corner entry push

[John Hannaford]

Don,

You're right that the leading edge of the FFR Spec racers seems to be moving toward significantly more rear weight transfer, which is counter-intuitive since they've largely gone to equal tire sizes on all corners. You'd think that we were giving up some useable grip at the rear.

The Cobras that I've heard numbers for seem to mostly run with fairly high front roll resistance distribution percentages (other way from your numbers - calculated by F/(F+R) ... and I just noticed what the variables spell - not a pun, I swear!) of about .6 to .7. This is the kind of balance that you used to see on the live axle Trans-Am cars of the glory days or on passenger cars, and seems to be used by guys who need or want to use a lot of trail brake and throttle to balance, or by those who are more concerned with getting the power down on corner exit.

My theory is that because the FFR spec cars are restricted to stock 5.0 engines, they are finding that they have to set up their cars to focus more on corner speeds than on excess traction for launching out of the corners. The looser setups are working very well for autocross too, as you would expect.

David Borden's two cars are an example of this, I think. His spec racer seems to run better lap times with a lower FRRD of about .48 as compared to the best setup on his supercharged non-spec car that runs better lap times with a little more push. I think that car is around .55 FRRD (Going from memory here, David might confirm this.) I think his 500 hp car benefits more from the extra corner exit traction of a slightly softer rear than it loses from the slightly lower corner speeds.

Based on the admittedly small sample of three Cobras (Superformance, Classics and FFR) I've tried in what their owners claimed were race setups, I think there is a tendency to run them tight. From a safety viewpoint this is probably a good thing since we're all just running for fun! Hell on the tires though.