[s-cars] New clutch, and rear diff limits

[Joe Pizzimenti]

Ah, the sweet music of expensive drivetrain goodies going crunch in the
quest to make Miss Piggie dance.

Your launch sounds dead on, FWIW, and good ol' mlp is probably right about
that fuse.

I do think that I remember doing some research on rear differentials and
while a Gleason/Torsen is great for sideways traction, I suspect that there
may be a bit of that dreaded "spider bite" going on left to right and those
shock loads are ripping those helical gears to shreds. I hope that
installing a stock locker diff is the answer, but at that point, you may
just find that you're ripping the half shafts out of the diff instead of
killing the diff itself. Another thing you might want to try is taking a
stock open diff and welding the guts together, but you still might have that
issue of shock loading.

Does anyone make a twin disc clutch for the 01E trans? From my experience in
Tokyoland, you transmit less stress throughout the drivetrain by spreading
out the pain across 2 or more clutch discs instead of just one.

Another thing to consider is rear suspension. Not sure if you're running
coilovers or not, but a switch to stiffer rear springs may reduce rear end
squat enough to take the pressure off of the back end and keep the
drivetrain in line.

Maybe a softer tire or less tire pressure is all the give you may need, but
I'm just bench racing at this point.

Keep on breaking stuff in the interest of science. Makes for good forum
traffic.

Joe

On 10/25/05, djdawson2 at aol.com <djdawson2 at aol.com> wrote:
>
> OK,
> So I was all excited... 12.4 at 113, and it seemed very limited by the
> clutch's inability to deal with a competitive launch. So I called Javad
> (034efi) to discuss clutch options. He had a unit built by Spec that he said
> was good to 600ft/lbs. So I ordered away... intent on a more successful trip
> to the dragstrip before the season ended.
>
> I drove the car back from Boise to Denver on Friday night. Got up
> Saturday, and started in. About 6 hours later, I had my new Spec clutch in
> the car. Everything's going fine. Out for a test drive...
>
> I decided to see how this clutch would hook up under power. I tried a
> moderate launch first... one that the Centerforce wouldn't hold. Wow... this
> thing stuck like white on rice... impressive. So now I'm all excited about
> the potential. So I go for an aggressive launch... 6k rpm with a gentle
> engagement to build boost, and then let 'er go. KABOOM!! This was a sound I
> knew well from previous experience with other cars.
>
> The rear torsen diff had unloaded, to the extent that a hole was blown
> through the side of the case. Fortunately, I still had my original diff...
> so I was able to swap that back in.
>
> So now I'm wondering... and scared. Is this the limit of the drivetrain?
> Are future trips to the strip just another blown diff waiting to happen?
>
> Anybody with experience... please share. How do you launch? What kind of
> abuse have you been able to put the drivetrain through without failure?
>
> Keep in mind, I'm not dumping the clutch. I usually start at a higher rpm
> (6k'ish), let the clutch out enough to put a load on the engine so that it
> rapidly builds boost, and then gradually let it grab completely. When done
> right, you get the feeling like you are in a slingshot... and there's
> nothing really sudden or abrupt about it.
>
> And yes... Mr. Pederson has repeatedly used the term "fuse." Maybe my rear
> diff is now the fuse, instead of my clutch. Hey, at least it wasn't the
> tranny.
>
> Dave
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