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WHY to not go WOT in OD!!!

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Old 08-23-2005, 12:05 AM
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Default WHY to not go WOT in OD!!!

Ok, I went to the track just last week, and I forgot to post this until now.

I made 4 runs that night. Two were in Drive, the other two were Overdrive........

I cut a 1.64 60ft in Drive, but had to shut down due to water at the end of the track.....

I cut a 1.74 60ft in Drive, and ran a 12.31 @ 109.82mph (Bad Burnout)

I cut a 1.918 60ft in OD, and the whole run was in 2nd gear, it never shifted into any other gear at all....ran a 13.25 @ 85.91mph

I cut a 1.917 60ft in OD, and the whole run was in 2nd gear, it never shifted into any other gear at all....ran a 13.39 @ 83.35mph, I coasted through the traps in Neutral......


These runs were D/OD/D/OD so it shows that the transmission was not messed up, just that the car should never be run down the track in OD.

I did the burnouts in Overdrive as well, and that worked fine, but right out of the hole the car felt slow.........I soon realized as the Rev Limiter arived shortly that the car was in OD and I started out in second gear.


BTW, car runs fine, drove home (fine over 70 miles :yup: ) Drove around fine, shift nicely, beat on it, shifted flawlessly.......

The 4L60E should NEVER be in OD at the track.....I know someone who shifts into OD later down the track because he actully goes into 4th gear, but he doesn't start out in Overdrive.....

Take this as a case in point.......

~Kevin
Old 08-23-2005, 10:23 AM
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Interesting. I also run down the track in drive only.
Old 08-23-2005, 11:18 AM
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Selecting OD or D shouldn't matter. The trans is only going to shift into OD if it reaches redline in 3rd gear. I leave mine in OD and it always shift's like it should.
Old 08-23-2005, 11:25 AM
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Originally Posted by buffman
Selecting OD or D shouldn't matter. The trans is only going to shift into OD if it reaches redline in 3rd gear. I leave mine in OD and it always shift's like it should.
But are you running slicks and a big converter?

Putting the car in OD also lowers line pressure, as well as a few other non performance increasing things, but I can't think of them off the top of my head. I was told this by my tunner, the only real solution is to just run in Drive.....
Old 08-23-2005, 11:55 AM
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It shouldn't matter.

I've ran 1.70 60's in D and OD.
Trans pressure is also the same. Mine is maxed out during shifts in D or OD.

Last edited by SmokingWS6; 08-24-2005 at 12:41 AM.
Old 08-23-2005, 12:07 PM
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I do not have any hard figres to compare, but I have always ran in OD (Drive in a TA). So you are saying that running in OD gave you bad 60ft's and lost a little down low? I don't know if there really is a difference but based on what I've seen and done, I would say no.
Old 08-23-2005, 12:32 PM
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interesting....

so your saying that in OD you went to second from the beginning? Do you have a tunning software? I dont want to be negative but your shift tables should be the problem. What i did, was after i adjusted the normal shift tables, i than copied/paste table to the rest of tables.

that might help. However, i did read that the trans shifts tighter in the D position and i have felt it being different..... maybe talk to you tuner about this and see what he says...
Old 08-23-2005, 12:55 PM
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This is what he said, and my car has no performance settings in OD because i requested it specificaly.....had no idea it woul react to slicks that way! :haha:
Old 08-23-2005, 12:58 PM
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Originally Posted by CamaroSS
But are you running slicks and a big converter?

Putting the car in OD also lowers line pressure, as well as a few other non performance increasing things, but I can't think of them off the top of my head. I was told this by my tunner, the only real solution is to just run in Drive.....
no, the only REAL solution is to re-tune the tables in the PCM so that it behaves PROPERLY at WOT.... and keep it tuned so that it behaves PROPERLY at part throttle..

sticking it in 3rd is a poor band-aid.
Old 08-23-2005, 01:24 PM
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Exactly! I have raced my 2001 Camaro SS many times on street tires, drag radials and slicks ... both with the car in drive and overdrive. I have never experienced what you did, and mine was factory bone stock tune. Either your tuner did something to your trans settings or your trans is messed up. It shouldn't go directly into second and stay there, it should go through all the gears at WOT when in either D or OD.
Old 08-23-2005, 01:31 PM
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Could it have possibly been from the larger slicks? My stock tires are smaller.....
Old 08-23-2005, 01:39 PM
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I heard if the trans overheats it starts in 2nd gear.
Old 08-23-2005, 01:42 PM
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Try it again except next time do you burnouts in 1st gear only and I bet you wont see any difference between D and OD. Something happens when you try to to let the trans shift during a burnout, may just plain overheat it and the PCM locks in in 2nd, but I have had the same thing happen when letting it shift during a burnout. It will leave in 2nd gear and stay in in 2nd gear for the whole pass.
Old 08-23-2005, 02:28 PM
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What size tires were you using? If you were using 26" tires, you should have been OK. If you used 28" or even 27", that will confused the ABS/Trac control and the correlation to the PCM and cause you to go into limp home mode (2nd gear only), sometime until you restart the car (my experience). I would say try it again as KP suggested and use only similar sized tires (~26").
Old 08-23-2005, 02:44 PM
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Originally Posted by CamaroSS
But are you running slicks and a big converter?

Putting the car in OD also lowers line pressure, as well as a few other non performance increasing things, but I can't think of them off the top of my head. I was told this by my tunner, the only real solution is to just run in Drive.....

well Drag Radials and 3400rpm isn't that big but it isn't stock either.

Matt
Old 08-23-2005, 03:02 PM
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Originally Posted by buffman
well Drag Radials and 3400rpm isn't that big but it isn't stock either.

Matt

no its not.


but let me put it it this way.. i have friends with 4200+ stalls on the street that run with slicks and/or DRs and they dont have issues either.

somethings wrong with either the tune, or the trans.
Old 08-23-2005, 04:36 PM
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i do my burnout in 1st and then it shifts to second gear every time. have about 400 passes on this car now. never had this shifting and staying in second problem myself. i half also noticed that keeping it in D instead of OD has produced slightly better ET and MPH consistently. it definately shifts quicker keeping it in 3rd gear for me. but these are my results.

1.53 on drag radials here.
Old 08-23-2005, 06:30 PM
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D or OD no change here.
Old 08-23-2005, 06:59 PM
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The only difference between D and OD is the application of the overrun clutches. All they really do is lock up the sprags to take load off of them. If you're sticking in 2nd in OD, you have a tuning issue most likely.
Old 08-23-2005, 07:00 PM
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Its the tune or the fact that hes running bigger tires than what the tune is setup for.. There is nothing wrong with doing a burnout in 1st and then shifting it up into 2nd. Matter of fact, thats the only way to do a good/proper burnout in my opinion.. I've run my car in OD and D and there has never been a problem at all. But, I will say that leaving it in Drive normally makes for quicker shifts which helps ET/MPH..


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