RIWWP

iTrader: (2)

No, they certainly do not. The only RE/REW swaps that retain all of the RX-8 harness and control is when they use the RX-8 front cover instead of the RX-7 front cover.

No, there are NOT people that do that here. You have us mistaken for RX7Club.com

That the Renesis has so much trouble making power is largely because of the side exhaust ports. The RX-7 exhaust ports are peripheral ports, meaning the exhaust ports are on the housing itself, where the apex seals sweep across them. You literally have the entire width of the housing to work with in porting.

The Renesis has side exhaust ports, and they are up away from the apex seals. This helps trap unburnt fuel to be burned in the next cycle, and drastically improves emissions. But, this means that the exhaust ports run through the end plates, and they run between studs, water passages, oil passages, etc... You have almost no room to work with to widen them. This acts like a restrictor in the amount of air/exhaust you can flow, and an engine is an air pump. More power means more air and exhaust. Throttle one and you will put a cap on your max power. You can cram more and more through there under significant pressure, but that brings us to the related problem of the side seals.

With the exhaust ports being so close to the side seals, as the exhaust ports overheat, it starts deforming the side seal springs until the side seal pops out of place, clips the exhaust port and shatters, with the debris destroying the rest of the engine. Higher power directly means higher heat on this port. Exhaust mods that help evacuate the heat help to a degree, OMP injection is critical (they are aimed at the side seals so the oil can help cool them), and running super rich can help, but it's largely unavoidable. Most people that can GET to 350+ whp on a solid tune, usually can't stay there all that long before their engine goes boom because of this issue. Other people that go boom trying to get there are usually because of tuning flaws.

ReV2ReD

Ok, got it.

I guess its an RE swap then. I suppose there's a lot more tuning support for that engine, and what i save in labour having to make custom manifolds and what not i'll just put into wiring harness and ECU.

For those power goals i should be able to just get off the shelf manifolds and turbos. The only custom part will be the intercooler and piping, and the exhaust from the turbo out. Makes life a bit simpler in one way i suppose.

d walker

Wiring? I thought we were talking race car here?

Let me help you a little bit here-

For the ABS you can use the non-DSC ABS unit for an RX8 which is more or less a standalone, or use the Bosch motorsports unit, which is programmable. If pressed I could come up with something for you

For the engine, MOTEC, AEM, etc. Nothing less, and use a specific harness.

NA20B is not a big deal, it is what Speedsource runs in the Rolex cars and makes a reliable 450whp. Turbo 20B is fine as well. Either will get the job done.

I would NOT buy an experimental gearbox set up. Been through that before. Buy a purpose built race gearbox and be done with it.

Now for a bit of a rant, not nec directed at you specifically-

When you are trying to build a race car, DO NOT be a dumbass and try and make some weird **** work just because. The object is to win race, period. So use what is known to work if the rules allow it. Just because someone says yeah we have a couple of this or that working here and there, doesnt mean jack **** in the racing world, and is likely to mean that a couple of guys are testing it here and there and may or may not be pushing the envelope you are. Be smart and save yourself money.

Gearboxes- Quaife Rocketboxes, Saenz (thanks for the correct spelling above, not enough sleep this week) Jerico, Tex Racing, etc. will WORK, wihtout experimenting or constant fiddling. If they were allowed in Pro racing you can bet your *** I would have one.
EMS- MOTEC is proven, as is AEM and a couple others. Unless you for some reason like to tinker, avoid Haltec/Autronic/Wolf etc.

The idea when your building a race car is to build the most reliable and purposeful machine you can with a minimum of "development" which costs money and has the potential to cost you races. Really try and avoid development cost, unless you have a lot more money than you have let on.

bse50

Wiring as in building a harness. It's a hard task for somebody with close to no experience with a given engine\ecu setup.
Keep in mind that he's in europe so shops like speedsource may be somewhat distant and not many builders have experience with 20b engines here, let alone race spec NA 20b engines build with 13g parts!

Part of my advice to go the trusted route (rew or re) was based on this. I'm planning to join some TA events too around europe and we're discussing both a PP 13b and a side intake\peripheral exhaust 20b as engine options... but I luckily don't have to outsource most of the stuff one may need.

Saenz makes good gearboxes that are somewhat cheaper than most other brands, i'd make the same advice suspension wise. Go with ohlins. At least the european union will be useful for something when needing a rebuild\revalve
That's the most you can do suspension wise since most rulebooks state that one has to keep the stock suspension points. That sucks... there's enough room to implement a push or pullrod setup in a caged car!

ReV2ReD

Alright, alright, I get the point. I'll quit fuking around.

I think for the first year I'll run the stock renesis with full bolt-ons and get the chassis, suspension, and aero dialled in, and then see where I need to be power wise to be more competitive. No point in having all that power and not being able to use it.

At least I have determined its definitely not worth porting it!

