Traction Issues - Work In Progess

[paulr33]

Hi All,

I am trying to do a work in progress to "correct" some of my traction issues.

Below is my current configuration and what I'm running. In first gear after about 4000rpm ish I get stacks of wheelspin and then into 2nd gear I get some wheelspin then I'm ok from there on.

I did a browse through the 3 pages of braking/suspension/tyres to find anything helpful and found some notes but nothing concrete, mainly looking at semi comp tyres really, which I may try next time for some fun

97 R33 with Active LSD (always comes in first gear with SLIP light on)

power fc

hks evc @ 0.85 bar

hybrid fmic

gtr33 fuel pump

235x40x17 fronts @ 40psi

255x45x17 rear @ 40psi ($400 each tyres)

(I think I may have the 40 and 45 around the wrong way, can't remember which is 40 and which is 45)

Standard Suspension

DBA Rotors

Sway bar and Strut Bar

The rears are Dunlop DZ101's and have more than half their tread left. They just seem to really light it up once the power comes on in first gear. I only recenctly (last 5 months) pumped all tyres to 40psi as we did a Driver Training day and they explained they should all be at 40psi to prevent the tyre walls from flexing and sagging and causing excess heat. This also helps traction in the wet I'm told as it pushes more water away. I have a subbox in the boot which I guess puts a little weight in the rear end but probably doesn't help massively.

Any ideas/tests/concepts I can try to assist my traction, I'm sure there are plently I just don't know what they are.

Cheers

[MerlinTheHapyPig]

i would run lower tyre pressure.

I run 38-40psi on rears in order to make it *easier* to drift, my fronts are normally 32-34psi - ish so that's probably something to try

[Robo's]

Ive tried all sorts of techniques and have come to the conclusion that these R33's don't have really good traction. I dont know whether its a light rear end or what but its quite simple to light them up. I even bought a set of stock suspension to try and get some squat, this helped a tiny bit but on the negative side in handled very poorly. I could still produce wheelspin in 2nd gear once boost came on.

My answer was tyres, i bought the RA1 Toyos. Traction is sensational to say the least, i can literally put the power down in first gear and it just raises the front and goes. I can snap second and i only get a tiny bit of wheelspin. From a handheld stopwatch, i am doing consistant 4.7's to 4.9's 0-100 with ease.

My vedict is, you may change suspension geometry to get maybe a 5% gain if you lucky, your still not going to get traction in first. Buy some tyres, maybe sell off yours, and get a 50% gain.

[Sydneykid]

Standard Suspension

Enough said

[Robo's]

I dont think we are talking about track racing here, just rear end traction on the road. So we are talking softer springs, weight transfer and proper allignment on the road so the tyre has its full flat surface on the tarmac. Nothing hard here!!!

[Sydneykid]

I dont think we are talking about track racing here, just rear end traction on the road.  So we are talking softer springs, weight transfer and proper allignment on the road so the tyre has its full flat surface on the tarmac.  Nothing hard here!!!

<{POST_SNAPBACK}>

So you don't think a rear subframe alignment kit with settings for more squat would help?

What about a rear camber kit for setting the static camber positive, so that when it goes dynamic towards negative under squat you have improved tyre contact patch?

How about a static toe aligment such that it allows for the shift to toe out under acceleration and squat?

Those 3 things on an R33GTST = 0.48 seconds faster 1/4.

And then I could talk about springs and shocks..........

cheers

[NickR33]

Hi Paul I have very similar mods to you and am saving up to throw a whole lot of the whiteline gear at my car... I ran a 13.7 @ 103mph recently and with the 3 things SK mentioned above (just alignment issues) I should be in the low 13's... which is where a well setup car running 100mph should be...

I couldn't get enough traction to drop my 60ft times below 2.2 sec (good launch) and god forbid I got an ordinary launch which would see me run a low 14!... not quick...

I got one of the worst launches all night whilst lining up against a BA XR8 ute and ran out of track before I could run him down... I ran a 14.4 and he got 14.1... I was dissapointed as I had the mph to beat him!

[Robo's]

So you don't think a rear subframe alignment kit with settings for more squat would help?

