belt slippage

[Fidstang]

How do I know if my belt is slipping?
I have a 91 5.0 with Edelbrock RPM heads, Edelbrock RPM II intake and a TFS stage one camshaft. I had the 2.93" pulley on and was only getting 5psi of boost reading on my gauge.
I have recently gone to a 2.75" pulley and see no increase in boost.
Why am I only seeing 5psi even while going to a 11psi pulley?

[speedytang]

2.93" to a 2.75" that rpm increase would only be a 1.5psi. You will be replacing the internal belt if you spin it much more. Belt slipping you will see either the pulley looking polished or black dust.

[Fidstang]

I understand about the pulley size and the maximum bearing rpm speeds. I have a rebuild kit coming soon with ceramic bearings from SKD engineering.
I was not aware that the increase in speed will cause the belt to snap.
I've read that the 2.75" pulley is the smallest you should go.

Why am I not seeing the boost register on my gauge?
With a 10psi pulley I should at least see 8-9psi.
I have a better head, intake and cam combo but I've seen better induction packages making more boost with the same kit.
What could be causing this?
I have tightened the belt as tight as the idler will go on the bracket.
Where should the line from the vac/boost gauge be ran from?
I currently have it running right after the EGR spacer on the upper plenum.

[speedytang]

Well the heads and everything else you have done has decreased the boost number you see but does not mean your not building more power. PSI-Boost is a reference of back pressure. And like I said earlier your not going to see a double increase in PSI going down that pulley size. People see 9psi with your 2.93" pulley because the car is stock and have restrictive parts. It is a science not just smaller pulley gives more boost.

[DSBLK93GT]

Put the 2.93 pulley back on it! You cannot get enough belt wrap with the smaller pulley, it's hard enough with the 2.93. If you want more boost go with a larger crank pulley instead from ASP.

For comparison on my 93 GT with dead stock motor I saw 7psi with the 2.93 pulley. After GT40 heads and Corba intake it stayed the same but I also went to a larger MAF and better inlet piping.

ALSO, my cousin's 93 LX with a 14lb ProCharger kit only saw 8lbs with a 8.5:1331 and free flowing heads/intake.

5lbs seems normal to me, but what do you have for an intake pipe? If you want some more boost get a Powerpipe form AFM or a Boostmaster from UPR. I'd do that over a pulley for sure if you want any life out of the belt. ALSO..make sure you have a bypass! A Powerdyne will NOT take compressor surge very well. Think of it as the stress on a timing belt in a car if you go from 4th gear to 1st gear!!!