OK...Well, here's another one. I am in contact with Quaife for them to build me a Torsen style helical gear, torque-sensing limited slip differential. These units do not rely on slip discs to limit the slip, but rather direct coupled gearing. for superior durability and metered locking. As we had to do with the Wortec rotors and the 4H-Tech short shifters, they will design and build them for the F-Type if a minimum of 10 units are ordered. As I currently only need one, I'm wondering if anyone else might be interested. The fact that we are starting with 3 different differentials with potentially even more final drive ratios will make this project a bit more interesting, but we should be able to sort this out. At the end of the day, knowing that the OEM differentials have not proven to be bullet proof, there may well be a long term demand for the Quaifes as a bullet-proof replacement for failing units. (They will also be less expensive than the OEM diffs.) I may well choose to stock a few of them myself for resale. (Or maybe VAP will step up to the plate). Let me know if you have any interest.

 

Are there any electronics that would be affected by such an upgrade?

 

Yes my only question is with the electronics of the sport diff, how will that work? Other than that, I am in. I need this asap. How long do you think it will take them to make it? I have a 15 R.

 

Will work with a base model?

 

*drool*

I am very interested, but this year I am unlikely to be able to afford the expense of a custom-built differential. The last time I looked into one, it was $5,000 CAD and up.

 

Will this work with the base (non factory LSD)?

 

All good questions, yet to be answered. We are dealing with at least 3 different diffs. Open diff, mechanical LSD & ELSD.
1. I suspect installing a Quaife in the ELSD will throw a code that will require some type of programming if you don’t want to see the “ELSD not available” warning.
2. The 3 varieties of diffs probably have different cases, creating an additional challenge as well.
3. Final drive ratios vary, which will require some thought and even additional programming to keep the speedo accurate.

Will keep you posted. Development on the short shifter took 18 months. This project will take a similar amount of time.

 

Someone on this forum had installed a V6s LSD on a base and had no issues whatsoever despite the different final drive ratios. It *might* just be that you would need one version for both

 

Following, i have the ELSD and its been solid thus far so im not in on the group buy, but this is interesting. Do we know the factory ratios? and is it stored in the CCF? all good info for down the road.

 

If that's the case, it'd be much cheaper to simply install a used LSD.

 

Yes, but a) they are rare, as only some V6S have them b) they are fragile, and nowhere near as robust as Torsen. Unhingd's isn't doing this just because and his V6S already has OEM LSD.

 

Was just the differential replaced or the housing as well? Quaife just provides the internal differential that mounts into the OEM housing.

Maybe Cambo has some insight as to how to recalibrate the speedometer.

Very true. The effectiveness of friction disc LSDs declines over time and will require a rebuild at some point, even if the OEM LSD doesn’t self destruct before then. The Quaife is virtually indestructible.

 

Most normal cars use wheel speed reference for speedo; you wouldn't have to recalibrate for a gear ratio change, only a tire size change. Do we know the F-type doesn't work this way? Or was everyone just assuming there would be an issue?

 

Just assuming an issue. I still have this vision in my head of a cable coming off the tranny tail shaft.

 

Speedo drive is almost always off the gearbox output, I don’t think I’ve ever seen one taken from
a wheel speed sensor. Kind if she’s sense when you think about it but I’ve been wrong before (several times just today in fact.

Ive used Quaife units in a few cars before now and have always been happy. They’re a racing family company, they know what they are doing. If mine was a 6-cylinder I’d be very interested.

i do suspect with the electronics on the v8 models though that this is going to have drastic consequences on the stability program. I personally wouldn’t care as I think the stability software is more or less classic British black humour but it may bother some folks. I wouldn’t want codes flagged every time I drive hard either.

Unhingd, if having them examine a ELSD car is helpful to the process I can volunteer mine (v8s, rwd) for them to examine as they are only a couple of hours drive from my home and I would be a potential customer as I find the latency of reaction in the ELSD distracting compared to the analog feelings I usually get from a mechanical slipper

 

OK i'll give you my 2 cents...

I've fitted Quaifes to both my XKR and my XJR. Having an LSD is a million times better than a crappy open diff. But to be honest the ATB design of differential is not perfect for every occasion. Quaife makes a big deal about their diffs "never locking" but honestly sometimes a locked diff is preferable... don't get me wrong i'm a big fan of the Quaife diffs, but part of that is because there is no other option for the 4.2L cars...

Anyhow, back to the F-Type...

The F-Types without E-Diff are;

3.15:1 V6 non-S, 8-speed auto (open)
3.31:1 V6 non-S, 6-speed manual (open)
3.31:1 V6S, 6-speed manual & 8-speed auto RWD (LSD)

The E-Diff cars;

2.56:1 (V8S, R, RWD & AWD)
3.31:1 (V6S AWD)

Frankly I would forget about the E-Diff cars, because unless you have a means of editing the CCF, you have to keep the E-Diff functioning, or have a dashboard full of fault messages (can't recall if power is reduced with an E-Diff fault or not).

The manual transmission cars simply do not care what the diff ratio is.

Automatics have the diff ratio programmed in, and if the ratio is determined to be outside of an allowable tolerance, you get fault codes and the transmission will go into limp home mode.

I don't know what the allowable tolerance is, but we suspect it's an arbitrary 10%, why 10%?

If you have a 3.31, then you can put in a 3.58 and there is no problem.
If you have a 3.15, and put in a 3.31, there is no problem.
If you have a 3.07, and put in a 3.31, there is no problem.
If you have a 2.87, and put in a 3.07, there is no problem
All these have been done & tested (in F-Type, XF, XJ and XK) and the change in ratio is not more than 7.8%

If you have a 2.87, and put in a 3.31, fault codes & limp mode...
If you have a 2.56, and put in a 3.31, fault codes & limp mode...
So something like 15% variation, is just too much.

For the F-Type V6 non-S owners, going from 3.15 to 3.31 is not a problem. i.e. bolting in a V6S diff, as others have done in the past.
For the F-Type V8 owners it's pretty much irrelevant, because of needing to keep the E-Diff, or finding someone to take care of the programming.

The factory diffs are made by GKN Driveline in the UK, they also make the diffs in the Land Rovers. And it's ironic (to me) that GKN says that they have a helical/atb differential in their product range.
But GKN has absolutely ZERO interest in aftermarket sales/support/service. You can't even buy seals or bearings from them. There are some guys in the US who have rebuild kits for the GKN diffs in the Land Rovers, but nothing for the Jags (different diffs, of course).

GKN is not just an OEM to JLR, no doubt their diffs are in other makes too. But I haven't had the incentive to investigate it further, I don't have a GKN diff in my cars...

Now, if you get a Quaife unit made to suit the F-Type V6... keep in mind that unit will fit in other models too, that are really in need of LSD...

XK 5.0L naturally aspirated V8 (people have put the F-Type V6S diff in)
XF 3.0L V6 supercharged
XE 3.0L V6 supercharged

Those all have open diffs, and the "same" diffs as the F-Type V6s, although not the same ratios in the XE & XF.

If you need 10x units, then find some XE and XF supercharged owners to make up the numbers. As I recall there was one guy with an XF V6 supercharged who went nuts with pulleys & tunes and was going out of his mind because of no traction with the open diff...

JLR decided to make these cars safe for everyone to drive, at the expense of those who want pure performance. So yes, the DSC is extremely intrusive.

We fixed this in our cars, the TRAC-DSC mode is altered, you still have the Stability Control functions, however it will not cut power in the event of wheelspin, if you mess up, understeer, are out of control and are going to crash, the DSC will still save you, but if you just want to put power down coming out of a corner or off the line, now you can because it will not cut power anymore.

This little tweak is why my 4.2L XKR was only 4/10ths of a second slower on a 1min 20s lap around Sydney Motorsport Park than an F-Type R, the standard TRAC-DSC was holding him up all the time.

 

Cambo,
Exactly the info I was looking for.
Thank you!

What other models might use the same differential.? I’ll go on those forums and see if I can get some folks over there to help with the 10 minimum order count.

 

I don't remember about the one VW Bug I owned (66 w/ sunroof), but I know that my brother's (either the 62 we Baja'd or the 58 we converted to 12V w/1600) had the speedo driven by a sensor on the LF wheel. Speedo cable was quite short that way, and pretty easy to get to.

 

I'm assuming it's all electronic now but haven't done any research at all.

In any case, I was not shopping for a diff but the Quaife is the diff of choice for my previous car and would be interested. I'm not sure how many variants there might end up for the F-Type, but I know that you have the same one I do, so know that if it fits yours it'll fit mine.

You can put me on the list. If the price is generally in line with their standard offerings it seems a good opportunity.

 

I'd like to revive this thread. I am very interested in a Quaife (or even retrofitted V6S LSD) for a base V6 manual.

What happened here, did it ever get ordered from Quaife?