Only making 3psi on a 5.5psi pulley. Hulp!

[SirThomas88]

I've been running a 5.5psi pulley fine for some time. Then as winter was ending I noticed that my boost gauge only reads 3psi throughout the RPMS until 5k RPM where it slowly rises to 5 or 6psi by redline.

-I replaced the belt (was a Dayco 88.5") with a Drive Rite 87.8" belt. No change in boost.
-I checked the tensioner, it is fine.
-I checked boost gauge and boost line for leak or kink. None found.
-I checked the actuator, both applying vacuum (hold perfectly) and bypassing the actuator even. No change in boost.
-I checked the radiator cap for bubbles. Ran the car for 10 mins until the thermostat opened, didn't see a single bubble.
-Checked intake for blow by. Looked pretty clean, surprisingly..

Supercharger sounds fine and car feels fine. If it wasn't for the fact that my boost gauge is reading 3psi and that my car feels like it's at 3psi, I wouldn't think anything was wrong.

It's DEFINITELY a 5.5psi pulley. Does anyone have ANY idea what else could be causing this? Blown engine? Supercharger needs a rebuild? I'm stumped. Help would be much appreciated.

[mig0s]

Well just install a 8psi pulley lol. Did you checked your boost gauges' wirings?

[1gSE]

did it just start happening?

[SirThomas88]

I checked the boost gauge wiring yes and vacuum tested it with my mouth (lol) and it held vacuum fine. I checked for kinks in the line, and I can tell there aren't any because when I tap the throttle the Boost Gauge Needle responds amazingly fast. I even switched my boost gauge with another one to see if it was reading incorrectly.

It seemed to start happening all of a sudden at the end of winter, so like a few weeks ago. But I'm not always paying attention to my boost gauge and not always going full throttle, so it's possible the problem might have started earlier and I just didn't notice. Still, from 5.5 to 3 is a BIG drop... I have made no changes to the car recently except an oil change.

Haha, I may just put on my 7psi pulley but I feel it's important to figure this out first.

[1gSE]

hhmmm thats a tough one. I know you'll show lower boost levels when you open up the exhaust side but this is odd since its climbing to what its supposed to be. I googled it and most of the stuff it came up with were vacuum leaks and the actuator. I'd get some card cleaner and start spraying around to find a leak

[SirThomas88]

I googled it and most of the stuff it came up with were vacuum leaks and the actuator. I'd get some card cleaner and start spraying around to find a leak

Vacuum leaks, huh? That's weird. I wouldn't think any of the vacuum lines would affect boost. I have most of my vacuum lines disconnected for favor of the insta-boost hook up.

I'll take a look into vacuum lines and see if something like that could be causing an issue. Thanks for the suggestion! By "card" I assume you meant "carb" lol. I was really confused there for a second.

[1gSE]

hahah yeah carb. its been a long night

[Dawgz]

restriction in exhaust will also cause this.

[1gSE]

But that should cause it read higher than what it is. Opening up the exhaust would show lower readings. SIrThomas, this is worth taking a look at. If anyone knows superchargers, it's Kenne Bell

http://www.kennebell.net/techinfo/gener ... dCures.pdf

[ToyoSolV6]

could be just be your charger man, the snout can be bad, a member here had a problem a while back with the s/c not holding boost. Does the supercharger have any weird noises, no grinding noises. Does it whine at a normal rpm or does it only whine way up top of the revs?

[SirThomas88]

I'll definitely check out that site, thanks 1gSE.

ToyoSol, If the supercharger is making any weird noises, I haven't noticed. It starts to whine quietly around 0 PSI in first gear, and sounds good and loud at higher PSI after that. At low RPMs (2k) it's not making much boost and is quieter. But at higher RPMs it definitely gets louder especially around 4-5k when it reaches around 4 PSI boost, and of course is loudest around redline when it reaches 5 PSI.

I haven't noticed any grinding sounds or other concerning sounds, but will listen in more carefully the next time im in my car to confirm this. Everything sounds good to my ears, then again, this IS the first and only supercharged car I own.

I'm considering maybe that my methanol injection ate away at my rotors, or that I have blown an intake gasket. Not sure how likely either of those possibilities are, considering how this issue seemed to come about quite suddenly at the end of winter. Or perhaps it started happening earlier and I wasn't watching my boost gauge closely enough.

[SirThomas88]

Tonight perhaps I will take a video of me boosting full throttle so people can see how my boost gradually raises from 3 PSI to 5 PSI. And in the video you'll be able to see my AFR gauge, as well as my SAFC readings.

[ToyoSolV6]

^yeah post the vid man.