I measured my stock pulley 2 different ways and came up with 7.24". Yea I doubt the 15% would clear the factory water pump also.

 

I never measured a stock one, but I did measure my powerbond to be 8.25. Exactly 10% more than 7.5 everyone thinks the stock pulleys are. I know ATI sells "stock diameter" pulleys at 7.48 and 7.53".

 

Were you measuring from the top of the belt when installed or the top of the ribs on the pulley?

 

 

I wrapped the belt, cut it to make a perfect circle and then laid it out on a table.

 

 

 

My set-up in sig, with a 3.9 pulley and about 5800 shift point makes 6lbs according to hptuners. Anyone have a guess on how much extra i would see with a 3.7?

 

Apples to oranges but Whipple's site says 1lb for each 1/8" smaller on the 2.9 Camaro 6.2. That apparently stays uniform on all sizes in that application.

 

I'm interested to see if anyone else has a Magnuson TVS1900 on a 2014+ 6.2L and what boost they are getting.

I'm getting frustrated with my setup (referenced above, only I have a 2017). With everything stock except the supercharger and catch can, the 84mm pulley that came with the kit only produced 4psi (when it was supposed to make 6psi). I showed Magnuson the data log and they immediately sent a 78mm pulley and a new tune, which then made 5.8psi. So why does Magnuson include the 84mm pulley with the kit if it only makes 4psi? And the 84mm is still what you get if you order a kit right now, I checked, so it wasn't a mistake. Is it possible that my truck is just weird or something went wrong with the install, and that's why I was 33% short in boost? My elevation is only 730 feet, too.