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Maximising traction in FWD applications

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Maximising traction in FWD applications

Post by kevhaywire on Fri Oct 24, 2008 8:53 am

Thought I'd throw this open to debate to share techniques and ideas for maximising traction on powerful FWD cars.

There's your usual Peloquin / Quaife diff but there's a new kid on the block now, the Autotech Wavetrac - [You must be registered and logged in to see this link.]

Some folk fit stiff springs at the rear (or solid mounted) to stop the nose lifting under power, but not practical for road use, oversteer could be a major problem!

Geometry. Anyone found some settings that work well?

I find more caster helps in straight line stability when gassing it, and also solid top mounts.

Tyres - Cut slicks. Are they good in the wet? particularly standing water?

Any other thoughts, suggestions? And don't say "go 4WD" Laughing

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Re: Maximising traction in FWD applications

Post by mrbeige on Fri Oct 24, 2008 10:12 am

Have you thought about adjustable top mounts Kev? I'd be interesting to see what castor/camber/toe people use on a track and if they can be transferred to road applications without compromising normal road manners..

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Re: Maximising traction in FWD applications

Post by saysomestuff on Fri Oct 24, 2008 11:20 am

lean forward? clown

what's your management again Kev? Many of them have launch control, you can tweak it until you get the perfect launch every time.

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Re: Maximising traction in FWD applications

Post by junkie on Fri Oct 24, 2008 12:05 pm

For those like me with non ABS, traction control in that sense will not work for me.
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Re: Maximising traction in FWD applications

Post by dirtytorque on Sat Oct 25, 2008 4:34 am

haywire,out of curiosity;do you ever brake traction in second?
What box do you run?
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Re: Maximising traction in FWD applications

Post by kevhaywire on Sat Oct 25, 2008 5:21 pm

Yeah, in the wet, 1st, 2nd, 3rd and sometimes 4th are useless. In the dry 2nd hooks up at about 5000rpm, 3rd chirps the tyres and 4th is usually OK.
And that's only with 12psi Neutral

Obviously if I part throttle it progressively, traction is there.... but if some chav comes along in a Vauxhall VXR, you just can't help yourself Very Happy

Got the quaife already, got the adjustable TMs at max caster, got decent tyres.... not sure there's much else I can do! Can't be arsed with a 4WD conversion!

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Re: Maximising traction in FWD applications

Post by dirtytorque on Sun Oct 26, 2008 1:50 am

Laughing

damn vxr's.
I pray for the day i can settle an arguement with one.

DTA dosn't have any traction control features?
I am considering using the MSExtra code as i understand it has traction control.Not sure how sophisticated it will be... Neutral
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Re: Maximising traction in FWD applications

Post by junkie on Sun Oct 26, 2008 2:59 am

Interesing point Kev, so if you could be arsed to do a 4wd conversion then you would do it?

Am i right in saying that traction control only cuts power wen it senses wheel spin through the ABS.

I prefer to use my driver skills to control wheelspin with my right foot. Very Happy
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Re: Maximising traction in FWD applications

Post by dirtytorque on Sun Oct 26, 2008 3:19 am

junkie wrote:Interesing point Kev, so if you could be arsed to do a 4wd conversion then you would do it?

Am i right in saying that traction control only cuts power wen it senses wheel spin through the ABS.

I prefer to use my driver skills to control wheelspin with my right foot. Very Happy

hmm,maybe.
My work car has traction control,and sometimes it is annoying how it kills the power.
I think it babies me too much.
I'd want something that I could tinker with.
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Re: Maximising traction in FWD applications

Post by junkie on Sun Oct 26, 2008 3:48 am

I suppose they do baby sit on factory systems been too safe.

You are 1 of lifes tinkerers Rob...
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Re: Maximising traction in FWD applications

Post by kevhaywire on Mon Oct 27, 2008 2:18 am

Yeah the DTA has Traction control. Haven't used it yet because it only works with hall senders, and guess what? VW ABS sensors are not hall effect....

