LSD + Exhaust

[GuidoK]

The short time that you're on 3 wheels (a split second) is imho usually short enough that the inertia of the wheel requires enough force to provide some lockup. And I have yet to see that a wavetrac performs better on that.
In this video you can clearly see that a wavetrac also has spinning issues (sub par lockup, one wheel still turns way faster than the other one) with one wheel on ice. There is traction, but ample (one wheel is spinning pretty fast when you hear it getting on the tarmac and squeeling). The acceleration with 1 wheel on the ice or 2 wheels on the ice doesnt differ a lot.

So its far from the holy grail they say it is. In the end the lockup under no load is defined by 2 things: 1 the friction between 2 metal rings, pressurized by the internal spring (like I said, wavetracks patent speaks even about putting a friction layer on this), and the wedging the wavy rings give as extra force/preload on the helix gears. Because the wavy rings themselves give no direct connection between the two side gears. Its what the diagrams on wavetracs site make us believe to a certain extend, but if you analyze the patent, you see that its a completely loose unit between the two side gears.
The power I see displayed in the video coming from the one wheel on the ice is not something that stands in relation to the powers used in acceleration on a track imho.

If you want to 100% counter that wheel lift on track situations you have to run a clutch lsd with extreme preload.
No problem on a track, but the next time you turn in a supermarket parking lot or try to parallel park, I'm sure you go back to another diff

[Steve84N]

I believe the Wavetrac was designed by someone who worked for Quaife before to purposefully address some of the shortcomings.

Some gear differentials rely solely on preload springs to combat loss of drive. The drawback is that you can’t add enough preload to prevent loss of drive without creating tremendous handling and wear problems at the same time. So, to avoid these problems, the preload from ordinary spring packs must be reduced to a level that renders them ineffective at preventing loss of drive. The Wavetrac® is the only differential that can automatically add more load internally when it’s required.

I still think the Quaife is very good but I believe the Wavetrac is better.

As you say, being on ice is something that never really happens but there are tangible differences under more usual scenarios. Those short periods when you experience inside wheel spin is when you get the start of a small wriggle from the rear. Not normally enough to be a problem but nevertheless not as smooth as if they don't happen. My Z4 was well setup and yes the C63 is heavier but with 510bhp & 480lb/ft I think it's fair to say that's enough of a challenge for the traction...

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

[GuidoK]

yeah I saw that video too, but it hardly shows anything what happens. theres just an in car view and the sound. For all we know on the second take a wheel is lifted up due to a slightly different racing line. Hardly any objective info in that video.
Anyway the first video I posted clearly shows how much traction can be expected from the wavetrac coupling mechanism with one wheel with ample grip. And that isnt a lot imho. In that video you can see with your eyes what really happens. Everything is shown.
So all mechanisms that try to counter the 1 wheel without grip situation are a mere bandaid imho. They might aid in not getting you stranded on an icey road, but performance wise they add nothing. The wavetrac mechanism isnt suddenly going to provide mega traction is clearly what the video shows.
Quaife is still the preferred ATB solution for many many professional racing teams, track cars and performance setups.
Comparing different parts in totally different cars is well....hardly objective.
At least the wavetrack vid I posted is based on a car that has exactly the same rear axle/drivetrain as the z4, so thats pretty much comparing apples to apples.

[Steve84N]

Think what you like but you haven't tried both so...

My C63 suffered more wheelspin before the Wavetrac so it's not naturally got more traction than the Z4.

They both multiply torque so x times virtually zero friction on ice will give little back. It's still able to transfer more torque than a Quaife so when the wheel is light but not actually in the air it's more effective.

[GuidoK]

It's still able to transfer more torque than a Quaife so when the wheel is light but not actually in the air it's more effective.

you dont know that. There's no actual proof or verifyable data.
A very speculative claim.

[Ed Doe]

Think what you like but you haven't tried both so...

My C63 suffered more wheelspin before the Wavetrac so it's not naturally got more traction than the Z4.

They both multiply torque so x times virtually zero friction on ice will give little back. It's still able to transfer more torque than a Quaife so when the wheel is light but not actually in the air it's more effective.

With respect you've never tried both on an identical car running an otherwise identical setup so.....

Afraid I'm inclined to side with Guido based on the fact he appears to actually know what he's talking about from an objective rather than subjective point of view.

[GuidoK]

Mind you I'm not saying the wavetrac is worse. They only differ from the quaife with that wavy ring construction in combination with those fiber end plates (at the end of the helix gear to provide the extra friction in zero grip situations). Thats a construction to get more preload/friction in zero traction situations. They say that themselves.
In the video I posted you can exactly see how much traction that gives in that specific situation, and I'm not very overwhelmed by it. The car gets barely moving. Its not the holy grail.
For the rest its exactly the same as the quaife; a 1:1 copy (quaife's patent on that design has long expired, thats why you see so many competitors like wavetrac mfactory etc with the same basic design)
The thing where I think the wavetrac is more appealing is that (from what I understand in the UK at least) they have a transferrable limited lifetime guarantee and I think Quaife only gives the original owner a limited lifetime guarantee. But I dont know the exact conditions to that. How much thats worth everyone can decide for themselves.

