. You’d have to spend more than the average used price of the car to buy new aftermarket wheels that are lighter and/or stronger.

The paint might not be great but a refurb is cheap and gives you the opportunity to change the colour.

The original fit tyres were Bridgestone RE40, which were a good all-round tyre for their day and complimented the car's handling, though they didn’t offer particularly good grip in the cold and wet.

Tyre technology has really moved on in the last 14 years and much better tyres are now available, some for reasonable cost even at 18” (19” for the R3). The OC has a live tyre pricing service for members to get the best deals.

“Budget” tyres should be avoided at all costs – they’re commonly referred to as ditch-finders for good reason. No car is at its best on poor tyres but the RX8 is particularly sensitive to tyre fitment.

If you’ve bought a car with cheap tyres then replacement should be right at the top of your priority list.

The original tyre size is 225/45R18 and it’s possible to fit wider tyres to the wheels without issues. Decreasing the aspect ratio can result in a tyre with (almost) the same rolling diameter e.g. 245/40R18. Never mix tyre sizes (or ideally even brands) across the same axle and take care when fitting different sizes front and rear. A difference in rolling diameter of less than 1% can cause the DSC/TCS to trigger prematurely, killing engine power, and/or the ABS to trigger too soon or too late – neither of which are a good thing. This obviously means that “staggered” wheels and tyres should be avoided on the 8.

Wider tyres may visually fill the arch better and look more aggressive but they don’t provide any greater grip, and they might actually reduce grip in some conditions, so this is a style rather than performance modification.

Fitting aftermarket spacers to move the outer rim nearer the arch may also improve the aesthetics but it does nothing for the ride and handling, both of which will be degraded by fitting spacers.
This is due to a number of factors including increased unsprung weight, and the impact of moving the contact patch further from the pivot points, both in terms of steering and suspension.

Any theoretical increase in roll resistance, due to the wider track, is negligible.

The only justification for wheel spacers is style or to gain clearance for a big brake kit.

Guess where we’re going next…

The original brakes fitted by Mazda are more than capable of triggering the ABS at any speed, even with the grippiest tyres on a perfect road. I’d challenge anyone to induce brake fade while driving fast and smooth, even well above legal speeds on the road, with good brake pads.

Even on track, the original brakes fitted with appropriate pads will handle just about anything you throw at them.

However, the single-sided piston design does mean that the performance is dependant on both the smooth movement of the pistons and the caliper sliders, which can prove to be the weak link if not properly maintained, resulting in the inner piston just pushing against the disc rather than the caliper clamping the disc. Such is the over-specification of our brakes that it can still be possible for an 8 to pass the MOT braking performance checks, even with the caliper sliders seized. When checking pad wear this also means that it's the inner pad (the one you can't see) that wears quicker than the out pad.

Unless you’re building a dedicated track weapon, or at least track time is your main requirement, I would argue that there is no engineering justification for replacing the brakes with any aftermarket options, other than maintenance replacement of disc rotors and pads.

However, should you feel the need, for whatever reason, then you need to consider the wider impacts, including unsprung weight, wheel clearance, front/rear brake bias, and future availability and cost of replacement seals, pads etc.

Replacing the original flexible brake hoses with braided stainless steel is usually credited with providing significant improvements in “brake feel” with reduced pedal travel. Having worked with the guys that designed the brakes for the Ford Sierra and Escort Cosworths, I’m more than a little sceptical about these claims.
Most often owners will fit braided hoses in conjunction with a much wider brake system overhaul, lubricating sliding parts, fitting new pads, etc. At minimum they will be replacing brake fluid and bleeding the system. Any/all of these actions could be responsible for the perceived improvements, let alone the self-convincing “I’ve just spent £££ on performance parts, so it must be better.”

I’ve yet to hear of an original RX8 flexible hose leaking, except following a major crash.
Many aftermarket braided hose kits aren’t even factory produced with any quality control, they’re put together by a local supplier from a standard box of parts on a workbench and aren’t even tested for leaks. Leaks aren't uncommon when first fitted and many hoses are supplied with the wrong orientation between the two ends, such that there’s a constant twisting force on the fitted hose.

Because of the limited options for ends, plus the size of the compression fittings, many kits foul the caliper castings and something has to be ground away to allow the banjo bolt to compress the sealing washers.

There are some good kits available that usually bolt straight on and don’t leak, but I’ve yet to see any evidence that even these are superior to the original hoses.

Feel free to “upgrade” to braided hoses if that’s what you want but don’t feel that you need to, to get the best from your brakes.

Okay, let’s quickly jump back to the powertrain and consider the transmission.

The original fit clutch is from Exedy and is the same as you can buy directly from Exedy, which may be cheaper than in a Mazda branded box.

There are lots of alternatives available, from cheap motor factor jobs like Blue Print, which have been known to explode within weeks, to “competition” clutches that take twice as much pedal pressure to operate and tend to be either On or Off.

If your clutch needs replacing and/or your engine is out for a rebuild and it seems sensible to do at the same time, give careful consideration before choosing either a cheaper or “performance” alternative. Many owners have gone down those routes and many have been honest enough to share their regrets. Search would be a good starting point.

The clutch master cylinder on early models had a production issue that can result in the clutch not fully disengaging when really hot, e.g. stuck in stop-start traffic. Replacing the master cylinder with either a later Mazda part or a quality alternative e.g. Pagid, will cure this issue.

It’s also worth mentioning that even when people remember to replace the brake fluid, they often forget the clutch line, so this has to cope with stale fluid for way too long.

If your clutch “isn’t right” then try bleeding the slave cylinder until clean fluid comes through, and you might just be amazed.
If the clutch action still isn't ideal then the pedal freeplay can be adjusted, see the Workshop Manual

As to the gearboxes, there aren’t any aftermarket alternatives - at least within a 4-figure budget.