As for the suspension, I do agree that Ohlins make great suspension, but there spring rates on there more track oriented coilovers still seem to be a little on the soft side. They seem to be more geared towards semi-slicks rather than full slicks.

d walker

AGAIN- RACE CAR!!! You buy dampers, then you buy springs! You do not buy a "kit". Thats for street cars!
I currently run 500lb fnt and 400-450lb rr springs at my current weight. That would be a good place to start. Since the RX8 has a real suspension, you CANNOT listen to Mac Strut car drivers about spring rate! Because of thier camber arc problems most of them have to run a far stiffer spring and far more camber etc than an RX8 does. PLEASE continue to ask good questions and I will be glad to share any info I have.

ReV2ReD

Ok sorry

Yes, I understand you can buy dampers and then the springs, but surely if some offers a set, theoretically they have done there homework and matched the right springs for that shock on a shock dyno.

If I just go and buy a set of shocks and then buy a set of springs that I "think" would work, I could end up completely screwing it, and since I don't have a shock dyno handy, it would make more sense for me to get them as a matched set, and eliminate that possible variable.

I'm sure there are many tried and true setups, like x dampers work really well with y spring rates, but then I've got to get the ride height right and all the rest of it. It's ok for you guys in the states were you have endless supplies of help and race teams around the corner. I'm going to be doing this on my own, working from my garage with no help, and there is very little rx8 knowledge in Europe.

I want to try and keep things as simple as I can. Yes separate shocks and springs are the way the pros do it, but if I can source that out to someone else that can provide me with a proven package, then I don't have to worry about it. I simply tell them the car weighs x, the weight balance is y, and the tires are z, and they tell me you need these, and done

Besides, it was the you guys that recommended the Fatcat setup, on another thread. Not necessarily you walker, just the members of this forum (racing forum)

ReV2ReD

On another note, am I just being stupid, or is the AEM standalone only 800 dollars? It says its for power sports vehicles and 4 cylinder race applications, and since the rotary would come under the 4 cylinder category that is what I would need no, or am I missing something? On the AEM website they only have the one standalone unit, but when I do a google search there is another one for around 1700, but I don't know if that's what the new series 2 plug and play replaces.

Seems like a no brainer when compared to a 7000 dollar motec unit. I know the motec is a much superior unit probably, but damn, that quite a price difference.

d walker

I actually have a lot of information on the AEM Standalone/PNP stuff, I literally just talked to them yesterday about it!

I have been thinking of trying the universal-4 ecu on a rotary it just has not worked out that I have had the need to yet.

As far as shocks and springs-

The Konis I have work exceptionally well and would be a great starting point. As you change things like aero, tires, etc. you may- or may not- need to change the shack valving. This is why it is very important to pick a brand with support in your area. Ohlins, Koni, Moton, are all supported in Europe and will be able to help you dial things in.
But lets not get ahead of yourself. Your program SHOULD look liek this-

Put together a good car. If you hired me to build your car, it would be along these lines-

Strip Car to tub
remove all undercoating/insulation/etc and have blasted to bare metal
do all weight reduction allowed
build our lightweight but legal(and strong) rollcage
seat, safety equipment, etc,
AIM dash
Have ECU flashed by Racing Beat to their "race" flash
build long tube expansion chamber exhaust
build intake- we use aluminum tubing with a conical filter
Koni dampers with 500fnt/400rr Eibach springs
build three piece sway bar front
modify stock rear sway bar
MazdaSpeed strut tower brace
stock motor with flowed/balanced injectors
Ron Davis custom radiator
ACT Racelite flywheel and clutch
5:12 r&p on OEM LSD
stainless steel brake lines
Cobalt brake pads, xr1 fnt, xr3 rr
brake duct kit, from Mazda or make our own
build transfer pump setup- ours allows us to get all but the last drops of fuel

At this point the car should weigh about 2500lbs empty.


Then go drive the car. In this trim the car with a decent setup will be very quick, so learn to drive the car this way. Hire a Pro driver to set a few laps and aim for those lap times, when you get there and can actually drive the car, then lets make changes.

First, go ahead and put in the more powerful drivetrain thats been developed while you were developing as a driver. Doesnt matter what flavor it is, but lets start with 300whp or slightly better, coupled to the Saenz sequential gearbox with a set of decent ratios. leave the OEM rear diff in for now.
Go drive the car, adjusting the driving style to the new power. You should be MUCH faster at this point and able to determine if you need spring or other changes

Next, add the rear wing and splitter. Go drive the car, now you should be very fast. Add in horsepower to compensate for drag. Once again Hire a Pro driver to spend a day with you benchmarking and developing the car.

I can recommend some Pro drivers not terribly far from you who will do a great job helping you with your project if you need me to.

ReV2ReD

Yeah, I've got the cage and gutting all sorted. I've also got a guy near me that removed all unnecessary wiring from his car to give me a hand with mine. He's literally got about a dozen cables running through the car. It's amazing how little wiring you actually need to run the car! I've already got the seat and harness I want, and all the safety gear for inside the car.

If that's really the price for the aem, plus a harness obviously, that make is it very attractive ECM option, and it's compatible with the aim dash too. Is the AIM dash is compatible with the stock ECM, as I'll run the racing beat reflash to start with?

