RX8 for sprinting/hillclimbing

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RX8 for sprinting/hillclimbing

Post by divetrucker »

Hi all,
I am looking to get back into sprinting and am considering a RX8 as a likely vehicle. I will not be taking things very seriously and want a car that I can drive to events, compete, and drive home again. I am considering a few possible vehicles (MGTF, Jag X-type 3.0, Fiesta ST 2.0) that can be purchased for low cost but the RX-8 seems to provide a lot more performance as standard than any of the others. I would have little hesitation in taking the others and hoping for the best, but the RX-8 looks like it could be rather fragile. Would any of you owners take a standard car sprinting??
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Re: RX8 for sprinting/hillclimbing

Post by qwakers »

I have done exactly as you propose. You will be in class a3 which is usually the most competitive class and frankly, my stripped ported and very played with rx8 gets to mid field In that class on a good day.

If you want to be competitive you need to look elsewhere. A 4wd Audi tt is a good competitive car to start with, for example. Take a look at what the competition runs in your local club and what cars are in the top 3 and you'll have a good start.
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Re: RX8 for sprinting/hillclimbing

Post by divetrucker »

Thanks for the reply. Not sure if there is a difference between events in Scotland and England, but a RX-8 is 1.3 litre with a 1.5 equivalency that makes it 1.95 litres. That would place it in A2 for up to 2.0 litre cars. Or am I missing something?
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Re: RX8 for sprinting/hillclimbing

Post by 79398 »

divetrucker wrote:
Fri Sep 17, 2021 12:22 pm
Thanks for the reply. Not sure if there is a difference between events in Scotland and England, but a RX-8 is 1.3 litre with a 1.5 equivalency that makes it 1.95 litres. That would place it in A2 for up to 2.0 litre cars. Or am I missing something?
It's classed as a 2.6 I think, may be wrong.
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RX8 for sprinting/hillclimbing

Post by GreySilver Beast »

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Re: RX8 for sprinting/hillclimbing

Post by divetrucker »

It's classed as a 2.6 I think, may be wrong.
That must be a difference between countries / championships. If you are up against Soobies and Evos, I'm not surprised that you struggle to get past mid-field. I will be up against Clios and Fiestas and the like which will have 200+bhp and struggle with FWD. My worry remains that the RX-8 engine will not like being treated harshly!!
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Re: RX8 for sprinting/hillclimbing

Post by New Duke »

The RX8 engine LOVES racing. It's got a very good reliable history in that regard so don't let that be a worry.
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Re: RX8 for sprinting/hillclimbing

Post by Conan »

divetrucker wrote:
Fri Sep 17, 2021 12:22 pm
Thanks for the reply. Not sure if there is a difference between events in Scotland and England, but a RX-8 is 1.3 litre with a 1.5 equivalency that makes it 1.95 litres. That would place it in A2 for up to 2.0 litre cars. Or am I missing something?
Hi, welcome to the forum :thumleft:
Different championships have different rules / regulations :
You are correct it is a 1.3 and the usual calculation is X 1.5 ( the 2.6 thing is just for tax and has no logic to it :roll: )
There was a member doing well in hill climbs with a standard RX-8 although power is a plus point in climbing.
The RX-8 handles very well around a circuit and can outperform many much more powerful cars if your on PZ suspension (I'll did out a video for you )
Quackers may have been in a different catogory because of the mods to his car ( modifications don't necessarily make the car much faster so you should way up all the options and check out the regulations in the series you want to enter.
The RX-8 can be very reliable. One of our members Casey did many 1,000s of miles and many track days over about 10 years or so before an engine rebuild as have many others
Regards
Pete
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Re: RX8 for sprinting/hillclimbing

Post by divetrucker »

Thanks,
Pardon my ignorance, but what is PZ suspension. The car would be getting a set of uprated springs + dampers regardless, but is the PZ setup more than just that?
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Re: RX8 for sprinting/hillclimbing

Post by Conan »