It is possible to mix-n-match the 5-speed (192) and either of the 6-speed (S1 231 & R3) original boxes. For example fit a 6-speed box onto a 192 or a S1 6-speed onto an R3. However, the ratios are different and you might not get the advantage you were looking for.

The 192 5-speed is by far the strongest box, at least based on reported failures. This is probably because it was based on the RX7 box but has to cope with less than 60% of the power. It also only has to deal with the lower rev limit of the 4-port engine compared to the 6-port.

The S1 231 6-speed can have issues with synchromesh on 3rd and 4th, often associated with “too-slippery” oil being used – GL5 specification rather than GL4 – or friction reducing additives. See here for our engagement with Fuch Oils regarding this issue but note that it applies to other brands too, most of whom haven't done anything to address it.

The R3 6-speed is the most fragile, with synchromesh cones destroying themselves on early models, requiring replacement under warranty. Some low mileage examples may not exhibit problems until after the warranty expired and repair is expensive. Some owners choose to fit a used S1 231 6-speed instead, despite the slight difference in ratios. If you have a poor change action on your R3, especially "popping out" of 3rd or 4th, don’t assume that you need a replacement/repair, as this is also the only ‘box with an external adjustment, that might just do the trick.

If you prefer less movement of the knob when changing gear then there are short-shifters available for all three gearboxes. These move the pivot point of the lever, such that less movement but proportionally more force is required to change gears. This can result in a more positive action.

I’ve been running with a short shifter since 2008, having first dramatically improved the gear change action by replacing the gearbox oil from whatever the Mazda dealer had last used, to Redline MT-90. This was great for the following 8 years but in 2017 my gearbox developed an issue with the 4th gear synchromesh, when changing up near the redline (e.g. on track) – despite not having used a GL5 oil and also not having any issue in 3rd. This problem is being reported more frequently on the forum and seems to be more common among drivers that also have a short shifter on their 231. Whether the fault is created or exaggerated by the fitment of the shifter, or whether it relates to the driving style or usage, e.g. trackdays, of the drivers that also choose to run shifters, there is too little evidence to say, so far.

Some people rave about supercars, like the Bugatti Veyron, with carbon fibre prop shafts.
Well our 8’s all have cf prop shafts too and it goes to show that Mazda were prepared to spend the money, where it could make a difference. It also explains why there are no “performance aftermarket” prop shafts listed for the 8.

The 8’s differential is also quite sophisticated being a 3rd generation limited slip diff (LSD) officially called a Superdiff. While alternative diffs are available for specialised use, e.g. drifting, these shouldn’t be considered as an upgrade for your road car. If your diff gets damaged then the best replacement is an original used one from one of our traders.

While we’re still on the powertrain, let’s skip back to the front and consider the Powertrain Control Module (PCM) , which some people may refer to as the Engine Control Unit (ECU) though ours is so much more than that.

Is there anything to be gained by replacing the PCM? Well the short and easy answer is No.

Unless you’re going forced-induction (turbo/super-charging) then there’s nothing that the original PCM can’t handle.

However, the PCMs come loaded with data in the form of multi-dimensional maps, strategies and rules. This data is basically the same for every car of the same physical build (though it does vary by market) and has to be a one-size-fits-all.

The PCM is constantly monitoring all its inputs and tries to do its best within the parameters it’s been given. There are three ways that this can be improved:

- A “mini-map”. This doesn’t really change any of the performance related data but it can include masking some of the triggers that would otherwise result in an Engine Check Light e.g. Don’t tell me that the cat has failed, as I’m running a decat. It may also drop the rev limit when the engine is cold, for protection, and increase the Oil Metering Pump delivery rate under some conditions. It may also adjust the dwell for some aftermarket ignition coils – more of that later.

- Performance Map. This may include any of the above but is focused on changes to the fuelling and other factors to move within the performance-economy-emissions envelope. All tuning is a compromise but you may choose to have more performance, with less concern for emissions, for example. The data applied is generic for your car's specification, based on the experience of the tuner.

- Bespoke Map. This is a superset of the above but the key difference is that it is fine-tuned to your car. The differences between that and a generic load may be due to the unique combination of physical modifications but it will also be impacted by the real-world behaviour of your engine in action. The process involves sequences of real-time data gathering and alternative data loads; rinse and repeat, Even unmodified cars can gain benefits from a Bespoke map and these can sometimes result in a win-win, e.g. a performance/drivability improvement with economy.

Let’s talk about the ignition system, which comprises the four coils, High Tension leads and spark plugs.

The spark plugs are unique to the RX8 and are expensive @ £220 from a dealer. Their replacement is included in 36,000 mile (3 year) service, though this was often missed and expecting plugs to last for 36,000 miles was always a stretch. While the business end of the plugs are busy firing the engine the tail was also under attack…

This is one area where Mazda clearly took their eye off the ball, as whoever specified the HT leads didn’t take into consideration the unique thermal challenges or the exposed location of the plug ends.

The head of a conventional piston engine is alternatively cooled by the incoming charge and then heated by the combustion, since all of the 4-stroke “Suck, Squeeze, Bang, Blow” cycle occurs in the same space.

In a rotary engine each step of the 4-stroke cycle occurs in it’s own dedicated space within the housing, which for the spark plugs this means “Bang”. Plugs in rotary engines aren’t subjected to heat cycles but that means that they have no chance to cool down. They're also firing 2-to-3 times more rapidly than in a piston engine – so they get really hot.

The plugs are located low on the left side of the engine block and are often subjected to water spray from the road, which may also be salty in the winter.

The poor quality of the HT leads often causes corrosion of the exposed plugs, resulting in tracking down the insulator and/or high-resistance at the connection. In extreme cases the plug connector can rot off completely. Loss of a trailing plug has little noticeable impact to engine power. It does increase fuel consumption and the incomplete combustion can permanently damage the cat.

