What is the correst start for 1/4

[Vovan]

Guys, how do you start on GTS-T? i know, you make tire pressure lower, but how do you play with clutch?

[SHUTO-BOY]

ride the clutch halfway, at 3500rpm, then release and go

[Jimbo2000]

thats gona get a little smelly isn't it?

[rev210]

drop the clutch, feed the throttle.

[Vovan]

>drop the clutch, feed the throttle

By doing this my wheels spin whole 1st and half second gear

[Steve]

Originally posted by Vovan

>drop the clutch, feed the throttle

By doing this my wheels spin whole 1st and half second gear

You could try:

feeding the throttle a bit slower,

get a wheel alignment and try and get the rears as neutral as possible,

fit cradle bushes,

set sus to hard so you dont sqat (this will change the wheel alignment),

warmup the tyres well,

buy larger softer rated tyres (Nittos are good),

fit an autronic or motec with traction control.

Lots of options.

And best of all, practice till you find what works well on your car:)

[Cubes]

I launch in my 32 at around 4200rpm-4500rpm and ride the crap out of the clutch basically just take your time and dont drop it. You will launch quicker.

Doing it this way I've managed to fend of a Stock R33 GTR right through 4th gear where we backed off. He launched at 5000rpm.

Tyres only slightly chirp over the white line with the car launching with what sounds like an auto stally.

BUT.. Every now and again I ride it just that little bit to much and when I click second it slips and the rev's bounce off the rev limiter. I then have to back off the accelerator and plant it again.

[zaero]

ride the clutch, works best for me anyway

[jlnewton]

In my 33 I find that 3000rpm and not dropping the clutch just letting it out works best for me. My 60ft times are ok considering I am using road tyres with 36psi. Can't bring myself to let them down yet.

[MattyB]

i find i ride the clutch big time for the that first initial take off. then after that feed her the fat.

practice lots and work out what works for you.

[Roy]

I dont think stiffening up the rear is going to help power down? Ok it may stop the rear susps from creeping in a little more camber when squatting, but soft rear susp is the go for traction in a RWD car.

Oh and i shouldnt relly be giving advice on how to launch a car... i have no idea thats why i like circuits, they make you leave the pits at a nice slow speed:o

[Steve]

Roy, squat is all good if you have a solid axle as it transfers weight to where it is needed, but if not, it will cause nothing but dramas.

[Cubes]

I've still got stock suspension and even though it does squat quite a bit the inside of the tyres are evenly worn all over.

Maybe the 33's are a little worse??

When I had my VS commodore with IRS I had the whiteline camber/castor kit fitted. That really did stiffen up the rear end and stopped squat. Prior to fitting the kit you could feel it squat and thats even with bilstein adj shocks and low hd springs, adj sway bars.

So if just the bushes made that much difference maybe that is all that is needed.

[Roy]

but if not, it will cause nothing but dramas.

What dramas? Im not too well versed with drag racing other then i enjoy watching it. Though when looking at suspension previously the factors considered for good power down must still hold true.

My understanding with a bit of thought to the mechanics of it all is that with soft/factory rear suspension, inertia moves a % of vehicles body weight over the rear axle. This added weight improves traction as it increases the normal load (load perpindicular to the ground) on the tyres. This is the reason FWD cars run very stiff rear susp in an attempt to stop this from occuring.

Basically more weight over the rear, better power down. Now for drag racing you are essentially running tyres with softer sidewalls, or at least low tyre pressures. So the contact patch of the tyre is not going to be as sensitive to camber change when rear suspension is under compression. What sort of change does the rear camber undergo anyway????

So if you stiffen up suspension then you inhibit the weight transfer from front to rear , which is a good thing for balance/braking etc, but not ideal if you are chasing purely traction.

Am i missing something

[Steve]

Your tyres will not be flat on the track. If you set up the camber on your car, then it squats, you no longer have optimum camber. TRY09 used solid metal bars in place of shocks/springs to ensure the camber didnt change, then used the sidewall compression to take car of the rest.

The only other option is to set up camber positive to make sure that the wheels sit correctly when launching. this is pretty difficult to do, so it is best to get a good alignment (for drag) then set up your sus so that it changes as little as possible when launching.

You may get all of the tyre on the track when launching, but that doesnt mean that the whole tyre is doing an optimum job. More weight on the inside will mean less traction.

This is of course with IRS, live axles are completely different as they wont change their geometry.

[Roy]

So what sort of change are we talking about... i think i have about 0.5deg neg camber at the rear. So under compression off the line do you know what sort of camber actually gets dialled.

When designing wishbone suspension a lot of work goes into minimising this, unequal lenght arms/suspension pick up points etc etc.

So , as a rule then is it fair to say that factory rear shocks and springs are better for stationary traction then harder aftermarket shocks/springs???

[Lippo]

I agree with Roy.Changing the camber and things like that will not make any difference.You would have to dial in about 20+ degrees of camber to make any difference and that is ridiculous.For a rear wheel drive,you have it soft in the rear so that it squats.And run high profile tyres with 10-15psi.

[Steve]

Perhaps you should let TRY09 know what he has been doing wrong all this time then.

[benm]

Tyres make a -massive- difference to rear end traction for the 1/4.

When I had crappy 20,000km old 225/50/16 Falken ZE502's first gear was literally useless too me when trying to accellerate hard off the line. The rear end would just axle tramp and sing n dance all over the place. (this was with brand new shocks and those pineapple bushes).

Threw on a new set of Michelin Preceda 225's ($235ea) and my god first gear is suddenly usable.

Its amazing the difference tyres can make, don't spare any pennys when it comes to tyres.

[Roy]

Steve, for Try09's application it is probably the way to go... wasnt he running 15" rims and slicks with monstrous sidewalls (26x8.5"???)

Completely different scenario to the road car (i dont care if its registered, Try09 is not a road car in my eyes... this isnt a bad thing its great to see him run those times... but tell me you wouldnt be sweating if you were pulled over by the local constabulary)

Im talking street car with maybe slicks bolted on for a pass or two.

...anyhow, ive never ran a car on the 1/4 mile so should probably shut up... anyone care to hold my hand when i finally muster the courage to give it a blat down at Eastren Creek:rolleyes: