Paxton loss of boost?

[cbrown9064]

Finally got my Novi 2k project done! Did some driving last weekend to dial in the MAF transfer curve and thought I hit 10psi on one pull. I have 3.5" blower pulley and a tock crank. 10psi was what I was shooting for.

Working on the tune last weekend and did a couple highway pulls. Come out to garage next day, back car out, oil on ground. I jacked it up and there was light oil down the right side of the undercarriage and some on the crank pulley.. I had one A/C line off being fabbed up, and guessed that there was parasitic drag on the ac compressor from the clutch (compressor turned over easy by hand) and it puked its oil out a high rpm.

Fast forward to tonight, got new ac line on, different 4" intake and still only seeing 5-6 psi. No belt dust. However, when I blip the throttle there is a slight "squawking" noise from the blower. Wondering if the belt got oil on it? The boost does not drop off, just seems to not get over 5psi.

So, two questions. 1- what boost should I be making? 2-if belt is slipping, can I clean it somehow (belt dressing?) or just get a new one? It is a real pain to change belts...

 

[fulanititoo8198]

I would do a boost leak test first.

 

[cbrown9064]

Didn't think of that...will do!

 

[cbrown9064]

UPDATE: More investigation today...oil leaking at the pan from where the drain back fitting goes in. It was getting blown by the BOV back across the AC pulley and RH underside of car. Made a Sharpie mark on the crank pulley and belt. Cranked car up and shut off immediately. Not even close to the same spot.

Also did highway pull and I get 5psi at 3800 RPM and it is still 5psi at 6800rpm. Major slip. Going to get that oil leak addressed and then see if the belt needs replacing or not. Figure I am going to clean up the pulleys with engine cleaner and if the belt suffers, then I will replace. But fix oil leak and clean first, then worry about the belt.

 

[coposrv]

Sounds like you have it figured out. As for the belt I know how much of a pain it is but removing it cleaning everything pulleys/idlers etc. and replacing it seems the only way to make 100% sure you won't have lingering affects. Best of luck.

 

[01yellercobra]

You're belt won't line back up for a while. Think about how long the belt is.

For the loss of boost check your BOV. A 5psi loss is pretty hefty. To lose that much boost to belt slip you'd hear it.

 

[cbrown9064]

You're belt won't line back up for a while. Think about how long the belt is.

For the loss of boost check your BOV. A 5psi loss is pretty hefty. To lose that much boost to belt slip you'd hear it.

I did think of this...What do I "check" for? It is a Tial 50mm. Crack it open and see what spring it has?

 

[01yellercobra]

It won't be the spring. It'll be damage to the valve itself or a damaged seal. The design is so that boost pushes on the back side to help keep it closed. If the diaphragm is damaged it won't seal.