Mazda gave prodrive 800 new cars to work there magic on
They developed the suspension at the Mira testing grounds and tested it on two RX-8s in 2005 over many miles.
It is a non hight adjustable coilover set with Bilstein dampers and Eibach springs and patented by Prodrive.
It is standard suspension for the PZ RX-8 so depending on series regulations can be a good option.
Many other suspension sets would not be an upgrade and would require testing and setting up to get the best from them.
The club has a thread somewhere hidden in the archieves but I believe you would have to be a member to read it.
Regards
Pete
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Re: RX8 for sprinting/hillclimbing

Post by Steve.82 »

Running mine at Shelsley next Friday on a members day with a view to doing a full season next year. It’s all run to blue book regs as far as I know so hoping it drops into the 2L class!
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Re: RX8 for sprinting/hillclimbing

Post by divetrucker »

Steve.82 wrote:
Fri Sep 17, 2021 9:34 pm
Running mine at Shelsley next Friday on a members day with a view to doing a full season next year. It’s all run to blue book regs as far as I know so hoping it drops into the 2L class!
Pretty sure that it will be in the 2.0 class. This is exactly my logic. It will be running against Clios and Fiestas that will take a hep of cash to get near 230bhp, which the RX8 has as standard. It is a bit heavier than the little hatches, but mid-engine weight distribution and rear wheel drive should make up for that. I believe that there are plastic bonnets & boot available from somewhere that will save a chunk of weight + a pair of alloy front seats + Li-On battery + removal of stereo, AC, etc.
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Re: RX8 for sprinting/hillclimbing

Post by warpc0il »

Most aftermarket bonnets, including the "Carbon Fibre" ones, are significantly heavier than the oem alloy bonnet, unless you're willing to pay £££££'s
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divetrucker (Sat Sep 18, 2021 1:57 pm)
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Re: RX8 for sprinting/hillclimbing

Post by divetrucker »

warpc0il wrote:
Sat Sep 18, 2021 1:31 pm
Most aftermarket bonnets, including the "Carbon Fibre" ones, are significantly heavier than the oem alloy bonnet, unless you're willing to pay £££££'s
Seriously? That is a surprise. I didn't know the bonnet was alloy. Maybe just removing the lock, hinges and sound deadening would be sufficient. Is the boot lid alloy too?
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Re: RX8 for sprinting/hillclimbing

Post by warpc0il »

The boot lid is steel but not that heavy, plus you'll need the strength if you're fitting an effective spoiler.

The front doors are steel, though the rears are alloy.

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Re: RX8 for sprinting/hillclimbing

Post by 13Black »

Conan wrote:
Fri Sep 17, 2021 2:07 pm
the 2.6 thing is just for tax and has no logic to it

I feel the need to respectfully disagree entirely.

They are 2.6L, as I have said and demonstrated many times before, as have other people (perhaps less convincingly), and as always, maybe 30% actually care to listen, only half of those who listen actually have the capacity to understand what you're talking about, and only a few of those actually have it within themselves to drop the "omg 1.3L 200hp unicorn magic triangle ultimate engine" facade they've built up to admit that actually: they make terrible power for their actual displacement.

Still good engines for many reasons, just they're not good enough to turn the laws of thermodynamics on its head, just for them.
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Re: RX8 for sprinting/hillclimbing

Post by divetrucker »

Quote from MSA Blue Book:
10.4.2. Rotary engine equivalence 1.5. Forced induction rotary
equivalence (1.4 x 1.5) = 2.1 or (1.7 x 1.5) = 2.55.

I am only interested in which class the car will be assigned, and the MSA are the folks who decide. Their calculation is that a 1.3l rotary engine is equivalent to a 1.3 x 1.5 = 1.96 litres.
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Re: RX8 for sprinting/hillclimbing

Post by divetrucker »

warpc0il wrote:
Sat Sep 18, 2021 2:09 pm
The boot lid is steel but not that heavy, plus you'll need the strength if you're fitting an effective spoiler.

The front doors are steel, though the rears are alloy.