Loss of a leading plug can cause the engine to take longer to start and will reduce power, but this might not be noticeable to an inexperienced owner. Combustion will be even worse and the cat is on borrowed time.

The RX8 ignition coils have a bad reputation and some of this is fair, as early examples did have a tendency to curl up and die. Whether this was suicide or murder by bad HT leads is debatable, since presenting a high-output coil with either a wide open circuit or a short circuit, is a sure way to stress it beyond its design limits.

Mazda had three goes at getting the HT leads right and four goes at the coils. We know this because the latest part numbers end in a B-suffix for the leads and a C for the coils (A being the second attempt…)

There is strong evidence that a quality set of HT leads with C-spec Mazda ignition coils is as good as anything else on a standard or even highly modified engine.

However, the bad rep and the high cost @ £470 retail from a dealer has lead to two responses, one good and one very bad.

The good response is that specialists have developed alternative coil systems, most complete with loom adapters and dedicated HT leads, based around coil packs for other vehicles, such as the D585 (GM LS2). As with most things, the quality of these kits can vary and failures are not that uncommon, sometimes the coil packs and sometimes the loom adapters can fail. Some suppliers now provide a lifetime (non-transferable) warranty on their coil kits.

Much more worrying is the bad response. Given the high retail price of the genuine Mazda coils it was only a matter of time before fakes started to appear and now the market is flooded with them. Even franchised dealers have sold fakes. As well as the true fakes, pretending to be the “real OEM part” there are replica coils sold through legitimate suppliers, that are no better and some much worse than Mazda's earlier attempts. All of these coils will fail, will damage your cat, and if the cat gets blocked, wreck your engine.

I often wonder how much of the bad reputation of the genuine Mazda coils is down to the failures of the early Mazda products and how much is from premature failure of coils that have never been anywhere near the Mazda supply chain.

I’m running out of obvious links from one part of the car to another, so I’m just going to jump in to Lighting.

Recent MOT regulation changes mean that it’s much more difficult to retrofit any later lighting technologies, especially headlights, to existing cars. This is a reaction to the poor quality HID retrofit kits that had become popular with some modifiers but very unpopular with other drivers.

Your safest modification to existing lighting is to replace the bulbs with the latest generation of Halogens for the 192 and 231 (main beam) and DS2 HID for the 231 (dipped beam). Old bulbs lose their brilliance over time, especially HIDs, and there have been significant improvements in bulb design from the likes of Phillips and Osram. For a relatively small investment you can increase your light output by more than 150%, for the same power consumption. Don’t be tempted to choose bulbs with an excessive colour temperature. Blue bulbs may look cool but your eyes see very poorly in blue light, compared to white.

In 2003 the only LEDs generally available were low output and only suitable for 7-segment displays (like the audio/climate on the dash) and warning lights. LED lighting only started in 2007 and LED headlights didn’t become a reality until 2012.

Converting existing headlights to LED runs into the same regulation issues as aftermarket HIDs and is a lot of effort.

However, direct replacement LED “bulbs” are available for all the other lights and these are an option. Be aware that these are also not strictly legal, though unlikely to cause a problem at MOT time. Cheap versions can flicker. All versions are polarity sensitive (they only work one way round) and indicator and centre brake lights have to take the same current as the original bulbs, otherwise the systems get upset - look for “CANBUS compliant” to avoid this issue.

Even more important than the exterior bulbs, which are normally only on when the engine is running, are the interior bulbs. The vastly lower energy consumption of an LED could make the difference between coming back to a flat battery or no problem at all, the next time you leave the interior lights on or the boot lid unlocked overnight.

Looking around the outside of the car we should consider Strakes. These are the small wings that fit on the vents just behind the front wheels. Apparently these add at least another 10bhp, some say up to 30bhp – allegedly.

Spoilers are another modification favourite and I’ll make it clear that for road cars these have no performance benefits whatever, in fact the larger ones will increase drag, making the car slower and consume even more go juice. With a couple of small exceptions, spoilers won’t even help on the track for otherwise road legal cars. Spoilers can work as part of a much greater aero package, including front splitters and rear defusers, for dedicated track cars.

If you want to fit an aftermarket spoiler, that’s your choice and good luck to you. Just don’t expect any “downforce” benefits.

One modification that is practical and was once very popular is replacing the bonnet prop with lifting gas struts. Mazda used to offer a kit #FE15-V4-620 “Bonnet Stay Damper” that required some drilling and fitting of rivnuts on the underside of the bonnet. However, these kits are no longer available new and infrequently appear used.

Aftermarket options have the advantage of not needing to drill the bonnet, as they make use of the existing hinge mounts. However the geometry is compromised and the much increased force on the hinges can result in the rear bonnet shut-line sitting proud of the panels. The re-production of a proper alternative could be a good opportunity for a specialist supplier ( Carl – have you read this far yet?)

Re-reading all the above I seem to be coming across as anti-modification and that’s not the case. My position is;
- Mazda got a lot of things right and changes that may be seen as upgrades for other cars could be a downgrade or at best a waste of money, on an RX8.
- Nothing lasts forever and, if a component is not working as is should, your best bet may be to repair or replace as original, rather than “upgrade”.
- Mazda didn’t get everything right and the community has recognised appropriate and valuable alternatives.
- Styling modifications are fine but even those designed to make the car look more sporty are likely to have a negative impact on performance.

I’d like to end this massive missive with consideration of the two most significant modifications to the RX8 – actually sets of modifications that recognise where improvements could and maybe should be made.

The first is the PZ, which was the ultimate “Special Edition”.
Produced by Prodrive, who were given carte blanche to make changes, only really limited by the need for the modification costs to be recoverable within the showroom retail price.

So what did Prodrive change, or perhaps we should start with what they didn’t?

They didn’t make any changes to the powertrain; engine or transmission, intake or PCM.

