Diffs - Quaife, Wavetrac, MFactory

[rgvlee]

Hola
Currently giving the pogo a birthday with a new clutch, SMF and gearbox overhaul. I'm taking the opportunity to drop an LSD in.
My options seem to be

• Quaife QDF26R (02R listed)
• MFactory MF-TRS-05GTI4 (for 02J, but have been assured it'll fit)
• Wavetrac (probably 10.309.181WK for the 02J)

Who has done what
Where'd you get it

Quaife and MFactory seem pretty much the same from what I can gather.

Particularly interested to hear from Wavetrac owners, generally you hear 2 types of comments;
That they are wicked
That they were a cu-in-the-nt to fit with more drama than home and away.

If they are that good and they can be purchased without the dramas, I'd like to know more. It's going in an 02R HWY if that makes any difference.

[kaanage]

The biggest issue (& what stopped me fitting a LSD) is knowing what size pinion you have in your diff before ordering whichever type you prefer. AFAIK, the only way to find out is to pull out and down your diff (unless you have a spare on hand that you will use as a total replacement)

I would have gone for the Wavetrac as it provides some locking effect when one wheel is fully unloaded and also under deceleration where the others will act as open diffs.

[rgvlee]

I am building a spare gearbox (from the legendary Squib) but it's not pulled down yet and I have itchy buy it now trigger fingers

[JTop]

Ello!!!

Really good points to bring up!
I have been looking around for a suitable LSD for my build and I settled on a Quaife last week.
Was tossing between Wavetrac, Kaaz and Quaife but again, trying to source from overseas is a pain and my cousin who is stuck in England is having troubles to send his stuff back home, let alone ship me a LSD.
Gave another look at this topic tonight and if you mentioned that MFactory one is assured to fit, might go for that instead, fits my budget heaps better and if by the idea of being better than the stock open diff, would do it. But then again, Wavetrac is just staring at me for just a bit more. Again, all comes down to the usage and flying that the car will be doing.
Only reason I'm considering one is because I'm already struggling if the road is soaked, I feel once I put the K04 on, it'll be even worse (I do like to send it every once in a while )
Also same position as you as having a spare box to build. So will crack it open next month when I get a chance to determine if it'll be possible because that diff left the building (prev owner did like to send it so)

Cheers

[sambb]

just got home from night shift. Too late to do a write up but i'll fill you in on wavetrac (torsen), quaife (torsen) and Kaaz (clutch plate) tonight when I crawl out of bed.

[rgvlee]

I was hoping you'd chime in.
Kaaz will likely be a no-go for me, I know they will be better but for a daily I don't think I can handle the maintenance of a plated diff.

[sambb]

So to that list there are a few others you could add.

So Torsens:

Peloquin US based
Quaife UK based
wavetrac US based

Plate/Clutch:

SQS 1 - way + choice of ramp angles, Czech based
Gripper 2 - way I think, UK based
M factory not sure
Kaaz DB1820 2 - way + choice of friction plate material, Japanese sold out of USA.


Broadly Torsens are considered maintenance free. Wavetracs point of difference to the other two torsens is that they have a wave shaped washer arrangement that applies a pre load to the lock up gears. Theory is that this will help negate the downfall attribute of a torsen which is that they can only do their LSD thing if both wheels are on the ground ie you are powering out of a corner but the inside front which is already lightly loaded rides over a depression in the road. The Quaife/Pelioquin may let go immediately and single wheel until two wheel grip is reinstated but the wavetrac will theoretically not loose lock up as quickly because the 'wave' washers keep the diff thinking that it hasn't single wheeled.

https://www.youtube.com/watch?v=QEhLGe_M6XU
https://www.youtube.com/watch?v=E4wY2NoJ6f8

