GT Performance Mods 2005+ Mustang GT Performance and Technical Information

Drag racing automatic launch question.

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Old May 31, 2007 | 08:11 PM
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Drag racing automatic launch question.

Ok, I know to turn off T/C while at the track...
But, what about over drive?

I ran a 13.5 with overdrive off and a 13.3 with it on.

I have been told to turn off O/D when racing so why the better time with it on?
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Old May 31, 2007 | 09:11 PM
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I don't think it would matter much, probably just a variance on the temp/humidity/launch...etc. The car should run the same with O/D on or off.
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Old May 31, 2007 | 09:36 PM
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Can you elaborate on that? I am not challenging you, just trying to better understand my vehicle.
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Old May 31, 2007 | 09:49 PM
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It's and O/D... 5th gear. Disabling O/D doesn't change anything (pattern or pressure). Doesn't matter if it's on or off when racing.
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Old May 31, 2007 | 10:11 PM
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Ok... but when I am driving down the street and punch the O/D disable. The engine revs about 500 rpms higher. Almost like a downshift. So I am sure the O/D is not just a 5th gear.
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Old May 31, 2007 | 10:48 PM
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I hope I can explain this well enough. When you hit the O/D button, two things happen. The torque converter unlocks, and the car shifts out of 5th gear (if it was in 5th when you hit the button). If the car is in any gear but 5th, the converter will still unlock I think, then relock if it feels necessary. That could be the 500rpm raise you see. Or it just shifted out of 5th gear.

The O/D button just disables the overdrive, which is 5th gear.
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Old May 31, 2007 | 11:05 PM
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I got it.... That makes alot of sense.
Thanks
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Old May 31, 2007 | 11:10 PM
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what did you launch at during your 13.3 run?
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Old Jun 1, 2007 | 12:17 AM
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The Green Light?
I am not sure what you mean?
60' time????
I'll have to find my slip.
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Old Jun 1, 2007 | 12:41 AM
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He means what RPM's did you brake torque to at the line.
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Old Jun 1, 2007 | 04:26 PM
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Oh, I preload the drive train to about 2000 RPM's any more and it breaks loose.
4:10 gears and all that.
I know you can put it in neutral and back into drive to allow the brake pressure to spike, I just seem too busy to do all that when I stage.
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Old Jun 1, 2007 | 06:57 PM
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You know, I never thought of that. Might be good for a few hundred RPM's. I hear ya though, I've got 4.10's in my auto too, and I can't launch any higher than 2k either.
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Old Jun 1, 2007 | 07:58 PM
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Same here with 4.10. Best 60" 1.90 on nitto radial.
Just passed my command for a TCI 3000. Can't wait to see the result.
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Old Jun 1, 2007 | 09:00 PM
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Originally Posted by enitalp
Same here with 4.10. Best 60" 1.90 on nitto radial.
Just passed my command for a TCI 3000. Can't wait to see the result.
Ohh that set-up with a line lock and you'd be set.
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Old Jun 1, 2007 | 09:33 PM
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if you never get going fast enough for the car to have a chance at shifting into 5th gear, it wount matter if the over drive is activated or not.
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Old Jun 1, 2007 | 09:33 PM
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when i launch at 1500 i get 1.9 on stockers.
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Old Jun 1, 2007 | 09:34 PM
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Originally Posted by Sharky
Ohh that set-up with a line lock and you'd be set.
why does he need line locks?
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Old Jun 2, 2007 | 10:47 AM
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Because in an auto you have to brake torque to load the drive train.
With a torqu converter you can get your launch at a higher RPM.
And with a line lock you can ship the brake torque and use the line lock as a launch controller in union with the torque converter.
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Old Jun 2, 2007 | 01:43 PM
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i still dont get it, line locks go on the front, that has nothing to do with the torque converter.
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Old Jun 2, 2007 | 02:58 PM
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I have a linelock in front of course for burn my new slick, but i think he's thinking about using a linelock for the rear for staging.
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