They did change the catback exhaust for a stainless steel system from Scorpion, which is a bit lighter, more free flowing and only slightly louder than the original – with Prodrive logos on the tips. Strangely, while Scorpion offered this exhaust directly as an aftermarket option for a while, the only Mazda exhaust they currently list is for the MX5 Mk3/3.5.

They fitted a medium sized spoiler, that is reputed “to actually work” at least above road legal speeds on track, having been developed in the MIRA wind tunnel.

They also fitted protective grills in front of the oil coolers, with a matching grill across the radiator opening.

However, by far the most significant changes are the wheels and suspension units.

The wheels were sourced from OZ Racing (hence the PZ name – Prodrive & OZ)
Interestingly, though they are slightly lighter, these wheels are exactly the same size, offset etc, as those Mazda fitted to the rest of our cars, implying that widening the track by reducing the offset (as you could by fitting spacers) has no performance advantage.

The suspension units were a bespoke commission by Bilstein with Eibach springs. Neither of these components have been available since, once the original spares holding was depleted.

50+ lucky members have recently joined in a group buy to have Bilstein produce a second production run of these units, which will allow those drivers to either bring their PZ suspension up-to-scratch or allow non-PZ drivers to achieve handling close to that of a new PZ.

Following the group buy, at least by the end of the year, a small number of these units should also be available in the Club Shop, for those that missed out on the group buy or only find that they need replacements at some point in the future


The second major change is the R3

Differences between the S1 and the R3 are documented here.
Unfortunately, there is very little interchangeability between the revised parts of the R3 and the original cars, in most cases you can’t just pickup an R3 part and fit it as an upgrade to your S1 – the differences are too great.

Conclusion

This was never intended to be a comprehensive list of upgrades, as that would be impossible. Some members' cars are still in a constant state of evolution (This means you – Tony), while I’ve not even mentioned audio upgrades, body kits, interior trims, rotating number plates, rocket launchers or ejector seats.

Hopefully you found something among this lot that has made it worth your effort to read.

Feel free to add your thoughts to this thread, following the same theme.

Please advise of any typos or errors by PM, to keep the thread readable for future reference.

Afterthought

All modifications need to be declared to your insurance company. Failure to do so may give them the opportunity to void your cover, especially after an accident, even if the event was totally unrelated. Worse case you could find yourself personally liable for a massive injury claim, leaving you bankrupt, and being charged with driving without insurance.

For younger drivers, it might be worth asking your insurer “What would the impact on my premium be if I were to...”. If you get an outrageous response then consider changing your insurer before making the modification. Sometimes what insurance companies see as “increased risk” defies logic. My previous insurer was happy that my stainless exhaust system and aftermarket alloys were like-for-like replacements and didn’t impact the premium, but then wanted to apply a 20% increase because I had vinyl side stripes!

Notes:
Having pasted the text I need to go through and add links to existing threads scattered around the forum. Once I have complete this task I'll remove this comment. In the meantime, try the forum Search or include "site:www.rx8ownersclub.co.uk/forum" to your Google search.
If you're reading this as a forum guest, rather than an Owners Club Member, then some of the embedded links might not work at all or may return limited results. This is because over 70% of the content of this forum is within "Members Only" access areas. Please revisit the links after you become a member and see the stuff that you'd been missing
These users thanked the author warpc0il for the post (total 23):
tayfun (Mon Sep 17, 2018 6:43 pm) • jondkent (Mon Sep 17, 2018 8:26 pm) • GreySilver Beast (Mon Sep 17, 2018 8:32 pm) • exiled--viking (Mon Sep 17, 2018 8:37 pm) • Harrizone (Mon Sep 17, 2018 8:50 pm) • brix79 (Mon Sep 17, 2018 9:14 pm) • Heb147 (Mon Sep 17, 2018 9:35 pm) • PeteH (Tue Sep 18, 2018 12:04 am) • delta0 (Wed Sep 19, 2018 9:53 pm) • HwAoRrDk (Wed Sep 19, 2018 10:46 pm) and 13 more users
Dave
The Spin Doctor ™
uǝǝɹɔs ɹnoʎ ʇɹǝʌuı ǝsɐǝld :ɹoɹɹǝ

User avatar
jondkent
Club Member
Club Member
Posts: 699
Joined: Wed Jan 25, 2017 10:17 pm
RX-8: 231
Colour: Stormy Blue
Location: Surrey
Has thanked: 54 times
Been thanked: 59 times

Re: Modifying for Performance & Style

Post by jondkent » Mon Sep 17, 2018 8:26 pm

Very interesting post, much appreciated. Great summary of then pros and cons of taken various routes

Cheers
Jon


Sent from my Pixel 2 XL using Tapatalk


User avatar
exiled--viking
Club Member
Club Member
Posts: 1420
Joined: Thu Apr 17, 2014 10:34 pm
Has thanked: 141 times
Been thanked: 249 times

Re: Modifying for Performance & Style

Post by exiled--viking » Mon Sep 17, 2018 8:28 pm

I quite Agree with the statement of modifications need to be told your insurers



Nice Write up by the way 8) well worth the Read
Last edited by exiled--viking on Sun Feb 24, 2019 7:26 pm, edited 1 time in total.
These users thanked the author exiled--viking for the post:
warpc0il (Mon Sep 17, 2018 8:32 pm)
WAS THE WINNER OF THE 2015 EUROPEAN ROTOR STOCK BEST RX~8 in Show ( Won me 40 trophy"s the Beast is Now Sold A New Beast To Be Built SOON :banghead: ) new car MX5 Now Called the SHARK 8)

User avatar
Delanor
Forum Moderator
Forum Moderator
Posts: 9726
Joined: Mon Jun 28, 2004 11:38 pm
RX-8: 40th Anniversary
Colour: Crystal White
Location: In the land of the big cat!
Has thanked: 9 times
Been thanked: 70 times

Re: Modifying for Performance & Style

Post by Delanor » Mon Sep 17, 2018 8:50 pm

With Insurance it can vary enormously whilst changing anything on your car I recall Moreth>n telling me " We are not interested in any modification unless it increases performance" whereas Aviva wanted to know if you changed the light bulbs!

