![Very Happy :D](./images/smilies/icon_biggrin.gif)
The car:
125" hard tail 23T altered
1550 pounds WITH driver
Hoosier 14x32 D5
4.11 gear
1.82 powerglide
385" SBC making approximately 550 HP.
5500 RPM stall
Best run so faris 8.83 @ 150
When we bought the car, it was run at 1/8th mile tracks only, so we put a 4.11 gear in it, but left the launch rev limiter where the previous owner had it set, which was 3000 RPM. Tire pressures were also copied from the old owner at 4.75 psi.
What we found is that the car porpoised pretty bad, pulling the front tires about 2" 3-5 times before it settled down, and it had the appearance of slapping the front tires on the track. General 60' times with those settings were about 1.28 to 1.25.
We have since raised the tire pressure to 5.5 psi with no other changes, and the car immediately went .02 - .03 faster in 60'. It also has much, much less tendancy to hop under braking.
Now we are starting to raise the launch RPM in 200 RPM increments. Each time we see a reduction in 60' times, and each time it pulls the front tires a tiny bit more, and skips them a little less. We are at 4400 RPM now and the front tires don't seem to slap the track so much as gently skip across it now. Best 60' time so far is a 1.203.
Are we on the right track here? Does our 5.5psi tire pressure seem inline? I still want to keep raising the launch RPM right up until we launch it on the converter, but I thought I would bounce this off you guys and see what you have to say. Again, we are very new to all of this, and there are very few hard tail cars in our area, and even fewer that have such low horsepower... most are fuel altereds and I can't see any of their parameters being usefull for our car.
Thanks guys,
Matt