Modifying for Performance & Style

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Hopkins
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Re: Modifying for Performance & Style

Post by Hopkins »

I don't think I've thanked you yet for this fabulous essay: thanks!
warpc0il wrote:
Mon Sep 17, 2018 6:09 pm
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.
I recently fitted the PZ springs/shocks and, after giving the recommended few hundred miles to bed in, had all four wheels aligned at a local KwikFit, recommended because they had a new, super-duper Hunter-something-or-other. It was an impressive machine, and the mechanic was happy for me to observe his work and ask him questions. He was also keen to get it just right, which was reassuring. The service was so good, that I chose to pay £130 instead of £85 because it gave me up to eight realignments over the next two years.

Anyway, the first thing I would say is that I was amazed at the difference it made. (He did say that they were "way out".) I was actually getting concerned about the PZ springs/shocks because it was feeling crashy over bumps, but this all melted away after I had the wheels aligned. This was an unexpected and much welcome change, and the car feels better than ever.

One question, though, based on one comment above:
warpc0il wrote:
Mon Sep 17, 2018 6:09 pm
who knows what they’re doing and is using the correct “Sports Suspension” table against your ride-height
Should I make any specific request now that I have the PZ suspension installed? Will they be able to look up the PZ settings independently if I ask them?
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warpc0il
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Re: Modifying for Performance & Style

Post by warpc0il »

The key thing is that they made the correct adjustments based on the measured ride-height.

The tables overlap, the Sports going lower than Standard Suspension.

The PZ would be at the lower end of "Sports"

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Hopkins
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Re: Modifying for Performance & Style

Post by Hopkins »

Thanks.
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warpc0il
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Re: Modifying for Performance & Style

Post by warpc0il »

There seems to be an increasing tendency for owners to assume that “a fault” is a requirement for modification, rather than diagnosis and repair.

Sometimes a fault is a good excuse for a modification and a perfectly valid example would be your original catback exhaust has rotted and now you can justify that shiny new stainless replacement.

However, most faults should be diagnosed and fixed, where the fix may be a repair or replacement, based on the analysis of the cause.

Let’s consider a recent example…

An owner believes that their car is overheating, so assumes that the solution is to install air vents in the bonnet to allow excess heat to escape. This is a normal road car, not being used as a track weapon or for drifting.

Going back to basics, is the car actually overheating?

• Has the owner just been told by someone that “rotaries run hot” and that’s a problem that needs rectifying?
• Has their chocolate bar melted, having been left in the centre console?
• Does the drivers seat rail feel a bit warm after a hard run?
• Do the fans run on for a minute after the engine has been switched off on a hot day?
• Does the temperature gauge read slightly above the midpoint?
• Does the bonnet surface feel hot after a run?

None of the above is any cause for concern, and is “normal”.

Does the coolant header tank overflow when the engine is hot? This can be an indication of a serious issue but is most commonly caused by overfilling the tank (the Max mark only being half way up the tank) or a miss-fitted or damaged filler cap.

Causes of actual overheating can include;
- reduced flow in the cooling circuit due to debris, because the system hasn’t been flushed for many years, or because the wrong mix of coolant has been used to top-up and this has resulted in a gel being created.
- reduced airflow through the radiator, because lower intake partially blocked by relocated numberplate or leaves etc, or air is bypassing the radiator core either because the rubber seal around the radiator has perished or the under tray has become detached.
- brakes binding requiring engine to work significantly harder to keep car rolling.
- cooling fan motors sticking or fuse blown.
- aftermarket shrouded fans fitted, which reduce airflow when fans not running.
- sensor faults (such as O2) giving bad data to the PCM resulting in engine running excessively lean.
- partially blocked catalytic converter overheating.
- thermostat is sticking closed (possible but no recorded cases).
- water pump failure (common on some cars but rare on the RX-8)

Internal water jacket seals can fail, allowing combustion gases to over-pressurise the cooling system. This isn’t “over heating” but does cause coolant to blow out of the header overflow.

Based on the above, does fitting bonnet vents really sound like a good solution to perceived “over-heating”? Or should the owner fit an upgraded radiator or aftermarket fans, before establishing the reality and cause of the issue?

Similar examples apply to perceptions of other failures, such as poor braking, handling or other elements, where the car isn’t living up to the original performance and therefore needs “upgrading” rather than repairing.

When thinking about this on a wider front, if you were limping because there was a stone in your shoe, would the answer be put a stone in the other shoe, to reduce the limp, or simply to remove the first stone?

If the limp was ignored for too long then the shoes may become unevenly worn and need replacing, though you need to seriously consider what you replace with what; as jogging is difficult in 6” heels (apparently).
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ChrisHolmes (Sun Mar 21, 2021 12:32 pm) • v-rex (Sun Mar 21, 2021 6:20 pm) • Celtic (Sun Apr 04, 2021 11:41 pm)
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WildMan10
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Re: Modifying for Performance & Style

Post by WildMan10 »

Bonnet vents are a fashion accessory on RX8s. Unless you have a 13B REW conversion used for extended track running the standard rad and oil coolers are more than adequate for the task of cooling the car.

Sure, if you like the look of bonnet vents and are prepared to overlook the problems of water ingestion then fit them. But, please, don't pretend that you're doing any good.