I was considering using Racelogic's TC system instead as that can hook up to the VW ABS sensors and most race teams seem to rate it very highly...
And you get a nice dial on the dash to vary the amount of slip, very neat Very Happy

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Re: Maximising traction in FWD applications

Post by mic_VR on Mon Oct 27, 2008 4:26 am

kevhaywire wrote:Yeah the DTA has Traction control. Haven't used it yet because it only works with hall senders, and guess what? VW ABS sensors are not hall effect....

I was considering using Racelogic's TC system instead as that can hook up to the VW ABS sensors and most race teams seem to rate it very highly...
And you get a nice dial on the dash to vary the amount of slip, very neat Very Happy

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What a brilliant link Kev, I'll definitely be getting myself one of those setups. Want to maximise all available horses!

And the tech section gives a good explanation of how it all works etc. Top stuff! Good Job
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Re: Maximising traction in FWD applications

Post by junkie on Mon Oct 27, 2008 9:00 am

So then whats the best options for no electronic devices.

Diff
Widetrack maybe as i dont think i am
Anybody found really good geometry settings
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Re: Maximising traction in FWD applications

Post by kevhaywire on Tue Oct 28, 2008 3:35 am

The diff can be a pain in the arse in the wet. I overtook a doddery old slug in a mercedes last night (from 35mph in 3rd) and the car started heading sideways (spinning both wheels) into a ditch....had to let off the gas and it corrected it's line again.

That happens quite often, but mainly on a particular tarmac type, which I'm sure we've all had hairy moments on. You'll know the stuff I mean when you're on it next when raining!

In the dry, diffs are spot on. So in the wet it's all about throttle modulation and feeding the torque in more progressively. Trouble is, winter seems to make turbos a lot more aggressive than usual, so they can catch you out at times.

Widetrack doesn't seem to help with straight line traction, but it helps with cornering grip a little.

I've tried most settings mate and the torque just over whelms the tyres regardless Very Happy

C'est la vie

I suspect the Racelogic TC is the way forward, or perhaps the DTA's. I found a circuit diagram that converts a VR signal to Hall effect, so simply tapping into the vehicle's existing sensors (at the ABS plug for convenience) would be a god send.

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Re: Maximising traction in FWD applications

Post by junkie on Tue Oct 28, 2008 1:20 pm

I have drove Leon's VR when he picked it up off Nick, on the roads i know and it did seem alot more planted on roundabouts, where as in mine it seems more a case of throwing it around aggressively his felt more relaxed at the same speeds and felt like i could do more speed comfortably through them but as it was his new toy i obviously did not want to be too harsh on it, but he was behind me driving mine keeping up with me lol, i take it this is due to the wide track?

If so is it a too involved job parts wise to convert to wide track? Corners is where its at.
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Re: Maximising traction in FWD applications

Post by kevhaywire on Wed Oct 29, 2008 4:06 am

Yeah the VR6 sites the wheels 15mm further out compared to the 4 pots (and why VRs have bugger all room for big rims) with longer wishbones.

The ARB anchorage points are also better and the ARBs are longer too, being right at the end of the wishbone to exert maximum anti-roll leverage forces.

I'm not sure if the rear beam is also widetracked on the VR6? I keep reading it's exactly the same setup as the 4 pots?

It is best, imo, to increase track mechanically, rather than just sticking low offset wheels on. It's the longer wishbones and ARBs which provide all the gains of wide track. I would also not go too wide at the rear, try and stick to the stock front to rear track differences.

I'm sure someone has fitted all the wide track stuff to a 4 pot. I can't remember all the finer details but it's doable.

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Re: Maximising traction in FWD applications

Post by SensibleDave on Thu Oct 30, 2008 11:43 am

The rear beam on my valver looks very MK2 Golf TBH, but being a 1990 car it's way before the VR setup emerged. It certainly handles very nicely and feels much more chuckable than the VR.

