Inliners International Forums General Discussion Engines Dynamic Compression Ratio

What are your guys thoughts on DCR in a street motor on 87 octane?

Crunching my numbers I'll be at about 8.95:1 Static Compression Ratio.

Talked to Comp Cams last week and they recommened two cams the 260H or if I wanted a little better mileage go with the 252H

The DCR for the 260H comes out to be 7.63:1 and
7.98:1 with the 252H

Will I run into detonation problems with a DCR of 7.98:1 with 87 octane?

Greetings . . .

This online source suggests you'll probably need 89+:

C/R Octane Number
5:1 72
6:1 81
7:1 87
8:1 92
9:1 96
10:1 100
11:1 104
12:1 108
Frequently Asked Questions site

But you can never tell until you try. You may run fine on 87 with things set a little rich and no heavy full throttle loadings.

regards,
stock49

Thanks, thats very interesting info.

I'll have to read that a coulpe of more times.

Thankd again, vince