The exact behaviour at the margins ratio-wise, I haven't got data for, but in terms of drivability I think people are getting worried that come mid corner, they'll be left with a half competent ATB, failing to deliver the performance that they've paid for. This really is not the case on fast road and track day motors, even highly developed ones.

Many racers use ATBs, due to predominantly cheaper cost, but racers in the business of winning at all costs will choose plates or experiment with other diff variants beyond ATB.

Interesting comments about plate vs ATB type units on the quarter mile.

With an open diff the G40s are very prone to spinning up their near-side front wheel, which presumably an ATB diff could help towards. Yet what happens when you're trying to promote a small amount of wheelspin? Presumably once spinning the ATB then starts to behave like an open diff, and you negate all benefits of running an LSD?

Was at Prodrive last week for work, and they showed a video of the Focus RS launching on an uneven surface compared to a Megane Sport. Obviously the Ford has a Quaife ATB in it, but only got off the line marginally quicker than the open-diffed Megane - it was close enough to muddy the waters as to whether the diff or chassis design could take the credit for the slightly better launch (though I suspect it could've been both factors).

They then showed the Focus with one of their own electronic diffs in, which from what I could gather can effectively lock both wheels under certain circumstances like a plate diff - and in others behaves like an open diff. Suffice to say it launched much harder!

Has anyone done any back-to-back comparisons on Golfs of plate vs ATB diffs? I know exactly what a Polo is like to drive with a plate diff, you have to be 100% on the ball 100% of the time - but it really gets the power down well and allows amusingly rapid cornering speeds. I can't bring myself to throw money at a Quaife 'til I've driven a Polo with 170bhp+ with one on, to see how effective it is.

The maintenance part of plate diffs doesn't worry me - the Polo 085 transmissions are made of butter anyway, so in my car I'd pretty much guarantee the diff would outlast the gearbox. Pulling a 'box off is a regular event, and splitting it down to pull out the diff unit doesn't take much longer than 20 mins once the 'box is off the car. Smelling of gearbox oil for a day or so isn't hugely desirable though!

Probably not the same for everyone, but the disadvantages to a plate diff don't worry me - so it's purely down to a cost/effectiveness comparison between ATB and plate...

For the purposes of 'fun' competitive quarter milling at various Run What You Brung events, an ATB will give the performance at a level that suits all but the most choosy.

The comparison with Focus electronic diffs though interesting is really off topic, since it's ultimately non-hydraulic traction control - expertise Prodrive have in spades, but nothing to do with the options available to most mere Polo mortals.

It's pretty important here for those commenting who have motorsport activity in their daily lives to acknowledge that they can deal with the issues plate diffs present far more easily than 'mere' car nuts who just go out to enjoy their hobby. Having contacts in motorsport, or expertise means getting free gearbox strip downs, either blagged favours or via self knowledge. That obviously doesn't represent the majority.

Yoof Vs Gregg, what the hell is all that about jez??

Yoof's opinion clashed with mine and we both made points to support our views, nothing more, nothing less

Edited 27 April, 200719 yr by LregG

Yoof Vs Gregg, what the hell is all that about jez??

It was opinion Versus another opinion

That did look a bit retarded second look, changed it now

Why thank you jez, just one more thing

Made this into a seperate topic

so the other one can be used to gain \/iews on what people want and this one so people can argue with Gregg

May want to take a second look at that as well mate

Edited 27 April, 200719 yr by LregG

Chris- Cheers for clearing that up, good to have your insight on the forum

When did anyone take a gearbox out for fun?

Best not ask Andy that It's what, 9 boxes now???

11 I think, stopped counting a while ago.

after all that, i still dont see the point in going 75% or ever 95% of the way - unless its considerably cheaper.

11 gearbox's!!!

You do drive hard andy??

Edited 27 April, 200719 yr by LregG

Chris- Cheers for clearing that up, good to have your insight on the forum

Pleasure, and glad useful

11 gearboxes!!!

You do drive hard andy??

