The RX-8 I picked up is finally going under the knife. Right now it's nearly stock, with staggered wheels and a couple Sparco goodies. We're acquiring a lot of parts over the next few weeks to do a build for a Time Attack RX-8. We got the last Greddy Turbo Tuned Exhaust from Greddy today. The parts should start showing up next week as we commence the build.

Everything we install and more will be on our site soon. I'm not trying to sell anything here or advertise much yet, but when the time comes I'll gladly sponsor here.

I made this thread to see if you guys were looking for anything specific with the turbo kits out there. We're using Greddy components as a baseline, and will be fully customizing the kit.

We are planning on multiple cooling upgrades and packages as well. If you guys are looking for a specific oil or water cooling system to be available, let us know. I'm starting to do some homework for some more durable race transmissions as well. I know these trannys don't take too much abuse but we'll see how it goes.

So stay tuned and check back for pics. If you guys have suggestions for the build, or want to see certain parts put to good use, let me know. We will be revealing this car at an upcoming time attack event we're throwing at Firebird International Raceway (in Arizona).

If you guys would like to check out the event, visit the following link. Thanks for viewing!

https://www.dezodwest.com/dds.htm


UPDATE 1:
Ok guys...

Here's the pics of the Greddy EvoTT exhaust system for the RX-8. It sounds incredible, and the fit and finish are among the best of exhausts I've seen. If you have questions about the exhaust let me know! (Can't list sales here :) )

https://www.dezodwest.com/DWPics/projects/lowrear.jpg
https://www.dezodwest.com/DWPics/projects/exhaustpackage.jpg
https://www.dezodwest.com/DWPics/projects/y-pipe.jpg
https://www.dezodwest.com/DWPics/projects/evoTTcanister.jpg

So far so good!

Couple tiny pics to show the car, we'll be putting some enhancements on it but you get the idea.

https://www.dezodwest.com/rx8rear.JPG

https://www.dezodwest.com/rx8FL.jpg

Nice!! I have a dezod turbo kit for my 7th gen civic and love it. I plan on boosting my 8 next year, so ill be watching this thread closely.

Nice man!

Yeah we started with the D17 turbo kits, then developed some Scion kits that are now #1 in the industry for the tC. Hopefully the RX-8 is another success story.

make sure you upgrade the ignition system. that is one of the bottle necks on the 8

Thanks for the tip. I know there's a few week points with the RX-8 that we plan on addressing. I've received good tips on a few things to do in regards to the ignition so we'll see how it goes.

We just received the Greddy Turbo Tuned exhaust today. I'll be installing it shortly and expect the first batch of pics in a little bit! I already installed the Apexi AVC-R boost controller yesterday.

Ok guys...

Here's the pics of the Greddy EvoTT exhaust system for the RX-8. It sounds incredible, and the fit and finish are among the best of exhausts I've seen. If you have questions about the exhaust let me know! (Can't list sales here :) )

https://www.dezodwest.com/DWPics/projects/lowrear.jpg
https://www.dezodwest.com/DWPics/projects/exhaustpackage.jpg
https://www.dezodwest.com/DWPics/projects/y-pipe.jpg
https://www.dezodwest.com/DWPics/projects/evoTTcanister.jpg

So far so good!

That looks really good

is it just me, or does that big back pipe go to a silly small pipe to the Y????

that is very, very odd.

beers :beer:

Ok guys...

