28" Drag Radial Times

[87NAT]

What tires are you running? Some Et street Radials at about 15 psi of air and a good burnout should net some good sixty foots.

My only suspension mods are some lower control arms and an airbag in the right rear and net 1.5 sixty foots leaving at 5 psi. Those MT tires are the way to go.

 

[bison]

You're over my head on the instant center and pinion angle, though i understand your logic.

Physics at work here. You can control the hit to a degree with the pinion angle and the instant center correction will keep the car from wasting motion and weight transfer squatting and will help firmly plant the rear suspension. It is very evident when you see a car with raised upper control arms or lowered lower control arms launch. It looks like the body is seperating from the rear. A trans brake gives you a much greater advantage in shocking the suspension and using th engines torque to propel the car.

 

[Dusty Bradford]

I appreciate the response from someone that is very knowledgeable in this sport. I'm sure I don't have close to the power that you do. I've got a 3200 stall converter, so I would think this would help it to leave hard. You're over my head on the instant center and pinion angle, though i understand your logic. When I left with 5 lbs I had a 2.1 or 2.2 60 ft. When I backed it down to 2 lbs I was in the high 1.7's. Thanks again.

So I'm assuming it spun when you left at 5lbs. You need to look at what rpm this happened. If your converter is too loose you could be at 3800 rpm and 5# of boost just for an example. When you try to leave on too much rpm the car will just spin rather than planting the tire. This is pretty unlikely though because the car should still plant the tire even leaving at that boost level.

A likely issue could be worn or cracked control arm busings. For a car to work properly you need a minimum of poly bushings in the both lower and upper control arms. Without them your rear end will have too much movement when launching.

There are instant center brackets available to help cars who need more hit initially. I would not install them without replacing every bushing on the rear with solid or poly bushings so you eliminate the possibility of movement.

 

[Dusty Bradford]

I think your winow tint is illegal Mister.



Car looks good Dusty....leaves HARD!

Already paid the fine twice for illegal tint

 

[bison]

Already paid the fine twice for illegal tint

Guess you dont learn the first time :biggrin: . Hope vacation is going well. Converter came Tuesday.

 

[flipmo]

Some really great info here guys on tires and overall traction. I've known many many people who slap on all the bolt-ons they could purchase to then go to the track and wonder what is wrong with their cars since they can't control or get it to hook up.

The first thing I've always done since having these cars is to upgrade the suspension (UCA/LCA, Bags, Beefy Sway Bar, X-Brace, Shocks, Springs) or something of the nature before anything is bolted on. The suspension is extremely critical to launch and keeping the car straight down the 1320.

Good Jew Jew Here

 

[ryan george]

So I'm assuming it spun when you left at 5lbs. You need to look at what rpm this happened. If your converter is too loose you could be at 3800 rpm and 5# of boost just for an example. When you try to leave on too much rpm the car will just spin rather than planting the tire. This is pretty unlikely though because the car should still plant the tire even leaving at that boost level.

A likely issue could be worn or cracked control arm busings. For a car to work properly you need a minimum of poly bushings in the both lower and upper control arms. Without them your rear end will have too much movement when launching.

There are instant center brackets available to help cars who need more hit initially. I would not install them without replacing every bushing on the rear with solid or poly bushings so you eliminate the possibility of movement.

Yes, right when I launched it spun. I'll check my log for the rpm to see where I was when I took off. Ok, I'll take a look at those as well. Have not done any replacing, or honestly even looked at them previously. Just learning the suspension aspect. When I put the hr rear sway bar on this spring I noticed a world of difference in how it launched on the street. Thanks.