My 300 SIX powered altered has a chassis tag dated 9-10-01. That's right, one day before the 9/11 attack. As I reflected on the fact that my front line racer is now nearly 19 years old I realized a lot has changed in that 19 years.
When I built the car I was racing quarter mile. Now almost all of the tracks have switched to racing the Super Pro cars to eighth mile. When I built the car track prep was marginal. Now at most tracks the track surface prep is so sticky you can't walk across the track starting line without walking right out of your shoes.
So I considered how my car was built and needed to make some changes. It has 4.30:1 gears in it. This is a typical gear set for a typical bracket racer that wants to keep the engine revs low to save on valve train parts. Optimal gearing for fastest e.t. would have been numerically higher but needing a more expensive valve train and other upgrades for a higher RPM band. Additionally, since I'm now doing the eighth mile the engine is running even less RPM going through the lights. This has led me to conclude that I need a smaller slick.
A smaller slick is lighter.
A smaller slick has less rotating mass / angular momentum.
A smaller slick is more aerodynamic.
A smaller slick gives a higher effective gear ratio.
I was using 12 x 31.5 x 15 slicks. A obtained a pair of 10.5 x 28 x 15 slicks to try. I guess I did not at first realize how much would have to change to use these tires. For instance,
The 4-bar instant center pivot point
The ride height of the chassis
The driveshaft angle
The pinion angle
The anti roll sway bar link
The wheel width and offset was different between the two sets I have
The wheelie bar height
So I have made the required changes to my chassis to run these tiny tires. I am waiting for a longer set of wheel studs to put the car back on the ground. I have had to go with longer coil-over shocks and new axle housing brackets. I'll post results as soon as we can get the car out. Stay tuned
FTF
Last edited by THE FRENCHTOWN FLYER; 04/23/20 05:03 PM.