Here's the pics of the Greddy EvoTT exhaust system for the RX-8. It sounds incredible, and the fit and finish are among the best of exhausts I've seen. If you have questions about the exhaust let me know! (Can't list sales here :) )

https://www.dezodwest.com/DWPics/projects/lowrear.jpg
https://www.dezodwest.com/DWPics/projects/exhaustpackage.jpg
https://www.dezodwest.com/DWPics/projects/y-pipe.jpg
https://www.dezodwest.com/DWPics/projects/evoTTcanister.jpg

So far so good!

is there any real difference with the sp2 greddy exhaust and this one?

is there any real difference with the sp2 greddy exhaust and this one?


yes the mufflers are not the same, but the ? about the Y is much more important.

beers :beer:

yes the mufflers are not the same, but the ? about the Y is much more important.

beers :beer:

yeah i noticed that right after i wrote that and also this one has a blueish color on the tips oh and about that pipe it does look kinda weird ima check my sp2 to see if it has that tommorrow

oh just found out the evo greddy exhaust are for cars w after market turbos:banghead: go ahead laugh at me

The SP2 also features smaller piping diameter. The EvoTT system uses 70mm piping, whivh equates to 2.76". This added flow will definitely help with a mid-pipe upgrade and turbo.

The Y pipe is cut all the way to the back of the weld. So the actually space where the exhaust is effectively split in half is quite large. It features a very smooth split, keeping turbulance to a minimum and the exhaust velocities as high as possible, given this diamter.

I hope that helps, but if you need more detail please let me know.

good luck with the build, looking forward to future updates

What is your hp goal you are trying to achieve?

Nice looking exhaust.

yep,

i will bite on that one. could you get a photo straight at.

the back pipe and y at a 90 deg angle to the camera. with the center of the shot be where the back pipe hits the connector to the y?

if they are the same size that would be great to know..(back pipe and y.) as to the 2.76 dia. that is better than 2.5. but is it enough? no one really has a black and white answer on that.

beers :beer:

The SP2 also features smaller piping diameter. The EvoTT system uses 70mm piping, whivh equates to 2.76". This added flow will definitely help with a mid-pipe upgrade and turbo.

The Y pipe is cut all the way to the back of the weld. So the actually space where the exhaust is effectively split in half is quite large. It features a very smooth split, keeping turbulance to a minimum and the exhaust velocities as high as possible, given this diamter.

I hope that helps, but if you need more detail please let me know.

What is your hp goal you are trying to achieve?

Instead of a peak horsepower goal, we're shooting more torwards the most useful torque curve. Having a broad torque curve geared towards performance and higher RPMs will yeild much better times than an engine that only peaks at 340whp with almost no power below 5k. We like to maintain a highly driveable vehicle without losing almost any of the throttle response of the car. We can customize our turbos quite heavily, with AR, housing, trim and wheel size. I think after a few different turbos through testing we'll find some that really stand out as the best to use.

I just finished installing the Apexi AVC-R boost controller yesterday. With adjustable boost by gear, and RPM, it will allow us to fine tune an already stellar system.

Here are some pics: (The Apexi RSM you see on top is used for G-sensor logging. I will be able to log the real difference in stopping power with better brakes and tires, and compare results. I can also show the difference in handling the OEM suspension offeres when compared to the coilovers we'll be using).

https://www.dezodwest.com/DWPics/projects/apexiinterior.jpg
https://www.dezodwest.com/DWPics/projects/apexicloseup.jpg
https://www.dezodwest.com/DWPics/projects/apexicloseupnight.jpg

wow, that is a very good plan. i am glad you are looking for the best torque curve instead of the highest peak hp. very smart.

yep,

i will bite on that one. could you get a photo straight at.

the back pipe and y at a 90 deg angle to the camera. with the center of the shot be where the back pipe hits the connector to the y?

if they are the same size that would be great to know..(back pipe and y.) as to the 2.76 dia. that is better than 2.5. but is it enough? no one really has a black and white answer on that.

beers :beer:


Great questions!

The exhaust is indeed perfectly symmetrical. Each runner is the same for both exhaust outlets, and the y-pipe is centered on the car.

The cat-back pipe, and the y-pipe are of the same diameter, which is 70mm. There is no tapering of the exhaust system.

The 2.76 is a vast improvement when it comes to flow. It doesn't seem like much, but the 2.76 can flow over 400whp. With the Renesis engine, this more than enough.