Not broken them all. Just a dead diff in one - repaired it, then 5th died. Had a lot of cheapo interim 'boxes, which were grief - then got a new 'box, but had to take it off as the seals were fucked, replaced them, then 5th died in that - got it repaired with new parts and it's still on the car now.

But the car has had at least 11 'box changes on it, ignoring doing the clutch. First ATV was on and off twice, second ATV has been off three times; three different 8Ps (broke only one of those - forgot to top the oil up!); an AHD, an 8N and a DXH that was broken before it went on the car.

I'm not sure I fully understand te situation with the ATB and it acting as an open differential. That wiki article and an article in evo state that it will act as an open differential if there is no load...wheel in air or over ice. It doesn't say that it will act as an open differential if a wheel spins....as there is still some load on the wheel.

Del has LSD in his Civic and I believe that is a geared type. It doesn't suffer any of the draw backs associated with one wheel spinning up. If it does break traction...which is pretty hard to do .... it'll do so in a controller manner and will continue to point straight down the road with no torque steer. Not exactly sure on the specifications of the differential though.

If the Quaife acted like an open differential when the wheels started to spin I couldn't see it being useful in rear drive cars like the Nobel M12 and Hartge BMW 335i?

Taken from ClubGTI forum, User name VR6T, guy called dave who obviously has experience with both types, kinda backs up what i was saying.

Have put a few thousand miles with both diff types.

ATB very good for what it does. Used it for hillclimbing in my old scirocco and it was CRAP but for everyday road driving you didn't really notice it. For fast twisty roads in the wet it worked well until one of the tyres lost traction, the diff will only transfer drive if you up set the car by turning the steering wheel hard left then hard right other wise the diff behaved like an open diff. The tyre that was spinning will just spin up even more.

The best way to understand this is if you break a CV the car is stranded, the diff will not transfer drive to the good shaft.

On MK1 drive train you usually find the short drive shaft tyre (LH side) with the standard open diff will ware faster than the long drive shaft (RH side) tyre. After 70K miles and 4 pairs of Yokohama A 539's using the ATB box the Long shaft (RH side) tyre wore faster than the short shaft (LH side) so the diff does do what is says on the tin.

Now when I build the full all steel Gemini box for the VR6t i put in a VWMS plate diff, this is in a different league. My idea was to use the plate diff (current slip setting 100NM) to relive the stress on the syncro rear diff. The theory is that when you spin up the front end on the rallye you have to spin both front wheels, which the plate diff does consistently. The VC on the rallye does take quite a few revolutions of slip before it transfers drive to the rear open diff. I have to spin 3 wheels before the rallye stops moving with the plate diff.

If i had used the ATB setup it would only require one front and then one rear to spin before it would spin up.......

If you have driven a big BHP rallye/synco drive train car with open diffs you will be surprised how slow they can be to get off the line, they just spin up front wheel and then after what seems like an age the rear kick in and off you go. This doesn't happen with the plate diff set up.

The science off plate diffs is quite interesting, you can specify loads of different ramp settings, it can be made so it locks on engine braking and on acceleration. You can have aggressive ramp contours or soft one, these all alter the the way car will behave on fast road driving or just heading down the shops.

So to some up you need to decide what you want your diff to do for you and then spec it to suit. But I would defiantly not use anything other than a plate diff in a large BHP 2 wd/4wd as long as your CV's are up to it.

I have a few plate diff parts i will post up some pics of what i am talking about.

Plate for me

Taken from the same thread

the problem is that I hear conflicting arguments - some folk say their better and another, who makes plate diffs, reckons atb is pretty much as good on tarmac and less hassle to maintain

the thing with atb is its fit and forget, no adjustment needed and no maintenance

plate diff - could be better, could be worse, but rebuilding a gearbox isn't the easiest thing in the world to do and tbh, I'm not sure I can be bothered with several ins/outs to get it right if need be

with gravel/dirt/snow there's no debate, plate diff is the way to go but tarmac......maybe its not so much of an advantage and I am wondering if the hassle/benefit factor is worth it

Understandably you want a plate diff yoof as you are born and bread motorsport, most people who want a diff on here use there cars as a daily runner so therefore a plate type diff will not be the best option for them. The quote you have used is motorsport related as he is on about hill climbing etc and is in the motorsport section

