Fast acceleration from start with Automatic

Fast acceleration from start with Automatic

Author
Discussion

mawallace

Original Poster:

184 posts

80 months

Friday 20th November 2020
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With a manual gear box you can get a quick getaway by raising the revs and then releasing the clutch.

How do you achieve the same with an automatic?

Edited by mawallace on Friday 20th November 09:36

DickyC

51,728 posts

205 months

Friday 20th November 2020
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coffee

DickyC

51,728 posts

205 months

Friday 20th November 2020
quotequote all
I apologise, that wasn't helpful.

Did you mean for your first sentence to be a question?

mawallace

Original Poster:

184 posts

80 months

Friday 20th November 2020
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No - first sentence was a statement!

joropug

2,700 posts

196 months

Friday 20th November 2020
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Left foot brake and gently apply pressure on accelerator

This will get the torque converter primed and it will go without any delay.

Do it for too long or too aggressively you'll probably do damage. The 'officially gassed' guy on YouTube blew up driveshafts doing it on an RS5.

DickyC

51,728 posts

205 months

Friday 20th November 2020
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Or you trust the car's designers to have thought of this and optimised everything to get you away as fast as possible. A lot of cars fight their traction control and make you slower if you try anything heroic. Smooth driving makes you faster. Less dramatic but faster.

rix

2,846 posts

197 months

Friday 20th November 2020
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Foot on brake. Foot off brake. Mash accelerator. Go...

In all seriousness, I've always found dual clutch boxes somewhat tardier on take off than a proper torque converter. The ZF8 in my 840i for example is pretty rapid at the toll gantry grand prix. The other half's audi box is approaching dangerous with its ponderous nature.

ruggedscotty

5,794 posts

216 months

Friday 20th November 2020
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look up launch....

but watch as it could lunch yer box


DSG on an A6 TDI....

google revealed a few button presses.... then foot on brake accelerate to a specific rpm, release brake and mash the accelerator,,


fk me.... seriosuly a 3.0 tdi did what id say a 60 in less than 6.. id also not be keen on doing it again as it is brutal indeed

Timberwolf

5,374 posts

225 months

Friday 20th November 2020
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Slam your right foot on the boards up until you're playing with cars that can happily break traction in gear, from which point a gentle roll on the pedal is preferred. (Modern traction control systems may be better, but at least up until a few years ago you could still get better results holding the throttle at the point where the drive wheels just start slipping).

You can bugger about holding it on the brakes but after some wasted youth I can report that while it might get you an extra 0.1s on the drag strip, in the real world the only perceptible difference is having a lot of unpleasant and mechanically unsympathetic noises emanate from the transmission tunnel while you look like a wally to anyone nearby.

Or buy something with launch control for all the endlessly repeatable full-bore acceleration and denied warranty claims you could ever want or need.

MarvinTPA

239 posts

136 months

Monday 23rd November 2020
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American method - put car in neutral, rev, drop in to drive.

Toltec

7,167 posts

230 months

Monday 23rd November 2020
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One of the benefits of a torque convertor is they allow the engine rotation to be higher than the gearbox input rotation, I think the difference is called the stall speed? It means you can have the power produced at the engine rpm fed into the drivetrain which effectively spinng at what would be a lower engine speed. Allowing for losses it basically multiplies the torque fed into the drivetrain.

I guess the American method is something like dropping the clutch in that the brake bands in the gearbox will slip until either the engine speed has been pulled down enough or the wheels have started to spin and raised the gearbox speed enough for the torque convertor to cope with the difference.

Getting it right will be something like gauging the perfect amount of wheel spin to get maximum traction and therefore acceleration, too much and you are slower off the line.

Maximum launch aside you can press the accelerator just enough to raise the revs to the stall point then release the brake and press down the accelerator and let the traction control, sport mode obviously, take care of the wheel traction.

A well designed TC automatic is a lovely bit of engineering even if not as rewarding as a perfect manual launch.

Gio G

2,978 posts

216 months

Monday 23rd November 2020
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joropug said:
Left foot brake and gently apply pressure on accelerator

This will get the torque converter primed and it will go without any delay.

Do it for too long or too aggressively you'll probably do damage. The 'officially gassed' guy on YouTube blew up driveshafts doing it on an RS5.
Worth bearing in mind Mr gassed re-mapped his car to develop a bunch more torque over stock and probably launched it way too many times....

