I have the parts to convert my NA s4 to a boosted S5 with the 9.7 rotors. To make the driveline fit I need to use the light rotors. I already have the s5 flywheel, turbo and intake manifold.
I guess Im doing it anyways despite what opinions come back but I would like to hear feedback. I was thinking 6-10 psi. 8 is probally safe.
Sky

 

you just have to be really careful, s4 rotors would be better, they have a little less comp.
Why would you need high comp rotors to put in the driveline? The rotors are completely swappable. you could easily put in TII rotors. I think you should just get low comp rotors, you'll have a lot more potential for power, and you won't have to buy ridiculous octane gas.

 

There's no problem with using hi comp rotors. S5 and S6 motors make big horsepower with big boost without any special gas or treatment. The lighter rotors make the swap worth it.

 

Well the rotor swap is only becuase I only have s5 flywheels. Shipping a s4 flywheel to Hawaii is kinda expensive. Im tryin to cheap out. I am concentrating on my real TII.

 

The S5 and S6 don't use high-comp rotors. Only the S4 and S5 N/A use high comp rotors (9.4 and 9.7), the S5 and S6 T and TT use lower comp rotors (8.9 and 9.1 is the compression if I remember the numbers correctly, but I know they're NOT high comp rotors). Also the engines do use a higher octance and/or treatment to make ridiculous horsepower (most of those cars don't run around with the same mapping on the street, they're tuned down and only use that power for certain occasions). I'm definately a fan of high comp boosted motors, but be careful not to get too happy without the proper setup to run too much boost. Good luck man

 

I agree as well, just make sure that without the proper tuning and fuel setup you could run into some problems turning up the boost on those high comp rotors. Other than that, awesome power potential.

 

I know a guy who is running an S4 N/A motor, boosted by a 60-1/T3 combo, custom exhaust manifolds, custom GM TB, and intake manifold, running 6 680 cc injectors, and a custom water to air intercooler, all in his 84 gslse, which has run a 12.3, though he can't launch hard because he keeps breaking axels , oh yeah its controlled by an SDS (simple Data systems) Standalone

 

so you wana bolt this stuff to your s4 N/A block?? ummm...

 

im just gonna say this one .... 9.4 rotors 4th gear 2300 rpms 6.5psi boost..... 2.5 inch exhuast no cats, soon as i tap the gas boost is there... until the motor ran like ****... never took it above 3500rpms....

 

No you don't.

Your project will fail (lack of knowledge) but yes, 6-10 PSI is safe as long as you pay attention to fuel and spark.

 

ok lack of knowledge????
coming from a guy with a FM TII IC???? Common I know you are a know it all just by looking at your sig. You dont have to list ever freakin detail about your car.
and just because I dont post alot doesnt mean I dont know crap.
I built my engine. I installed an E11 in my TII. I can do any mechanical work on my cars. Engine to Diff to suspension. Serisously dont say crap you dont know about, like me!
Oh I hope with all the crap youve done to your engine you spent the time to swap to the TII driveline.
AND why the hell didnt YOU just buy a TII motor instead of making all this spacer crap. JUST to have a TII NA???
YOu did make me think alittle more. I should just throw down the cash and get a J motor.
Maybe I should thank you for realising how stupid it is to turbo a NA.
sky

 

Based on your first post it appears that you know very little. The questions you asked were elementary at best. Typical newbie BS.

 

Good luck keeping boost down to 8 psi with s5 rotors!
On my streetported s5 N/A block with the stock TII turbo, boost has crept up to 13 psi in 3-4-5 gear. That's with a ported wastegate, a big FMIC, and a stock TII downpipe, I can't imagine what it would spike up to without all that!
The higher comp really puts out the power! Unfortunately, my TII fuel system wasn't enough, and I leaned up at anything over 10-11 psi, I only brought it up there a few times - I was trying to be carefull before my fuel upgrades, it only happened a few times, but it was enough to shatter my seals apart.
My engine is getting rebuilt right now, with ported 4 port end housings, and lower comp s4 N/A rotors (not much difference, but they were free!) ALso I have the wideband, and now a Walbro... should be OK!
You are going to really need to port out the wastegate, or use an S5 manifold, unless you want to drive around with your intake filter wrapped with duct tape!

