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LSD + Exhaust

2003 - 2009, roadster, coupe, facelift
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LSD + Exhaust

Post by motoroller » Fri Aug 03, 2018 1:49 pm

Do many members have LSDs fitted? Has anyone tried the kit which gives most of the LSD effect but fits within the existing diff?

What diameter is the exhaust? I have been listening to a few aftermarket options on youtube, but have some ideas of my own. Do many members live with straight pipes?
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Ed Doe
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LSD + Exhaust

Post by Ed Doe » Fri Aug 03, 2018 2:05 pm

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,
Last edited by Ed Doe on Fri Aug 03, 2018 2:06 pm, edited 1 time in total.
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LSD + Exhaust

Post by PerryGunn » Fri Aug 03, 2018 2:05 pm

motoroller wrote: Fri Aug 03, 2018 1:49 pm Do many members have LSDs fitted? Has anyone tried the kit which gives most of the LSD effect but fits within the existing diff?
I had a Quaife ATB LSD fitted by Birds just over 3 years ago - all fits within the standard diff casing - thread at viewtopic.php?f=2&t=74954

Don't know what you mean by 'kit which gives most of the LSD effect' as the Quaife is a proper LSD, but it's a torque sensing LSD rather than a clutch pack LSD
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Post by Ed Doe » Fri Aug 03, 2018 2:13 pm

^Perry technically the Quaife needs some load on one wheel to 'bias' torque to the other axle - if you actually lift a wheel up in the air, a Quaife will act almost the same as an open diff. Plated diffs will not -they have preload and will lock the wheels together when more than a certain speed differential is experienced across the axle. This is generally a far more agressive diff, and tends to not be very road-friendly!

Interestingly I believe Wavetrac diffs have an additional mechanism to mitigate the 'open' issue with Quaifes when you lift a wheel, whilst still essentially being an ATB-type diff. No idea how it works though - my research ended there!
Carbon Black '07 M Coupe: Intrax 1k2 Coilovers, AP-Racing, Raybestos ST45s, Tillets, Schroth, Vibratechnic, Apex EC7, Strongstrut, Eventuri, H&S, RTD, 4.1FD :evil:
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Post by PerryGunn » Fri Aug 03, 2018 8:47 pm

Ed Doe wrote: Fri Aug 03, 2018 2:13 pm ^Perry technically the Quaife needs some load on one wheel to 'bias' torque to the other axle - if you actually lift a wheel up in the air, a Quaife will act almost the same as an open diff. Plated diffs will not -they have preload and will lock the wheels together when more than a certain speed differential is experienced across the axle. This is generally a far more agressive diff, and tends to not be very road-friendly!

Interestingly I believe Wavetrac diffs have an additional mechanism to mitigate the 'open' issue with Quaifes when you lift a wheel, whilst still essentially being an ATB-type diff. No idea how it works though - my research ended there!
This came up when I had the Quaife fitted and, according to Guido, Quaife have a pretension mechanism that provides the preload...
GuidoK wrote: Thu Mar 12, 2015 7:17 pm
TomK wrote:
Ironically, with a torsen diff (like your quaife) as opposed to a clutch pack type (like Mdiff) the only major relative disadvantage is in the scenario you describe where one wheel looses grip completely (i.e. in the air, or on ice). When 0 torque is sensed on one of the axles the diff is unable to lock and you will get no drive at all.
Actually that is often said, but not quite true in many cases (maybe prejudgemental theoretical deduction?). If you look at a diff like wavetrack they have a cone system that prevents 0 load. That is how they say 'their diff' is different.
But here comes the funny bit. Quaife diffs have 6 belleville washers inside (not many people know this.. and quaife is not unique in this type of build), creating a pretention on the sun gears (sun gearcogs pushing against the the planetary gear cogs).
So they have system inside that always locks the gears to a certain extend.
This is one of quaife's patents (over 30 years old....) that adresses this type of build (they have more variations on this in different patents):https://www.google.com/patents/EP0130806B1?cl=en
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* Intravee & KCA-420i * Mini 0806 * Cheetah C550 * Stubby *

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Post by Ed Doe » Sun Aug 05, 2018 8:19 am

Bloody hell - learn something new every day! Thanks Perry, that's some useful info!
Carbon Black '07 M Coupe: Intrax 1k2 Coilovers, AP-Racing, Raybestos ST45s, Tillets, Schroth, Vibratechnic, Apex EC7, Strongstrut, Eventuri, H&S, RTD, 4.1FD :evil:
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Post by Yorkie Z » Sun Aug 05, 2018 9:55 am

I had an Mfactory lsd diff on my last Z and it transformed the car. Cheap mod at the time (£600) unfortunately prices have gone up and the exchange rate is crap. A diff from Birds is your best option now.
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Post by PerryGunn » Sun Aug 05, 2018 11:27 am

Ed Doe wrote: Sun Aug 05, 2018 8:19 am Bloody hell - learn something new every day! Thanks Perry, that's some useful info!
Ed Doe... just look at the last post on this page

Don't worry, I think a lot of us are getting to 'that age'... :lol:
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* Quaife ATB LSD * StrongStrut Braces * Turner RTAB Limiters * Gap-Tech RCH+ *
* Intravee & KCA-420i * Mini 0806 * Cheetah C550 * Stubby *

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Post by Bodyboarder » Sun Aug 05, 2018 5:48 pm

