R33 Gtr Abs Or No Abs Race Car

[Travis Trayhern]

hi,

just after some info on the gtr r33 abs system and if i should still run it?

looking at upgrading to some quite larger brakes also having the the rears on a hydralic hand brake setup.

so should i run with the abs or do away with it and if i keep how will i go setting up a hydralic hand brake system?

[Sydneykid]

Please take this the right way Travis, but it depends on how good a driver you are. If you know how to modulate the brake pedal, have a feel for imminent lock up, take the time to learn the skill of maximising the braking effort, then there is no doubt no ABS is the way to go. Plus save 20 kgs or so at the same time. A good circuit race driver will always be better than the factory ABS. But if you are not so skilled then stick with the ABS, it will save your ass and $some in not flat spotting tyres.

What's the hydraulic hand brake for? GTR's are already too heavy, why add even more weight?

Cheers

Gary

[Travis Trayhern]

car is used for hillclimbs and found at 1 event it has a hair pin at top and im losing alot of time without a decent hand brake as the std one wont lock up slicks.

yes i was thinking about weight loss also by deleting the abs setup. i dont have much doubt in my driving ability and shall be extending it to the track very soon and into tarmac rallys, hense the brake upgrade as the std brembos are just ok for hillclimbs but wont hold up on the track.

i would like to keep abs but the hydralic hand brake is a must, also was thinking with the bigger brake upgrade will deleting the abs have side affects to the brake bias? and have any negative affects?

here is a clip of the top runner 1st place around the hair pin

http://www.youtube.com/watch?v=2TxsoyXomLQ

this is me

im a second slower, and that second can be made up easly with car setup

how can i stop my wheels lifting also in tight corners?

[NickR33]

have you tried just upgrading the handbrake shoes? Made a big difference on my car

I'm not a huge fan of the ABS system, I never had ABS on the GTSt and just learnt to live without it... the GTR ABS cuts in fairly late and if it does you have already overcooked the corner so no point to it I reckon... is your car Vspec? I think they have different ABS to standard? mine is regular GTR and the ABS is fairly crude, not anywhere near as sophisticated as modern systems

mine tripods too, not sure how to get rid of that though... more travel in rear suspension, softer rears... dunno, SK should be able to shed light

[Travis Trayhern]

was thinking that upgrading the shoes to the drift spec ones and extending my handbrake leaver.

[NickR33]

Its a relatively cheap mod you may as well try it first, before you go hydraulic... I've got the Project Mu ones... they seem to do the job for the guys running semis at Deca... some of the courses require a few handbrake turns and they don't seem to fade... not an issue for you as you'll only be using it once in the run by the looks of it...

nice video too, looks like a fun hill climb:)

[Sydneykid]

Let me start off with some track observations, that is one painful artificial hairpin. It’s not normal to find such a drastic U turn in a normal hillclimb. Hairpins yes, but carpark U turns no. The set up for that track would be quite different to most of the hillclimb tracks around. I can only assume it’s there to slow the cars for the right hander which would have a very high speed entry if not for the U turn.

Back to the question at hand, it’s amazing how a little more information makes the question so much easier to answer;

I'd lose the ABS and at the same time save the weight over the front which is always the weakest link in setting up a GTR. Anytime you can save weight in the front do it. Anytime you can transfer weight from the front to the back, do it.

When you remove the ABS you will have to reroute the hydraulic brake lines. So that’s a good time to change the split from diagonal to front and rear and then you can add a simple rear brake bias adjuster. I generally use the Tilton, lever style.

For hillclimbs I use quite different brake pad compounds front and rear, than I do for circuit racing. I would use something like a Hawk HT10 in the front and a HTC70 in the rear. That will give you faster initial bight in the rear, added to the ability to adjust the bias and you should be able to control the rear on corner entry.

