dash wrote:Very nice setup! Looks strong..... must be a rush driving it.
what source for the 20G ?
Does that 20 have a surge ported cover.... or would it help ?
Funny you should ask dash!
The turbo is actually an old Greddy item. Had an 8cm 3-bolt turbine housing on it before I swapped it to a Kinugawa 10cm T3 to work with the Chinafold.
Below is a more recent chart with a Kinugawa surge ported compressor housing installed. I've got boost spiking off 25psi after which point it tapers to 20psi. No worries about surge at WOT any more, though it still surges a teeny bit at part throttle (I'm thinking it may actually be prerotation.)
Same setup as the previous chart save for the comp hsg:
Notice the lower power output and much, much slower spool.
Couple things going on here I think: The surge ported housing is less efficient than a non-ported housing because surge ports are just recirculated boost leaks and I've still got the same old Greddy compressor wheel. A modern, more efficient compressor wheel would probably work better with the ported housing, improving spool and power.
This setup is slower than the previous setup, but if you use your gears right that 25psi spike feels awesome. I've got the short rear end too. 1st gear is actually useful for getting you up into the sweetspot in 2nd with this setup. My 2nd to 3rd shift puts me at ~5000rpm so it works great on the roadcourse.
I might try and go back to the non-ported housing with some guide vanes in the intake pipe to try and stop what I now suspect is prerotaion, but I think I've about had it with the old MHI tech. Time for a BW Airwerks or something, fewer compromises, better powerband...