i installed my procharger i wanted to see 10#'s at the intake, i got a d1sc with a 4.13" pulley, ati said this pulley is offered on the GTO kits, i'm only seeing 5-6#'s of boost max in gears around 5k rpms, i've double checked my tubing and clamps everything looks good, i have a 3.40" pulley that came with it and i'm wondering if i should try that or if it'll give me too much boost, btw this is on a 305 with ported accel base/runners, other specs in sig.

 

If it's still the stock engine, I would leave the boost at 6psi.

 

10 lbs wont be to bad. Alot of my buddies run 10 lbs on stock 5.0 mustangs without a problem.

 

Have you had your car dynod yet?

Where in CT are you?

 

What rib belt do you use? I have a 3.25 or 3.5" I could sell you cheap. That pulley was supposed to make 9lbs on a 350 with my P1SC. I runt a 2.75 now.

 

no i havent dyno'ed it yet, i want to, my engine is not stock, although it doesnt have forged internals, i'm located in vernon

 

86Z, oh yeah before I forget. You have to still do emissions in your car? I'm moving back to CT this summer and don't want to have to register my car in VT when I'm living in CT.

 

i'm using an 8 rib belt i believe, yes still have to go through emissions, i failed with the carb setup, now i got the tpi and supercharger

 

Um, if that same pulley ratio is supposed to make 10# on a GTO and you’re only getting 6 on your 305 something is bigtime wrong.

I’d start with looking for plumbing issues and tuning problems (yes, a proper tune will make more boost).

 

i'm not sure what that pulley is supposed to make on a gto

 

I read in another post the 4.0" is for 10lbs on a stock 305 and they rated it at 6k rpms. HERE

If that is the case you have ported intake and other mods so you should see slightly less boost.

Willie documented he only got 8 lbs @ 5,200 rpm using the 4.0" pulley. The 3.70" got him 10 lbs. HERE

From that post I would very careful with the 3.4" if you try it out as:

 

86Z, go with my 3.5" It may even be a 3.75"...I'd have to check.

 

hey AC, i have a 3.4" pulley, will the p1sc pullies fit the d1sc? if so double check i've been looking for a 3.70" pulley to try, if you have one in that area send me a pm with the details/price

 

86Z, well, I have a spare 4.0 and my 3.7 is on my blower. Yes as far as I know they are interchangable, NE1 chime in if they aren't. If I see the size your looking for in my travels I'll drop you a PM.

 

Yes, the pulleys are interchangable. The P1SC and the D1SC are the exact same blower other than having different impellers. When sizing the pulleys for boost, every .1" of the pulley size is equal to about 1 psi of boost. For example, if you're getting 6 psi with a 4.1", then you'd probably see 12 psi with a 3.5".

 

AC what kind of engine are you running how much boost are you making with the 3.7" pulley?

 

86Z, I haven't ran the new 383 w/ a 3.7" or the 383 at all for that matter. With a stock L98 (350) and 4" blower pulley and 8" crank pulley I was just shy of 8lbs at 4600'ish....Whenever I was above 5k I typically wasn't looking at my A-pillar where my boost guage is (I've sinced moved it into my center guage cluster).