Sent from my Samsung using Tapatalk
I will not be allowed to fit a spoiler, and most the hillclimbs and sprints are fairly low speed events, so aero is not a big advantage.
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Re: RX8 for sprinting/hillclimbing

Post by Conan »

Hi,
I could of worded it better but it’s just an easy way to say it, there have been arguments about Rotary displacement calculations since it was conceived.
I believe all British series use the 1300 x 1.5 as you have stated
A wing would be a waste of time but look at the PZ spoiler which is designed to stabilise the rear end without too much compromise on drag.
It depends on your championship regs but I would say go for the most standard class you can. Once you start modifying the RX-8 for higher classes you lose out big time against other cars.
You won’t have 230 horse power, it was 231 ps which is 228 on an engine dyno, which means an old car will probably give you about 160+ ish at the wheels. If you build a good engine or buy new and blueprint you can expect around 195 ish at the hubs.
The most is gained through the exhaust system especially the header.
16 or 17 wheels would help depending on regs and the original wheels can be pared down to 8 kilos if you life them ;)
The RX-8 gains from its smooth power delivery and rev range and can beat some cars with twice the power over a circuit lap.
Sound insulation and leather drivers seat give you good weight reduction depending on regs etc.
There was two lads sharing a PZ I think in hillclimbing that did well ( always depends on your competition as well )
Regards
Pete

PS : You have to go a long way to find a comparable car on handling
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Re: RX8 for sprinting/hillclimbing

Post by divetrucker »

Thanks Pete,
Yeah, I am aiming at the 2000cc Road Cars class, which restricts how much you can do to the car. It is the weight distribution and rear wheel drive that are its main attractions. Power wise, a Clio comes with almost 200bhp as std and they are the most common cars in this class, along with Fiesta STs. I will need to get very creative with weight saving to minimise their weight advantage, so single-skin plastic or alloy bonnet/boot will be an important step. This ain't gonna be a shopping car! :)
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Re: RX8 for sprinting/hillclimbing

Post by Steve.82 »

Or just go into the modified non road legal 2L class for a bit more freedom?
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Re: RX8 for sprinting/hillclimbing

Post by SprintRX8 »

13Black wrote:
Sat Sep 18, 2021 2:15 pm
Conan wrote:
Fri Sep 17, 2021 2:07 pm
the 2.6 thing is just for tax and has no logic to it

I feel the need to respectfully disagree entirely.

They are 2.6L, as I have said and demonstrated many times before, as have other people (perhaps less convincingly), and as always, maybe 30% actually care to listen, only half of those who listen actually have the capacity to understand what you're talking about, and only a few of those actually have it within themselves to drop the "omg 1.3L 200hp unicorn magic triangle ultimate engine" facade they've built up to admit that actually: they make terrible power for their actual displacement.

Still good engines for many reasons, just they're not good enough to turn the laws of thermodynamics on its head, just for them.

The original 12A where 2300
Later 13B where 2600
Because of the very high tax in Japan they where dropped down to 1300.
So how can a 2600 engine be classed as a 1300 when in theory it’s the same engine?.

The RAC blue book also points out the a single Rotor will be classed as a three cylinder
Plus the two rotor would be classed as a six cylinder.

I’m still in the process of measuring the the actual capacity of a Rotary engine.
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Re: RX8 for sprinting/hillclimbing

Post by Steve.82 »

It’s 1300, anything else is interpretation. Same as my 300 2 stroke not being called 600cc just because it fires twice as often.
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Re: RX8 for sprinting/hillclimbing

Post by divetrucker »

Steve.82 wrote:
Sun Sep 19, 2021 11:08 am
Or just go into the modified non road legal 2L class for a bit more freedom?
I have a 3/4 finished VVC Metro Mod Prod that I was going to use, but I have decided that I can't face the loading/offloading of the trailer and all the long distance towing. If the road car gets my enthusiasm going full strength, then I might finish the Metro. No point in trying to ModProd a road car because it would be far too heavy... the Metro is a 1.8 VVC with about 180bhp and weighs 600kg, for comparison. It runs on 10" wide slicks too.
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Re: RX8 for sprinting/hillclimbing

Post by Steve.82 »

There’s enough road legal/still reg’d and MOT’d stuff in the modified class down here. Granted a few are still trailered. But yes with you, trailering is another faff I don’t want in my first year…