My plan was to actually run the car in full race trim including aero and suspension for the first season so as to have the chassis completely sorted by the second season. Because no doubt I will have to have the suspension revalved or tweaked once I do the aero, as there is going to be a lot of it, so rather than having to do it twice. I've got a friend with a fluid dynamics program that will be able to estimate (more or less) the down force produced, and I can then pass that on to a suspension guru. I will however look into the KONI's, and maybe run slightly stiffer springs to start with to compensate for the aero. With the KONI's at what point when you uprate springs do you need to revalve them? I mean can you add or subtract 20lbs here or there without having to have them revalved?

Everything is pretty much along the lines of what I was thinking. The only thing was keeping the stock LSD. You don't think that should be one of the first things I should be changing? Or is the factory one good enough. Like I mentioned before, I would like to go into the fist season with the chassis pretty much in the trim I want to finish it in, so that I have the whole season to tweek things as opposed to replacing parts through the season and having to start again. That's just my thought process though.

stinksause

iTrader: (5)

OP, I still think you think about running a supercharger ... less back pressure means that side seals should be okay

ReV2ReD

That's a very good point. Problem is I'm not a fan of the pd type superchargers. I'm more of a fan of the centrifugal type, in particular the rotrex ones, as there pretty efficient. The only problem I would see would be fabricating a mounting bracket for it, but I definitely like the idea!

I'll have to look into that one!

bse50

I wouldn't even bother on a race application.
Go turbo, if you really have to

d walker

I do not believe the backpressure/side seal theory. I do believe that very, very few people know how to tune a Renesis engine, as evidenced by the continued engine failures being experienced out there when engines are tuned using "conventional" rotary tuning philosophy and technique.

To be perfectly clear- I would not use a Renny in a time attack car where more than 300whp is required. I would also not use any form of supercharger on a rotary, mostly because of the engine speeds required, but thats just me. I had a centrifugal charger blow up due to high RPM/high temp wheel growth and sent machined bits of compressor housing into a very expensive engine. not cool.
In order my engine choices would be-
twin turbo 20B using Evo9 16G's or similar (600+whp)
Turbo 13B-RE using GT3582R (400+whp_
NA PP 20B (450-ish whp)
NA 20B (300+whp)

I would not bother with a PP 13B of any sort, or a turbo Renny, and I would really only mess with an NA 20B if I had no other options.
But thats just me.

bse50

Most time attack serieses here have only 2 engine classes: sub\over 3000cc, plus turbo\na variants.
A NA 13b is consider sub 3000cc (2400ish according to fia rules), a turbo one is 2400x1.5.
A NA 20b is considered over 3000cc. Worth it though, imho.

The point is that racing a ***** out NA 13b with 300ish hp may give a weight \ class advantage versus its turbo counterpart that would set you against big big big boys.

RXR8TD

It seems most people here have the right Idea. The entire reason the Turbo was invented was to take wasted energy and heat produced by the engine, and use it to do work..In this case feed a denser volume of air into the engine. This is by far the most cost effective (and weight effective usually) way to gain large power on an engine. This is especially true of small size/high output engines, where thermal efficiency is very important. The supporting mods required to make an NA engine gain the same power would cost you the world, and you would end up with wildly unreliable peaky engine...

stinksause

iTrader: (5)

this does not seem possible ... source?

d walker

The E9 US market turbo is good for a little over 40lb/min each. which potentially will yield around 800hp. Rotaries are a little power stingy, but a 20B with enough airflow will make the power, and they will spool like none other.

ReV2ReD

Well after re-reading the rule book, i've decided to stick with the NA renesis and squeeze what i can out of it, as it turns out in Pro class there is also an engine displacement sub category, so by keeping it NA i stay in the sub 2 liter NA class which puts me up against the likes of honda S2000's and integra type r's, so i'm going to go that route, until i have the funding to go for a ***** out turbo 20b or 13b-re, as there are a couple of 700hp gtr's in the next class up.

bse50

A rotary is considered a 2.4l engine according to FIA rules. You have to see how they value the engine's displacement.

ReV2ReD

Yes, thats for the FIA, but for the timeattack series i'm entering, its displacement x1.5 for NA, making it 1.95 liters. And displacement x2 for FI.
I think clasifying the renesis in the 2.4 displacement category is a massive handicap for the renesis, and i would say its a bit unfair.

TeamRX8

iTrader: (25)

Anybody can talk BS and promise anything to some sucker willing to pay for it. Get back to us with when you have results rather than forum dreams and suppositions
.

ReV2ReD

lol....we can always rely on you to be blunt and to the point.
If you read on the original post, i'm racing it in 2015, that is a certainty. At the moment i'm doing my research, and research invloves asking questions. Questions which have been answered thanks to the helpful members of this forum. Now i know what route to take with regards to the power plant. So this thread was done and dusted before you arrived with your useless input as per usual.

d walker

nothing that far out is a certainty.

If you want a properly setup NA Renny race car, just buy one of mine, all set to go, and will be chaper in the long run

ReV2ReD

lol.... I'm sure it would. I'm just not sure about the color.