Silvia S13 Question About Launching (0-100 Test Automatic)

[La Bomba]

Well after babying my car for the past several days since having it, I have tried to do a 0-100 test, however I am unable to launch it :S. Here is the problem.

I loaded up on the breaks, and had the handbreak on, and put the accelerator down, and it wouldnt rev past 2000rpm? I had the gear selected in drive.

So why does it do this? :S

[02stagea]

Beacause it's an automatic N/A SR20. It knows what a waste of time a 'launch' would be. So your car just can't be bothered.

I thought you were going to get a manual one?

[SKiT_R31]

Because you only have 2000rpm of stall up in your torque convertor, this is a good thing because it makes your car more responsive in gear above those revs. If you want more you would need to buy a higher rpm stall convertor, you can get them as high as you want - 3500rpm etc, but they make the car a lazy pig to drive and bad on fuel.

You are stuck with the 2000rpm to launch from, unless you want to do the neutral drop into drive trick (I used to do it a lot when I was ‘a wee lad’ trying to kill my gearbox before manual conversion). This is not a good option for your box as it will misalign the selectors, and could f**k the box all together. That said, my box loved it, every now and then the selectors would stuff up, I'd just have to put it in park and hold it on the throttle (it would stall up like it was in gear) until it would clunk then free rev, meaning it was then fixed.

If you want a car you can 'launch' and still drive everyday, you really want it to be a manual. An SR20 S13 with a 5 speed behind it and a couple mild modifications would actually be quite zippy. Manual conversion will cost <$1k and is relatively easy to do if you have a weekend spare and a handy mate.

[mad082]

it does it because it is an auto. as has been said, an ordinary automatic gearbox doesn't have a clutch, it has a stall/torque converter. automatic gearboxes get their drive in quite a different manner to manual gearboxes. they have a clutch plate that gets jammed against the flywheel so that whenever the clutch is engaged the input shaft to the gearbox moves as fast as the motor, but when the clutch is disengaged the engine spins and the gearbox doesn't.

automatic gearboxes on the other hand are somewhat more complicated. the first thing to know is that they are much less mechanically driven than a manual gearbox and much more hydraulically driven. the easiest way to explain the stall converter side of things is by comparing it to stirring a cup of tea/coffee/hot chocolate or whatever takes your fancy. you will have noticed that when you stir and then stop the liquid keeps moving and the faster you stir the faster the liquid goes, and if you are only using a plastic spoon the force may be enough to even move the spoon a little bit once you let go of it. well an automatic gearbox works in a similar way. the stall/torque converter is like the cup and the spoon, except there is a second spoon in the cup which simply spins around. that is the bit that drives the gearbox. at the same time though, the spoon representing the gearbox also plays a part by limiting how fast you can spin the liquid if the spoon is held still.

if you were to alter the size of the spoons you would alter how fast you have to stir before the gearbox spoon started to spin. for example if you to turn the spoon upside down so that the handle is in the liquid, you would have to stir much faster to have the same effect because of the much smaller surface area. in the case of the stall converter this would result in the engine reving much higher before you started to move. this can be beneficial for getting off the line as you can get the car into a difference part of the powerband, but it can make it a pain to drive on the road. if you had a 3500rpm stall, then without actually stalling up the car (foot on the brake), everytime you take off normally you will have to put your foot down further and have the revs build up higher. this can also mean that going up hills at lower speeds you may find the car changing down to a lower gear than it previously did, or simply revving higher.

that is a basic run down of how the stall/torque converter of an auto gearbox works.

[La Bomba]

Beacause it's an automatic N/A SR20. It knows what a waste of time a 'launch' would be. So your car just can't be bothered.

I thought you were going to get a manual one?

Yeah I'd been looking to get a manual, but all the manuals I Looked at on carsales etc werent in good condiiton. I found a one owner car since being imported to Australia in 2000, some lady had owned it for 10 years, was in absolutely immaculate condition, no rust no nothing. Only problem was it was auto but I thought eh at least I won't get as many problems mainly because its genuine low km's and it hasn't been thrashed. So I just went ahead with the auto. Will do a manual conversion most likely once I'm off my P plates.

And thanks guys for the explaination of the 2000rpm stall, makes sense now. I'm not going to bother with a higher stall because I'm not going to be thrashing my car, just wanted to test the 0-100 and thought something msut of been wrong that didnt go past 2000.

[curlyjimbo]

Look into a Manual conversion

[timr32gts]

rev it too 7000 in neutral and put it up to drive that will launch you

[ARTZ]

rev it too 7000 in neutral and put it up to drive that will launch you

Yeah this is your only hope, i used to this in my 4ltr cortina it would fry the little 13inch rims for 100meters.. But that was a 4ltr. With a 2ltr and 15inch rims you aint got much hope kid.

[La Bomba]

Yeah this is your only hope, i used to this in my 4ltr cortina it would fry the little 13inch rims for 100meters.. But that was a 4ltr. With a 2ltr and 15inch rims you aint got much hope kid.

My silvia has 16 inch or 17 inch Zeptor rims, they run 225 for the rear tires.

Anyway wouldnt that like ruin my gearbox if I slammed it into Drive at 7000 rpm? and like destroy the stall converter?

Edited July 14, 2010 by La Bomba

[mad082]

it's not the best for them no, LOL.