Ive driven a quaife ATB in a NA Clio RS W172 and I must say it behaved exactlt the same as the Wavetrac did in my turbo car. That might seem as though I'm saying they are the same but I think there's more to it than that. The NA clio had a bout 160hp at the wheels and probably half the torque of my car and on the same corner was locking and unlocking and moving the torque from one front to the other inducing torque steer, when my car had to be really hammering at far higher speeds to do the same. Its an apples and oranges comparison but I was surprised that the quaife was struggling over that corner/that surface with so much less grunt being conveyed to the road and both our cars had yoko 195 softs on.
In addition to that I have a horrible driveway. My battle axe frive is about 30 degrees steep and then my personal driveway peels off that at about 45 degrees. We are in the process of buying a car for my wife and 50/50 subarus are all that are light enough and traction well enough to get up and out of that. The Polo though with traction off, just pulls itself straight out of there. You might get a squirt from the inside front but at the most you will hear a little whine from the LSD and it'll just grip and pop straight over the ridge and drive out. So I'd tend to think there might be something there between the quaife and wavetrac designs BUT that does not mean to say that the wavetrac doesnt do ugly things when a lot is asked of it. While it may argueably be better than the quaife it still unlocks and then has to re lock afterwards. When this happens its not always smooth in doing so and at minimum is accompanied by a good steering wheel kick and also has a way of apportioning drive from one front to the next. ie you can feel at the steering wheel that most of the drive is going to the left front, then suddenly it'll shift across and you can feel the front right pulling harder, and then back again. You sometimes really have a bit of a cut snake in your hands, which I believe the plate diffs dont suffer from - just two wheels driving together and doing what your foot tells them.

[rgvlee]

MFactory do torsens and plate diffs, the part number above is for a torsen.
The Wavetrac looks to be about $400-500 more than either the quaife or the mfactory; that's not a deal breaker to me.
I'll speak to my gearbox guy and see what he reckons. He said it was an option and that I'm probably wasting my money, but YOLO

[sambb]

So I got my Wavetrac through Brian at Gti imports (hornsby - sydney area) for a very good price. If anyones interested PM me and I can pass on his details.

Thing to remember though is that you cant buy the diff before your box is stripped and the ring gear measured. For whatever reason there are 2 different ring gears in Polo boxes. There's no rhyme or reason to it. You can get two HWY boxes and one will have a ring gear with 113mm ID and another will have 114mm. The so called newer design ring gear was the 113mm but you'll find as many 114's in the later model boxes/cars.
So the stock diff needs to have its rivets drilled out and the diff pressed out of the ring gear so that the ID measurement can be taken. Only then will you know which quaife or wavetrac to order. eg my first box was had a 113mm ID ring gear and so a matching wavetrac was ordered for it. When I got my hands on the Kaaz diff though it measured at 114mm. I crossed my fingers but the box that was stripped for that though had a 113mm ring gear. The option was then to either get the 113mm gear machined or buy another ring gear. Brian happened to have a 114mm ring gear to get me out of trouble so I was lucky but being a slightly different ratio it needed the pinion too so the dollars went up. But if you've gone out and bought a 113mm diff and your ring gear ends up being 114mm you are pretty stuck, so dont jump the gun.

[sambb]

Oh ok I didnt know M Factory did torsens for our cars. I think I checked a few years ago but Truetrac might even do a torsen for our car.

Going back to your original post I do hear you regarding the plate diff for street stuff. I've had my Kaaz LSD'd box sitting in the garage ready to go for ages now. I don't want to waste its clutches on street driving and an underwhelming engine so its waiting for a good engine to go with or probably if my clutch goes on the current wavetrac gearbox ill swap it in.

If you do go with a torsen I can definitely say that chassis setup can be tailored for it. For instance changing from a stiff front bar and softer springs, to stiffer springs and going back to the stock FARB was a better setup. Same front end roll resistance but that inside front feels like its pushing down harder or that the front anti roll bar is less able to hold it up, but that definitely helped to keep the inside front on the deck and the wavetrac working away rather than spinning it up.

[sambb]

oh and one last thing, you have to factor in the diff casing to ring gear bolts/rivets. The stock one is rivetted. These get drilled out so you have to have fasteners to go with the LSD. My Kaaz came with their own design of metric fine high tensile bolts. The wavetrac came with ARP's and I believe Peloquin used to as well. From memory they were press in studs with nuts to go on the underside of the ring gear. This might be where some of the diff fitment stories come from. I've seen pics of guys where the studs wouldn't press all the way in ie the hole was too small or even where the hole was too big. I don't think you can get away from that though with any of the different diffs. There's always going to be some quirk somewhere in the job. The ring gear might just fall off the diff when its rivets are drilled out. Others need a huge press to get them apart. You just don't know till you commit to it. Worth checking if you do go for a Quaife ATB whether or not you'll need to shell out seperately for ARP's as from memory they may not be included and will cost. just something to be mindful of when you are comparing pricing.

