I've heard a stock L67 should hit 7.5 lb of boost. At what RPM (during WOT) does this typically occur?

Lately my car has been feeling slower than normal, and it runs ~4 PSI at WOT until it'* past about 5k RPM, but it still never gets to 7.5 psi, maybe 6.5 at best.

I remember at one time I could get the needle right at the base of the orange bar without too much effort. Any explanation for this?

this is DANTHURS area.. not sure if he has been on here... try PMing him

You may want to check out the supercharger belt and tensioner, belt slip is one of the many things that could cause the issue you are describing. Does the supercharger sound like it always did?

air density and humidity can effect this greatly. You will also notice less boost if you are getting KR. Summertime is going to be slightly lower boost than winter as well. Again..density.

That seems to be what it is. When I first noticed it, it was in the mid 90'* and humid, pretty typical in mid summer here.

When I got on it this morning (temps were back in the 70'*) it was right where it should be at WOT, and even jumped into the orange on the upshift. Didn't think temp/humidity would have that much an effect, but it does.

I've also noticed at higher elevations (took couple trips to Colorado this summer), it would only reach 5 psi on a good day, I'm guessing same thing. Car felt slower than molasses.

Check the boost control actuator and boost control solenoid. Make sure the arm that controls the betterfly valve is travelling to full extension. There are write ups on the forum you can search for, but let me know if you can't find them.

When the car is not running, the arm on the boost control actuator will be fully extended. When you start the car, the arm "pulls up" into the actuator. Under WOT the arm will again extend (to the position it is in when the car is not running) to open the */C gate valve. In other words, when the arm is retracted into the actuator you have no boost. When the arm is extended out of the actuator you have full boost.

One test you might want to try is to remove and plug the vacuum lines gong in to and out of the actuator (this will mean the actuator will not move from the fully extended position it is in when the car is not running) and take the car for a drive. This will give you full boost at all times, regardless of throttle position. If you notice a difference in boost, your problem is a bad bcs or bca. Do not drive the car like this for more than a quick test, or the gods of engine damage will pay you a visit.

Thanks for the tip! I will try this and report back if things don't appear to be working correctly.

Also, if you notice that the little black foot isn't going all the way down when you give it a good rev, you may need to grease the rod that goes into the supercharger and turns the boost flappamajiggy.

I hit mine from the outside with some PB Blaster and let it sit for an hour, then hit it again and wiggled it around a bit. It loosened right up and has been fine ever since.