Turbo and 9.4:1 rotors
 

Hi there ! Has anyone used the N/A 9.4 rotors in a turbocharged application? what are the benefits and what are the drawbacks of using these?
I have a S5 13b Turbo engine street ported and I just picked up a T04z with a 1.0 rear using A Microtech I have the rotors in my garage and have seriously considered using them in hopes of getting more bottom end response
any info would great

You wont run into any issues, but one thing you will gain is more power with less boost, engine will produce more power with high compression rotors as what it would produce with low compression rotors.

Good setup and idea, go for it, you wont regreat it..:icon_tup:

I know some will say it's low for a T04z but I am planning on running around 12-14 psi (with a bit of methanol if I really have to) and pump fuel will be 93 ,Unfortunately E85 is not available around the Amherst MA area there is only 1 gas station that carries it .

PM aaron cake, he has 9.4:1 rotors and a GT40

i ran a s4 turbo 6port with 16psi and i raped it hard lol it was all experimental and it took a pounding for 3 months with a non turbo ecu and 55cc primary and 800cc secondary injectors. It was pretty fun. i ran a t70 yes a ebay one but the hot side was a .82 and it was perfect for the street. the response of higher compression with boost is more crisp also.

There are autocrossers out there (I wont name names, unless they want to) that run 9.7:1 rotors in an FD engine.

did the motor blow?

I am an advocate of high compression turbo set ups, but I will try to be even handed.

Agreed you can not beat hi compression for response; most opponents of hi comp turbo are leery and dont realize that 95% of the time they are not in boost.

A typical response to high com turbo is: why bother you can make power with turbo rotors?

The answer is better efficiency.


So be careful who you get your information (opinions) from.


The drawbacks:

All your power gains are not for free, you will have to compensate while boosting with either much more fuel water injection, less timing, less boost, and/ or higher octane fuels. In any combination that works for you.

9.4.1 rotors are heavier than 9.0 and 9.7 rotors

*Note* I am not sure about 9.4 rotors but too much boost on 9.7s and you will compress the rotors face (21+psi)

*Side note* E-85 does work yes its cheiper and A LOT of guys are using it down here (S. Florida) but you need 30% more e-85 than gas, most set ups I see are running 8 1600 injectors and of course this comes with a huge fuel system.

I would not try this with stock ecu and piggy backs either you need 100% accurate timing control.

^ +1

also, you'll have to pay close attention to your exhaust manifold/wastegate design.

as far as a engine blowing with a boosted high compression the answer is no. look at a boosted rx8 greddy makes a kit that is basically a factory bolt on of like 6 psi with no problems and a renisis engine is 10:1 compression ratio.

^ The Greddy Rx-8 turbo kit is a bad example man, that thing has a LOT of problems. Take a look in the "major horsepower upgrades" section of the Rx-8 forums, there is a whole sticky on this.

High compression setups leave less room for error. Ask yourself: if you make some kind of mistake (any kind) and the engine does blow up (perhaps due to the less forgiving nature of high compression engines), can you afford to rebuild it?

I tuned an RX-8 with a T78 clone a few months ago @ 12 PSi with an ugly manifold design and its running pretty strong. I'm pretty sure the owner beats the piss out of it too and its still running strong. Of course I was very careful and even a bit nervous the first times going into boost and watching the wideband like I never had before lol. I made sure the car always worked the same in all conditions over the coarse of a week and was happy with the end result.

I wouldn't have chosen that turbo personally since it gets full boost kindof late but it does pull nice once it comes on all the way to high RPM.

thewird

nice..

Agreed Hi comp turbo has less room for error, but now that we have the right technology it can be done (if you do it right). When I was much younger we would run fuel computers lock the DISTRIBUTOR timing, thinking we knew it all… until we blew up of course. BTW it is the old technology that gave rotaries in general a bad name for being a weak engine.

Now days we have:

Stand alones ecus
Stronger Seal
Wide Bands
Knock sensors
Better Fuels
Water Injection
Digital CDI Ignition Systems
More reliable Injectors
Better General Understanding of Rotary Ignition
(the Internet)

If you are looking for 15-20lbs of boost on a high comp engine then these are the systems you need to look at. If you are only looking for 7 psi you MIGHT be able to get away with good fuel and an AIC piggy back (not recommended).

Rotary engines have become way more reliable, but we are limited in the confines of the engine (size). We cannot bore or stroke our motors for more displacement but we can raise the compression which will give us a similar affect.

Down the road I think more people will be running high compression turbo as it is a real untapped source of power within our 13b confines.



The Rx8 Renesis Engine is just not a good engine from what I hear, so turbo on that weak foundation is not a good idea IMO.

I can get you some apex seals for the renesis if you'd like ;)

I boosted mine to 20psi and laid down 508whp on a PT71GTQ billet turbo in my 8 with my apex seals.

http://i679.photobucket.com/albums/v...g?t=1256766544

http://i679.photobucket.com/albums/v...g?t=1256766581

http://www.esmerilracing.com/Apex_Seals2.JPG

Search google for the name on the apex seals :)

Everyone is right, it does take more finesse than a low compression engine but is completely doable. I made my mistakes when tuning it but it handled them, they just weren't huge mistakes...

Chris

I know about the Esmeril seals. I would rather use ceramics personally. Very nice setup you have there though. What EMS are you using?

thewird

I have a plug and play Microtech LT10s. It used to be called the Interceptor-X but its nothing more than a box with a Y harness in it and a Microtech. It works great and didn't require wiring.

Thanks.

Chris

Oh, thats the EMS in the RX-8 I tuned too.

thewird

With more and more people jumping on e85 and aux injection, higher compression rotors could be a good way of getting some power in the earlier rpms and also increasing fuel economy. Unless you plan on running less boost I wouldn't go with high compression rotors and regular pump fuel. Seeing as how we have people running 500 600 and even 700+ hp on pump fuel setups and and AI with no knock to speak of, adding more compression doesn't seem like it would be an issue.

Chris thats a nice setup on that rx8, hows the drive-train holding up?

9.4:1 rotors are my personal choice, I run them in my 7's

I only use 9.4 and 9.7 for my personal projects, Just make sure your tune up is correct...

I agree it's all in the tune.