Boost help part 2

**ElAlacran2010** · 01-23-2011

so i checked all my vacuum lines.did find a leak and fixed it. replaced map, and bbv. but still i boost at wot all but one square. it flutters sometimes from all but one square to full boost. and sometimes two squares less at wot. one thing i noticed is that i dont feel any vacuum from the boost bypass solenoid to the actual bbv. the only thing i know i need to replace for sure is the supercharger coupler. my question is could the worn coupler cause a slight change in boost. or is it the boost bypass solenoid. or a combination of both. if anyone could help i would really appreciate it. LOW BOOST SUCKS ASS!

**TheYanz** · 04-26-2012

Hey dude. Did u take the BBV out of the car & carefully push the metal thing in & hold ur finger tightly over BOTH ports of the BBV? Even on 1 of the few BBVs I have it passed this test yet still had some sort of internal tear/ vacuum leak inside the actual thing which led to high LTFTs (indicative of a vacuum leak) with only that specfic BBV. I was def having low Boost issues at the time as well. On the BBVs there's this orange like thin rubberized membrane crap that can tear & cause issues. I would also advise AGAINST getting a replacement one from ZZP. I bought one from them & it's all retarded with the top port located in a fashion where I have to use a longer vacuum tube for the top port. I'm not saying it's ur BBV but as soon as I saw u mention that & vacuum issues relating to that I figured I'd make a comment.

What pulley? 3.4 I assume? Yeah it should fill up.

Worn coupler may cause such an issue. IIRC it should def affect when the boost kicks in/ boost/ throttle response feel type stuff more but not sure if it'd affect actual Boost PSI since the shaft & blades will still spin. U'll def get NOISE & boost response feel issues.

Not sure if ur supposed to feel vacuum where u described at idle. Maybe at WOT there's vacuum there & the BBS deals with Boost dump type stuff. U mean u checked it with the car running, right?

Also look over everything for normal maintenence like belts, make sure all the other pulleys spin freely, check the SC tensioner pulley, & make absolutely sure ur vacuum lines are rigged up poorly. Use zip ties everywhere. U can get 200 for sh*t like $5-$10.

**TheYanz** · 04-26-2012

Another thing I forgot to mention... Flow mods. I was reading up on one of the posts. Everyone was listing their max Boost PSI. I was curious 'cause I thought I had an issue with a 3.4". However I have MASSIVE flow mods w/ the SD Headers, rockers, full 2.5" exhaust, big res, big tips, etc, etc. I only make an efficient 7-8 lbs of Boost. Some people with less flow will see higher numbers. Higher Boost doesn't always mean better results. Ppl will tell u Boost = restriction in some cases. Hope some of this helps.