Eaton TrueTrac - loose handling? poor tire temp? Reports after my first autocross on it vs. a Torsen T2R

[Duane Black]

So if you've followed my little disaster with my Torsen T2R.... now I kind of wonder if somehow my suspension is magically lifting a tire or some nonsensical shiznit and messing up the tire grip.... There was definitely a noise in the Torsen so I am kind of ruling it out... and hoping some hot Hankooks will hookup with no drama....

So anyway, here's a quick rundown of the situation.

• It was about 50 degrees ambient and similar pavement temp with the cloud cover
• If you watch my full video, it seems ot get better as the the runs go on and the tires warmed up.
• On the 2nd half of the course, the tires would break free in the harder turns as I applied power. You can kind of hear it but I am also commentating on it.
• I did run some reasonably competitive times for cold Hankooks against guys on RE71RS, Falken RT660, and Yokohama A052's.
• I talked to a fox body driver whom I recommended an Eaton TrueTrac to last year, and he commented on having a similar handling issue that I had and he fixed it by softening his coilovers 2 notches on each end of the car.

The car seems ot turn in like.. magically well compared to the Torsen T2R. Too well. The car was pointing and firing through the slalom's better than I can remember the car running on Hankook RS4 tires. I definitely heard the rpm's surging and coming back down as the rpm's came back down when it did. I also had two witnesses confirm that both tires were indeed spinning off the line at least.


Here is a video of the car today.

And a video from 2 years ago in similar weather with the same Hankook compound

And, for continuty, the video of the dif coming apart last month.

So is it possible something in the suspension is causing the rear tires to lose grip in this way? Is the Eaton just making the car much looser in part throttle to full throttle to part throttle transition situations and making the car loose and I need to work on finding a way to tighten the rear end of the car back up, for instance, I am running a Strano bar on full stiff with Boss 302 springs... so I could put my V6 springs back in or use a softer setting on the rear sway bar.

 

[blacksheep-1]

So if you've followed my little disaster with my Torsen T2R.... now I kind of wonder if somehow my suspension is magically lifting a tire or some nonsensical shiznit and messing up the tire grip.... There was definitely a noise in the Torsen so I am kind of ruling it out... and hoping some hot Hankooks will hookup with no drama....

So anyway, here's a quick rundown of the situation.

• It was about 50 degrees ambient and similar pavement temp with the cloud cover
• If you watch my full video, it seems ot get better as the the runs go on and the tires warmed up.
• On the 2nd half of the course, the tires would break free in the harder turns as I applied power. You can kind of hear it but I am also commentating on it.
• I did run some reasonably competitive times for cold Hankooks against guys on RE71RS, Falken RT660, and Yokohama A052's.
• I talked to a fox body driver whom I recommended an Eaton TrueTrac to last year, and he commented on having a similar handling issue that I had and he fixed it by softening his coilovers 2 notches on each end of the car.

The car seems ot turn in like.. magically well compared to the Torsen T2R. Too well. The car was pointing and firing through the slalom's better than I can remember the car running on Hankook RS4 tires. I definitely heard the rpm's surging and coming back down as the rpm's came back down when it did. I also had two witnesses confirm that both tires were indeed spinning off the line at least.


Here is a video of the car today.

And a video from 2 years ago in similar weather with the same Hankook compound

And, for continuty, the video of the dif coming apart last month.

So is it possible something in the suspension is causing the rear tires to lose grip in this way? Is the Eaton just making the car much looser in part throttle to full throttle to part throttle transition situations and making the car loose and I need to work on finding a way to tighten the rear end of the car back up, for instance, I am running a Strano bar on full stiff with Boss 302 springs... so I could put my V6 springs back in or use a softer setting on the rear sway bar.

Try an 18mm rear bar, or possibly no bar in the rear.
You've basically redesigned the diff characteristics so you are almost starting at zero.
The fact that you are spinning BOTH tires coming through the corner is a positive sign, now you just need to hook it up.
I always run... like 6 psi on autocross courses over road courses because you can never keep the tires warm enough.
Try this..
1. Determine whatever your hot psi should be with those brand of tires.
2. Inflate the tires to that target and drop 2 psi
3. Check the psi as soon as you come off the track and adjust up or down based on those results. ( I usually shoot for over, because it's easier to dump psi on pit lane).
Remember hot ALWAYS determines cold, not the other way around.

 

[twistedneck]

So if you've followed my little disaster with my Torsen T2R.... now I kind of wonder if somehow my suspension is magically lifting a tire or some nonsensical shiznit and messing up the tire grip.... There was definitely a noise in the Torsen so I am kind of ruling it out... and hoping some hot Hankooks will hookup with no drama....

So anyway, here's a quick rundown of the situation.

• It was about 50 degrees ambient and similar pavement temp with the cloud cover
• If you watch my full video, it seems ot get better as the the runs go on and the tires warmed up.
• On the 2nd half of the course, the tires would break free in the harder turns as I applied power. You can kind of hear it but I am also commentating on it.
• I did run some reasonably competitive times for cold Hankooks against guys on RE71RS, Falken RT660, and Yokohama A052's.
• I talked to a fox body driver whom I recommended an Eaton TrueTrac to last year, and he commented on having a similar handling issue that I had and he fixed it by softening his coilovers 2 notches on each end of the car.

The car seems ot turn in like.. magically well compared to the Torsen T2R. Too well. The car was pointing and firing through the slalom's better than I can remember the car running on Hankook RS4 tires. I definitely heard the rpm's surging and coming back down as the rpm's came back down when it did. I also had two witnesses confirm that both tires were indeed spinning off the line at least.


Here is a video of the car today.

And a video from 2 years ago in similar weather with the same Hankook compound

And, for continuty, the video of the dif coming apart last month.

So is it possible something in the suspension is causing the rear tires to lose grip in this way? Is the Eaton just making the car much looser in part throttle to full throttle to part throttle transition situations and making the car loose and I need to work on finding a way to tighten the rear end of the car back up, for instance, I am running a Strano bar on full stiff with Boss 302 springs... so I could put my V6 springs back in or use a softer setting on the rear sway bar.

if i recall, the Torsen releases on braking and the Eaton true track does not, you have the same thing in the forward direction as you do in reverse, but if anything this increases understeer going into a corner..

I have a True track and its great! i run an 18mm rear stabar and JRI coilovers all around with nice soft 350 lbs/in front springs and 150 lbs/in rear. originally i was running 500 front 300 rear (cortex recommendation for track) but i realized in Michigan there is no such thing as smooth pavement.

 

[blacksheep-1]

if i recall, the Torsen releases on braking and the Eaton true track does not, you have the same thing in the forward direction as you do in reverse, but if anything this increases understeer going into a corner..

I have a True track and its great! i run an 18mm rear stabar and JRI coilovers all around with nice soft 350 lbs/in front springs and 150 lbs/in rear. originally i was running 500 front 300 rear (cortex recommendation for track) but i realized in Michigan there is no such thing as smooth pavement.

That's really not a bad combination, it is remarkably similar to the old Grand Am cup car, except using a torsen and Pen$ke shocks