I now make a point of telling them of anything I have done.
I don`t know if its still the same today but at one time if you had leather as an optional extra you were supposed to tell your insurance as it changes the value of the car from the standard equipment.

*
*
Del.
1st Brilliant Black 190. 2nd Brilliant Black PZ. 3rd Strato Blue 230. 4th Crystal White 40th Anniversary.
Rotary FX fender grills, Japspeed stainless exhaust, K & N filter, Kinetix slotted & dimpled discs, EBC Red stuff pads, Ryan Rotary MK11coils, Magnecor leads, Stainless front & rear grills, HID main beams, LED tail lights, front side lights/front fogs.

User avatar
warpc0il
Spin Doctor
Spin Doctor
Posts: 22769
Joined: Sat Sep 06, 2008 10:56 pm
RX-8: 231
Colour: Lightning Yellow
Location: Groomsport, Co Down, NI
Has thanked: 324 times
Been thanked: 1214 times
Contact:

Re: Modifying for Performance & Style

Post by warpc0il » Wed Sep 19, 2018 8:58 pm

Some links added within the original post, more to follow...
Dave
The Spin Doctor ™
uǝǝɹɔs ɹnoʎ ʇɹǝʌuı ǝsɐǝld :ɹoɹɹǝ

User avatar
Essex2Visuvesi
Forum Moderator
Forum Moderator
Posts: 4093
Joined: Sat Jul 05, 2014 2:05 pm
Location: Essex
Has thanked: 4 times
Been thanked: 273 times

Re: Modifying for Performance & Style

Post by Essex2Visuvesi » Wed Sep 19, 2018 10:25 pm

On the subject of insurance, the insurance on my MR-S actually went down when I declared the mods, which included a turbo conversion, bigger wheels, exhaust, suspension and brakes.
And not by a little either.... It went from 450 to 220 so more than 50%
Proud Member of the Essex Wankelist Massive

User avatar
HwAoRrDk
Club Member
Club Member
Posts: 2135
Joined: Mon Sep 18, 2006 7:07 pm
RX-8: 231
Colour: Velocity Red
Location: West Yorkshire
Has thanked: 7 times
Been thanked: 51 times

Re: Modifying for Performance & Style

Post by HwAoRrDk » Wed Sep 19, 2018 10:45 pm

Great job. :thumleft:

I didn't see any mention of lightened flywheels or modified engine pulleys. Perhaps worth covering those?

Also, might wanna warn people to make a cup of tea/coffee before they sit down to read it. It takes a while... :D
warpc0il wrote:
Mon Sep 17, 2018 6:09 pm
The 8’s differential is also quite sophisticated being a 3rd generation limited slip diff (LSD) officially called a Superdiff.
Not 'Superdiff', it's 'Super-LSD'.
warpc0il wrote:
Mon Sep 17, 2018 6:09 pm
They did change the catback exhaust for a stainless steel system from Scorpion, which is a bit lighter, more free flowing and only slightly louder than the original – with Prodrive logos on the tips. Strangely, Scorpion never offered this exhaust directly as an aftermarket option...
I'm 99% sure they did. I have previously seen it advertised by several aftermarket parts vendors. It was exactly the same as the ProDrive one except for with the Scorpion logo on the tips. They seem to have discontinued it at some point though, so not available these days.
Speed-sensitive windscreen wipers project
Need new tyres? Check prices before buying with the club tyre prices service! (Club members only)

User avatar
Essex2Visuvesi
Forum Moderator
Forum Moderator
Posts: 4093
Joined: Sat Jul 05, 2014 2:05 pm
Location: Essex
Has thanked: 4 times
Been thanked: 273 times

Re: Modifying for Performance & Style

Post by Essex2Visuvesi » Wed Sep 19, 2018 10:50 pm

HwAoRrDk wrote:
Wed Sep 19, 2018 10:45 pm
Great job. :thumleft:

I didn't see any mention of lightened flywheels or modified engine pulleys. Perhaps worth covering those?

Also, might wanna warn people to make a cup of tea/coffee before they sit down to read it. It takes a while... :D
warpc0il wrote:
Mon Sep 17, 2018 6:09 pm
The 8’s differential is also quite sophisticated being a 3rd generation limited slip diff (LSD) officially called a Superdiff.
Not 'Superdiff', it's 'Super-LSD'.
warpc0il wrote:
Mon Sep 17, 2018 6:09 pm
They did change the catback exhaust for a stainless steel system from Scorpion, which is a bit lighter, more free flowing and only slightly louder than the original – with Prodrive logos on the tips. Strangely, Scorpion never offered this exhaust directly as an aftermarket option...
I'm 99% sure they did. I have previously seen it advertised by several aftermarket parts vendors. It was exactly the same as the ProDrive one except for with the Scorpion logo on the tips. They seem to have discontinued it at some point though, so not available these days.
Yes, Scorpion did sell the Prodrive system as a scorpion unit as well
I spoke with them a few years back about another run of the exhausts and they said it would need to be a run of at least 100 to make it worth their while
Proud Member of the Essex Wankelist Massive

User avatar
Delanor
Forum Moderator
Forum Moderator
Posts: 9726
Joined: Mon Jun 28, 2004 11:38 pm
RX-8: 40th Anniversary
Colour: Crystal White
Location: In the land of the big cat!
Has thanked: 9 times
Been thanked: 70 times

Re: Modifying for Performance & Style

Post by Delanor » Thu Sep 20, 2018 10:26 am

warpc0il wrote:
Mon Sep 17, 2018 6:09 pm
My previous insurer was happy that my stainless exhaust system and aftermarket alloys were like-for-like replacements and didn’t impact the premium, but then wanted to apply a 20% increase because I had vinyl side stripes!
As most insurance concerns can be handled yourself with an online account I fitted some chrome plastic trims around the rear lights and the lower front grill on my Ford Kuga which I then listed on my Admiral account with the result they wanted a further 20% increase, I protested and they apologised and dropped the charge bearing in mind I have 3 cars insured for two of us on a multicar policy so at any one time one car is off the road and not in use so they are doing quite well out of that.