.... sorry bit ( ready very :wink: ) off topic ...
ed doe.... notice you have 6 pots on 345 csl( z4m ) discs .... any chance of popping over to the M specific section and posting up the details on the vagbremtechnic thread? Looking at some BBK options . Any help much appreciated :thumbsup:

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Post by GuidoK » Sun Aug 05, 2018 6:37 pm

Ed Doe wrote: Fri Aug 03, 2018 2:13 pm Plated diffs will not -they have preload and will lock the wheels together when more than a certain speed differential is experienced across the axle.
Actually only an m differential (e46m/z4m/e92m) will do this. Thats a 'gerotor' style LSD where an internal oil pump actuates a pistion pushing the clutch pack together. The more speed differential, the more the piston pushes.
A normal clutch pack lsd is actuated by the amount of force acting on the propshaft, so it is also torque dependant (the ramp/peg system only works if torque is applied). In theory, a normal clutchpack lsd thus also needs a certain amount of grip on both wheels to be actuated, but normal clutchpack lsd's have an internal preload spring (just like quaife ATB) to try and minimize this.
In the end only a computer controlled lsd can really cope with these circumstances (it uses abs speed sensors and steering input as parameters for lock/unlock and is therefore more precise and fully flexable), and can even work in negative mode (torque vectoring)
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Post by Steve84N » Mon Aug 06, 2018 1:02 pm

I had a Quaife on my Z4 Coupe and it was much nicer to drive afterwards, a direct feeling between your right foot and the rear end when powering through corners.

I have just got a Wavetrac fitted to my C63 and it's better. I'm getting more traction off the line with twice the power/torque than I did with the Quaife. It's also notably better at T-junctions when you accelerate hard over the crest in the road and the inside wheel goes light.

Whilst Quaife has some preload the Wavetrac can create more friction under a zero load condition because of the wavy rings in the middle. Also, they have carbon plates where the planetary gears spin to maintain the same level of friction for life. Quaife spins on the metal so polishes it over time thus becoming less effective.

I'd now choose Wavetrac every time as it's just as invisible/unobtrusive the rest of the time but better at 'locking up'.

Here's my post with pictures on the subject over on MBClub UK: https://forums.mbclub.co.uk/threads/wav ... rt.239911/

This is what's inside a Wavetrac...

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Post by GuidoK » Mon Aug 06, 2018 8:36 pm

I have never had one wheel spinning with the quaife with over 40% more power than you had in the 3.0si, so if you've had that, it was either a tyre issue, or a suspension issue, or an alignment issue. But its not the quaife.
That you now have more traction with the MB can be because its a different car, different tyre size, different weight, different suspension geometry, different electronics or whatever. But the characteristics you describe to your zed dont match up with how mine handles.

Also the wavetrac still relies on a springpack inside to set the initial preload. Not the wavy rings. Look it up in their patent. You see the spring pack sitting inside the wavy rings pack (fig. 7b in the patent). The wavy rings more or less only create a change in bias. Without that springpack the wavy rings cant interlock/unlock. Essentially that also happenes within the Quaife diff but then through the gearsystem, but that is with another bias.
But all this is only relevant on situations like ice, where there's no grip at all. On the normal road there is plenty grip to actuate the locking. And the way the bias transition between gears and wavy rings occurs has to be seen. That doesnt necessarely has to be a good thing. The bias ratio of the helix gears has been chosen for a reason. if there's a secondary system at work with different (greater) bias ratio that can also mess up the drive characteristics under normal/high performance situations.
Also for the wavy rings to work effectively, the other side (so opposed to the wavy rings) has to be coated with a friction surface. This is because the wavy ring actuator is in no means physically connected to the side gears!. One side is the wavy side, the other side is just a flat side rotating on the other flat side of the of the opposed side gear. the patent also talks about this. This is a part that could wear if its a friction surface.

For sure Quaife has a far far greater experience / has seen a far greater scope of use in motorsports (ranging from le mans, F1, rallysport, touringcar championships, dedicated trackcars like radicals etc etc) than wavetrac. From that pov quaife only has drexler and osgiken as real competitors (for bmw applications).
Almost all serious racing cars/track cars choose between those brands. Hardly any of them goes for a wavetrac, so apparantly its not the specialists' choice
Last edited by GuidoK on Mon Aug 06, 2018 8:57 pm, edited 1 time in total.
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Post by Scooba_Steve » Mon Aug 06, 2018 8:45 pm

I hope you can both agree that the car should have come with one! :thumbsup:
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Post by GuidoK » Mon Aug 06, 2018 8:59 pm

Yes, every from of lsd is better than an open diff in a sportscar, even the crappy silicone lsd's in an mx5 (some generations at least).
But what lsd has what advantage is another matter. Personally I think the '1 wheel with no traction at all' situation is absolutely not interesting for Z usage. It might be interesting for cars driven on snow, ice, of offroad, but a Zed typically has 2 wheels on the pavement, albeit with different load. Thats what it has to cope with.
Z4 3.0i | ESS TS2+ | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | fully polybushed | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers | Sachs Race Engineering clutch

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Post by Scooba_Steve » Mon Aug 06, 2018 10:31 pm

How about for track use? I think I might have a photo of mine on 3 wheels :lol:

Either way, the difference is night and day - transforms the car :driving:
3.0si Sport: F10 Illuminated ZHP, Retrofit Cruise, OE Stubby, Gaptech RCH+, Kenwood BT73DAB + Handsfree, HIDs, LED Sidelights, OE LED Number Plate Lights, Custom LED strip bootlight.

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