What about a rear camber kit for setting the static camber positive, so that when it goes dynamic towards negative under squat you have improved tyre contact patch?

How about a static toe aligment such that it allows for the shift to toe out under acceleration and squat?

Those 3 things on an R33GTST = 0.48 seconds faster 1/4.

And then I could talk about springs and shocks..........

cheers 

<{POST_SNAPBACK}>

Tried the subframe camber kit set to squat, done very very minimal. Again a rear camber set towards negative under squat is going to produce minimal results down the 1/4. 0.48 is a huge margin to gain, are you sure your back to back runs are identical runs ie (launch, gear changes, tyre temperatures)??

Proper 1/4 racing involves 90/10 front struts, soft rear springs, soft compound and heat.

99% of 1/4 races drop 0.50 second with the addition of slicks!!

[siksII]

i used to have hks hyper-d suspension, changed to whiteline springs and bilsteins, that made a small difference in straight line accelleration,

next step was to buy a set of toyo t1-rs. now i have sh*tloads of traction, even if i dump the clutch at 4500-5000rpm the car takes off.

so good tyres = huge difference for straight line.

and in terms of tyre pressures, if you have low profile tyres in my experience it makes virtually NO difference for straight line grip if u lower the pressures.

for example with my old tyres i dropped pressures from 38psi down to 22psi it made no difference to the amount of straight line grip.

but since u say u have very good tyres already, looks like the only option you have left is alignment products, which will definetly help.

i have driven a gtst with a lot of power and stock suspension, the back end wobbled around heaps under accelleration resulting in a really unstable car, so i can imagine what yours is like.

Edited September 15, 2005 by siksII

[Robo's]

Hi Paul I have very similar mods to you and am saving up to throw a whole lot of the whiteline gear at my car... I ran a 13.7 @ 103mph recently and with the 3 things SK mentioned above (just alignment issues) I should be in the low 13's... which is where a well setup car running 100mph should be...

I couldn't get enough traction to drop my 60ft times below 2.2 sec (good launch) and god forbid I got an ordinary launch which would see me run a low 14!... not quick...

I got one of the worst launches all night whilst lining up against a BA XR8 ute and ran out of track before I could run him down... I ran a 14.4 and he got 14.1... I was dissapointed as I had the mph to beat him!

<{POST_SNAPBACK}>

When i used to run 103mph, i ran a best of 13.3 with plenty of 13.4-13.5. The 13.3 run i ran a 1.94 60'. If i ran a 2.0' you could guarantee a 13.4 run.

If you dropped your 60' from 2.2 to 2.0, you could guarantee it would knock off between .3 - .4 at the top end.

[Sydneykid]

Tried the subframe camber kit set to squat, done very very minimal.  Again a rear camber set towards negative under squat is going to produce minimal results down the 1/4.  0.48 is a huge margin to gain, are you sure your back to back runs are identical runs ie (launch, gear changes, tyre temperatures)??

This particular car and driver had been at 3 street meets and the best time was 12.47 at 119 mph, that's over 30 runs. I changed the alignment (camber and subframe) a lot and the ride height a little and it did an 11.99 at 119.9 mph. Been back to 2 subsequent meets (that I know of) and the slowest was a 12.13. No extra power, no tyre changes, nothing. That's about as back to back as you can get as this is not the sort of stuff you can do between runs.

Proper 1/4 racing involves 90/10 front struts, soft rear springs, soft compound and heat. 

I hope you mean in the tyres not in the air. So reducing the rear bump vlkaving on the shocks is not important?

99% of 1/4 races drop 0.50 second with the addition of slicks!!

Bummer, I must be one of the 1%, I dropped 0.9 seconds, but I did set the suspension up for the drag radials (not slicks).

cheers

[Robo's]

So reducing the rear bump vlkaving on the shocks is not important?

cheers 

<{POST_SNAPBACK}>

Not as important as 90/10's or soft compound rubber, im talking maximum gains not minimal

Edited September 15, 2005 by Robo's

[Robo's]

Bummer, I must be one of the 1%, I dropped 0.9 seconds, but I did set the suspension up for the drag radials (not slicks).

cheers 

<{POST_SNAPBACK}>

You must be! Majority of quick racers use drag tyres or slicks (there all significantly better than road tyres)

So you are saying, you will benefit more from the rear end geometry allignment than a good set of nittos, RE55's to gain traction?