For those interested, I attach a copy of the analysis that I produced some time ago when I was designing a cooling system for a 13B REW conversion.
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warpc0il (Sun Mar 21, 2021 10:19 pm)
Ian
Now back to one, a white R3. Gone but not forgotten: 04 Tit Grey 231, 06 Copper Red Evolve (231), 09 VR R3, 10 Aurora Blue R3, 06 Black PZ; RX87 13BREW project car ;-( ; 04 White with Greddy turbo conversion ;-(

Buying a used RX8 turbo is like marrying a stripper.
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Re: Modifying for Performance & Style

Post by ChrisHolmes »

I downloaded the manual previously and it’s a great factual read.
Rotary History;

Sep 2005-Aug 2006 EO55 XOL VR 231 New
Oct 2014-Mar 2019 OE06 EWJ VR 231
Jan 2019-Jun 2020 T200 CAD Orange SC 231
Feb 2020-May 2023 RR54 AJR VR 231 Modified for Track
Oct 2020-Mar 2021 YA56 EUE Copper Red Nemesis
Jun 2022-Apr 2023 TN07 JHD KURO Resurrected
Jun 2023-Jan2024 OV09 BFF Sparkling Black R3
Avatar courtesy of my grandson Cameron
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warpc0il
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Re: Modifying for Performance & Style

Post by warpc0il »

There's been quite a lot of discussion on US and International forums and FB groups concerning "My car is over-heating..." which have often triggered suggestions to "fit a lower temperature thermostat".

IME THIS IS A BAD IDEA

The thermostat controls at what point in the warm-up cycle the coolant no longer just circulates within the engine block and is redirected to flow through the radiator.

Fitting a lower temperature thermostat just means that this happens sooner (at a lower temperature) so the major impact is that the engine now takes much longer to reach that critical operation temperature, not just the coolant but also the oil.

Cold/cool oil doesn't provide anything like the same protection as hot oil, and we all know about the need to let the oil get up-to-temperature before giving it the beans. Why would you want to make that delay any longer?

The OEM thermostat is already fully open at normal operating temperatures and would only start to close again under extreme conditions, e.g. open road running with a sub-zero airflow through the radiator.

When you dig deeper you often discover that these guys with "over-heating" engines are either running with the undertray removed, or at least not secured, or they've left off the rubber surround from the radiator; either way most of the cooling air is simply going to bypass the core. This has become another case of "I have a problem therefore my car needs modifying" rather than "My car has a problem therefore my car needs fixing" #-o
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Re: Modifying for Performance & Style

Post by warpc0il »

Coincidently, I was chatting to an ex-Fordie mate this afternoon and the conversation got around to "replacement parts" either as direct replacements or for performance.

He was a powertrain development engineer for 30 years and was reminding me of an incident with some early Mondeo ST200's.

Then, as now, it was common for dealers to take wild guesses as to the cause of a problem and just change components until it was cured. The problem with the ST200 was actually caused by an airlock in the cooling system not being bled properly but the dealers would change various things, often including the thermostat, in an attempt to cure the symptoms.

The replacement thermostats would be left installed and the problem would eventually be fixed by following the correct bleeding procedure (RTFM!). However, these same cars would often be back at the dealers suffering from other related problems, which were assumed to be due to damage caused by local heating from running with the air lock.

It took a couple of cars being returned to Ford engineering for investigation before they worked out what was happening.

Both of these cars had had the thermostats replaced, as above, with genuine Ford parts. However, back in those days the buyers for Motorcraft (the spares arm of Ford based in Daventry) wasn't under the same procurement constraints as the production engineers.

This meant that even a real genuine Ford Motorcraft component might not have come from the same supplier used in production, and may even have come from a supplier that failed to meet the quality requirements for OEM. :(

That was the case for these thermostats which, when tested, were out-of-calibration by more than 30% :shock:

Out of interest, they went out and bought a selection of "compatible" thermostats from Halfolds and local motor factors and tested them. He didn't recall the results exactly but the calibrations varied by something like +/- 5% to over 50% [-X

The OEM standard requirement was +1%/-2%.

Basically the long term problems these cars were suffering were caused by the replacement thermostats, and in all cases this idea had been dismissed by the dealers as "It can't be the thermostat, as we fitted a new one" #-o

He went on to talk about similar stories with O2 sensors, MAFs and other components that were (are?) often changed by dealers as part of their fault-finding scatter-gun approach.

Even top quality replacements can't be relied upon to be perfect, as we went on to talk about "bathtub curves" and "infant mortality"; which isn't as dark as it sounds - try Google

Basically the last thing that was changed is the most likely thing to have failed, not the least likely.
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qwakers
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Re: Modifying for Performance & Style

Post by qwakers »

your last point has bitten me in the arse more than once :)

dads horsebox was overheating. was recovered home and we diagnosed it (correctly) as a failed thermostat.

bought a genuine Iveco part (least likely to fail right?) from the dealer.
fitted it and all was well. then a month later, overheating, recovered home.

new water pump, belt and coolant flush, still overheating, even when parked and bleeding the system.
checked the stat... doesn't open. fitted a new genuine stat.....

two weeks later, overheating (close enough to home this time to just let it cool down and drive it back..)

we're thinking the worst, blocked rad has been ruled out so cracked block, slipped liner... dead engine?

nope 2nd stat wont open.

fitted a non genuine stat. been fine for over 3 years.
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Re: Modifying for Performance & Style

Post by warpc0il »

I wonder if "Iveco Parts" have a similar procurement policy that Motorcraft used to, when sourcing compared to production OEM.

This doesn't bode well, does it...
FO every vehicle.jpg
https://www.iveco.com/uk/services/pages ... -brochures

Maybe they used up all the Arrrrr's on talk like a pirate day :pirate:
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