Author Topic: Off the line with an automatic trans?  (Read 3183 times)

Offline jforest1

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Off the line with an automatic trans?
« on: December 09, 2011 - 01:43:54 PM »
Guys with standards can just use the clutch to lay down the engine + flywheel to the tires.

I have been recently playing around with getting a quick start and I'm not sure if there is an equivalent for an automatic.  Only thing I can think of is going from Neutral (at high RPM) to Drive, but I haven't tried it because frankly I don't understand what is happening. 

So my questions are: 
How is popping the clutch different from going from high RPM neutral to D in an automatic? 
Does it stress different components? 
Is there another way to go about dropping the hammer off the line with an automatic?

Sorry in advance for such a noobie question.

JF
« Last Edit: December 09, 2011 - 03:40:31 PM by jforest1 »
'73 Cuda 340 Slapstick, A727 Torqueflite Transmission, Edelbrock Thunder Series AVS 1806, Vintage Air Gen IV A/C system




Offline footin70rt

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Re: Off the line with an automatic trans?
« Reply #1 on: December 09, 2011 - 04:22:42 PM »
You do not want to do a neutral drop with an automatic! When you rev the engine in neutral the input shaft and torque converter are at about the same speed,  pump in the trans is spinning at that higher speed too, more line pressure, so when you drop it into gear the forward clutches will come on and try to transfer the power through the trans.

If the car is slow out of the hole, (bogs) won't spin the tires, you may have to tall rear end gears, not enough converter, too much cam ( if that's possible :bigsmile:) or a combination thereof.
Thomas
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Native of Bozeman, MT

Offline burdar

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Re: Off the line with an automatic trans?
« Reply #2 on: December 09, 2011 - 05:02:14 PM »
To get "manual like" starts with an auto, people install a transbrake.  What this does is hydraulically lock the trans in 1st AND reverse so the car can't move.  It is activated by a switch.  When the last yellow light on the tree comes on, all you have to do is reliece the button.  Reverse is disengaged and you dart forward.

I think Chrysler(in the 60's)  experimented with a 727 that had the converter replaced by a clutch.  Didn't they call it a Clutchflite or something like that?  I don't think it worked very well.     

Offline 62Furious

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Re: Off the line with an automatic trans?
« Reply #3 on: December 19, 2011 - 08:04:14 AM »
If I understand your question you would like to do a smokie burn out.One foot on the brake and one on the gas, push on the brake and ever so slowly push on the gas untill you feel the car push, release brake and stab the gas. If this does not give you the satisfaction you are looking for than it is time to get a High Stall converter,[around 3000] should be good for the street. but with a High Stall converter comes heat, ad a trans cooler and a deep trans pan, it will add a little more fluid and keep the heat down in your trans
Keep a skip in your step and a smile on your face makes for a great day

Offline Geoff1200

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Re: Off the line with an automatic trans?
« Reply #4 on: December 19, 2011 - 09:01:03 AM »
To get "manual like" starts with an auto, people install a transbrake.  What this does is hydraulically lock the trans in 1st AND reverse so the car can't move.  It is activated by a switch.  When the last yellow light on the tree comes on, all you have to do is reliece the button.  Reverse is disengaged and you dart forward.

I think Chrysler(in the 60's)  experimented with a 727 that had the converter replaced by a clutch.  Didn't they call it a Clutchflite or something like that?  I don't think it worked very well.   

Aahhh the memories...clutch automatic...Great way to break ALOT of parts. Pulled the pinion out of the differential (8.75) on my 71 Demon

Offline Cooter

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Re: Off the line with an automatic trans?
« Reply #5 on: December 19, 2011 - 12:54:07 PM »
Bottom line? Trans brakes, Manual 5000 RPM clutch dumps damage parts. If you want your 8 3/4 axles/pinion and ring gear in a bucket, hard launches will do it eventually.


 Trans brakes are NOT for the faint of heart. High stall Converters are NOT for the faint of heart, but they do work. A nice 4000 RPM Stall converter with some gear in the rear and traction aids usually take care of the  launch. Course, you need enough engine to make all this stuff work properly too.
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