Stock Boost on 3800 SC - GM Performance Tuning

Sublime22 · #1 (**permalink**) 05-30-2007, 07:38 PM

Sorry. Does anyone know what the stock PSI Boost on the 3800 SC for 04 w/compG package?

I have heard 5PSI and 8PSI.

What is a good size pully to keep the car streetable, but weekend only car.

If you did not know by reading this, I only have experience with older motors and all V8, since I had a baby I had to get something to satisfy my need for power with 4 doors, so I know nothing about fuel injected or boosted motors.

Any help I can get would be much appreicated.

Chuck3300 · #2 (**permalink**) 06-17-2007, 11:27 PM

3.4 pulley if you do the supporting mods, 3 inch downpipe, 3 or 2.5 inch cat back system, intake box, roller rockers will let you go even lower than 3.4 inch pulley.

Sublime22 · #3 (**permalink**) 06-18-2007, 01:55 PM

Thanks, that gives me a little bit to go on going forward and I appreciate that, but right now, I am looking for the stock PSI Levels, do you happen to know what it is?

Mike

Chuck3300 · #4 (**permalink**) 06-21-2007, 09:07 PM

stock boost levels depend on temp and humidity. Higher temps=lower lower boost because less dense air to compress. Stock should be 7.5 psi according to GM.

summer you might see from 7-8.5psi

winter around freezing up to 10.5.

91parkave · #5 (**permalink**) 06-22-2007, 12:30 AM

id rate the gen5 eaton supercharger a little higher than that with a 3.4 you should be a 10-12 the gen 5 is the most efficent roots blower out there for the moment

phat_ridegt · #6 (**permalink**) 07-09-2007, 01:20 AM

older thread, but with your mods, you should be running a stock 3.8 pulley. im sure you have 8-10* kr right now. your 04 probably runs about 8-10 psi stock. if you havent swapped pullies yet, dont. if you have, stay out of the boost until you get some supporting mods. i have had my car for 4-5 years now, and have been through all the trials and tribulations with them.

your downpipe isnt too bad stock, but a good 3" unit will help out a bunch, at least a front power log ( http://www.zzperformance.com/grand_p...=208&catid=110 ), if not a set of headers, a fwi, not the fuel injection kit from k&n (sell it on ebay), some 104 plugs not 103's. the hotter the plug you can run without KR the more power you will make. and a 180 t-stat as well.

even with the p-log (headers would be best), a zzp pcm, 180 t-stat, 104's and a fwi, you should probably only run a 3.5 pulley at the smallest. with a scanner you dont know what's going on, and these motors dont like to detonate very long before they chew through pistons :)

for more reference check out my mod list at zzp's site:
http://www.zzperformance.com/grand_p...ws1.php?id=142

also check out clubgp.com too.

btw i see your sig says you are going to get a cat-back. dont do it for performance. you wont notice ANY difference adding a cat-back exhaust to the car. it is pretty free flowing as it is. you can take the stock catback to 300whp (mid-high 12's). I would spend that money on some rockers or a cam.