rotarygod

You can supercharge or turbocharge any engine. Why not?

crazydrifter

okay...i have been researching most of the new import cars coming from japan and europe...first off everyone is trying to make cars built up as much as possible as an N/A...thats why the new M3 has such high compression and same with the 350z, rx-8 and other cars...unless it comes charged in some way its going to cost money to do such...the new greddy kit for the 350z is about 5k installed...for an extra 90hp....the problem is the high compression...now on the rx-8 the problem comes in as well it doesnt have a head gasket...cause if it did just get a thicker gasket for more boost...to boost the rx-8 to at least 1 bar well heck your better of buying an rx-7....i think we need to face the fact that there will never be super cars like the rx-7, supra, 300zx, or skyline again....thats why i might just settle for the new vw r32...awd, 6 speed and 300hp ...cant go wrong...cause after test driving the rx-8 i feel that new dodge sst or what ever might be faster

Sputnik

The rumormill also says that Mazda will turbocharge the rotary for the Mazdaspeed RX-8, and it has said that it will be a simple increase in displacement.

---jps

Keshav

To lower compression on a rotary you need to increase the size of the recession in the rotor. This will probably mean entirely new rotors.


my opinion is that a high compression/low boost turbo option is quite attractive for this kind of car. While you won't end up with as high a peak horsepower figure, you will retain good power off-boost and give yourself strong, linear power on-boost. much more in-line with this car's character.

JohnnyG

Another supercharger vote here. No spooling up and much easier to manage

OverLOAD

According to all the rumors, if you listen to them, is a 1.6L rotary engine in the works, intented for the future RX-7, as well as a 3-rotor variant of the RENESIS, as well as super and/or turbo charging the existing engine. Most of the people linking to the technical experts say that it's not going to last well with more than 5psi of boost.

Tempt-8-tions

I would love to see some pics or some other specs on a supercharged version of the 8!! Long Live The Rotary!!

dcfc3s

Considering one doesn't exist yet, good luck .

Dale

Tempt-8-tions

Saw some guy on the web talking about one with 575 hp and was just wondering... THANKS!!

Digisan

Nope, Trust has an RX-8 with a TD06-18G mounted on it. 50HP gain for the TD06.

mikeb

were still waiting for pics of that setup

Jt-Imports

Pics are above.. hehe

MikeB--You have to have a little faith man. I do what I can...

Tempt-8-tions

Thanks !!

mikeb

thanks jt

WTF no turbo

Yep im waiting on eaton or yaw to start selling the bolt on

jdwk

My guess is that turbos kill normal driving in these high rev high compression sports cars. Think about the Comptech S2000 that just won the Fourgasm C&D contest. The S2000 has no low end torque, wouldn't it benefit from a turbo instead of a supercharger?
The supercharger helps the engine where it isn't really needed, resulting in the spin or bog it characteristic all the magazines have claimed.
A turbo would make more sense, but that little engine doesn't create enough exhaust at low rpms to spin anything that could keep up with the engine when it kicks into it's atmospheric power band. A little turbo would now restrict the engine and it would actually lose HP.
They could put a big turbo on there but now you have some big fan blades slowing the car down at low rpms and the car is slow enough already down there.
The rotary is very similar, that's why the RX-7 (FD) had a sequential system. Small turbo for low RPMs and a big turbo for the upper band. However, this made the RX-7 very expensive and complicated.
A lot of people swap out their two turbos for one massive guy for serious top end power. But those cars lose their daily driving characteristics.
However, in the next couple of years we may see VATN ( I think that is right) turbos that can dynamically change their A/R ratio thus acting like a small turbo at low rpms, and a big one at high rpms. This would be a huge step for the automotive industry. It definitely isn't going to be here soon enough to wait on turboing your RX-8 though. Just properly size the turbo for your application. Compressor maps are beautiful thing.

Efini 8

dont forget tuning is a critical part of turboing a vehicle properly

rx-8club.co.uk

Hi all,

If you can get a turbo into the engine bay (I still haven't seen any hard evidence from anyone actaully doing one yet?) then would the 4 port or 6 port be better for doing so.

Also, does anyone know how much more different the throttle body is on the 4 port engine to the 6 port? (I understand that the plennum is different for sure).

Serious replies only please (last thing I want is another messy thread!).

dcfc3s

Here ya go -

https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/turbo-kit-has-landed-9603/

Greddy's already got a kit coming. I think pics of the prototype are on the 2nd page.

Anyhow, it's really hard to say which would be better - the 4-port or 6-port motor. You would probably want to change the port operation so they're fully open under boost. Time will tell there.

Dale

B-Nez

This is a sidebar regarding porting and the 4 and 6-port engines. In the past, most (if not all) folks recommended NOT porting the 6PI engines. That meant if you wanted bad-*** porting, you had to swap in a 4-port motor (or was it just the housings?). I would imagine we're in kind of the same boat with the RENESIS, unless someone got really smart about porting the tertiary ports (and modding the actuators). That could mean that the Standard Power RX-8 may have more N/A potential than the High Power. Would need upgraded fuel supply, I'm sure, as well as a tranny swap (or high(er)-stall torque converter) since all that new power will be at upper rpms.

wakeech

*search*

the 4 port motor would be better.

rotarygod

The past 4 port engines have always flown more air than the 6 port engines on a flowbench. However the 6 port engines have still always been able to get very close to the power levels of the 4 port engines. First of all, the 6 port engines intake ports are open longer which allows more time for air to enter the engine. The small runners are poor for good flow though. Luckily there is a phenomenon that is a very good side effect of having several seperate ports. When the rotor turns and closes off the bottom port on the end housings, all of the remaining air is forced to flow into the engine through the small upper port and runner. This increased amount of air through the upper port causes it to speed up and charge more air into the chamber. It is all about velocity and not volume. Many RX-7 people make the huge mistake of combining these ports for added flow. The problem is that you kill the velocity that you get from them being seperate and power goes out the door even though it flows better. Go search the RX-7 forum for anything that says "monster port" or "siamesed ports", etc to see what not to do.

Either engine will respond very well to forced induction. I have turbocharged both types and gotten great results from both setups. On the RX-7's the 6 port actuators are in the way so it is easiest to just leave them open full time. Power falls off too hard below 4000 rpm and light loads. It isn't as nice for just driving around and gas mileage gets worse. Then again that could also be a side effect of staying on the gas more too. The plus side is that with all of the port area the turbo likes to spool faster. If I were to turbocharge a 6 port engine again, I would find a way to leave the port actuation alone. You really want to increase power across the board rather than at the expense of another area. The 4 port engines are still wonderful performers. All of the big high power RX-7's use 4 port engines although this is mostly due to the fact that it is this engine that came with turbos. The 4 port Renesis has a higher torque peak and it is lower in the rpm range. This means that power is slightly greater in this engine than in the 6 port up to about 7000 rpm or so. A turbo can overcome the top end deficiencies but it will boost the midrange much better. My choice for the street would be a turbocharged 4 port Renesis in a 6 speed car.

That's my .02

AbusiveWombat

A well designed supercharger can give big gains across the rpms. Look at some of the Jackson Racing kits for cars like the Prelude. It gives a 40% increase across the rpms.

I think that for the RX8 a supercharger is the way to go. Since you're going to be limited on boost you might as well go with a low boost supercharger. It will be easier to maintain and easier to design. Forget the turbo because it's too many parts for too little of a gain.