What's up guys, I'm having an issue after swapping the blower pulley on a LS1 Vortec setup. I was running the base kit 6psi pulley but recently swapped over to a 9psi pulley and lost all boost. My question, does the the 9# pulley require a different tensioner as opposed to the 6# ? I've swapped the appropriate belt to accomodate the 9# pulley. I thought at first that my belt was slipping but there aren't any signs of belt debri anywhere, I've tried running it with no bypass valve just incase it was leaking, swapped boost gauges. I haven't done a boost leak test but I have went over every coupler checking for severs or loose clamps, swapped all clamps to T-bolt clamps. It's a very basic non-intercooler setup. I've done a bunch of blower installs on various cars but this one's got me stummped. I was seeing boost on the 6# pulley but nothing on this 9#. Any insight would be greatly appreciated, thanks guys!

 

Take off the intake piping and run it for a minute or two to see if that helps. That was the problem on my T-Trim. If that fixes it, you will need a larger intake pipe.

 

I'll give that a shot, Thanks. Do you think a leaking intake manifold gasket could have such a big impact on the boost? I mean I can't even get it boost, not a single pound.

 

Ny, Lets go from here....

So all that was changed was the blower pulley and the belt? Nothing else was touched?

How does the car run compared to how it did on the 6lb pulley?

Are you running an FMU? If you are, are you seeing rising fuel pressure when you should be in boost?

-Scott.

 

i have the same problem have checked bov, piping, innercooler, pulley kew way match up i was thinking my belt is slipping i have a smaller head pulley now and am using the same belt from the 3.33 not sure the belt looks fine and no noise of squeal did u find anything out? mine seems like the same problem but the car runs good just no boost shown on guage

 

lt1zpwr,

What is your blower pulley diameter now? A shorter belt might be in order if it was not changed along with the smaller pulley.

Is the gauge indicating correct vacuum, but just going to zero when under full load?

How did you verify the BPV operation? Should be open and venting at idle, closed under load......are you running a bypass or blowoff valve?

-Scott.

 

i believe the 2.95 and not i havent changed the belt but did a new tensioner with the new pulley. yea the gauge reads vac ad normal at idle and at load it decreases and at wot only goes to zero maybe 1-2 psi
i have a bov i checked it by bypassing the whole fmic and bov by making the pipe go right from unit outlet to the t/b and still no change

 

Haven't checked fuel pressure, but NOTHING has changed aside from pulley and smaller belt to accomodate the pulley. I'm stumped.

 

I've heard of some people putting PCV caps (Home Depot plumbing section) on the system and installing a schrader valve. This allows you to check the system for leaks with a vacuum gauge. +1 for removing the inlet but you still should be seeing more than 2psi.

 

changed the belt and still seeing 3 psi, i am positive i have no leaks i checked the inlet that was fine and then i hooked a pipe from the outlet coupler to the t/b elbow and still no change im stumped as well
do u think maybe something broke inside while i was bolting on the pulley?
please help

 

maybe check the gauge at this point.

 

gauge is fine also hooked up another gauge samething