Automatic Transmission and quick off-the-line

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Koppel

Koppel

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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.
 
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...
 
what u do is... rev to optimum point in N then dump it in D
...
automatic transmission safety launch 101 ;)
 
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:think:
 
buy a proper manual
 
Izari said:
buy a proper manual
Click to expand...

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?
 
Koppel said:
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?
Click to expand...

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..
 
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.
 
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!
 
matt2000 said:
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:think:
Click to expand...

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... :)
 
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
 
Koppel said:
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?
Click to expand...

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.
 
Conclusion: Don't do quick starts with an automatic transmission if you want your car to stay in tact.
 
Izari said:
what u do is... rev to optimum point in N then dump it in D
...
automatic transmission safety launch 101 ;)
Click to expand...

Izari said:
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..
Click to expand...

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.
 
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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