If you step in to a large 3" rear section you run into a couple different problems. The first is weight. Extra weight without extra gains is not necessary. A 3" rear section will not make much of a difference in horsepower on a turbo 1.3L RX-8. A 3" exhaust gives the exhaust fumes a lot of space to move around. This will decrease the velocity of the exhaust, due to turbulance. The large pipe could also cool the exhaust faster, again creating turbulance and back pressure. A hot exhaust, going through a smooth mandrel bent system with minimal bends is essential. I spend a lot of time doing research on what exhausts would work well, and this seems to be the best system to use for a turbo.

The second problem (though smaller) is price. Stainless is expensive these days. 3" piping is no joke, and will definitely increase the cost of the exhaust, in addition to the weight.

So all in all, I think many will be happy to use this exhaust. I do offer it on my site now, but I can not list things directly here, for I'm not a paying sponsor (yet).

For those who want me to make a video let me know. I will definitely have some more pics later today. For anyone that wants to see the event in person, visit our race event we are having at Firebird International Raceway on May 31st. We will be showing off the 8, among other projects. Right now I have about 15 different Mazdas alone that will be attending this. https:www.dezodwest.com/dds.htm

wow, that is a very good plan. i am glad you are looking for the best torque curve instead of the highest peak hp. very smart.

The car will be faster as a result :)

We only plan on using the dyno to show off our torque curves and to better tune our AFRs.

The car will be faster as a result :)

We only plan on using the dyno to show off our torque curves and to better tune our AFRs.

yes it will. looks great. keep up the good work.

looks nice

Great questions!

The exhaust is indeed perfectly symmetrical. Each runner is the same for both exhaust outlets, and the y-pipe is centered on the car.

The cat-back pipe, and the y-pipe are of the same diameter, which is 70mm. There is no tapering of the exhaust system.

The 2.76 is a vast improvement when it comes to flow. It doesn't seem like much, but the 2.76 can flow over 400whp. With the Renesis engine, this more than enough.

If you step in to a large 3" rear section you run into a couple different problems. The first is weight. Extra weight without extra gains is not necessary. A 3" rear section will not make much of a difference in horsepower on a turbo 1.3L RX-8. A 3" exhaust gives the exhaust fumes a lot of space to move around. This will decrease the velocity of the exhaust, due to turbulance. The large pipe could also cool the exhaust faster, again creating turbulance and back pressure. A hot exhaust, going through a smooth mandrel bent system with minimal bends is essential. I spend a lot of time doing research on what exhausts would work well, and this seems to be the best system to use for a turbo.

The second problem (though smaller) is price. Stainless is expensive these days. 3" piping is no joke, and will definitely increase the cost of the exhaust, in addition to the weight.

So all in all, I think many will be happy to use this exhaust. I do offer it on my site now, but I can not list things directly here, for I'm not a paying sponsor (yet).

For those who want me to make a video let me know. I will definitely have some more pics later today. For anyone that wants to see the event in person, visit our race event we are having at Firebird International Raceway on May 31st. We will be showing off the 8, among other projects. Right now I have about 15 different Mazdas alone that will be attending this. https:www.dezodwest.com/dds.htm

yes i will still wait for the photo..

i will say 2.75 or 3.0 back pipe into a y that is an equal size is what is needed.. out of the y.. 2" per side is all that is needed.. but i think 2.5 would be good, and less expensive, and more choices..

and now a muffler ? what is the system. baffles? or other. if other what is it?

as to the flames and exhaust smell stuff.. that is marketing. are you marketing.. or providing info???

beers :beer:

yes i will still wait for the photo..

i will say 2.75 or 3.0 back pipe into a y that is an equal size is what is needed.. out of the y.. 2" per side is all that is needed.. but i think 2.5 would be good, and less expensive, and more choices..

and now a muffler ? what is the system. baffles? or other. if other what is it?

as to the flames and exhaust smell stuff.. that is marketing. are you marketing.. or providing info???

beers :beer:

The exhaust is a baffle system. The exhaust is built with 2.76" piping from the midpipe back. Not sure what you are talking about with the exhaust flames. I never made any mention of flames in this thread. I can not post here to sell product for I'm not a sponsor. I plan on signing up soon, but right now I am simply providing info. I do have a store, and I do sell product (a lot of product) but can not link things directly on this thread per forum rules.