Optimum acceleration can be had by, switching traction to sport (not fully off) left foot firmly on brake pedal, right foot to bring rev's around 3,500 - 4000 rpm (there is a sweet spot for different cars) foot off brake and mash the accelerator..

G

tivver500

370 posts

277 months

Saturday 5th December 2020
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Gio G said:
Worth bearing in mind Mr gassed re-mapped his car to develop a bunch more torque over stock and probably launched it way too many times....

Optimum acceleration can be had by, switching traction to sport (not fully off) left foot firmly on brake pedal, right foot to bring rev's around 3,500 - 4000 rpm (there is a sweet spot for different cars) foot off brake and mash the accelerator..

G
Worth noting if you drive a VW (or Skoda or Seat) with a dsg box..... As soon as you touch the brake the 'electronics' kill the accelerator so cannot raise the revs while braking!!

On my Cupra it has launch control which does allow success at the traffic light GP. One of the guys on the forum has timed his Cupra ST (4-wheel drive) at under 4sec for the 0-60 dash.
If, on the other hand, you mash the throttle on my TVR you get loads of smoke and indications to look up new tyre prices!!!

waremark

3,256 posts

220 months

Saturday 5th December 2020
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In normal driving with reasonable mechanical sympathy an automatic is faster off the line than a manual because in the auto you can mash the throttle and benefit from torque multiplication while you are still engaging the clutch smoothly in the manual. The auto gets further ahead when you change from 1st to 2nd in the manual.

The fastest off the line is probably a 4 wheel drive Tesla - instant torque and the traction to use it. But now very fast cars do 0 - 60 under 3 seconds I cannot believe anyone takes advantage except on the drag strip.

mawallace

Original Poster:

184 posts

80 months

Saturday 5th December 2020
quotequote all
tivver500 said:
Worth noting if you drive a VW (or Skoda or Seat) with a dsg box..... As soon as you touch the brake the 'electronics' kill the accelerator so cannot raise the revs while braking!!

On my Cupra it has launch control which does allow success at the traffic light GP. One of the guys on the forum has timed his Cupra ST (4-wheel drive) at under 4sec for the 0-60 dash.
If, on the other hand, you mash the throttle on my TVR you get loads of smoke and indications to look up new tyre prices!!!
Found out tonight that VW have a launch control mode - see https://www.youtube.com/watch?v=UelttDybkw0

GEllisM4

59 posts

72 months

Thursday 7th January 2021
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It’s not the same in my current car with it being a DCT, but my 335d was an ‘automatic’ (Torque Converter) which I assume you’re talking about trying to launch.

I found the best way to do was to hold it on the brake and also apply some throttle, and then release the brake once you’re ready to go. You’re effectively ‘loading’ the torque converter up and when you launch you get, what feels like, an elastic band effect. That’s essentially what launch control did in that car anyways. Give that a go mate!

If you have a Double Clutch transmission, it’s a little different

PhilAsia

4,858 posts

82 months

Thursday 7th January 2021
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First time I saw left foot on the brake and build the revs was by Ron Easton, the Chief Photographer for Autocar. I was going out with his daughter and got to sit in some of the latest cars as they were introduced to the public.

It is not particularly good for the bands on a traditional torque converter gearbox and I would definitely avoid it on a CVT and DCT gearbox.

Edited by PhilAsia on Thursday 7th January 17:22

Sticks.

9,016 posts

258 months

Thursday 7th January 2021
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Why not select first and then every time it hits the red line it'll change up? And when you're at the speed you want, move it to auto mode.

Thorodin

2,459 posts

140 months

Wednesday 24th February 2021
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My Auto 'box has auto select and sequential 1/2/3/4 manually. (Rover 75). It enables holding the selected gear until max revs in any gear before you push the stick to change up. Obviously, judicial use is recommended. Fortunately, Reverse is at the far end, just before Park! . It also means you can select any gear and hold it there in snow etc to maintain progress. Brilliant.

The spinner of plates

17,955 posts

207 months

Thursday 4th March 2021
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joropug said:
Left foot brake and gently apply pressure on accelerator

This will get the torque converter primed and it will go without any delay.

Do it for too long or too aggressively you'll probably do damage. The 'officially gassed' guy on YouTube blew up driveshafts doing it on an RS5.
Yup, my old Merc slush-matic responds well to this on the rare occasion I need to get away sharpish. Very light pressure just to take up the slack.

Also clicking the sport button ensure it sets off in 1st. By default it will pull away in 2nd.

When doing this I'm always surprised that for a 15 year old lazy dag-dag, it can still be quite brisk. Initially.