It's Friday and my boredom at work has got me thinking. I'm just curious, what would happen if I was to redline my supra (autobox) and then put it into drive?
I can think of three possible outcomes:
1 - Something breaks in the gearbox, although I'm not sure what, gears or clutches? Would the torque converter fail?
2 - Failure in the drive train, either the diff or UVs
3 - Two smoking tyres!
I'm never going to try this out, but there must be someone here who's had experience of this?
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Standard practice in the US for drag racing with autoboxes.
Doubt if it does the car much good, but a Supra should stand up to it a few times surely?
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A surprisingly popular test for those involved with development of transmission, driveline components whether it be auto as you describe of slipping your foot sideways of the clutch in a manual. New cars are clearly capable of surviving this, but with older cars (where some components will be worn to an unknown degree) I would be somewhat cautions.
Best avoid doing this sort of thisn on the road. It may proove a little too "exciting" for that environment!!
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Used to do this all the time with hire cars in the states. Answer is if the car is a load of carp you get massive driveline tramp and then a nasty sounding whump as it slowly wheelspins it's way up the road- A Buick le sabre does exactly this.
Try it in something better like an auto Subaru Outback and the car just hooks up and goes although this may be the effect of awd as well as a tighter drivetrain.
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Yep, that drivetrain shunt may break thing - if it doesn't simply stall the engine.
However, depending on the state of fill of the box, you could get a hydrostatic shockwave, which will rupture casings and seals - especially those on lines going to any ATF-cooler you have .. AND also run the risk of stuffing said cooler...
basically, it is a silly idea.
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you describe of slipping your foot sideways of the clutch in a manual.
I was a passenger in a 4x4 350bhp cossie when the driver did that. I nearly swallowed my tongue it went that quick.
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Aim low, expect nothing & dont be disappointed
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If you are that stupid why don't you just do it? We can then all have a good laugh.
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you will either as said get a few good goes out of it before it disapears in a whiff of white smoke
the driveshaft will break
you will hear a nasty noise fom under the bonnet
a better one is to try and blow an engine up deliberately, unless its already knocking then its very difficult, even harder these days what with rev limiters etc,sometimes all the fun is taken out of life.
please dont try this at home as the oil ruins fancy block paving
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Actually, a more exciting way of making progress is to plonk it into D and then rev the engine with your foot on the brake. Foot off the brake and all the energy you just stored in the torque convertor goes straight into the gearbox with the engine already at high-ish RPM.
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Just drive your car into a brick wall / large tree, job done and you get to see the airbag go of too.
Warning a few weeks on crutches may follow.
;O)
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The only way to find out is to actually do it. I'm all agog!
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L\'escargot.
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Good point from David - This is a good technique which I already use - holding on the brake and loading the torque convertor. Although it puts a large load on the car there are no nasty shocks or jolts as there is no slack in the drive train. The only downside to this that I can think of is that the trans fluid will get pretty hot if you hold it for too long.
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holding on the brake and...
foot to the floor (briefly) used to be a way of "testing" auto boxes to see if the clutches would slip. The RPM at that point could tell you if the engine was down on power too.
There was also an undesireable ailment called "squawk", but I can't remember what that was about..
This is half remembered from the BL manual for an automatic 1850 Dolomite - Borg-Warner 65.....
Auto change up points with foot buried in the carpet - to second at 40, to third at 65.
Kick-down into first from third in town traffic at a bit under 30 MPH was interesting.
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Good point from David - This is a good technique which I already use - holding on the brake and loading the torque convertor. Although it puts a large load on the car there are no nasty shocks or jolts as there is no slack in the drive train. The only downside to this that I can think of is that the trans fluid will get pretty hot if you hold it for too long.
I've tried this on various cars which has resulted in some spectacular wheelspin and a serious kick in the back from the acceleration, especially from large capacity american cars. The exception was when I tried it out on a Chevrolet Trailblazer in 4wd mode. It resulted in some very odd clonks and bangs from underneath and a very strange smell (presumably of cooking ATF fluid).
