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-   -   Torsen LSD better or worse in the rain? (https://www.rx7club.com/race-car-tech-103/torsen-lsd-better-worse-rain-874077/)

ericgrau 11-17-09 08:22 PM

Torsen LSD better or worse in the rain?
 
I've been reading mixed opinions on using an LSD, even a torsen LSD, in the rain. So let's say, um, for sake of argument, that I don't spend my weekends at the track and my first RX-7 spun, flipped, flipped again and landed upside-down in the rain and I wanted to reduce my chances of that happening again. LSD or no LSD?

jgrewe 11-17-09 10:18 PM

No LSD, less risk of a spin in normal driving.

BLUE TII 11-18-09 01:26 AM

My first RX-7 had no LSD and with my novice driving in the rain it would spin one wheel and if I kept on it and tried to correct w/ steering it would switch to spinning the other wheel instead and I would end up over correcting and spinning the opposite direction (the noob spin).

When I got the TII with the clutch type LSD, yes both tires would spin and the rear would come around, but I could actually correct w/ steering, stay on the gas and vaguely keep it on course.

No, not "normal" driving by any means.

Now that I have the FD Torsen LSD in the TII I feel it really is the best of both worlds.

It does not lock the rear wheels together abruptly bringing the rear end around like the clutch type in power on exiting turns.

You don't have to drive it as gently settling the chassis before each input at higher speeds and at low speeds you can get on the gas before the apex without the understeer you get doing so with the clutch type LSD.

I am no authority, just my observations.

ericgrau 11-18-09 03:47 PM

Yeah, I'm specifically looking into getting a torsen LSD. So... compared to an open diff it's easier to regain control in the rain then??

Thanks, the more input the better.

chohakai 11-18-09 04:33 PM

stock or low torque/power, then Torsen is a decent lsd, better than open diff. But when one wheel is off the ground, then it becomes an open diff...

For high hp cars, the Torsen is worse than open diff. The rear end will be come very unsettled during hard acceleration when you're trying to put down, say 400+ whp in a FD, even for a straight line. As its torque-sensing nature will try to shift the torque back and forth, esp for poor surfaces.

Clutch type is def a must for high hp cars...

BLUE TII 11-18-09 08:17 PM

stock or low torque/power, then Torsen is a decent lsd, better than open diff. But when one wheel is off the ground, then it becomes an open diff...

For high hp cars, the Torsen is worse than open diff. The rear end will be come very unsettled during hard acceleration when you're trying to put down, say 400+ whp in a FD, even for a straight line. As its torque-sensing nature will try to shift the torque back and forth, esp for poor surfaces.

Clutch type is def a must for high hp cars...


Guess it depends on what you consider high HP, but at 340RWHP in a 2600lb FC with a very responsive turbo I was quite impressed with going from the stock S4 clutch type LSD to the Torsen.

I was worried about spinning the inside wheel, but the amazing thing is it does spin the wheel but keeps delivering some percentage to the outside wheel in all the situations I have been in so far.

There are a couple corners where the inside gets light or off the ground on the Hillclimb I do and the truth is you could use this spinning inside wheel to keep the RPMs up in the powerband while still accelerating out of the corner putting power down with the outside wheel. It was pretty cool.

Besides these couple crowned tight corners on the hillclimb I haven't noticed anything unusual in the Torsen LSD behavior and nothing negative at all yet.

I drag raced it, Auto-Xed it and on did a track in rain and dry conditions and I NEVER felt anything from the Torsen LSD, it just worked and I started getting top times of day finally.

I haven't felt it switching back and forth between drive wheels yet, which I expected to in the slaloms we have in the gravely Auto-s area.

DriveFast7 11-19-09 03:28 PM

Torsen is much better in auto-x than open diff. As long as both tires stay on the ground. It is quite rare to lift a tire completely off the ground but if it does, that tire spins until the truck gets settled. The gravel slaloms - all I can say is it puts more down than open diff. I used to autocross a 1st gen clutch diff and the back got squirrely, Torsen in the REPU is much more controlled.

I think the golden rule is, drag race or 400+hp or off road jump racing = clutch. Otherwise Torsen, especially in road racing.

racingdriver 11-19-09 11:57 PM

Blue T2 I couldn't have said it better myself. Just for the record and speaking with actual experience and not bs, Too much power is NOT a problem for the torsen . I roadrace and slolam my 705 rwhp 20b 93 rx7 with a stock torsen diff, and we have never had a failure in 12 years of roadracing. The car also is one of the fastest in the rain (and dry) and has set tons of lap records. We regularly demolish gt3 porsches and have beat several trans am gt1 cars, so guess what , the stock diff works. Don't waste your money on a clutch diff which needs constant servicing, adjusting, and set up adjustments for wet/dry. Succcinctly , indycars run a torsen.

check the videos on youtube and see for yourself. user : boumanauto22.

Anyways , open diff will give you the least chance of crashing as 1 wheel just spins. But the torsen is going to get you off the corner much better and in my opinion very contrllable, , and safer than the clutch diff.

Hyper4mance2k 12-19-09 01:52 AM

it depends on what torsen. The only torsen tht fits in the FB rearend is the miata one and I ate one up in less than 3 weeks on only 2 autoX's and daily driving...

Gene 12-19-09 05:55 PM


Originally Posted by ericgrau (Post 9628844)
I've been reading mixed opinions on using an LSD, even a torsen LSD, in the rain. So let's say, um, for sake of argument, that I don't spend my weekends at the track and my first RX-7 spun, flipped, flipped again and landed upside-down in the rain and I wanted to reduce my chances of that happening again. LSD or no LSD?

If you don't spend your weekends at the track you shouldn't be going so fast in the rain that it matters :p:

wrankin 12-20-09 10:05 AM

Open LSD and invest your money in some good tires. Also keep your foot off the loud pedal when there is water on the road.

More importantly, (and please take this constructively) learn how to drive in the rain. If you flipped your first car, that was 0% the fault of the rain or the car and 100% the fault of the loose nut behind the wheel. Save up your money and go take some good classes in driving - the ones that teach car handling techniques like emergency lane changes and wet skidpad work.

Looking back, I wish that they had been more available when I was a young driver.

Good luck,

-bill


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