Here are some new pics showing the exact layout. The exhaust fits perfect, and has no evidence of melting or disfiguring the shrouds, which is a good thing! I've heard of other exhaust with large tips doing this, but no problems here.

https://www.dezodwest.com/DWPics/projects/may/rearleft.jpg
https://www.dezodwest.com/DWPics/projects/may/rearright.jpg
https://www.dezodwest.com/DWPics/projects/may/rear.jpg
https://www.dezodwest.com/DWPics/projects/may/rearabove.jpg
https://www.dezodwest.com/DWPics/projects/may/sidetip.jpg

sorry i read fast some times. you mentioned exhaust fumes.. that is what i caught. so many here ask for flames..

still would love to see the 90 deg shot where the back pipe hits the y.. and you can always send me a pm.. i like to learn..

the bad thing about exhausts is you really really have to hear them live..

beers :beer:

I have some decent cameras. I could attempt to record the exhaust, and maybe a couple drive-bys if you guys want. Next time I have the car in the air I'll take a picture for you.

Good to see your making some headway with the system. Loking good.
See you on the 31st.:eyetwitch

Please post a clip of how this exhaust sounds. I'm thinking about getting this exhaust, but i want to hear how it sounds first.

Video coming soon.

I want to inject a little skepticism into this thread, not as a flame, but more as a challenge and a prompt for discussion.

Instead of a peak horsepower goal, we're shooting more torwards the most useful torque curve.

That's fine I suppose, but it's still a rotary... how much "useful torque" do you expect under 3 or 4000 rpm without a restrictive turbo setup with a small hotside? It's all relative I suppose. Face it, these engines are relatively gutless down low anyway, so why not build it for where it's strong, 5000+ rpm? Having a good response down low has a lot to do with manifold design, with a divided tubular hotside ideal, and appropriately sized for your application. On an old setup with a stock turbo on my 88 Rx-7, I made 250rwtq @ 3500, but that's because the boost quickly dropped off due to the restrictive hotside on a stock turbo only made to hold 6psi to redline. You can also improve spool by messing around with your timing map.

If you step in to a large 3" rear section you run into a couple different problems. The first is weight. Extra weight without extra gains is not necessary.

True. Rx-8's are all about keeping weight down, which is the enemy of performance.

The 2.76 is a vast improvement when it comes to flow. It doesn't seem like much, but the 2.76 can flow over 400whp. With the Renesis engine, this more than enough... A hot exhaust, going through a smooth mandrel bent system with minimal bends is essential.

I agree with this as well...

A 3" exhaust gives the exhaust fumes a lot of space to move around. This will decrease the velocity of the exhaust, due to turbulance. The large pipe could also cool the exhaust faster, again creating turbulance and back pressure.

Here's where I think you are getting off track. Talk to anyone who designs turbo manifolds. They will agree that if you make the runners (as in PRE-TURBO EXHAUST, not POST-TURBO) too big, it will slow velocity and hurt spool. So you are operating off a correct principle.

But constricting exhaust after the turbo is NOT good for performance! Why do you think when you put a bigger downpipe on an otherwise stock turbo car, the boost increases and can sometimes spike? It increases volumetric efficiency, and it increases spool. Why do you think people run big hotsides on large turbo setups? a 4" downpipe is going to make more power with better spool on a custom setup. Now you still have to optimize, and I'm not saying a 4" exhaust is going to be the best option for a 280-300rwhp car or that it will make a huge difference over 2.5" at such a relatively low power level. And that doesn't mean either you can't get away with something under 3 inch and still make good power.

