Automatic Transmission and quick off-the-line

Koppel · November 30th, 2006, 01:35 PM

My friend tells me that trying to get a fast start in a car with an automatic transmission can damage the car.
The idea is to hold down the brake pedal, rev the engine quite high and then suddenly release the brake, right? As you would release the clutch in a manual.
(I don't have much experience with automatics, because I don't like them)
My friend thinks that this will destroy his gearbox or something. He had a car with a manual gearbox before and there was no problem there, we fooled around with it a lot.

There's a lot of Americans in here, automatic transmissions and drag racing have a long history there so you guys can probably help me out on this one.

But I have to explain the stuff to my friend so that he'll understands and believes it.

Adunaphel · November 30th, 2006, 01:38 PM

Revving the enine with the box in P or D with brakes on can seriously damage the torque-converter (or however it is called in english).

Benson · November 30th, 2006, 01:47 PM

Yup...
And there's massive tension in the drivetrain when you do that, which won't do your drive shafts, cardan-shaft (whatever it is in english.. images/smilies/smile.gif

) and differential any good...

Adunaphel · November 30th, 2006, 01:49 PM

prop-shaft images/smilies/smile.gif

Izari · November 30th, 2006, 01:55 PM

what u do is... rev to optimum point in N then dump it in D
...
automatic transmission safety launch 101 images/smilies/wink.gif

matt2000 · November 30th, 2006, 02:17 PM

does anyone remember which car had the belt driven auto box? it had 2 cones and a few belts in between them. as the speed increased, the belts moved up the cones, thus increasing the gearing. great until they snapped and you had to take half the car apart to get to it.

i think it was citroen or some other french company images/smilies/think.gif

Adunaphel · November 30th, 2006, 02:21 PM

That's the CVT, Continuously Variable Transmission, invented by the Van Doorne Brothers in Eindhoven and first intorduced in their Daf cars.

Sot · November 30th, 2006, 02:59 PM

Thanks for that. Look like Im taking off like a grandma from now on.

Izari · November 30th, 2006, 03:04 PM

buy a proper manual

Koppel · November 30th, 2006, 03:10 PM

Quote:

Originally Posted by Izari

buy a proper manual

I will buy a manual, no doubt about it, the question was aimed at my friends car.

So rev-ing in N (neutral) and then pulling the gear lever to D (drive) is the way to do a fast start with an automatic gearbox?

Izari · November 30th, 2006, 05:08 PM

Quote:

Originally Posted by Koppel

I will buy a manual, no doubt about it, the question was aimed at my friends car.

So rev-ing in N (neutral) and then pulling the gear lever to D (drive) is the way to do a fast start with an automatic gearbox?

ugh... yeah if u dont want to break the torque converter in like 5 tries...
the braking technique is quite hard on the auto tranny..

VR6 · November 30th, 2006, 05:09 PM

there is no way to do a fast start in an automatic, even if you do hold the brake and the gas most cars wont rev above the point where the torque converter engages so if you just floored it off the start you would get the same engagement point. If you ever rev the engine in N and drop it into D you better ask for a new transmission for christmas. Doing that would be like revving a manual and then somehow shoving it into first without the clutch.

WheatKing · November 30th, 2006, 05:38 PM

umm

automatics are AWESOME for drag racing.. much faster and more consistent than a manual.

is it hard on the torque converter.. possibly.. it's harder on the fluid.

Get a big tranny cooler installed.. and DONT do neutral drops with an automatic.. the instanteanous torque will break motor mounts, drive shafts and trannies many times quicker than riding to the stall on a torque converter.. maybe if you had a torqueflite 727 or a 2sp powerflite, then go ahead and do neutral drops.. not many trannies can survive the punishment.

get a tranny cooler installed like i said.. the trick is to put your foot on the brake and not hit the gas until its needed.. get on the gas until the converter stalls (point at which the engine cannot generate more rpm despite the throttle being wide open) and then get off the brake as quickly as you can.

it generates a TON of heat (hence the need for the fluid cooler) but will give you very consistent fast starts.

