S1sevenNZ

Been searching around and have found a guy using a TII block :

I am using stock S4 8.5:1 rotors (ground down to about 8.2:1)
Modified intake, Increasing the runner cross-sectional area from 2.32 in2 to 3.20 in2 (a lot of die grinding),
Mild street port
So peak power was 216.4 WHp at 7575 rpm and 160.2 Wlb-ft at 6100 rpm w/ 38 BTDC timing, 13.3:1 AFR,0 degree split.

http://*************.com/rotary_foru...hp/t-8550.html

It got me thinking for my next build as i already have got a balanced s4 TII rotating assembly, It run's good now so i may not go to high comp rotor's yet ...

How many people out there are using s4/5 turbo low compression rotor's in there n/a motor ? What porting ? How much power are you making and are you happy with how it run's ?

j9fd3s

iTrader: (3)

i did a 9.4 vs 9.7 engine, in a GSL-SE (the 83-85 cosmo engine for you, 6 port 13B) and the 9.7 engine felt better below 2500-3000rpm, but above that is made no noticeable difference.

the other thing, and i'm not sure how big of an effect this really is, is that lower compression = more clearance volume = more space for air/fuel = more power. the data point of course is that the racing engines stayed 9.4 compression until the R26B

S1sevenNZ

Thank's for that, So the higher comp rotor's give better response down low, Yea i just thought what i posted above seem'd pretty good, 216whp on low comp s4 turbo rotor's @ 7500rpm with a mild port, I will just stick with what ive got which will save some coin, Cheers.

rexy91

iTrader: (2)

So it is possible. That's a lot of hp for na

rexy91

iTrader: (2)

I thoght each rotor were stamped for each of model and year it should go in.