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View Full Version : Front Torsen Diff for the All Trac



temperacerguy
11-12-2011, 07:10 AM
Hey guys,

Just an FYI. M-Factory is going to start work on a torsen front Diff for the ST185. I have sent them a factory open diff for them to design the unit off of.

allTRACway
11-12-2011, 08:19 AM
sweet thank you im excited for this

temperacerguy
11-12-2011, 08:35 AM
To be honest.... I am highly doubtful that this will actually get made... That being said... I am offering my unit, and my time for testing to see if it fits/works.... in other words... I am hopeful, but not placing money on it happening.

allTRACway
11-12-2011, 08:45 AM
agreed but im still excited for it to even be brought up shoot maybe if they cant get it done we can find someone who can

thank you again

Nitro_Alltrac
11-13-2011, 04:34 AM
This will be really nice if it happens. Keep us posted.

alltracman78
11-13-2011, 05:07 AM
I thought there were problems with the rear TORSEN when racing?
When the inner wheel lifts it was tearing the TORSEN apart?

If that's the case, is a front TORSEN worth it? I would assume it would be used for racing, if you're lifting one of the front wheels in corners it would do the same?

allTRACway
11-13-2011, 12:20 PM
personally if yur lifting the front wheels at all your way to powefull for that track or you have a junk set up imo

KoreanJoey
11-14-2011, 07:11 AM
I thought there were problems with the rear TORSEN when racing?
When the inner wheel lifts it was tearing the TORSEN apart?

If that's the case, is a front TORSEN worth it? I would assume it would be used for racing, if you're lifting one of the front wheels in corners it would do the same?

It's all a function of setup. And for a front diff a clutch diff is usually too aggressive (hard to turn). And yes, a torsen in the front makes a big, big difference in the way a car handles, difference between the front digging in and the rear drifting out. Try driving an Evo 8 and an Evo 9 back to back.

temperacerguy
11-14-2011, 06:03 PM
Try driving an Evo 8 and an Evo 9 back to back.
Close, but some 8s also had a torsen front diff.

I agree, it's huge for traction. I love my Evo's Diff setup with front torsen.

alltracman78
11-16-2011, 02:17 AM
Having a front TORSEN is definitely better than having no front LSD, I wasn't questioning that. :)

I was just wondering about the reliability of a TORSEN when raced on pavement, I know Martin from alltrac.net was killing TORSENs and I'd heard it mentioned that they were problematic when you have wheels lifting.

I don't race right now, so it's not something I'd necessarily ever deal with, I was just curious about it.

Terracar
11-16-2011, 04:16 AM
It was great of Flyin Bajan to start the front LSD conversation with M Factory and get to the point we needed a front diff sent for review.

It was nice of you temperacerguy to step up and offer your parts for the task.

-Terracar

celica9303
11-16-2011, 04:25 AM
i thought josh was doing thiss? im confused.......

KoreanJoey
11-16-2011, 06:02 AM
Having a front TORSEN is definitely better than having no front LSD, I wasn't questioning that. :)

I was just wondering about the reliability of a TORSEN when raced on pavement, I know Martin from alltrac.net was killing TORSENs and I'd heard it mentioned that they were problematic when you have wheels lifting.

I don't race right now, so it's not something I'd necessarily ever deal with, I was just curious about it.

I have a feeling Martin's problems were more from the ProSolo launches... High power AWD launch + wide hoosier A6s = somethings gotta give.

But yes, if the one wheel lifts the torsen goes open (which sucks) and if you get massive wheelspin. While that one tire is spinning at over 9 thousand and then the tire hits the ground, the diff tries to become an LSD again... that can cause some problems.

temperacerguy
11-16-2011, 07:42 AM
i thought josh was doing thiss? im confused.......

What was happening over at AT.net was there was tons of discussion going back and forth, and no real action being taken... lots of good intentions, but the people with the parts wern't motivated, and things just wern't happening...

I had the parts out and ready to go. So I started communication with Stephen at Mfactory and kinda pushed this forward and sent my unit out to them. They also agreed to let me do testing on the unit (if it ever actually gets done)

I agree with KJ... It's not that the Torsen is weak, it's that when you start applying serious torque to something with serious traction, something's got to give when it's shock loaded.

alltracman78
11-16-2011, 04:21 PM
I agree with KJ... It's not that the Torsen is weak, it's that when you start applying serious torque to something with serious traction, something's got to give when it's shock loaded. Definitely, I wouldn't think that it's weak either.
My understanding was that's one of the advantages to a clutch diff, it can "give" and not break when this does happen.

If a clutch diff in front makes it much harder to turn [didn't know that], I guess there's a trade off either way.

But don't FWD cars w front LSD have clutch diffs [I was under the impression they were more popular than TORSEN LSDs]?

I'm not trying to be difficult, just curious. I don't race so this is something I don't know a lot about.

temperacerguy
11-16-2011, 11:23 PM
Definitely, I wouldn't think that it's weak either.
My understanding was that's one of the advantages to a clutch diff, it can "give" and not break when this does happen.

If a clutch diff in front makes it much harder to turn [didn't know that], I guess there's a trade off either way.

But don't FWD cars w front LSD have clutch diffs [I was under the impression they were more popular than TORSEN LSDs]?

I'm not trying to be difficult, just curious. I don't race so this is something I don't know a lot about.

With a clutch Diff, The wheels are always TRYING to turn at the same speed. When you turn a corner, the distances that the wheels travel are different. So when turning a corner with a clutch style at 100% lock-up, one or the other wheel has to slip, which means that it has no traction. So with a clutch style LSD on the front, and you turn the wheels, one of the wheels that trying to cause the car to rotate is slipping. Once a wheel has lost traction, the direction of the wheel doesn't matter, the momentum of the car will overpower the rotation of the wheel. a torsen LSD will transfer torque to the wheel regardless of the rotational speed. Therefore it will allow the wheels to travel different distances while transfering equal torque between the wheels.

And most cars with factory front LSDs use viscous coupling LSDs, the higher end cars use torsen LSDs... Clutch style LSDs require periodic maintanance, which factorys shy away from.

alltracman78
11-17-2011, 12:23 AM
Interesting



Good to know :)

KoreanJoey
11-17-2011, 07:24 AM
This is not saying that a clutch type LSD doesn't work in the front. It's just harder to setup to drive well. In fact as power increases you'll need more of the 50-50 lock of a clutch type LSD than the given bias ratio of a torsen lsd. I think the main thing is tuning the pre-load and also the amount of LSD additive to adjust the initial lock-up.

Seems like with FWD you want low initial lock up with a progressive engagement to 50-50 at full torque. And well... with AWD I don't think you'd ever want the front wheels to get to 50-50, seems unnecessary unless you really need the traction.