[Fot] Triumph GT6 Differential - LS versus welded

[Mike Harmuth]

I can echo Scott's results, but with a Quaife unit. I switched over two
years ago and lap times are really similar but driving (and pushing it
around the paddock) are really much easier. I looked at videos from the
same track and I'm working harder to keep the car where I want it with the
welded diff. More steering angle = more scrubbed off speed. This weekend I
was at Thompson with a fresh engine and I started getting wheel spin on a
few corners, which never happened with the welded diff.

Very hot track, more torque, old tires, probably a combination of both but
the net result after it happened a few times and I realized what as going
on, I adjusted to it and put in lap times the same as Russ Moore's old
Spit, basically the sister car to mine but with an open diff. Jim, in that
car, was getting wheel spin as well but I think he said in more spots.

Quaife for a Spitfire (no clutches to adjust either, just install and
drive) on sale now $893 + shipping directly from Quaife. Install was
straight forward in a GT6 housing with a little grinding of the back of a
bearing race to shim properly.

Would I do it again? Probably yes, for the same reason I went to a billet
crank. No performance improvement but I think more reliability and less
stress on the hardware.

mike h

On Fri, Jun 21, 2024 at 1:40 PM Alexandre Camoletti via Fot <
fot at autox.team.net> wrote:

> Thanks Scott for sharing in detail, most interesting !
>
> I have had a Gripper in the TR3 for the last 10 years. No need to rebuild
> so far despite the many track, hillclimb and fast motorway and smaller
> roads driving miles. Very smooth and you can set it up the way you
> need/like.
>
> One additional benefit : there is no friction material on the plates (as
> the usual Salisbury have), so the wear is very limited. Had I had a
> Salisbury I would have replaced the plates a few times already.
>
> A presto !
>
> Alex Camoletti
>
>
>
> *De :* Fot [mailto:fot-bounces at autox.team.net] *De la part de* Scott
> Janzen via Fot
> *Envoyé :* vendredi 21 juin 2024 17:26
> *À :* 'Friends of Triumph' Triumph
> *Objet :* [Fot] Triumph GT6 Differential - LS versus welded
>
>
>
> You might recall I posed a question about this a year+ ago.  Jason came
> down strongly in favor of welded, others had different opinions.
>
> I ended up buying a Gripper limited slip unit out of england and put it in
> (clutch type).  I’m very pleased with the unit - I told them how I use the
> car, approx HP, tires, and they basically set it up for maximum pressure.
> I can push the car around the paddock more easily, but I’m getting no
> inside wheel spin in corners, no matter what corner or speed, so that seems
> good.
>
>
>
> Lap Times - the real test.  I ran last year with the welded unit at both
> Summit Point and Lime Rock.
>
> My best time at Summit was a 1:30.8 in 2023, at Lime Rock it was a 1:07.2
>
> Last year the engine was freshly rebuilt over ’22-’23 winter.  Tires were
> new Speedsters for Summit Point, slightly less new by the time I got to
> Lime Rock.
>
>
>
> This year my best time at Summit was a 1:30.3, Lime Rock 1:07.9.
>
> Engine is the same, probably somewhat tired after six race weekends (I’m
> actually pulling it now to change rod bearings).
>
> Tires (speedsters) were fresh for Summit again this year.
>
>
>
> Conclusion?  The driving style is definitely different, and I feel like I
> can place the car more precisely with the LS. I think it helps me a bit
> with speed in the Carousel at Summit.  However, there appears to be no big
> difference in lap times.  If I’d been consistently faster at both tracks
> I’d make more of a case for it, but that was not the clear outcome.
> However, the lack of a fresh engine this year is probably good for
> something.  It will get a full rebuild or an alternate new engine for next
> year and the east coast Kastner cup, so we’ll see what that data shows.
>
>
>
> The jury is still out, but right now, I’m not making a strong case for
> spending $1,100 for  the LS.  It’s fine, but not apparently inherently
> superior by much of a margin.  I like turning the car into the turns,
> rather than throwing it in to get the rear sliding like I did with the
> welded unit, but I can adapt either way.
>
>
>
> I do like the Gripper, it has seamless engagement, seems to be excellent
> quality, no wheel spin like I hear from Quaiffe users.  BTW, I did have to
> get out the air grinder and do some minor clearancing on the diff housing.
> It’s a tight fit, and there was minor interference with bolt heads and the
> circumference of the diff.
>
>
>
> More than you wanted to know!!!
>
>
>
> Scott
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