i'm using a 4.2" (7psi on AP1) pulley but only getting 6lbs of boost. also when fitted with FMIC kit that takes a more efficient route than the UR kit (through the headlight hole as opposed to U-bend from stock blower position) with a rather small intercooler (intended for up to 12psi/400whp) i was only getting 3psi. it was verified that there were no leaks by my tuner, who did a good bit of work to fix the one small leak in the BOV flange. is it likely that my blower needs a rebuild? i think it has somewhere around 30k miles on it.

 

are you running a new belt with proper tension ?

 

it is a new gatorback that was properly tensioned. we had to take it off a few times and put it back on for various reasons. could this have caused the belt to stretch more than it really should be? so i'd need to get a new belt?

 

Sounds like a big drop in pressure. UR does not claim this much drop with their FMIC.

If the only thing you have changed from the original setup was adding the FMIC, I would have to say that it is your problem. Blower rebuilding may not solve drop in pressure. Double check everything and what type of filteration do you have, the stock Comptech Icebox?

 

i currently just have the plain comptech pipe that goes from the blower to the throttle body. i put a breather on my air pump instead of using the hose that goes from the air pump to the intake. i also no longer have a blowoff valve. so the BOV flange and the opening for that air pump hose are currently capped off and tightened with clamps. i currently have the HKS mega power flow (mushroom style) filter and it's just sitting on the front of the blower (bad location for taking in heat) because i previously had the fmic piping where the comptech icebox puts the filter. sometime soon i'm going to get a 3" pipe and relocate the filter to a cooler location. right now i'm getting max 6psi. i'm no longer running the inefficient fmic setup.

oh yea, my clutch has been slipping on every shift and whenever i gun it above 5k rpm. i'm sure that wouldn't affect boost, but i thought i'd put that out there for those who know more than i do.

thanks for the feedback thus far!

 

Tighten the crap out of the belt!! I use to use a breaker bar for leverage against the pulley to get it tight enough.

 

ok i'll try that next!

 

Caution with this method!!

The tighter you get, the more stress on the tensioner. It may start to click.

20 ft/lbs is all that is neccessary.

 

yea i'll check it again for the proper (.5" - .625") slack that it should have when 20lb-ft of force is applied to the driver's side of the belt.

 

Did you get anywhere with this ?