But to claim that having a restrictive exhaust post-turbo is a performance benefit in and of itself is just not true, all weight and space considerations aside.

Again:

The large pipe could also cool the exhaust faster, again creating turbulance and back pressure.

A larger exhaust INCREASING backpressure????? think about this man!

uh yes, he is right. as the gas cools, they slow down. this creates turbulence and can create back pressure by forming eddies.

also, larger pipes = more weight, and as you said yourself, weight is the enemy of performance.

ask yourself, why dont turbo 911s have 12" exhaust pipes?

I guess I should have been more specific then with the posts I've made. We know a lot about manifold and exhaust design. Not as much as certain tuners out there, but we've been making custom and production based turbo kits for about 6-7 years now. We even setup and program AEM universal EMS for car specific applications, and with out own serial number, AEM warranties it.

We have a good know-how when it comes to thermal dynamics, exhaust design, turbo design, and more. Smaller runners do indeed keep velocities higher which helps for turbo spool. I did not say in my my post that making turbo manifold runners larger will be beneficial.

A 2.5" exhaust supports over 300hp. A 2.76 approaches 400 with no problems. The idea is to not go larger than you need to. My argument is the added benefit vs cons when switching to a 3" rear section. The design of the Greddy Evo TT is very efficient. There are very little bends in the system which allows it to flow well. I agree that 3" can be beneficial, and that a 3" mid-pipe would still help. My argument is that if you go too large, it can indeed create back pressure IF the exhaust gases aren't great enough (both in speed and temperature) to fully utilize the amount of space it has to move in.

An example for exhaust efficiency:

We make our own custom stainless turbo backs for the Scion tC. With our turbo kit and a stock exhaust, the tC was dyno'd. We then switched only to our custom turbo back exhaust and on the same dyno picked up 34whp. This is all on a 2.5" exhaust. By keeping the pipe from getting too large, we kept a nice fat torque curve, and to this day have the widest power bands on the tC turbo kits available. At 8psi we had a car dyno 314whp. Here in AZ, the kit that came off my car made 261whp, at only 5psi.

There are a few different variables with the turbo when it comes to design. Sure the AR makes a difference, but the exhaust and compressor wheels play a huge factor as well. You then take into account the inlet diameter, and compressor and exhaust housing sizes. We've fit wheels into T3 housings that you never thought possible. I had a turbo on my last car that made a few psi at 2000rpm, but had more top end available than the head could even carry. Luckily we have many different lines and custom setups at our disposal. We can test different turbos on different cars to see how they react.

I know the rotary is a different beast than a piston engine, and we look forward to the challenge. With proper R&D, I think a really affordable race-ready setup can be attained.

Hopefully I addressed your challenge well. I know you're basically looking for statements in response to yours. If you have more questions or feel that I've missed on something, let me know and I will be happy to answer it. Thanks!

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F the exhaust gases aren't great enough (both in speed and temperature) to fully utilize the amount of space it has to move in.


It's a rotary, these cars have no shortage of high velocity, high temperature exhaust. Our typical exhaust EGT's (1200-1400 degrees) would be pretty dangerous on a piston engine but are just fine for our cars. Have you ever measured EGT's on a rotary? Do you think 1400 degrees is going to cool down to the point of causing turbulance? I took my car out to Virginia International Raceway a while back and my EGT gauge pegged at 1600 degrees from hard running (I was running 100 octane race gas, the car was not detonating). I then sold the EGT gauge and will eventually move to EGT probes that can log up to 1800 degrees and output a 0-5v signal for datalogging. EGT gauges designed for piston engines are useless under those hard conditions. There is no shortage of hot exhaust in a rotary, and I doubt the Renesis is any different than the older ones. Why do you think cat life is such an issue?

