MIGHTYMOUSE

iTrader: (59)

last i checked my backpressure was 25psi at 17psi boost

keep in mind my boost figures are a bit higher than some b/c of the stock intake

at 23some psi boost i figure my backpressure is slightly worse on the ratio at around 35

my timing at that time was 13* advance

between the small(er) cubes and the stock intake i figure i am squeezing a little more out of the turbo because i am closer to peak efficency of the unit re: pressure ratio

z28boysteve

iTrader: (9)

wow I never realized that the backpressure could still be so well within the 2:1 ratio like that. Looks like I should really give the PT88 a good, fair chance. Hopefully it doesn't take me alot more to make the boost you did david considering I have a single plane intake and LS3 heads and a rather large turbo cam.

roostingthe65

How much boost have you put in your engine with the ls3 heads? I have read that 15 is like max because the decks are thin, thanks

z28boysteve

iTrader: (9)

It's not really boost, it's more like... power, the more cylinder pressure you make the more likely it is to lift a head, these problems are compounded by excessive ign. timing or inadequit fuel (detonantion) or just by having too much boost or timing, there is no line where that lies, Im sure some can push 20PSI if you run conservative timing like 18 and some race fuel as long as you aren't making crazy HP. HP comes from torque, and torque is a direct function of cylinder pressure. A safe guess from me would be do whatever you want as long as you have no detonation if you are below 700 RWHP, up to 800 or more you will probably be doing alot of maintnance