Could you imagine someone with a daily runner trying to get rouind, say, a multi-story car park in a plate diff equipped G40?? The chassis legs, diff, cv joints and clutch would all take a beating

Edited 28 April, 200719 yr by LregG

Taken from the same thread

the problem is that I hear conflicting arguments - some folk say their better and another, who makes plate diffs, reckons atb is pretty much as good on tarmac and less hassle to maintain

the thing with atb is its fit and forget, no adjustment needed and no maintenance

plate diff - could be better, could be worse, but rebuilding a gearbox isn't the easiest thing in the world to do and tbh, I'm not sure I can be bothered with several ins/outs to get it right if need be

with gravel/dirt/snow there's no debate, plate diff is the way to go but tarmac......maybe its not so much of an advantage and I am wondering if the hassle/benefit factor is worth it

Uderstandably you want a plate diff yoof as you are born and bread motorsport, most people who want a diff on here use there cars as a daily runner so therefore a plate type diff will not be the best option for them. The quote ypu have used is motorsport related she is on about hill climbing etc.

Could you imagine someone with a daily runner trying to get rouind a multi-story car park in a plate diff equipped G40??

Does Weston Favell count as a multistorey?

as I've seen Matt do it

Noble and Hartge share one thing in common - they're road cars, albeit fast ones.

This correlates entirely with what I'd written in my comparison - these companies cannot affort to furnish road cars with fancy aggressive plate diffs.

The hardest bit to get over here is the desire to plant hardcore motorsport components into cars which visit Tesco and multi storeys. ATB behaviour can be analysed to the hilt, but it still doesn't present an argument for a plate diff on a car which visits said Tesco and multi storeys.

Rising above the detail, and in the final analysis, that is the only question the majority here need to ask themselves. Those that have got the trailers, or the farm workshops and resources or indeed sprint/circuit racecars can afford to go either way.

I don't know of Weston Favell so i can't comment.

You quoted me before i had finished editting jez, due to the nature of how a plate type diff works it is not best suited for road use.

When i had my gripper fitted by J P race they asked what i was going to using the car for so he could set it up to suit, i told him it was a weekend toy, the occasional track day and for the occasuional 1/4 mile at run what you brung days and they replied "that alright then, you wouldn't want to use you car for the weekly shop with this diff, taking slow tight turns will not do your car any favours!" and laughed

Edited 28 April, 200719 yr by LregG

My driving in the G will prob. amount to something like: 250 days of the year = fast road/pleasure. Scottish A and B roads as well as in and out of town.

15-20 days of the year: track days and 1/4 mile runs.

I don't know of Weston Favell so i can't comment.

You quoted me before i had finished editting jez, due to the nature of how a plate type diff works it is not best suited for road use.

Ah yea, i realise that, I'm just saying Matt manages to live with his, so it can be done,

but for someone like me, just boils down to cost/advantage ratio

i want the most track/ 1/4 mile time gain for my cash

In that case you want the gripper and not the peloquin then jez!!

I do beleive matt uses his G40 for shows, weekend pleasure driving etc etc and has a mk2 coupe as a daily runner. This was cetainly the case when he was kind enough to drop off my gripper and ATV box at J P Race and drop it back to me once it was all built back up (thanks again matt)

Edited 28 April, 200719 yr by LregG

You say that, but you have yet to hear how much Peloquin can do them for !

I say that because the peloquin is an ATB as well (they stole the design from quaife!) so therefore if jez wants to compete mainly in timed motorsport events then he should go down the same route as yoof and get the gripper (plate type) diff

Edited 28 April, 200719 yr by LregG

I'm quite sure Jez can make his own decision

But you said he should go for the gripper because of the cost advantage ratio. If the Peolquin worked out significantly cheaper overall and if it doesnt need servicing then it's at a significant cost advantage ratio !

You are right dan, it would be unfair to base any decision without knowing the cost of a peloquin, shipping, import tax and upkeep compared to the motorsport proven gripper diff