The subject of boosting 9.4 and 9.7 rotors is just crazy! Crazy that some are still against it. What is the differant between pushing 20psi with 8.4 rotor and pushing 15psi on 9.7 rotors. It is the effective compression ratio that one must understand. Rotary internals will handle lots of pressure, it is the tuning that kills these things and the lack of understanding what causes detination.

S5 and S6 turbo rotors are 9.0, that is .4 less then s4 non/turbo rotors. This is nothing!.

I was boosting 20psi with 9.4 rotors, now pushing the same amount of boost with 8.5 rotors. This car "feels" slow, throttle response is not like the 9.4 rotors. I have to push the turbo and intercooler harder now to make the same power compared to the n/a rotors. Next motor will be 9.4 rotors. One of the reasons for using the 8.5 rotors in this motor was becasue the bad information I got from others always saying "you can't boost n/a rotors". Now I know better. Do a search, you will find a few older guys using n/a rotors.

This guys is not building a all out race car, just something with a little more power. <span style='font-size:14pt;line-height:100%'>If done right</span>, it will last a very long time.

chuck

 

What if I just put n/a rotors in my TII block? Wouldn't that be the same, w/o having to do all the other fabbing involved?

 

It has been over a year since this post. There is a lot more input now that there was then. I have a 91 Turbo N/A (9.7 rotors) running 10lbs. It is impresive! I am using EMS, however my tranny, driveshaft and differencial are still N/A. I DO NOT abuse it on launching! It has been running for 1 yr now.

I WILL NOT run pass 10lbs on pump gas (93). Anything more than 15 lbs would require a higher octane.

Total investment (including rebuilt , turbo & ems) $2400.



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