Expert: Dan Liddy - 1/15/2010

Question
I am racing at a 7/16th mile asphalt oval in Michigan.  Berlin Speedway.  I am driving a 1999 Escort ZX2 with a 2.0 doc.  It has a manual transmission.  I run the track in third gear and am having a lot of trouble through our turn 4 with severe understeer and forward bite coming out.  I wanted your opinion of installing a helical lsd in the car.  From what I am reading it should help with traction and reduce the understeer in the car.  I am already running with camber in the wheels and have some spring rubbers in the right rear.  The front end is toed out around 1/8-1/4 inch.  This helps a little but still can't get the "tight" out of it.  I am losing a ton of time to some of the other cars, especially some of the Hondas.  IN your opinion will this help fix the problem. Thanks in advance.

Answer
Hi Rob:

You didn't tell me how MUCH camber you run, I recommend 4 Deg. negative in the RF and 2 Deg. positive in the LF  Then you take tire temperatures , outside, center and inside. The sides are measured 1" in from the edge of the tread.   Temps should be even all the way aacross, but a bit warmer, say 10 Deg. on the insides. Your RF tire will be hotter  than the LF .

Toe out is usually good but you should also know more about your Ackerman effect. That's a complex subject and difficult to figure the first couple of times, and only the winners do it regularly. Now read that last sentence again with emphasis on the word "winners".  Back to the toe out.  change it but MEASURE IT ACCURATELY and take notes. include lap times and track temperatures in your notes. Also tire temperatures. All of this is important.

To learn more about this stuff , get the book "How To Make Your Car Handle" by Fred Puhn, I think you can order it from Summit Racing ( www.summitracing.com ) or you might just find it at a lerger book store like Borders.

Now to answer your question, YES the LSD will do wonders, both for your understeer, and forward bite, the only problem you will have then is keeping both tires on the track.

If you still have understeer, you will have to determine if it's power understeer which only occurs with throttle down. If that's the case, there's not much more to do, other than use better tires. If however it's just a miserable awful push, you may be over driving the corner, or it could be your front springs are a bit stiff. Also the front sway bar may be too stiff.

This conversation could go on forever. Try the things I've mentioned and write back after you've had it out a few times. Remember to take notes, I'll need to know where you started, and what you've done .

Good luck !

Dan Liddy
Sarasota, Florida