Recently Upgraded-
*Went from the Procharger 6-Rib belt setup to the Procharger 8-Rib setup
*Pullies are setup for 10lbs of boost
*AFR 225 Heads
*EPP Blower Cam
(This is just to give the heads up on what I have changed so that help may be easier)

The Problem-
*Car runs as an Untuned FI car should (surging, rich, etc...)
*Under hard Acceleration the car only builds 3-4lbs of boost each time
(This is my only Concern, car runs crappy at Idle but is expected to)

What Ive done-
*Put VHT on the belt (Help build boost up to 5lbs steadily, but no more)
*Changed out Gauges (both read the same)
*"Kinda" looked for leaks (I glanced over all the hoseclamps and none are loose)
*Checked the BOV (its working properly)
*Tightened the belt (as Bob at EPP told me to)


Does anyone know what my problem may be? Bob at EPP has been alot of help, just tired of bugging him. Being that the VHT helped a little bit, do yall think my belt may be slipping that bad? Im trying to get this figured out so that I can get my car tuned and running before the 28th.

*So to sum up my entire post, Why isnt my car building the boost it should!*

Any help will be greatly appreciated, and if I didnt describe the problem enough let me know.

Thanks, Blake

 

I would clean the VHT off the belt and pullies. you might need to replace the belt. Tighten the hell out of the belt just to see if it is slipping causing the low boost. If you installed the AFR's, you should see less boost because the heads flow alot more+ the cam change(less restriction..less boost). Change pullies to get more boost. If boost goes up then the belt isn't slipping, just your motor is more efficient. Prochargers pullies ratings are probably for stock motors. Maybe you have a vacuum leak..this would explain your bad idle and losing boost?

hope this helps

 

I've seen some guys split the aluminum plenum along the seam.

 

are you getting your boost readings from a gauge or tuning software my gauge only reads 6-7 #'s but my software reads 8.85#'s its like the gauge cant move fast enough and i cant spend to much time looking at it
if you have the plastic air box check that, mine collapsed a bit in the middle of the oval opening and i was losing a little pressure there as well

 

-Check hoses
-Welds on duct work
-Where is your boost guage reading from? I hope the TB (I had this same problem and it was the guage and the way it was hooked up...)
-Get the SDCE Tensioner if you havnt already

Did you already tune the car? Go to a tuner if you havn't...

I could get 10lbs on a 8 rib w/o slippage and NO vht... Got the SDCE and run 14-16... My car sucks at idle too...

 

Get the SDCE kit. What size blower pulley are you using?

 

Don't worry about bugging me, I'd like to see you get it up and running! Bob

 

You don't need the SDCE tensioner. 10lbs should have a 4.0 pulley and no slip at all with a 8 rib setup.

Really check all the piping,then make sure the air filter is clean and the inlet isn't sucking closed.

Then get it tuned.

 

What air filter do you have? If it is the supplied one with the kit, you may want to replace that. Although I'm sure thats not your only problem. It will help tho...

 

Well, Ive pretty much eliminated the Belt Slipping from the list. Im feeling that the BOV might be screwed up. Today I clamped off the Vaccume line to the BOV and it still did the same thing. Im clamping off the 1" Tube to the BOV tomorrow to see if that helps anything (I did the vaccume line because I had nothing big enough for the 1" hose). Any Imput on this?

What does the Procharger air filter hurt? Should I really replace it with something else, Ive read numberous times of people mensioning this (does it work and what should I use?)

Does the "Untuned" part come into play with the Low boost numbers? I mean, the car Rev's up to the normal RPM's and runs quite smooth doing so. Shouldnt it build the boost if the motor is reaching the RPMs it needs?

 

do a boost leak test. that will tell you if the problem is related to the BOV or your charge piping.

 

I picked up 2psi with the bigger filter EPP sells. Call Bob, he will hook you up. But you need to find the other part of the problem so you only have to make one order from EPP

 

Thanks for the help. Im Hoping this weekend I will be able to find my problem, going to test anything and everything until I come up with something! lol. Im going to give Bob a call on that Filter once I get the problem figured out (thanks ChevyChad). If yall think of anything else I can check or should check be sure to post up and let me know. I will keep yall posted on what I figure out.

Thanks again Fella's
Blake

 

Make sure there is a boost signal going to the BOV.If it is vacuum only it can open under boost.Also check the piping real good,expecially the clamps.

 

Make sure you do a boost leak test. Don't just "look" at the clamps, pressurize the charge piping and listen for leaks. You would be AMAZED at how many leaks you'll find even though a clamp may "look" tight.

 

How exactly do you do a boost leak test?

 

^^

Word...Need to know how thats done. Im going to go over everything and hit up that boost test if I can get some info on how its done.

Slowhawk, Only thing going to my BOV is a Vaccume line. By boost signal, what are you referring to?

 

Just another update...

Put the car on a Rack tonight and Marked EVERYTHING. Nothing is Slipping...BOV Is working properly...Air Filter IS NOT collapsed...I just dont know what is the problem. Anymore input would be appreciated. Need more ideas on what to check!

*For the record, Im running the 4.25 Pullie (will this make the boost?)

Thanks fella's,
Blake

 

to do a boost leak test you need to pressurize your intake piping. Pull the air filter off the compressor housing. you can use the silicone coupler that attaches your intake to the blower. you then need to get a PVC cap the same size as your coupler, usually home depot has the right sizes, and then drill a hole into the PVC cap and install a tire valve or schrader valve. then you attach the cap & silicone coupler from your intake to the compressor inlet of the blower and with an air compressor you pressurize the piping and listen for leaks.

this basically simulates the compressor pumping air into the intake track but w/o the motor spinning. watch your boost gauge and don't go higher 15psi max. you'll be AMAZED at the amount of leaks you find.

its kind of hard to explain because I'm half drunk and its late but if you do a google search or something it will come up. Its a pretty common thing to do on a FI car. you should get used to it because ALOT of boost related issues can be diagnosed this way. On my other car which has a turbo I boost leak test it everytime before I race it.

 

Are the pullies rated for a stock LS1 or one with your heads and cam?
If they produce 10psi on a stock motor, they won't make that on yours. Change pullies to a 15-18psi and see if the actual boost reading goes up or does it still reading 3-4psi?