Formula to convert 660 to 1320

[Stan Weiss]

I like to use 1.57 but like everything else one size doesn't fit all.



► 9.985 / 6.315 = 1.58116
► 10.10 / 6.394 = 1.57961
► 10.103 / 6.421 = 1.57343
► 10.154 / 6.444 = 1.57573


Stan

[Alan Roehrich]

An 1/8 mile to 1/4 mile formula isn't really going to work well for most Stock/Super Stock cars simply because the vast majority of them are handicapped in one way or another, and often do not run as well on the "back half".

[SS/AM]

ET is made in the first half, after that it's a valve spring test.

[Jim Caughlin]

Originally Posted by Alan Roehrich

An 1/8 mile to 1/4 mile formula isn't really going to work well for most Stock/Super Stock cars simply because the vast majority of them are handicapped in one way or another, and often do not run as well on the "back half".

Totally agree with you that these sort of formulas don't apply in Stock and SS particularly on the slower low HP combos. In order to make these types of combos to run often require way overgearing which results in making all the power in the first 1/8 and then hanging on to the 1/4. At least that's the case in my SS/FS 4 cylinder car, probably most of the smaller displacement V8 cars as well, all done by the 1/8 mile.

Jim Caughlin
SS6019

[Billy Nees]

Originally Posted by Jim Caughlin

Totally agree with you that these sort of formulas don't apply in Stock and SS particularly on the slower low HP combos. In order to make these types of combos to run often require way overgearing which results in making all the power in the first 1/8 and then hanging on to the 1/4. At least that's the case in my SS/FS 4 cylinder car, probably most of the smaller displacement V8 cars as well, all done by the 1/8 mile.

Jim Caughlin
SS6019

AMEN!

[Jeff Niceswanger]

Originally Posted by Alan Roehrich

An 1/8 mile to 1/4 mile formula isn't really going to work well for most Stock/Super Stock cars simply because the vast majority of them are handicapped in one way or another, and often do not run as well on the "back half".

Back when Gulius was building ours (L-98), he wanted the RPM @ 1000 foot. Not the finish line. 8800 etc....Don't want to be specific, but he didn't care what it was for the 1000-1320. Said the 0-1000 is what is important. That likely don't jive with most of those calculators.

[Billy Nees]

Originally Posted by Jeff Niceswanger

Back when Gulius was building ours (L-98), he wanted the RPM @ 1000 foot. Not the finish line. 8800 etc....Don't want to be specific, but he didn't care what it was for the 1000-1320. Said the 0-1000 is what is important. That likely don't jive with most of those calculators.

and thus the term "aired-out".

[Mike Schwartz]

I determined a conversion factor of 1.57, based on the actual times of the low-powered, street-driven cars I raced for most of my career. I find bumping it down to 1.56 or 1.55 for more powerful race-only cars gets decent results. It's easy to figure it out from time slips.