[Steve84N]

I'd wager that arguing the toss on what you've read versus actually driving both is far more speculative.

At the end of the day I'm comparing two RWD cars with no electronic intervention turned on and the car with double the power gets it down better. I also drove both cars for some time with open differentials so I know what improvements they are giving.

The Wavetrac is a bit more aggressive which feels like more torque is being transferred across the axle. Here are some views of Quaife versus Wavetrac on the same car... They all agree with me that it's close but the Wavetrac is notably better.

https://www.focusst.org/forum/focus-st- ... 053?page=1
http://www.vxronline.co.uk/forum/showth ... v-wavetrac
http://www.shonutperformance.com/Wavetrac.htm

[GuidoK]

two of them are sponsored reviews.
I now see what you do and what you dont mean under 'speculative'.
And from the 3rd, not sponsored link:
"The wavetrac diffs have an entirely different operation to any other, and unlike other diffs they allow transfer of power even if the axle is not loaded..."
We've seen how well that works in the video I've posted. I wasnt impressed by that 'unique selling point'. It gets the car moving, but barely.
In fact I could hardly see any improvement in acceleration between 1 wheel on ice and both wheels on ice (and that improvement in acceleration is the difference the locking mechanism makes)
I wonder if it has enough zero load lockup to get you from a standing start up an overpass.


First of all you post characteristics on your former car that my car hast displayed at all, despite the 40+% power and torque advantage my car has over your previous one (so this is not 'something I've read'), plus I show a video on how effective it is in the conditions wavetrac claims to target and solve, with featuring a car that has the same rear axle/drivetrain setup as a z4.
How is that in any way speculative?
If my car doesnt display the miscomings you descibe what happened on your car (and mind you, I've had the quaife for 8(!) years, a LOT longer than you've had yours), and you claim its not the setup. Isnt that speculative?

[Steve84N]

I don't disagree that it's not perfect in zero load but I do agree that zero load hardly ever occurs.

The Quaife is good enough that I don't doubt you're happy with it, I liked mine too. I'm also convinced the Wavetrac is more effective at torque multiplying across the axle and until you've tried it you're just stabbing in the dark dismissing all other views based on an ice video. You won't see the benefit of the extra feature there as much because you're trying to multiply virtually bugger all, yet in reality you've got more friction to play with. I didn't buy it to drive in the snow, I got it to stop inside wheelspin at T-junctions as you go over the crest in the road where you get close to zero load and it deals with it very well whereas the Quaife would still give more slip.

At the end of the day it's a moot point as you're happy and so am I.

[GuidoK]

I got it to stop inside wheelspin at T-junctions as you go over the crest in the road where you get close to zero load and it deals with it very well whereas the Quaife would still give more slip.

My car doesnt give any slip on one wheel in those situations. And thats with over 40% more power and torque than your previous car. If that isnt due to the setup of your car like you claim, your previous diff must have been faulty. There's no other explanation.
Since I've got my quaife (like I said: 8 years ago), I've never had an inner wheel spinning anymore on the road, in dry or wet conditions (I dont drive on ice). When I break traction, which is fairly easy with the twinscrew compressor, its always on both wheels. Also in cambered corners (like alpine hairpins) or on T junctions.
It works flawlessly.

[motoroller]

I thought the Quaife was expensive - the Wavetrac is £1350 without fitting!

[Scooba_Steve]

I thought the Quaife was expensive - the Wavetrac is £1350 without fitting!

Shut up and get one already

[Doddsy]

I have a Quaife LSD. Fitted by Birds into the existing diff housing (as with all differentials) with a lifetime warranty. In my opinion it's a must have. You can do without it for most road driving but it does make a noticeable difference. It's in a totally different league on track though. Definitely recommended depending how you drive the car.

Exhaust I believe is 50mm diameter for each pipe.
Personally I had a backbox delete on my car for all of 2 weeks - I couldn't bear it as a daily, it was ridiculously boomy between 1500-3000rpm.

I've had my mid-box deleted now and replaced with straight piped for the princely sum of £50 - makes it a bit louder but not intrusive - perfect for me with noise limits on tracks, and for daily driving,

Got a video of it now? I did a backbox delete on my last 2.5si and loved it. However this time around I’ve done a backbox mod so is half way in between, and I’d like just that little bit extra.

[Ed Doe]

I have a Quaife LSD. Fitted by Birds into the existing diff housing (as with all differentials) with a lifetime warranty. In my opinion it's a must have. You can do without it for most road driving but it does make a noticeable difference. It's in a totally different league on track though. Definitely recommended depending how you drive the car.

Exhaust I believe is 50mm diameter for each pipe.
Personally I had a backbox delete on my car for all of 2 weeks - I couldn't bear it as a daily, it was ridiculously boomy between 1500-3000rpm.

I've had my mid-box deleted now and replaced with straight piped for the princely sum of £50 - makes it a bit louder but not intrusive - perfect for me with noise limits on tracks, and for daily driving,

Got a video of it now? I did a backbox delete on my last 2.5si and loved it. However this time around I’ve done a backbox mod so is half way in between, and I’d like just that little bit extra.

Sorry I'm afraid I don't - I've sold the car now

It was a bit louder than oem but with no boom is the best I can describe it!