 

Nothing stupid at all about turboing an N/A motor, turbo high comp engines are wicked.
Just have to be a bit more careful tuning them thats all.

 

from what ive read I agree with ya. Its not territory id like to go into due to having to buy c16 every day or just the weight on chest of "if i scew one thing up, pop goes motor"

but yeah, a turbo'd highcomp motor will make tones o power and have great power off boost

 

But w/ the stock turbo there is no "off boost" on even a low compression TII if you have even a 2.5" downpipe.

My '87 TII had 150,000 miles on it, a RB 2.5" downpipe and presilencer, TID mod and fuel upgrades ONLY (no catback etc) and it got full boost by 2,000 rpm.

It would boost full psi as fast as you could push the pedal.

How the heck is higher compression rotors going to help anything besides a bit of tip in "throttle response" feeling?

I would just rather run more boost more safely using low comp rotors- given the choice.

I understand not everyone has this choice (finances, time etc).

 

Actually Autospeed did some tests on stock ICs and the TII intercooler did quiet well in both flow rates and cooling capacity. Unfortunately they changed their site recently so non-paying users no longer have access to that article.

Try to ignore those antagonistic comments.

 

i was using less than 1/2 throttle.... 1st soon as i left a stop sign i was at 6psi... high comp turbo motors are wicked, just like that guy said before if you got the fuel system to suport it and tuning capabilties go the highest compression possible in my book...think about this one for a second.... a 9.7:1 rotary will have alot stronger exhuast gas pulses than a 8.5:1 comp. rotary... and a 9.7:1 rotary will be more friendly at part throttle and daily driving if you can keep it out of boost... theres a reason why most of the honda guys are choosing now 10:1 pistons when they go turbo? if there taking time removing perfectally good 8:1 pistons and going to 10:1 there must be a good reason rite? also if i remember correctly the rotary sees bigger gains then the piston motor due from the same thing...... im kinda lazy to explian but im sure some of you get what im saying if you know engine basics..

 

heres a cool artical i came apon thisafternoon, i know its not rotary specific, but it pertains to the convo

http://store.yahoo.com/speedupgrade/efcominchoos.html

-Jacob

 

From what i understand (as long as the engine has been rebuilt so that it is sturdy) the two problems with boosting an NA with high comp rotors (aside from the actual instalation problems) are:

1. boost creep
2. leaning out easily

so if you were to get a big turbo like a T-66 with a boosted S4 NA block and a big wastegate (making sure you keep up the fuel system) wouldnt that equate to a faster spooling large turbo with the ability to put down high hp numbers on a reliable engine? Would that be a safe setup?

 

Aaron Cake knows his ****......

 

i think so, more exhaust to spool a big *** turbo for even more power. Also you could have more streetablity, turn down the boost for stop and go daily driving and still have power

How ever i wouldnt want to use a complete n/a block, id probly go 4port block with high comp rotors.

-Jacob

 

OK I dont doubt cake knows his stuff.
I already have a TII so HP isnt the issue. I use my NA for drift session and it just doesnt have enough torque. The engine is streetported with no 5/6 ports. I spent alot on the engine and I guess Im kinda attched to it so I dont want to swap it out. Money also isnt an issue. I already have an E11 in the TII and Im really happy with it. It is super smooth. I will E11 the NA wether it has a turbo or not.
I think arrons FMIC is kinda dumb because of all the time he spent on everything else, BUT it is his car and if he isnt aiming at huge #s than I guess its cool.
Im running a spearco core.
There plain and simple. I need just alittle more power and a fatter powerband. THe NA doesnt cut it for what I want, but I like the engine too much to just bail on it.
sky

 

OH and to let you know.
Im not a newbie. The e11 tuning is being done by RETED. This is my first so I need to learn from someone.
I think RETED is the best. How would I not know my crap from kickin it with him??

 

Too easy..... (sorry Ted. )