The major problem I see is geometry set up, for the lower speed hillclimbs (with tight corners) I use a lot of toe out on the rear of GTRs. It makes them nice and nervous under brakes. I have used up to 3 mm each side.

It’s hard to tell from the video but it looks like you might not have enough caster, that’s maybe also be why it’s lazy on turn in. The reality is you can’t have too much caster on GTRs, they could always do with more than is physically possible. I don’t know how much you have now but I’d try and get some more.

For hillclimbs I run very little rear camber, around 1 degree negative is usually enough. It helps get off the line and it means the camber curve goes positive under brakes. This also helps on the turn in.

I don’t know what shocks and springs you are running but they don’t appear to have sufficient droop for hillclimbing. Plus the front spring and/or bump damper rates are possibly too high or maybe the front anti roll is too high.

Hopefully that is of some help. If you want to go deeper into it, I will need the current alignment settings, including ride heights (centre of wheel to guard of course) plus spring rates and swaybar rates.

Cheers

Gary

[Roy]

yes i was thinking about weight loss also by deleting the abs setup. i dont have much doubt in my driving ability and shall be extending it to the track very soon and into tarmac rallys, hense the brake upgrade as the std brembos are just ok for hillclimbs but wont hold up on the track.

If you are going to be driving the car in hill climbs and tarmac rallies then my 2c is you are mad to delete the ABS, no matter how good a driver you think you are. On changeable roads, where there is moss, dirt, loose gravel etc on certain corners etc then i think the ABS will make you more consistant and quicker overall.

On a pure circuit car i can see the sense in deleting the ABS, but not a tarmac rally car.

+1 for handbrake shoes, grab some drift ones. I know plenty of people using them for motorkhana work, two people actually went away from the hydraulic setups they had in their cars and went to URAS shoes

[Duncan]

I'm 100% with Roy. pound for pound there is nothing as valuable in tarmac rally than ABS. In fact I'd rather remove the turbo first to save weight.

You just *cannot* get every stop perfect in unknown conditions or unknown tarmac in unknown weather conditions with changing car weight, tyre grip, surface and even driver attention on a long day. Even if you are a champion and only need in 1 time in 100 it will still be worth the trouble.

save potato farmer's fences. vote 1 ABS.

[sav man]

Another vote for ABS if your planning to tarmac rally. No flag marshels to tell you of crap on the road, surface changes, and no run off's if you get it wrong.

[Travis Trayhern]

abs is staying in i guess.

and i went with the whiteline suspention aligment setup they have on there site.

Race Pack

Settings only acheivable with Whiteline alignment kits

front Camber -2.25 to -4

front Caster - max

front Toe - -0.5

rear Camber -2 -1.5 to -2.5

rear Caster - n/a

rear Toe - 0.5

[Sydneykid]

abs is staying in i guess.

and i went with the whiteline suspention aligment setup they have on there site.

Race Pack

Settings only acheivable with Whiteline alignment kits

front Camber -2.25 to -4

front Caster - max

front Toe - -0.5

rear Camber -2 -1.5 to -2.5

rear Caster - n/a

rear Toe - 0.5

Since I wrote those specs for Whiteline I can hardly argue with them

But it is worth keeping in mind that they are only a point at which to start from. I would run very different settings for hillclimbs and circuit races, let alone tarmac rallies. On that subject I agree with the guys, for tarmac rallies stick with the ABS, but for hillclimbs and circuit racing I would run no ABS. It's all part of the compromises when you run such different events.

Cheers

Gary

[Travis Trayhern]

Since I wrote those specs for Whiteline I can hardly argue with them

But it is worth keeping in mind that they are only a point at which to start from. I would run very different settings for hillclimbs and circuit races, let alone tarmac rallies. On that subject I agree with the guys, for tarmac rallies stick with the ABS, but for hillclimbs and circuit racing I would run no ABS. It's all part of the compromises when you run such different events.

Cheers

Gary

sounds good then but i had those specs with std caster rods, guess i have to get some then