*
*
Del.
1st Brilliant Black 190. 2nd Brilliant Black PZ. 3rd Strato Blue 230. 4th Crystal White 40th Anniversary.
Rotary FX fender grills, Japspeed stainless exhaust, K & N filter, Kinetix slotted & dimpled discs, EBC Red stuff pads, Ryan Rotary MK11coils, Magnecor leads, Stainless front & rear grills, HID main beams, LED tail lights, front side lights/front fogs.

User avatar
warpc0il
Spin Doctor
Spin Doctor
Posts: 22769
Joined: Sat Sep 06, 2008 10:56 pm
RX-8: 231
Colour: Lightning Yellow
Location: Groomsport, Co Down, NI
Has thanked: 324 times
Been thanked: 1214 times
Contact:

Re: Modifying for Performance & Style

Post by warpc0il » Thu Sep 20, 2018 10:36 am

Back in the days when I was less concerned about actual cover and more about the size of the premium, I did take advantage of my then insurers attempts at "plain english" on their forms.

On the form there was the question "Has the car been chipped?" "If yes, provide details"
I ticked the Yes box and then wrote "Some small stone chips on the front of the bonnet" - which was true.

The car - a 2.0l Focus Ghia was running a custom map in the ECU - but there weren't any "chips" involved. #-o

My premium remained unchanged [-X
These users thanked the author warpc0il for the post:
ChrisHolmes (Tue Sep 25, 2018 10:54 am)
Dave
The Spin Doctor ™
uǝǝɹɔs ɹnoʎ ʇɹǝʌuı ǝsɐǝld :ɹoɹɹǝ

PjP
Former Member
Former Member
Posts: 37
Joined: Wed May 02, 2018 11:10 pm
RX-8: 231
Colour: Strato Blue
Location: Greenhithe, Kent
Has thanked: 14 times
Been thanked: 10 times
Contact:

Re: Modifying for Performance & Style

Post by PjP » Thu Sep 20, 2018 3:57 pm

Good read and has saved me some money! Thanks.

Adrian Flux
Forum Trader
Forum Trader
Posts: 171
Joined: Tue Feb 17, 2009 9:51 am
Has thanked: 0
Been thanked: 6 times

Re: Modifying for Performance & Style

Post by Adrian Flux » Mon Sep 24, 2018 9:34 pm

Hi,
If anyone needs any help with insurance at all then please feel free to drop me a line.
Regards,
Dan.

User avatar
Dr. FrankenRex
Club Member
Club Member
Posts: 4620
Joined: Thu Jan 08, 2015 1:30 pm
RX-8: R3
Colour: Velocity Red
Location: Cotswolds
Has thanked: 237 times
Been thanked: 517 times
Contact:

Re: Modifying for Performance & Style

Post by Dr. FrankenRex » Tue Sep 25, 2018 10:50 am

I have a great many points to put in to words around this, Dave.

It's a great article, but some of the R3 parts and gearbox parts aren't - to my knowledge at least - 100% correct. I shall grab a cuppa on my lunch break and put the keyboard through it's paces ;)
FrankenRex2, leaner and meaner. RR Full Bridge rebuild with Race Extension porting, Cusco Strut Brace, RB Header, RB Dual Res Decat, Pettit Catback, Eibach lowering springs, Maserati 6 pot brakes, braided brake lines, custom built DRLs, track wheels, Custom front and rear lights, braided clutch line, RB ARBs - the list goes on!

https://www.youtube.com/channel/UC7BW_h ... Ym6eGqEIWg

User avatar
ChrisHolmes
Committee Member
Committee Member
Posts: 16417
Joined: Sun Jan 29, 2006 10:04 pm
RX-8: 231
Colour: Custom
Location: Cheltenham
Has thanked: 4222 times
Been thanked: 1706 times

Re: Modifying for Performance & Style

Post by ChrisHolmes » Tue Sep 25, 2018 11:02 am

An excellent phillibuster of a read Dave dispelling numerous upgrade fallacies whilst at the same time also acknowledging the purely aesthetic reason for making some upgrades, Re: 4 pot brake calipers and confirming the clear performance benefit of fitting strakes!
Supercharged
Racing Beat Alloy flywheel
Exedy Stg 1 Clutch
White Line ARBs
Tein Monosport Coilovers
Speedline diamond cut alloy wheels
Racing Brake 4 pot calipers, slotted discs & alloy bells
Racing Beat Custom front bumper, grills & Side Skirts
Mazdaspeed Rear Spoiler (Customised)
Rear Diffuser
Vented Carbon Bonnet
SOHN Adaptor
Custom Leather interior & Boot trim
Adaptronic ECU

User avatar
Dr. FrankenRex
Club Member
Club Member
Posts: 4620
Joined: Thu Jan 08, 2015 1:30 pm
RX-8: R3
Colour: Velocity Red
Location: Cotswolds
Has thanked: 237 times
Been thanked: 517 times
Contact:

Re: Modifying for Performance & Style

Post by Dr. FrankenRex » Tue Sep 25, 2018 1:31 pm

cracks knuckles Right-o.

In order of appearance, my comments on things :D - These aren't scientifically tested by any stretch and I'm happy for people to laugh me out of the room or correct me, but just a few observations made using my own experience.

Porting - I ran a street ported 192, rebuilt by rotary revs, and have to admit that there are no drawbacks that I could see at all. I drove it for well over 40k miles and found the power to be up, the fuel economy to be the same if not slightly increased (same driving style, the engine before was not low on compression, I rebuilt for more power and more revs). The only differences from Mazda design was the street port, oil pressure increase and a cold rev limiter added. Honestly, I didn't see or experience a single drawback to this - and I imagine any engine builder will tell you the same these days.