The torque converter is also a primitive CVT, there a mechanical ratio in play, and it will multiply the available torque of the engine before it's transferred to the wheels.. meaning you get a deeper gear ratio initially than what the transmission can provide by it's gearing.

Another trick is to prevent the tranny from going into it's "lockup" mode.. this is usually most easily defeated by finding the pin on the tranny wiring harness for the brake signal, and sending it to ground (torque converter unlocks when your on the brake, so you fake it).. again.. using the torque multiplication properties of the torque converter to your advantage.

real racing automatics have an integrated "transbrake".. it essentially locks the tranny into reverse and 1st gear at the same time.. preventing the car from moving.. and no need to have a foot on the brake, or stress the driveline.. until you take your finger off the switch.. LOL then all hell breaks loose!

Benson · November 30th, 2006, 06:14 PM

Quote:

Originally Posted by matt2000

does anyone remember which car had the belt driven auto box? it had 2 cones and a few belts in between them. as the speed increased, the belts moved up the cones, thus increasing the gearing. great until they snapped and you had to take half the car apart to get to it.

i think it was citroen or some other french company images/smilies/think.gif

DAF was the first make to bring it into production...
But Audi first had it in the older-model A6 and still sell it...As does Nissan in the Micra at least and some of the Frenchies... images/smilies/smile.gif

bone · November 30th, 2006, 06:37 PM

almost all 50cc scooters have that system as well

and i think it's kick ass. with some simple tweaks like another weight, or another slope on one of the discs, you can create a whole different power delivery

patrick10 · November 30th, 2006, 07:07 PM

Quote:

Originally Posted by Koppel

I will buy a manual, no doubt about it, the question was aimed at my friends car.

So rev-ing in N (neutral) and then pulling the gear lever to D (drive) is the way to do a fast start with an automatic gearbox?

neutral bombs are about the worst thing for a tranny, brake launch like what was said in the intital post. i had about 25 passes in my automatic 240sx all using brake launch with no problems. car had 90k on it with original tranny.

Koppel · November 30th, 2006, 07:27 PM

Conclusion: Don't do quick starts with an automatic transmission if you want your car to stay in tact.

BerserkerCatSplat · November 30th, 2006, 07:51 PM

Quote:

Originally Posted by Izari

what u do is... rev to optimum point in N then dump it in D
...
automatic transmission safety launch 101 images/smilies/wink.gif

Quote:

Originally Posted by Izari

ugh... yeah if u dont want to break the torque converter in like 5 tries...
the braking technique is quite hard on the auto tranny..

Jesus. If you don't know what the hell you're talking about, just shut the fuck up for once. Neutral drops are the best way to break an auto tranny, short of slamming it into reverse while driving.

If you don't have a transbrake, don't bother trying to launch your auto like that.

teletubby-warrior · November 30th, 2006, 10:39 PM

Quote:

Originally Posted by Izari

what u do is... rev to optimum point in N then dump it in D
...
automatic transmission safety launch 101 images/smilies/wink.gif

FATMOUSE · December 1st, 2006, 01:01 AM

Here's a fun question. What happens if you just put it into D and step on it?

Civic that I've driven I think would spin its tires if you did that.

November 30th, 2006, 01:35 PM	#1
Koppel Joined: May 30th, 2005 Last Online: January 4th, 2009 Location: Estonia Posts: 128 Rep Power: 17	Automatic Transmission and quick off-the-line My friend tells me that trying to get a fast start in a car with an automatic transmission can damage the car. The idea is to hold down the brake pedal, rev the engine quite high and then suddenly release the brake, right? As you would release the clutch in a manual. (I don't have much experience with automatics, because I don't like them) My friend thinks that this will destroy his gearbox or something. He had a car with a manual gearbox before and there was no problem there, we fooled around with it a lot. There's a lot of Americans in here, automatic transmissions and drag racing have a long history there so you guys can probably help me out on this one. But I have to explain the stuff to my friend so that he'll understands and believes it.

