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

BillK · 02-11-2012, 04:40 PM

Tom,

I really dont think you can make a general assumsion about this. There are a lot of variables involved. I just read that some of the new direct injection engines are running almost 13 to 1 on 87 octane pump gas. A lot of it depends on how much time you are willing to spend optimizing the ignition and fuel curve to prevent detonation throughout all operating conditions. A fuel injected engine with knock sensors can get away with a lot more than one with a Holley and a distributor.

That all being said, I tell my customers 9 1/2 for iron heads and 10 1/2 for aluminum but I tend to be very conservative.

02-11-2012, 04:40 PM	#3
BillK Member Join Date: Nov 2005 Location: Waldorf Md Posts: 230 Likes: 12 Liked 30 Times in 17 Posts	Re: maximum compression for pump gas aluminum head Tom, I really dont think you can make a general assumsion about this. There are a lot of variables involved. I just read that some of the new direct injection engines are running almost 13 to 1 on 87 octane pump gas. A lot of it depends on how much time you are willing to spend optimizing the ignition and fuel curve to prevent detonation throughout all operating conditions. A fuel injected engine with knock sensors can get away with a lot more than one with a Holley and a distributor. That all being said, I tell my customers 9 1/2 for iron heads and 10 1/2 for aluminum but I tend to be very conservative. __________________ Bill Koustenis