Anyway ive driven around on Sumitunos for nearly 2 years with over 30 paces under my belt, and i ran a mid 12's on them with a 2.0 60'. With no other changes i bought some R compound rubber and truely say they are 50% better. It grips like a 4wd now. There is no way a suspension geometry will give you the same returns.

Anyway thats my experience

[paulr33]

wow thanks guys for the many many replies, plently of info there i will do some research and see what i can come up with

[paulr33]

will be speaking to centreline to see what they can do for me.

what exactly should I be asking for? go at them with my traction issue and ask for a suited better squat setup for accerlation and take off as i wont be on the track just want good squat so i can put the power down without spinning. Or should i put forward some of the stuff listed above and see what they can come up with?

[Duncan]

First up you said you were running Dunlop D01Js which are some of the best tyres around so rubber is not your problem. I would run them at a lower pressure around 34 hot as semi slick tyres work differently to road tyre, for a start they have a &much* harder sidewall and flex is almost never a problem.

Next is also easy, get the wheel alignment done. If you are looking for street and occasional drag or whatever make sure you have a only a little camber on the rear, say 1.5degrees. If you are building a dedicated track car maybe you are happy to wreck your street driving with something like 90/10 shocks. Also, make sure you have 0 toe at the rear.

Try all that first for about $80 and see what difference it makes

[Sydneykid]

Not as important as 90/10's or soft compound rubber, im talking maximum gains not minimal

<{POST_SNAPBACK}>

What do you think 90/10 means?

I my terminology 90 = the rebound % of the total damping and

10 = the bump % of the total damping

Road shocks are 70/30 'ish.

Hence reducing the bump from 30 to 10 for more squat, which is exactly what I posted shoud be done.

On the front you want the reverse, less rebound damping, maybe as much as 50/50. So that the front wheels droop as quickly as the rear wheel squat. If the shock rebound is too strong on the front it will cause the front wheels to lift off the ground. Not a good idea if you want to be able to steer.

Runing a good time is a combination of all factors in setup. Sure a $1,000 spent on tyres will give a better result than $100 spent on suspension setup. But after you have spent the $1,000 on tyres, what are you going to do to improve the times? What if you don't have a $1,000 to spend on tyres, what can you do with $100 that will improve the times? That's why some cars that should run 11's barely get into the 12's.

It's like buying a new turbo and not tuning the engine, you wouldn't do that. So why wouldn't you tune your suspension?

cheers

[paulr33]

First up you said you were running Dunlop D01Js which are some of the best tyres around so rubber is not your problem.  I would run them at a lower pressure around 34 hot as semi slick tyres work differently to road tyre, for a start they have a &much* harder sidewall and flex is almost never a problem.

Next is also easy, get the wheel alignment done.  If you are looking for street and occasional drag or whatever make sure you have a only a little camber on the rear, say 1.5degrees.  If you are building a dedicated track car maybe you are happy to wreck your street driving with something like 90/10 shocks.  Also, make sure you have 0 toe at the rear.

Try all that first for about $80 and see what difference it makes

<{POST_SNAPBACK}>

Nah they are DZ101's. Definetly not semi comp or semi slicks, although I have considered a set for some road/street fury but wont be doing it any time soon. I mainly want to be able to put all the power I have (193rwkw) down without spinning, or at least minimizing it as much as possible. I have A-LSD so this helps a little bit but still lots of spinning in first gear, and then a bit into second gear. This is only in a straight line. I don't know what 0 toe means sorry I will speak to centreline and see what they say re: suspension changes

[Duncan]

ahh I not pay enough attention. In that case job #1 is to put some good tyres on

0 toe means that your rear tyres are exactly parallel to the car, not pointing in or out.

[paulr33]

so hang on, is my suspension crap or the tyres? i thought theese were good tyres, at $400 each fitted they would bloody well wanna be good tyres. whats some good tyres