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Auto shifting issue after 3.73's

Old 09-09-2008, 11:13 AM
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grampa_stang
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Default Auto shifting/traction issue after 3.73's

Updated with times & Vids - I noticed that with the 3.31's, when it hit 2nd..it would chirp and snap your head back. Now, after the 3.73's....it's seems to spin the tires. I don't really feel my head getting snapped back. The shift into 2nd feels seamless or smooth, if you know what I mean.

This is ONLY at WOT. Normal driving or partial throttle, I can still feel the hard shift. I'm wondering if I should lower the shift pressure as this might have hurt me at the track? I still don't have a problem launching...barely even chirp the tires. But into 2nd, I'm hanging on.

At the track I actually went a little sideways (when hitting 2nd) and still ran my best times to date.

Last edited by grampa_stang; 09-10-2008 at 11:56 AM. Reason: title change
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Old 09-09-2008, 01:09 PM
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zkiller
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Tire chirping is caused by the tire biting and getting traction. Sounds like you are getting more spin than before at the 2nd shift. If your are getting sideways on the shift to second while on a prepped track with your power level, you need some drag radials.
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Old 09-09-2008, 02:46 PM
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grampa_stang
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I will admit, the track was unusually slick that night. Thanks for the advice.
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Old 09-09-2008, 08:35 PM
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GT Bob
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Did you rescale all the shift points and shift pressures to account for the change in gearing. Auto trans work by comparing rpm, throttle position and road speed to figure out shift points and pressures (at least, with the S197's they do). By changing the gearing your changing the road speed that the computer is seeing and it is either shifting early or late with too much or too little line pressure.

Give Doug a call and have him update your tune for the 3.73's. It's VERY critical to do this with the Auto's.. Manuals, still important, but not as much.
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Old 09-09-2008, 10:52 PM
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grampa_stang
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Sure as hell did. Had the new tunes from Doug before the gears. It was definitely a slick track issue. Had to be....on the street, 2nd gear chirps like normal.
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Old 09-10-2008, 07:27 AM
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Chris07GT
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What kind of times were you running?
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Old 09-10-2008, 08:07 AM
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pharmd2010
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Originally Posted by Chris07GT
What kind of times were you running?
+1 - very curious...
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Old 09-10-2008, 11:26 AM
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grampa_stang
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I ran 14.2 @97. Here's some videos. The race against the Camaro was before the modified race tune.
Remember, Im at 4400' and the DA that night was 6350'
You guys really just want to see how bad my auto beat a manual...don't you?

Let me add this, stock the manuals are running 15-15.6. A 15.0 is with them hooking up. After they get tunes/CAI they're running 14.6-14.8. The White Mustang has pypes MM/C&L/Predator with a canned tune. His best was a 14.8. There has only been one (that I know of) manual Mustang that has beaten my 14.2, he ran a 14.1, he has C&L racer/Brenspeed tune and Kooks LT's w/3.55's. He's gets to launch at 3500. I'm stuck at 1800-2k. That night he ran a 14.225 and I ran a 14.224 I swear.
Anyways...that's altitude for ya!

I betch ya if we would've lined up that night..he would've tried a little harder (knowing our times were so close) and screwed up his launch...and I'd have eaten him up. LOL

http://s188.photobucket.com/albums/z...ke09052008.flv

http://s188.photobucket.com/albums/z...2209052008.flv

http://s188.photobucket.com/albums/z...=FirstRace.flv

http://s188.photobucket.com/albums/z...GTvsCamaro.flv

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Old 09-12-2008, 02:15 PM
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grampa_stang
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WTH..no comments on my vids, my kills. No kudos from the auto guys regarding my kills vs the manual. Nothing from the manual guys saying I got lucky.
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Old 09-12-2008, 02:24 PM
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Derf00
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I'm curious why you're running a 91 Race tune on a drag strip instead of the TQ tune?
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