Weight over the front would obviously help traction but doesn't help weight distribution and cornering ability. So the VR is on a looser from the outset, the engine isn't that much heavier but its position doesn't help compared to a 16v or G60.

Getting the unsprung mass down would help with the reaction rate of the suspension. I wonder if any of the VAG alloy suspension components would fit?

Tyres are the obvious one that I've considered lately, but I don't think R888's are much good in wet weather and anything soft enough to gain traction isn't going to last that long.

As usual it's a compromise.


Just for info, MS has an acceleration rate traction control which can induce a cylinder selective misfire and or remove boost. Never tried it though.
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Re: Maximising traction in FWD applications

Post by dirtytorque on Thu Oct 30, 2008 12:03 pm

SensibleDave wrote:

Just for info, MS has an acceleration rate traction control which can induce a cylinder selective misfire and or remove boost. Never tried it though.

Yum.
I'm guessing that's a MS Extra feature.
Any links re this Dave?

ta.
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Re: Maximising traction in FWD applications

Post by James H on Thu Nov 06, 2008 2:25 pm

My Golf's front end geometry is set up for max grip on the strip but on the road its hard work. Heavy steering, off boost understeer etc. Although the ATB diff drags it round the bends under power! I run R888's and they are great in the wet until you hit standing water! They dont last long though! 1500 miles!! I wouldnt use any other tyres on the road!
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Re: Maximising traction in FWD applications

Post by dirtytorque on Fri Nov 07, 2008 12:38 am

Who is running a LSD?
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Re: Maximising traction in FWD applications

Post by kevhaywire on Fri Nov 07, 2008 1:45 am

LSD or ATB? Very Happy

I use a Quaife ATB.

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Re: Maximising traction in FWD applications

Post by dirtytorque on Fri Nov 07, 2008 4:25 am

kevhaywire wrote:LSD or ATB? Very Happy

I use a Quaife ATB.

I don't know the difference.
Embarassed I'll do a google search.
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Re: Maximising traction in FWD applications

Post by kevhaywire on Fri Nov 07, 2008 4:50 am

Ah OK, no worries.

LSD = "Limited Slip Differential" and ATB = "Automatic Torque Bias".

Sorry if this is a bit numptified and egg sucky, but the differences are:-

LSD uses friction to lock the two axles together. "Limited" refers to the amount of lock, usually in percentage. You need some "slip" or you wouldn't be able to turn corners, so the amount of locking percentage has to given some thought, especially in FWD applications.

LSDs use plates usually which behave a bit like a clutch. They can be a handful in FWD applications if the % lock is excessive but mechanical straight line traction is second to none.

ATB Diffs use special gears to move the torque to the wheel with most grip, but they don't work when there's no drive, such as when an inside wheel leaves the ground and on over run entering a corner etc.
Another example is one wheel on mud and one wheel on tarmac, the quaife should shift the power away from the wheel spinning on the mud and onto the wheel on tarmac..... I'll have to try that next time I'm in that situation!

LSDs are in operation all the the time and aren't affected by a wheel lifting or no drive situations, but they are subject to wear and need maintenance.

ATBs are maintenance free Very Happy

The new wavetrak ATB diff kind uses both technologies in one unit and works very well apparently.

The Focus RS, Megane R26 and Fiat Coupe 20V all use an ATB diff. The Fiat and Renault's work well, but the Quaife (as in the Focus) can cause some wayward behaviour over rough roads under power, as I and many Focus RS drivers can testify! My quaife doesn't quite cause lane swaps like the Focus's can, but you do need to concentrate and hang on tight!

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Re: Maximising traction in FWD applications

Post by dirtytorque on Fri Nov 07, 2008 5:03 am

/\/\/\/\

Excellent.Thnks.
I shall digest.
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Re: Maximising traction in FWD applications

Post by Toad on Fri Nov 07, 2008 3:35 pm

Out of interest, with lots of power, and lots of traction, what can be done to stregnthen components like wishbones and subframe mounting points?

I know stuff can be seam welded, but is that enough?
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