A So-So race night. . . . . .

Originally Posted by jeffstar

Dennis,

Our cars are similar and I'm surprised that you're not really yanking the front wheels with the 393 power and Caltracs.

I don't seem to have traction problems as long as I warm the tires enough. Perhaps the softer aspect of the iron clutch makes a difference.
or maybe the 28x9 slick gives that much more bite?

The 28x9 is supposed to have a bigger footprint, which is why they are desirable. I may consider them next time, but I truly thought that the 26x10's would do the job. I am concerned about wheel well clearance at the far end of the track with the taller tire.

I heat the tires up in 2nd gear at about 6k rpm until the motor rpm's drop about 500, which is only a 2-4 seconds after I start the burnout. My understanding is I shouldn't need much more than that after the 1st good burnout.

Once the RPM's drop, I leave off the the gas and push in the clutch to keep it from getting hot.

I too would think that I could pull the wheels up more consistently than I do, which is rare. It has been pretty much the same no matter which type of clutch I have had installed. The new adjustable clutch was added with the hope to correct the launch problem, as it seemed that I was pretty much at a dead end messing with the suspension all last year.

These are truly great ideas and I know that I am at a point that I need to do something other than I have been doing before, but not sure what will help.

Originally Posted by dennis111

The 28x9 is supposed to have a bigger footprint, which is why they are desirable. I may consider them next time, but I truly thought that the 26x10's would do the job.

I heat the tires up in 2nd gear at about 6k rpm until the motor rpm's drop about 500, which is only a 2-4 seconds after I start the burnout. My understanding is I shouldn't need much more than that after the 1st good burnout.

Once the RPM's drop, I leave off the the gas and push in the clutch to keep it from getting hot.

The 28x9's also raise the rear of the car up, which isn't good for traction. My best 60ft of 1.43 was launching on the nitrous with a brand new set of 28x9 slicks, but the 26x10's had a best of 1.46 with a worse clutch setup. Personally, I think the 26x10's worked just as good or better on my car. (BTW, those times were done with an old set of plain ole' slapper bars, 4-leaf springs and stiff KYB shocks) LOL

I do a 2nd gear burnout and get the tires nice and hot, then let off the line-loc and push the gas down a little further and power out of the burnout. (of course the burnout should be done just AHEAD of the water box, but you probably already know that)

I made another post (#10) at the same time you made your last one.

Good Luck!

Originally Posted by n2omike

I believe we're seeing things differently. On my car, you can push the clutch pedal in around an inch or two before the clutch starts to disengage. That's what I am referring to. If you don't have any free-play with the clutch pedal all the way up, then any torquing and binding can cause the clutch linkage to partially disengage the clutch.

OK, I think that we simply had a communication breakdown on this one and that we both have the same adjustment. I can push my clutch pedal down about 2" before it disengages, so there is lots of free-play. I can also see it at the fork, which has about 1/4" free play when at rest.

Originally Posted by n2omike

As for the chassis... You need to make sure that the rear is square in the car, everything is tight, and nothing is moving around under power.

Everything is square and tight. I've had the housing out a couple of times over the past year and have carefully installed it and get the same results. The tires even sit identical from side to side and have the same front, top and rear clearances.

Originally Posted by n2omike

The driver's side is the more heavily loaded tire under power, which -generally- causes a car to go LEFT. It's the reason the passenger's side generally gets extra pre-load... to put more load on that side for more equal traction. Your car going to the right is backwards! LOL This is the reason cars with an 'open' rear differential spin the RIGHT side tire. The driveshaft torques the driver's side tire down into the ground, giving it more traction, and allowing the right rear wheel to spin.
Good Luck!

This is something that I have never known, but would certainly explain the one wheel peal outs that an open rear would have. I wonder if this is something peculiar with a True trac differential, which is limited slip? The True trac was added last year just before my first track appearance and the car needed the reverse pre-load offset right from the get-go in order to launch straight. Since then, I have not gone back and tried it the other way so maybe there is something there. . . . . Although it is not the same as being on slicks, I get 2 equal length tire marks (in 4 gears) when I get a little crazy on the street.

Thanks again, Mike. To bad you don't live about 250 miles closer in order to get some hands on as to what I am experiencing.