So my motors been pulled, engine bay has been gutted and sprayed, this weekend its going back together.

When I split my motor my rear housing and rotor were pretty bad. I have a new housing but I was wondering if anyone has experiance running S4 N/A rotors in their S4 TII? I have 2 pefect N/A rotors. I understand this will raise compression so crazy boost will require better parts/tuning. I'm looking for a solid motor with 8-12 psi.

Here's what's goin on so far.

All parts have been cleaned/inspected
Streetport
All new gaskets,seals,springs,bearings
Emissions/ac removed
P/S intact

Fuel is handled by a rewired walboro which will soon shoot through 720 sec. and a SAFC or Rtek

All new hoses and a koyo rad/e fan

I'm really close, just worried how these rotors are act.

Thanks ahead for the replies.

 

Not a very good idea, the n/a rotors are too high of a compression for what you want to run. I think Aaron Cake did 5psi on his N/A-T but im pretty sure you will need a standalone to deal with the higher compression. Just get another set of TII rotors from the 2nd gen parts section.

 

+1 A Stand alone is required as you will need to tune it for high boost.

 

and you will need bigger injectors than that

 

+2 High compression + boost = extra spark retard needed.
Another option is water injection, AKA Aquamist.

 

A standalone will be required, but if you're running the stock turbo @ 10psi I don't see a need for anymore then the 720 secondaries you're listing.

The S4 N/A rotors are only marginally higher compression then S5 TII rotors really....

But it should work fine. Keep the timing conservative (with your AHEM - standalone) and you shouldn't have any problems.

 

I believe Aaron Cake ran and is running more than 5psi. I just watched his videos and looked up his page.. you might want to check his page or email him...

 

Yes, he's actually running 13psi on a GT40 last I checked - unless he's gotten a boost controller.

So yes, exceedingly more boost/power then this person's proposed setup.

 

Chatchie, I am currently running a setup close to what you are proposing. I have a streetported S4 TII block with S4 NA rotors (9.4:1) and use an Rtek 2.0 to control the engine. You should be totally fine if you are only trying to boost 8-12 psi. I was able to boost 12 psi on this set up with an Rtek 1.7 with out tuning my SAFC and with the stock intercooler. I'm able to hit 1 bar since I've been working with the Rtek 2.0.

The higher compression ratio helps reduce flooding, adds a little extra grunt in the lower rpm range , increases fuel efficiency, are easier to find and cheaper to buy.

IMO and from my experience, the 8.5:1 rotors are only needed if you are planning on boost levels higher than 14 psi. The stock engine, turbo and intercooler aren't reliable above this boost level and our stock boost sensor can't read above 15.7 psi anyway so unless you are planning to go standalone and full turbo upgrade before your next rebuild, the NA rotors are your best bet.

 

Im not lookin to run 11 seconds. I have a full, dynamated interior, this is a street car.

TurboVert your mods are pretty close to mine as well, with the exception of the 4 720's, does it run/idle smooth?

Also you run an Rtek ecu and a SAFC on top of that?

I think I might go with the N/A rotors.

Thanks again guys

 

Do it.

 

Do it NOW!!! I think the most you can run with your timing control would be about 8 psi max. I'd polish the face of those rotors too. you'll have really good throttle response, and a much Torquier motor.

 

anything is do-able with the correct tuning, etc. Sonic-rat, (I think), and Im assuming many others have done this, or simmilir setups. 9.4:1 is not ungodly compression, so its more than manageable with the correct setup...

 

Rtek will give you the flexibility you need without having to go standalone, I'm assuming you're getting the 2.0 that let's you control both fuel and timing?

 

Is 2.0 availible? I thought 1.7 was the latest version.

 

Anyone I've ever known to run N/A rotors on a turbo engine popped it quicker than they could break it in. I wouldn't advise it.

 

Yea anythings possible. Im running 15+ on my tii with n/a rotors. Although it is a bridgeport with fuel mods and frt mount with a haltech.

 

Remember that the compression ratio of a rotary can't be compared with a piston engine. It would be about equivalent to a 6 port turbo, which spools very quick.

Just make sure you get it tuned well and have fun with it.

 

whats wrong with 5 psi haha why 8-10... what are you looking for?

flamin roids gotta know more people that ran n/a turbo

 

i been running for around 2 years a high comp. turbo motor(9.4.1 rotors)with the stock ecu,fuel cut def. and stock 550 CC injectors and it runs perfect,daily driven at 12 psi no complains at all.

 

Well you could drive a car with your feet, but that don't make it a good idea.

 

have done that, on stock ECU and all stock car and it was pretty cool ...





...until it blew up (but it was worth it, owner had fun with it)

Stock boost levels or less and bigger IC would probably give it more life.

 

It's not something I would recommend to someone without experience. Tuning is a bit more difficult and critical.

That said, even the NA ECU will easily handle 5 PSI.

 

yummy, me likey!

 

Stupid question, but its been a while. If you run the N/A rotors (s4) which e-shaft do you have to use? Which flywheel and counter-weight? Anything else?

Chris-