Last thing, how much hp gain do you think ill see going from whatever im running at now to 20-21 psi?

 

on a ko3 would only be a few more hp, but if you cool that, it will be a few more on top of that.

 

ok i think i can help with this thread......with my mods i hit 21 peak and steady at 19psi....this was by using the yellow spring with a metal shim(washer) boost machine is around 5.5 turns and onset is 1.5 turns. i had the same problem as the other 225s above stated. now i'm a happy camper!!! also noticed that when i ran a front feed to the air box i got a little power increase. i have the TTDA but i took the endcap off with the two rings. so its basicallty a VTDA but bigger...and i have the hose(front feed) aiming right into it.