I was out logging A/F on a tune, and on my 2nd run I pegged the meter(10.0:1). My theory is that the belt started slipping, causing less air with the same amount of fuel. Has anyone else noticed belt slippage while logging, did your meter peg? My first run was pretty much straight accross. Here is a graph of the run, I got out of it after noticing the gauge.

 

Could be a sign of belt slippage. Your power and torque should also have fallen off. Have you thought about a crossbrace to increase belt wrap? We saw similar results on an 03 Cobra and 01 L today on the Dyno that both had belt slippage.

Ron

 

Are you noticing belt slippage on stock upper pulleys, or smaller ones?

 

Folks....is there any other way to get rid of the belt slippage other than the crossbrace? I was thinking of increasing the pulley size for the 2 idler pulleys but I am not sure if that will work.....

 

I have the stock upper pulley, and just added a metco idler bracket (90mm) trying to cure the slippage. I'm thinking about going from a 4lb to a 8lb lower, and throwing a Cobra upper on. Should be plenty of surface area then.

 

this has worked for me.It is the new metco style idler with a 90mm pulley on it along with another 90mm pulley on the opposite side in the stock location between the s/c and the tensioner. when i added my 2.8 upper i lost boost in the upper rpms now it just keeps building all the way to redline and 16lbs
I still think i might buy a 100mm pulley to put on the aux idler to make a little more belt wrap.