First, let me start by saying my truck is running great, no problems, no issues and a couple weeks ago ran a 12.66@105 at the track.

However, for the last couple months, i've noticed that i'm not making the amount of boost i should be making. Under WOT, i am only seeing 7.5 to 8 psi MAX. Last year i was seeing 9 to 9.5 psi. I'm using the 2.8 pulley with a Gatorback 110.5" belt. There is absolutley NO belt dust anywhere in my engine bay, so i know my belt is not slipping. I havn't pinned my crank pulley yet, however i strongly feel that it is not the issue. My vacuum always reads perfect so i know there are no leaks, and i regularly check my Radix intake and header bolts for proper torque. I just can't seem to find any reason why im not making the boost i should be. TimB was at my house a week or so ago and he has the 2.9 or 3.0 pulley, i can't remember, but he is making more boost than i am. He is around 9 or 10 psi. what do you guys think i should look at here? i'm kinda stumped.

 

willing to bet it is the issue......if you see it decreasing and NOTHING has changed....that is the problem.

 

...sure your gauge is accurate?

 

that I do not know? how can you test if it is accurate or not? I mean my vacuum reads fine, the same as everyone elses so i don'w know?

my crank pin kit is already on order from magnuson, they are suppose to ship it today.

 

I didn't think I had this issue either until I went to remove the crank pulley....

Did you happen to add the headers, cats, and exhaust work since last year? Anything done to open the exhaust will make the setup less restrictive which will show less boost pressure. Thats a good thing as boost creates heat. In that case, you are still processing at least the same CFM of air, but not generating as much heat.

 

good point

 

I'm guessing my balancer is spinning on the crank as well(or has), especially after I discovered a less than fingertight crank damper bolt some time ago. My setup is essentially a stock Radix system, although the owner does suffer from "heavy right foot syndrome"

 

I'm sure BigTex hit it right but I'll just throw this out there...
I've know guys to have similar issues without such a drastic result from a filthy and semi clogged air filter... not saying that's it but if you haven't checked recently it may help.

like I said this can't be the whole issue but may attribute some... just another variable on top of what has already been mentioned.