Hmmm, I would think that if it was just belt slippage, you wouldn't be making the boost you're claiming.

That said, absolute dyno numbers are full of all sorts of errors. Comparing 2 cars on different dynos under different conditions can have + error larger than the claimed gains of some bolt-ons. There was a great article a few years ago about tuning at DINAN. In response to "how much power does this car put down?" the tech said (smiling) "how much do you want it to?" implying that he could set up the run with enough artificial conditions to make it look good in a pissing contest. Or, he could set it up to produce far less.

Where the dyno is most useful is measuring % gains before and after a change, especially if the 2 runs are done close together in time. So, while 315 seems low for what you're describing, what did the car make stock on that dyno and what did it do with just the SC with the standard pulley? If the % increases sound about right (35-40% increase in peak rwhp for stock -> SC for example) then everything might be just fine.

 

with aftermarket headers and exhaust im sure you will see A LOT of gains. what kind of dyno was it???

 

a 3inch pulley got 14 psi on my comptech setup...

 

I made that much power w/ a stock pulley and a VAFC. Very low #'s

 

i have 4 inch pulley .. ap1 ... inline pro 3 mm hg .. test pipe .. buddy club single exaust and i put down 346 whp .. i have aftercooler allso so i see around 11-12 psi on my boost gauge .. if you are stock comp you should be alot higher hp for sure .. i went with 3mm hg because i plan to run a 3.8 pulley one day.. wanted my SC to break in some before maxing it out .. i allso think you may be pushing the limits with 4 inch pulley and stock comp ..

 

he has the 3mm hg.
im putting down 300hp 186tq stock pulley header back 3'' exhaust low-comp fulley built 2.2l
ur numbers seem a bit off

 

yeah because you have a comptech