CLASS RACER FORUM - View Single Post - maximum compression for pump gas aluminum head m

Mike Croley · 02-14-2012, 11:06 AM

That would depend on which pump gas ( 87 , 91 , 93 ) and on what day . Pump gas is not consistent batch to batch , day to day . It doesn't have to be . The computer and EFI in street cars can easily compensate for the differences in ethanol content and the different blends .
As a rule , aluminum heads allow a little more CR than steel heads , but on pump gas i'd stay below 11.1 and maybe even a little lower to be safe .

02-14-2012, 11:06 AM	#4
Mike Croley Member Join Date: Apr 2010 Posts: 182 Likes: 0 Liked 0 Times in 0 Posts	Re: maximum compression for pump gas aluminum head That would depend on which pump gas ( 87 , 91 , 93 ) and on what day . Pump gas is not consistent batch to batch , day to day . It doesn't have to be . The computer and EFI in street cars can easily compensate for the differences in ethanol content and the different blends . As a rule , aluminum heads allow a little more CR than steel heads , but on pump gas i'd stay below 11.1 and maybe even a little lower to be safe .