Full bridge port, crazy race extension porting or what-have-you is another question altogether, but I would definitely say that a street port is a no-down-side mod. It passed MOTs absolutely fine (at least on emissions! :lol: ) as well using an OEM cat, not even close to failing.

SOHN/COFS - Not available for the R3, dunno if that's worth putting in the initial write up or not, but because the R3 uses an EOMP design which is more sophisticated, you can't just whip it out and replace it with a COFS. I say sophisticated, but this doesn't mean that it is better or worse than it's predecessor, just that it can't be ripped out and replaced with something else (yet?)

Exhaust - Manifold wise, whilst there are very little gains to be had from a stainless mani, it is worth noting that it is recommended with full bridgeport builds and can have a positive impact there.

Following on, also exhaust related, the PZ exhaust system is still heavy as balls compared to others on the market. Just a point that isn't really addressed in the above, as it just says it's lighter, without noting that it isn't really that much lighter than an OEM zorst. The clamps were also not stainless, so if you buy one second hand I would recommend replacing those components whilst it's off the car :)
warpc0il wrote: It is possible to mix-n-match the 5-speed (192) and either of the 6-speed (S1 231 & R3) original boxes. For example fit a 6-speed box onto a 192 or a S1 6-speed onto an R3. However, the ratios are different and you might not get the advantage you were looking for.

The R3 6-speed is the most fragile, with synchromesh cones destroying themselves on early models, requiring replacement under warranty. Some low mileage examples may not exhibit problems until after the warranty expired and repair is expensive. Some owners choose to fit a used S1 231 6-speed instead, despite the slight difference in ratios. If you have a poor change action on your R3, especially "popping out" of 3rd or 4th, don’t assume that you need a replacement/repair, as this is also the only ‘box with an external adjustment, that might just do the trick.
With regards to the above, there are a few discrepancies. First is that the R3 box will not fit the S1 - at least based on the information I have been provided previously. Again, happy to be corrected on it, but I believe it will not marry up to an S1 engine without some serious modification - more than would be sensible given the S1 6 speed is on the whole a good box.

Second is the syncro issue on the R3 box - it's worth noting that the syncro material was changed on the late 59 plates onwards and are, in my experience so far, fairly bulletproof as gearboxes go. They are the same unit internally as the NC MX5 and I know of a lot of people who have built race cars out of their NCs without needing to do anything to the gearbox. OK, they handle less revs in an MX5, but they are still on the whole a reliable unit.

Repair isn't that expensive, coming in at £360 for parts and labour last time I looked. This is based on the box being out of the car, so you'd want to factor in labour if you can't do it yourself. OK, not cheap, but not as expensive as some people may be thinking.

Differentials - For parity, I wonder if it's worth including that the R3 diff is a different ratio to the S1. This is increasingly more interesting for those looking to mix-n-match gearboxes in the point above as the ratios all change depending on what diff is at the back.
warpc0il wrote: Differences between the S1 and the R3 are documented here.
Unfortunately, there is very little interchangeability between the revised parts of the R3 and the original cars, in most cases you can’t just pickup an R3 part and fit it as an upgrade to your S1 – the differences are too great.
As a final note, the above is obviously a mixed bag, but a decent chunk is infact transferable. As said the diff can be swapped, the suspension will work and the interior has various transferable bits - so don't rule anything out if you don't want to :thumleft:

On the whole a good write up, though, and a good read - thanks :)

Dr. FR.
These users thanked the author Dr. FrankenRex for the post:
Szerelem (Fri Dec 07, 2018 2:48 pm)
FrankenRex2, leaner and meaner. RR Full Bridge rebuild with Race Extension porting, Cusco Strut Brace, RB Header, RB Dual Res Decat, Pettit Catback, Eibach lowering springs, Maserati 6 pot brakes, braided brake lines, custom built DRLs, track wheels, Custom front and rear lights, braided clutch line, RB ARBs - the list goes on!

https://www.youtube.com/channel/UC7BW_h ... Ym6eGqEIWg

RobinPZ72
Former Member
Former Member
Posts: 1390
Joined: Sat May 19, 2018 4:55 pm
Has thanked: 67 times
Been thanked: 33 times

Re: Modifying for Performance & Style

Post by RobinPZ72 » Sun Sep 30, 2018 9:13 am

Holly molly what a read WarpcOil that played havoc with my dyslexia, but nailed it!

Robin
These users thanked the author RobinPZ72 for the post:
warpc0il (Sun Sep 30, 2018 10:27 am)

User avatar
warpc0il
Spin Doctor
Spin Doctor
Posts: 22769
Joined: Sat Sep 06, 2008 10:56 pm
RX-8: 231
Colour: Lightning Yellow
Location: Groomsport, Co Down, NI
Has thanked: 324 times
Been thanked: 1214 times
Contact:

Re: Modifying for Performance & Style

Post by warpc0il » Sun Sep 30, 2018 10:27 am

I'm dyslexic too, so you can imagine how much fun (not) I had writing it.

That's one reason why it took me ten years ;)

Sent from my SM-G800F using Tapatalk

These users thanked the author warpc0il for the post (total 2):
RobinPZ72 (Sun Sep 30, 2018 10:29 am) • GreySilver Beast (Sun Sep 30, 2018 11:54 am)
Dave
The Spin Doctor ™
uǝǝɹɔs ɹnoʎ ʇɹǝʌuı ǝsɐǝld :ɹoɹɹǝ

RobinPZ72
Former Member
Former Member
Posts: 1390
Joined: Sat May 19, 2018 4:55 pm
Has thanked: 67 times
Been thanked: 33 times

Re: Modifying for Performance & Style

Post by RobinPZ72 » Sun Sep 30, 2018 12:03 pm

Aye that must of been a mission writing it, so hats off!