[rgvlee]

I spoke to Dave in the UK about his Quaife and it came with the bolts. I've also seen most shops sell the ARP kit separately.

I hear you with the suspension setup. My local wants me to run MCA reds and remove the FARB entirely. He has a few race Polos so I figure he knows how to set them up for our tracks.

[sambb]

Is that Dave Howlett you spoke to? Didn't know he had a quaife. What did he say about it?

I don't know about running completely without a FARB. I haven't ever tried it. Just talking from personal experience with a few stiff setups the problem I could see would be your cornering roll stiffness all would have to come from the springs. Then at the straight ahead the thing would be overly stiff and have a horrible ride. My MCA XR's (they were one down from reds at the time I think) have pretty lets say inadequate high speed damping that you cant adjust separately. I think if it was going to be stiff enough without a front bar for good cornering, you'd have no teeth left when just going down the road if you still intended on commuting anywhere with it. Say you were to run 205-215 width R specs on the track from what Gary has said to me, the most spring you can run on those tryes is about 350lb/in at the wheel'ish. I'm around that already with 7kg/mm front springs. I'd wanted to go to 8kg springs at one stage because the front felt a bit soft on the track once I'd gone back to the standard FARB and Gary said that'd be the limit for those spec tyres. But if you take out the front bar then you loose a huge chunk of front roll stiffness that you can only regain with springs and that'll have you needing something well beyond 7-8kg/mm springs to regain that front roll stiffness. Mine is choppy as hell as it is and I wasn't game to go for the 8kg fronts. I guess it really comes down to how you'll use the car. If its going to be a track car that only has its rego to drive to the track
then why not but if you intend on still driving it everywhere I can tell you the a stock front bar + 7kg/mm on MCA's can be rough as guts and that would only get worse if you were to remove the front bar and then have to throw even stiffer springs again at it.
There was a Brazilian guy on here years and years ago who did the same experiment. He had a super track focused Gti and used to race at Interlagos. Stiff suspension etc. I cant find the before pic but this was his 'without FARB' pic. It went from being flat and planted to this without the bar. The outside front has to then be sooooooo stiff to support that corner:

A compromise might be a front bar off a Polo Match or 1.4i. Never know they might be smaller than our stock one?

[sambb]

actually speak to Seangti. He has a wavetrac and I think he tried his car at the track without a front bar. I think from memory he said it did help with power down traction getting off the corner with the diff but hurt overall max corner speed.

[Sydneykid]

We mostly use KAAZ 1.5 way diffs in the FWD race cars, have done for over 30 years. In that time I have serviced 1 diff due to wear and reduced function and that was after 3 x Bathurst 12 Hour races and 4 x 6 Hour races. That's equivalent to hell of a lot of road kilometres. My experience is that the need to service them at short intervals is an urban myth. Personally in a road car I'd throw some new plates in whenever I serviced the clutch and that's about it. We do use torson diffs in some RWD race cars and we service them every off season, they wear out the ramps as evidenced by the metal in the diff oil at every change. Torsons are horrid for race drivers that have an affinity with jumping the car off the curbs. FWIW KAAZ make a lot of plate diffs that are sold under other brand names.

In a FWD car, especially those with high torque levels, a plate style diff is much easier to live with every day, they are gentler in engagement and don't provoke torque steer like a "locking" diff does. Viscous diffs are the best for gentleness in a road car, but they allow too much unloaded wheel spin on the track. At the other end of the scale the locking style of diffs can be uncomfortably savage in their engagement / disengagement. Plate diffs are the goldilocks, just right, in the middle.

I think Sam covered the FARB debate very well (spring rate versus anti roll rate), if I was running a FWD car in a gymkhana/motorkhana event with lots of very tight short duration low G corners then I probably consider it. But with open corners, high lateral G and plenty of diagonal weight transfer a FARB is a necessity.

Cheers
Gary