Now there are clearly diminishing returns in increasing exhaust diameter, and the design of the manifold and hotside are more important for reducing backpressure, but 2.75ish seems like an arbitrary cutoff point for diameter. People run those on turbo 4 cylinders all the time. Racing Beat makes 3" exhaust for both 2nd and 3rd generation Rx-7's that are quiet and flow very well. But yes, I have seen 400whp rotaries with 2.5" exhaust. That doesn't mean 3" wouldn't be an improvement though.

Good luck on the build! Since you asked for suggestions, I would strongly suggest a Mazmart water pump. And, depending on what you are using for engine management, perhaps a Mazsport cooling fan mod.

It's a rotary, these cars have no shortage of high velocity, high temperature exhaust. Our typical exhaust EGT's (1200-1400 degrees) would be pretty dangerous on a piston engine but are just fine for our cars. Have you ever measured EGT's on a rotary? Do you think 1400 degrees is going to cool down to the point of causing turbulance? I took my car out to Virginia International Raceway a while back and my EGT gauge pegged at 1600 degrees from hard running (I was running 100 octane race gas, the car was not detonating). I then sold the EGT gauge and will eventually move to EGT probes that can log up to 1800 degrees and output a 0-5v signal for datalogging. EGT gauges designed for piston engines are useless under those hard conditions. There is no shortage of hot exhaust in a rotary, and I doubt the Renesis is any different than the older ones. Why do you think cat life is such an issue?

Now there are clearly diminishing returns in increasing exhaust diameter, and the design of the manifold and hotside are more important for reducing backpressure, but 2.75ish seems like an arbitrary cutoff point for diameter. People run those on turbo 4 cylinders all the time. Racing Beat makes 3" exhaust for both 2nd and 3rd generation Rx-7's that are quiet and flow very well. But yes, I have seen 400whp rotaries with 2.5" exhaust. That doesn't mean 3" wouldn't be an improvement though.

I'm not sure who your arguing with. In my last larger post, I even agreed to a 3" being benificial, and did not say it was too big for the Mazda. I'm aware that rotaries run hotter than piston engines. I've seen the racing manifolds on the RX8 race cars (which I know are 20b powered), I've read threads, and it's well known that the rotaries run hot.

I did not say the car couldn't use a 3" mid pipe, cat-back, or anything else. I just argued that this specific exhaust will well support almost anyone's power goals that can be safely acheived with Renesis. Sure a 3" is another option. From the products I carried, and as a matter of performance, preference, fit and finish, and style, this seems to be the best exhaust I would put on my own RX-8. I went to a meet recently and everyone LOVED the sound of the exhaust. It doesn't sound like many out there and I feel it works well even for a non turbo RX-8.

You make valid points and I've never disagreed with you. There is no specific cut-off with exhaust diameter. I just feel that the Greddy TT is a great system out there.

Good luck on the build! Since you asked for suggestions, I would strongly suggest a Mazmart water pump. And, depending on what you are using for engine management, perhaps a Mazsport cooling fan mod.

Thanks for the tips. I've been eying the Mazsport cooling fan mod for a while. We plan on coming with 2 different packages for an oil cooler upgrade. One being a full bolt on, with SS line replacements, the other just being upgraded coolers.

Thanks!

I would eye the Mazmart water pump as well. Designed by one of the world's leading rotary engine builders. I see water temps drop much more quickly with it.

As far as the fan mod goes, it depends on what engine management you go with. I believe a reflash unit like the cobb can control the fans. But if you go with an IntX, etc, you would need to do it with a mod like Mazsport's.

Yeah we're still unsure of what EMS we'll be using. We may work with a company or two to try and come out with a new EMS all together.

The water pump mod definitely seems like a great unit. I'll post up what we decide on. Right now we're getting ready for the time attack event we're hosting next week. Busy times!

......so where is the sound clip of the exhaust? :)

^^^^ +1

I'll try to do it today, I don't have anyone to tape it so it'll be hard to record load, but I'll see what I can do.

AEM is sponsoring our time attack event so I bought an AEM CAI fore the car for next weekend. I need to install that in a little bit, then I'll tape the exhaust. :)