Hey most geniuses are, but you'll know that!

Robin

User avatar
ChrisHolmes
Committee Member
Committee Member
Posts: 16417
Joined: Sun Jan 29, 2006 10:04 pm
RX-8: 231
Colour: Custom
Location: Cheltenham
Has thanked: 4222 times
Been thanked: 1706 times

Re: Modifying for Performance & Style

Post by ChrisHolmes » Sun Sep 30, 2018 1:34 pm

Daves must be a Geni with the magic info he has!
These users thanked the author ChrisHolmes for the post:
warpc0il (Fri Dec 07, 2018 7:40 pm)
Supercharged
Racing Beat Alloy flywheel
Exedy Stg 1 Clutch
White Line ARBs
Tein Monosport Coilovers
Speedline diamond cut alloy wheels
Racing Brake 4 pot calipers, slotted discs & alloy bells
Racing Beat Custom front bumper, grills & Side Skirts
Mazdaspeed Rear Spoiler (Customised)
Rear Diffuser
Vented Carbon Bonnet
SOHN Adaptor
Custom Leather interior & Boot trim
Adaptronic ECU

User avatar
Pensive
Former Member
Former Member
Posts: 223
Joined: Tue Jun 20, 2017 7:21 pm
RX-8: PZ
Colour: Galaxy Grey
Location: Basingstoke
Has thanked: 31 times
Been thanked: 13 times

Re: Modifying for Performance & Style

Post by Pensive » Mon Oct 15, 2018 10:50 pm

That was an excellent read - thank you :)


Sent from my iPad using Tapatalk
These users thanked the author Pensive for the post:
warpc0il (Tue Oct 16, 2018 10:26 am)

Vian
Club Member
Club Member
Posts: 4118
Joined: Sun Nov 23, 2014 6:33 pm
RX-8: 231
Colour: Sunlight Silver
Location: West Sussex
Has thanked: 52 times
Been thanked: 109 times

Re: Modifying for Performance & Style

Post by Vian » Mon Oct 15, 2018 11:23 pm

Loved the read, and not only because it put it one place, but also because it reinforced for me the consistently excellent advice I've followed on this forum over the last number of years.
These users thanked the author Vian for the post:
warpc0il (Tue Oct 16, 2018 10:26 am)
"Don't care if they say we are a dying race, I'd rather be here than any other place"

RobinPZ72
Former Member
Former Member
Posts: 1390
Joined: Sat May 19, 2018 4:55 pm
Has thanked: 67 times
Been thanked: 33 times

Re: Modifying for Performance & Style

Post by RobinPZ72 » Wed Oct 24, 2018 4:36 pm

Can we use this thread to discuss tuning etc. Instead off us having threads all over the shop or is there a thread already in existence?

Robin

User avatar
casey
Committee Member
Committee Member
Posts: 8851
Joined: Sun Jun 27, 2004 7:14 pm
RX-8: 231
Colour: Titanium Grey
Location: Colchester
Has thanked: 858 times
Been thanked: 1047 times

Re: Modifying for Performance & Style

Post by casey » Wed Oct 24, 2018 4:41 pm

RobinPZ72 wrote:
Wed Oct 24, 2018 4:36 pm
Can we use this thread to discuss tuning etc. Instead off us having threads all over the shop or is there a thread already in existence?

Robin
I think this is what you are looking for?

viewforum.php?f=134
These users thanked the author casey for the post:
RobinPZ72 (Wed Oct 24, 2018 5:21 pm)
Club Secretary
Essex Rotary Full Bridgeport

Seibon Carbon Fibre Bonnet
"Racing Brake" front calipers, Racing Beat (RB) ARB's F&R, RB REVI intake, full RB Stainless Steel Exhaust & Mani, 20mm Eibach spacers, KOYO Ali Rad, Lightened Fly, Tein MonoFlex coilovers & strut brace, Axial short-shifter, BHR Coils & Engine Mounts, Greddy Sump
Federal 595RS-R or Rainsport 3

User avatar
warpc0il
Spin Doctor
Spin Doctor
Posts: 22769
Joined: Sat Sep 06, 2008 10:56 pm
RX-8: 231
Colour: Lightning Yellow
Location: Groomsport, Co Down, NI
Has thanked: 324 times
Been thanked: 1214 times
Contact:

Re: Modifying for Performance & Style

Post by warpc0il » Mon May 06, 2019 12:01 pm

Updated the original post with more content and links to existing threads, mainly in FAQ and DIY sections.

Please suggest any additional internal forum links that might help take readers to "the good stuff" :D
These users thanked the author warpc0il for the post:
ChrisHolmes (Mon May 06, 2019 7:22 pm)
Dave
The Spin Doctor ™
uǝǝɹɔs ɹnoʎ ʇɹǝʌuı ǝsɐǝld :ɹoɹɹǝ

User avatar
ChrisHolmes
Committee Member
Committee Member
Posts: 16417
Joined: Sun Jan 29, 2006 10:04 pm
RX-8: 231
Colour: Custom
Location: Cheltenham
Has thanked: 4222 times
Been thanked: 1706 times

Re: Modifying for Performance & Style

Post by ChrisHolmes » Mon May 06, 2019 7:23 pm

That is a serious Philibuster of a thread, oh and an excellent resource too!
Supercharged
Racing Beat Alloy flywheel
Exedy Stg 1 Clutch
White Line ARBs
Tein Monosport Coilovers
Speedline diamond cut alloy wheels
Racing Brake 4 pot calipers, slotted discs & alloy bells
Racing Beat Custom front bumper, grills & Side Skirts
Mazdaspeed Rear Spoiler (Customised)
Rear Diffuser
Vented Carbon Bonnet
SOHN Adaptor
Custom Leather interior & Boot trim
Adaptronic ECU

Post Reply

Return to “RX-8 Discussion”