November 30th, 2006, 01:38 PM	#2
Adunaphel Global Moderator Joined: Jan 18th, 2006 Last Online: 05:40 PM Location: [ˈne:dərlɑnt] Age: 29 Posts: 3,597 Car: 1990 Mercedes-Benz 190E (W201) Rep Power: 67	Revving the enine with the box in P or D with brakes on can seriously damage the torque-converter (or however it is called in english). __________________ 01001001 00100000 01000001 01001101 00100000 01010100 01001000 01000101 00100000 01010011 01010100 01001001 01000111

November 30th, 2006, 01:47 PM	#3
Benson Joined: Jul 2nd, 2005 Last Online: 12:44 PM Location: Fulda, center of Germany Age: 23 Posts: 160 Car: BMW E28 525eA Rep Power: 15	Yup... And there's massive tension in the drivetrain when you do that, which won't do your drive shafts, cardan-shaft (whatever it is in english..) and differential any good...

November 30th, 2006, 01:49 PM	#4
Adunaphel Global Moderator Joined: Jan 18th, 2006 Last Online: 05:40 PM Location: [ˈne:dərlɑnt] Age: 29 Posts: 3,597 Car: 1990 Mercedes-Benz 190E (W201) Rep Power: 67	prop-shaft __________________ 01001001 00100000 01000001 01001101 00100000 01010100 01001000 01000101 00100000 01010011 01010100 01001001 01000111

November 30th, 2006, 01:55 PM	#5
Izari Resident Forum Noob Joined: May 25th, 2005 Last Online: December 28th, 2008 Location: Villanova Age: 23 Posts: 638 Car: 330XI Rep Power: 0	what u do is... rev to optimum point in N then dump it in D ... automatic transmission safety launch 101 __________________ First car - Audi A4 5MTQ (Traded in) Second Car - Nissan 350Z 6MT (Traded in) Third Car - BMW 330XI 5MT (Daily Driver)

November 30th, 2006, 02:17 PM	#6
matt2000 Hedgehog Sandwich Joined: Feb 17th, 2006 Last Online: 02:45 PM Location: Market Harborough, UK Age: 18 Posts: 3,682 Car: '77 Land Rover Series III LFS Status: Rep Power: 56	does anyone remember which car had the belt driven auto box? it had 2 cones and a few belts in between them. as the speed increased, the belts moved up the cones, thus increasing the gearing. great until they snapped and you had to take half the car apart to get to it. i think it was citroen or some other french company __________________ 'I've spoken to the scientist in that article. He is convinced that the parrot is "just resting".' - Plissken "My daughter has... errr HAD one, and I was given one" - Scott

November 30th, 2006, 02:21 PM	#7
Adunaphel Global Moderator Joined: Jan 18th, 2006 Last Online: 05:40 PM Location: [ˈne:dərlɑnt] Age: 29 Posts: 3,597 Car: 1990 Mercedes-Benz 190E (W201) Rep Power: 67	That's the CVT, Continuously Variable Transmission, invented by the Van Doorne Brothers in Eindhoven and first intorduced in their Daf cars. __________________ 01001001 00100000 01000001 01001101 00100000 01010100 01001000 01000101 00100000 01010011 01010100 01001001 01000111

November 30th, 2006, 02:59 PM	#8
Sot Joined: Sep 12th, 2006 Last Online: March 29th, 2007 Location: Adelaide Posts: 8 Rep Power: 0	Thanks for that. Look like Im taking off like a grandma from now on.

