F body 60' times

[alnoe]

I have a 67 rs/ss with a 315/35/17 drag radial, and an air ride 4 link with afco coil overs. I wanted to ask what are typical 60' times that people are seeing-this is for a PT style car with front sway bar attached, and preferrably a stickshift 4,5,6 speed car.

My best 60' is 1.80, which seems like it should be much better-the engine makes 535 HP, and traps 117-119. One issue I have is that the car either bogs or spins the tires pretty hard-it is tough to bring it our hard and have it hook well. I run 20 lbs of air pressure, and have tried a number of settings of air pressure (16-24), shock settings, etc.

I wanted to see if anyone had typical results, etc. I know it will vary greatly depending on combination, driver, etc.

Thanks
Al

[ponchopwr70]

Thats not that bad but should be better. I've cut a 1.7X with my lemans but my car is a little different. I used 16" m/t et streets and they dead hooked on me. I think if you switch to the smallest dia rim that will clear your brakes with a m/t et street you would see improvement. What brand radials you running? Im going to try that same size nitto dr this year and see how they compare.

[alnoe]

Hi Frank

I run a M/T drag radial. It is a quality tire, and seems to hook well-the difficult part is that if I launch at 3,000-3,500 and sidestep the clutch it will bog, or sometimes it blows the tires off. I think the front end may be coming up, the car squats, and it unloads the rear tires-depending on the track. I have tried leaving soft and walking the car out of the hole, but that usually is a 1.9 60' time or slower.

A good friend of mine watched the car, and he said the same thing-maybe a taller sidewall slick will wrap up and work better?

Al

[70camaro406]

I'm worried what my times are going to be once I get the 5 speed and 17" wheels on it (it's still a year away). I've only raced mine with the TH350 and 275/60-15 M/T drag radials (set at 16-17 lbs.).

Since you have coil-overs in the rear, you could try softening them up a good bit and dis-connecting your front sway bar. That could give you a bit more weight transfer and make the tires bite better. How much of a burnout are you doing? With those tires, I've found that about 3-4 seconds of tire smoke is enough. Anything much more than that makes it worse (gummy).

[BillyShope]

...and dis-connecting your front sway bar.

Definitely!!

Doesn't help the weight transfer all that much, but it does help to equalize rear tire loads. The driveshaft torque, as you know, tends to unload the right rear. The reaction to that torque is taken by the front and rear suspensions in proportion to their relative roll stiffness. By decreasing the front roll stiffness (disconnecting the front sway bar), more of that reaction torque goes to the rear to aid in equalizing rear tire loading.
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[ponchopwr70]

Based on what I've seen and herd is a bias-ply type tire is more forgiving where as a radial the suspension has to be dialed in better. I would think getting a bias-ply drag tire on there would keep you from blowing off the tires. Set the shock a little stiffer on the passenger side. I run airbags in mine just so the car leaves level. You want your car to lift in the back when you leave the line not squat also.

[ponchopwr70]

Also on my car I have a converter that will flash to 3500, I foot brake to 2800 then floor it and let off the brake leaving the line and my 26x11.5-16 mt dead hook at 13psi. I have about 450-475 flywheel horse but its an automatic. I leave my sway bar connected but should try disconnecting it to see what it does.

[Bowtie1z28]

Check out this website I found yesterday. Strictly dedicated to manual trans drag racing. The common concensus there seems to be that drag radials do not perform as well as a bias ply drag tire like the MT ET Street. The drag radials tend to be somewhat inconsistent. The best 60' with with second gen Camaro with a similar setup to yours was 1.74-1.77 running 13ps1 in a 275/60 x 15 on a 7" rim which is no doubt part of my issue, should really be on a 8-9" rim. I am considering seeling the MT DR's and getting a set of the ET Streets.

http://www.umtrnorth.com/

[Shawn MacAnanny]

You're not going to get much better than 1.6-1.7 on that sidewall either. having a taller sidewall helps with traction immensly. Running a 17" wheel leaves you with a very narrow sidewall. The sidewall of the tire acts as a shock absorber for traction and allows more of the footprint of the tire to remain on the pavement as power is transfered.

[alnoe]

Guys

Thanks for the feeback. I know that removing the front sway bar would make things easier, and I have tried a few different burnout techniques-you are right that 3-4 seconds works well.

I am probably being greedy and want to drive the car to the track, change nothing, race it, and drive it home. My goal is to get the 60' times in the high 1.60's, but I may be asking for too much. I also want to not change tires when I get to the track-I have a goal to get the car as fast as I want in exactly the same trim as I drive it on the street, autoX, etc. I am not a big fan of icing down the intake, letting it cool for 2 hours, etc. I am trying to run "real" numbers rather than go for the 1 time only great ET slip.

So, maybe I need to work on additional shock tuning, etc.? Driver mod?

Al