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First Time At The Drags...

WazR32GTSt
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WazR32GTSt Grand Master

WazR32GTSt

Posted
Posted

broke my drag racing virginity last night at Willowbank, QLD

car:

r32 gtst

rb20det automatic

155rwkw

time:

14.714

98mph

60' 2.503

The 2 things that were hurting me:

takeoff with the auto and rb25 turbo was hard. stomped on accelerator and brake and pulled up handbrake, but couldn't build positive manifold pressure as it has an rb25 turbo that's slightly too big to get boost at that load

i run out of power about 6000rpm as it gets too rich, so the auto changing at 7500rpm wasn't helping.. would ideally have changed at 6500rpm of there abouts

any ideas to improve?

I would have thought that with a 60' time of 2.2ish i could get mt ET down to 14.4ish with just that?

cheers,

Warren

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TurbostyleR Collaborator

TurbostyleR

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Posted

I would say thats about right hey...

The 60 footer is pretty ghey but there is not much you can do with the factory stall on autos unless you get it restalled...

I would probably try and do kinda a line lock and before it starts to build up decent positive pressure in the inlet release the brake and kinda skid off the mark...may sound stupid, but i would give it a go...

WazR32GTSt Grand Master

WazR32GTSt

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shifting manually doesn't make a difference as it still changes are redline..

when you put your foot down, it activates the "power" function automatically and it can't be turned off when you're flat out...

and as i have an rb25 turbo, the exhaust wheel is slightly too big to make boost when stalling the auto at 1800rpm.. I would say its about -2psi (relative to atmospheric) at that load, so its quite close to making positive manifold pressure, but not quite there

rev210 Grand Master

rev210

Posted
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like I said in the other one 98 mph is good for a high 13 with a better 60ft and a few decent shifts.

If you are holding consistant revs to stall you might find that you can't get positive boost. To hold the rpm at that level there isn't engough load to have the throttle opening enough for boost.

So perhaps just stomping the accellerator down is a better approach and forgetting the handbrake thing for now since you don't have a enough stall speed. having a snick of wheel spin off the line will get the turbo into boost otherwise you are bogging down.

lastlineofdefence Experienced

lastlineofdefence

Posted
Posted
shifting manually doesn't make a difference as it still changes are redline..

when you put your foot down, it activates the "power" function automatically and it can't be turned off when you're flat out...

and as i have an rb25 turbo, the exhaust wheel is slightly too big to make boost when stalling the auto at 1800rpm.. I would say its about -2psi (relative to atmospheric) at that load, so its quite close to making positive manifold pressure, but not quite there

could you just ease up off the pedal in a gear to make it down shift and then floor it again. if the previous rpm was around 80%+ then the car should just hold the next gear without down shifting.

Sydneykid Grand Master

Sydneykid

Posted
Posted (edited)
shifting manually doesn't make a difference as it still changes are redline..

when you put your foot down, it activates the "power" function automatically and it can't be turned off when you're flat out...

and as i have an rb25 turbo, the exhaust wheel is slightly too big to make boost when stalling the auto at 1800rpm.. I would say its about -2psi (relative to atmospheric) at that load, so its quite close to making positive manifold pressure, but not quite there

If you can make a little boost you will find the stall speed goes up, if you can get the stall rpm up you will make more boost (Catch 22).

What you need is a bit more ignition advance around 1800 rpm.

What are you using to tune it with? SAFC? Rechip? Power FC?

If you have an SAFC, try leaning it out around 1,800 rpm. That will give it some ignition advance at the same time. If you then get some pre-ignition with 98 ron, try Shell Optimax Extreme 100 ron. That will avoid the pre-ignition problem.

Once you get some boost (torque) you will find the torque converter stall rpm will go up. Even as little as 100 rpm might be enough to break the circle.

:( cheers :pirate:

Edited by Sydneykid
WazR32GTSt Grand Master

WazR32GTSt

Posted
  • Author
Posted

gary - stock ECU (i know, i know, its my next engine mod.. but goign the shift kit first)

don't have the snow mode button, only the "hold" which i believe is the same thing - will try the 2nd-gear-takeoff-then-into-first method before i go next

neutral dump? i'm not an idiot...

no point buying smaller tyres as it defeats the purpose of my drive in, drive away approach

oh, and i ran it on optimax extreme, like i do everyday :D

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