Whats the difference between boost from a turbo and from a S/C? If any, besides the time it is delivered..

Also, ive been holding up on the 3.0 pulley installation because im afraid of damaging the engine since everyone says to stay under 10 #'s. Right now im at 7-7.5 with the 3.40, do you guys think ill be fine or just stick to the 3.40?

4.8, mods: mp112, 4.10's, Lt's, custom 3" Y, truetrac, 3k stall, and tune

 

Boost psi is just a measurement of restriction. It doesn't matter what the source is.

Assuming a stock 4.8l, the compression is around 9.5:1 so you can easily run 10lbs with the right tune. What kind of psi do 4.8's with long tubes see with a 3.0"? Might be better to try a 3.20" and see where you land.

Rick

 

well it was at 8lb's before the LT's and rear end so i thought it'd drop at least 2lb's so thats why i got the 3.0

 

anyone else?

 

Do it if you or your tuner has an idea of what they're doing. I ran 12lbs on my old 5.3. Buddy has a procharged Silvy w/220k miles and 135k of them are w/ blower at 10-12 psi on pump gas.

 

A procharger can usually get away with a little more boost than a turbo, as it builds boost based on RPM, and in the upper RPM range detonation is less likely than at peak tq.

 

under 10#, what fun is that? i'd say up to 12# is safe w/ good tuning

 

so dont have to worry about the bottom end giving out or anything?

 

you wont have a problem with the bottom end giving out, like most have said you'd be fine with the 3.0" pulley with the correct tuning. only thing is belt might slip a since the pulley is smaller and belt probably stretched some.

 

Swap the 3.0 pulley on there, and get the tune nailed. You'll be happy with the results. Keep an eye on your IAT's, and watch out for KR. Everything else is gravy!

The tune is gonna be more important than ever.