November 30th, 2006, 03:04 PM	#9
Izari Resident Forum Noob Joined: May 25th, 2005 Last Online: December 28th, 2008 Location: Villanova Age: 23 Posts: 638 Car: 330XI Rep Power: 0	buy a proper manual __________________ First car - Audi A4 5MTQ (Traded in) Second Car - Nissan 350Z 6MT (Traded in) Third Car - BMW 330XI 5MT (Daily Driver)

November 30th, 2006, 05:09 PM	#12
VR6 Joined: Aug 8th, 2006 Last Online: 06:07 PM Location: Calgary Alberta Canada Posts: 409 Car: 04 MSM LFS Status: Rep Power: 11	there is no way to do a fast start in an automatic, even if you do hold the brake and the gas most cars wont rev above the point where the torque converter engages so if you just floored it off the start you would get the same engagement point. If you ever rev the engine in N and drop it into D you better ask for a new transmission for christmas. Doing that would be like revving a manual and then somehow shoving it into first without the clutch.

November 30th, 2006, 05:38 PM	#13
WheatKing Joined: Nov 11th, 2004 Last Online: 08:05 PM Location: Ontario Canada Posts: 215 Car: '01 Sebring Coupe Rep Power: 0	umm automatics are AWESOME for drag racing.. much faster and more consistent than a manual. is it hard on the torque converter.. possibly.. it's harder on the fluid. Get a big tranny cooler installed.. and DONT do neutral drops with an automatic.. the instanteanous torque will break motor mounts, drive shafts and trannies many times quicker than riding to the stall on a torque converter.. maybe if you had a torqueflite 727 or a 2sp powerflite, then go ahead and do neutral drops.. not many trannies can survive the punishment. get a tranny cooler installed like i said.. the trick is to put your foot on the brake and not hit the gas until its needed.. get on the gas until the converter stalls (point at which the engine cannot generate more rpm despite the throttle being wide open) and then get off the brake as quickly as you can. it generates a TON of heat (hence the need for the fluid cooler) but will give you very consistent fast starts. The torque converter is also a primitive CVT, there a mechanical ratio in play, and it will multiply the available torque of the engine before it's transferred to the wheels.. meaning you get a deeper gear ratio initially than what the transmission can provide by it's gearing. Another trick is to prevent the tranny from going into it's "lockup" mode.. this is usually most easily defeated by finding the pin on the tranny wiring harness for the brake signal, and sending it to ground (torque converter unlocks when your on the brake, so you fake it).. again.. using the torque multiplication properties of the torque converter to your advantage. real racing automatics have an integrated "transbrake".. it essentially locks the tranny into reverse and 1st gear at the same time.. preventing the car from moving.. and no need to have a foot on the brake, or stress the driveline.. until you take your finger off the switch.. LOL then all hell breaks loose!

November 30th, 2006, 06:37 PM	#15
bone "bangle for president" Joined: Jan 14th, 2004 Last Online: 07:01 PM Location: belgium!! Age: 24 Posts: 6,085 Car: yamaha banshee (and an opel astra from work) Rep Power: 29	almost all 50cc scooters have that system as well and i think it's kick ass. with some simple tweaks like another weight, or another slope on one of the discs, you can create a whole different power delivery __________________ groups/artists i've seen live: coldplay, the cure, cypress hill, damian marley, deftones, depeche mode, dEUS, franz ferdinand, grandaddy, guns n' roses, interpol, jamiroquai, korn, lenny kravits, marilyn manson, massive attack, metallica, moby, muse, the pixies, placebo, prodigy, queens of the stone age, the raconteurs, radiohead, red hot chili peppers, REM, skin, tool, the who, Wu-Tang and so many more...

November 30th, 2006, 07:27 PM	#17
Koppel Joined: May 30th, 2005 Last Online: January 4th, 2009 Location: Estonia Posts: 128 Rep Power: 17	Conclusion: Don't do quick starts with an automatic transmission if you want your car to stay in tact.

December 1st, 2006, 01:01 AM	#20
FATMOUSE Joined: Jun 30th, 2005 Last Online: 07:48 PM Location: NYC Posts: 3,088 Rep Power: 35	Here's a fun question. What happens if you just put it into D and step on it? Civic that I've driven I think would spin its tires if you did that.

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