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I like to think i'm not that stupid and I already said in my original post that I'm never going to try it. I'm curious to know if other people have done it and what the result was.
I'm having a good laugh at your silly post :)
(please note the smilely!)
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There used to be a programme on the television called Brookside, and a character named Sinbad did this in a Peugeot 205. It just screeched off.
There is no direct drive in an *true* automatic, so the torque converter fluid will take up the shock.
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in the intrests of science i've just gone and done it on my nissan note auto.
it jolts forwards very quickly but no noise or disquite from the gear train. did it 3 times and ca't seem to break anything.
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in the intrests of science i've just gone and done it on my nissan note auto. it jolts forwards very quickly but no noise or disquite from the gear train. did it 3 times and ca't seem to break anything.
The only way you'll break a Jatco autobox is by dropping it off a tall building. I'd expect a frail, failing transmission wouldn't thank you for the strain of doing this, but a healthy box would take it in its stride - heating the ATF by a few degrees isn't going to do any harm.
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did this inadvertently once in one of BL's not so finest
automatic Austin Allegro 1.7 wouldn't start........jump started it and revved the nads off it for a moment, in the hope that when i let it tick over and selected D it wouldn't stall
whilst at the rev limit, the damned thing somehow selected reverse..........it wheel spinned backwards and rammed a Talbot Avenger parked behind it
was quite dramatic and my work colleagues congratulated me on getting an Allegro to wheel spin
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I wouldn't like to do it with my own car, but any heavy duty transmission can take this all day long. A JCB will have to change direction hundreds of times a day and will usually be going one way when the other direction is selected.
On a modern tractor the operator would be very upset is he was unable to change direction with out pressing the clutch and he would rightly expect to pull away under full load every time for the life of the machine.
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Great to hear from those who have tried this, it seems that most cars should be able to cope with it.
I took the supra in for its MOT this morning and on the way home I went via a country lane that goes from nowhere to nowhere so it has virtually no traffic. Theres a very long striaght piece of road (unusual for a country lane) so I took the oppurtunity to experiment a little with loading the torque convertor more than I would normally (when I've tried this before I've only rev'd to around 3k rpm).
Unfortunately it had just rained so the road was wet so not the best of times for this.
I came to a stop in the road, checked for other cars, left foot on the brake, right foot hard down on the gas, the result....
The nose dipped down, suspension and brakes groaned and then wheelspin, wheelspin and more wheelspin. As I let go of the brake - just more wheelspin.
I'll try again when the roads dry, but I still dont want to risk dropping in to 'D' (these cars are getting rare and parts are hard to come by) so for me loading the torque convertor is the way to go. I think on a dry road it should maintain its grip and give less of the hooligan behaviour.
Top marks to those have been brave/stupid enough to try it, some of you with your own cars! :)
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Don't know about dropping into D from the red line, but my old Renault 19 auto just jolted when doing this from about 3k, not deliberate, just the result of me forgetting that it takes a couple of seconds for D to engage after moving the selector.
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With a front wheel drive car I imagine you can really load it up... :)
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I came to a stop in the road checked for other cars left foot on the brake right foot hard down on the gas the result.... The nose dipped down suspension and brakes groaned and then wheelspin wheelspin and more wheelspin. As I let go of the brake - just more wheelspin.
I remember reading a road test for an early '90's Camaro IROC/Z, in a US car mag (why do I remember all this stuff?). The stated method for best acceleration times was something along the lines of:
Left foot on brake, select Drive, progressively press accelerator until torque just begins to beat the brakes and wheels begin to turn, then release brake and mash throttle at the same time.
You'll have to report back when you have tried it on a dry road!
;o)
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I believe it's known as a 'lawn job' in the US.
Someone upsets you, park on their front lawn, redline it, followed by 'D'.
Guess what it does to their nice lawn?
JS
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In the 1960s my work colleagues used to brag about how they had found you could put a Ford Thunderbird (on loan for disc brake R&D purposes) into reverse at 80 mph without any problem.
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L\'escargot.
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