GNon18s

My friend has been running 7psi with an MP112 supercharger on his stock long block LS6. He recently broke a stock piston but doesn't want to get crazy with a high dollar build. We will probably just do forged pistons and ARP rod bolts and get it back on the road. My question is should we alter the compression ratio for his 7psi setup when we order pistons? Or just stick with stock LS6 compression? What is stock LS6 compression? (We will be using LS9 head gaskets we already have).

Always2Slow

iTrader: (8)

To be honest its hard to say without seeing the tune files and the cam. You can run a higher compression setup which leaves you with a stronger setup with less boost and still be safe on pump gas. You will get many opinions stating to lower compression so you can throw crazy boost at it, but if this is your combination and you want to maximize it I would take cylinder pressures to the limit which means keeping the compression higher depending on the rpm you want to turn with it. Stock LS6 compression by the way was 10.5 to 1.

GNon18s

The setup will remain at 7psi with the Magnuson 112. Stock cam and stock heads on an original 13k mile LS6. Just want to replace the hurt piston and wondering should we stick with 10.5-1 compression?

redtan

iTrader: (5)

If you're not going to up the boost then 10.5 will be a great compression for 7psi.

If you do plan on spinning that thing to say 10+ psi then I would lower it to just around 10.0

Alvin@PCMofNC

That is a really inefficient blower. Keep the compression high.