Actually i just rebuilded my h2 hummer 6.0 engine which is iron block to -13.7cc forged pistons and good rings also iam using the stock rods but inforced them with APR bolts ,


i was only running 5 psi sts turbo with Garret 67 when the engine was stock

the question is

what would be my CR with my forged pistons am using . the piston bore is 4.00 using the stock rods with apr bolts

would i lose hp in dyno if am still running 5psi with the lowered compression?

what hp would u think it will be my max , i have on hand 7.2 psi & 10 psi springs am getting hard time to decide which to use


car is heavy it has 3600 stall converter, GT7 camshaft lingenfelter, stock manifold


transsmision is well built

your answer will hopfully save me alot

 

52 views no single answer ? lol thanks any way


have a good day

 

Put the 7 lbs spring in and let it fly. Yeah it will make a little less power due to the pistons, but you put them in to use them right? Put the 7 psi spring in and tote it over to the dyno and get it tuned. Take the 10 psi spring with so you can slap it in when your done with the 7 pounder. Not sure on the comp ratios with that setup.

 

You are right at 8.8:1 if you are using stock MLS gaskets that are .052" thick. .040" gaskets will give you 9.0:1. With compression that low and a really good custom tune you could safely run as much as 14-15psi on 93 octane if it is intercooled. Hope this is what you were looking for.

 

thanks am gonna use stock gaskets going to tune it at 7lbs then going to slap it to 10lbs soon , will post pictures soon , thanks for the comments guys