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Old 10-30-2010, 12:18 PM   #41
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My KAAZ is soooo loud, even with the KAAZ diff fluid. Could have something to do with the solid diff mounts, idk.
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Old 10-30-2010, 12:56 PM   #42
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Quote:
Originally Posted by BenR View Post
I mention the sway bar because there is a really tight banked hairpin at my local track that was causing me to lift the inside rear tire. I would just spin that tire on corner exit. Pulling the rear sway bar solved it for me. I assume it helped increase droop travel and let the inside tire get some grip. Worked for me on that particular corner. I think some of the spec drivers found the same thing. May have zero relation to what Sav is seeing. YMMV
Read my posts here about disconnecting the rear sway bar.

http://forum.miata.net/vb/showthread...=362012&page=3
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Old 10-30-2010, 04:33 PM   #43
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Originally Posted by hustler View Post
I was searching for a diff after driving Johnwag's car with a Cusco. However since putting the AST dampers in I don't feel the need to buy a diff. I was getting on the gas just as soon as I did in John's 130whp car with no-more inside wheel spin when sucking-up the curbs.
Maybe you have an advantage you haven't fully explored yet. This discussion is about Lotus'. Perhaps it's applicable, perhaps not?:

"The Elise was always designed from the outset to work without an LSD. We have recently started to offer an LSD as an option on the Toyota engined cars, primarily in response to market demand from the Autocross enthusists in the USA, who need one to be competitive when accelerating away at full throttle from very slow, tight corners in first or second gear.

In this type of competition they do not tend to run high speed (100mph +) corners and therefore the increase in understeer on this type of corner which you get with an LSD is of little negative consequence to them and they therefore are better off with an LSD.

In our experience an Elise or Exige equipped with an LSD is at a disadvantage to one without an LSD on a typical European race track. On top of that the LSD bluntens the steering feel and respsonse of the car which we don't like.

If you want an LSD then by all means fit one, but please understand that there are negative as well as positive effects. In the instance you describe, instead of spinning the inside wheel as you accelerate away at full throttle (which can be easily fixed by modulating the throttle! Very Happy ) a car with a 2:1 LSD like the obne we supply will provide twice the torque to the outside wheel as it does to the inside one. This will increase the slip angle of the outside wheel and the car will tend to oversteer heavily on corner exit, requiring a reduction in throttle if you are not to spin.... It isn't much quicker, honest.

The optional diff we supply is a Torsen unit, the aftermarket unit supplied by Motorsport is a plate diff, with a similar 2:1 bias and no preload so in terms of action it mimics the Torsen closely."
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Old 10-30-2010, 05:21 PM   #44
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Originally Posted by Thucydides View Post
Maybe you have an advantage you haven't fully explored yet. This discussion is about Lotus'. Perhaps it's applicable, perhaps not?:

"The Elise was always designed from the outset to work without an LSD. We have recently started to offer an LSD as an option on the Toyota engined cars, primarily in response to market demand from the Autocross enthusists in the USA, who need one to be competitive when accelerating away at full throttle from very slow, tight corners in first or second gear.

In this type of competition they do not tend to run high speed (100mph +) corners and therefore the increase in understeer on this type of corner which you get with an LSD is of little negative consequence to them and they therefore are better off with an LSD.

In our experience an Elise or Exige equipped with an LSD is at a disadvantage to one without an LSD on a typical European race track. On top of that the LSD bluntens the steering feel and respsonse of the car which we don't like.

If you want an LSD then by all means fit one, but please understand that there are negative as well as positive effects. In the instance you describe, instead of spinning the inside wheel as you accelerate away at full throttle (which can be easily fixed by modulating the throttle! Very Happy ) a car with a 2:1 LSD like the obne we supply will provide twice the torque to the outside wheel as it does to the inside one. This will increase the slip angle of the outside wheel and the car will tend to oversteer heavily on corner exit, requiring a reduction in throttle if you are not to spin.... It isn't much quicker, honest.

The optional diff we supply is a Torsen unit, the aftermarket unit supplied by Motorsport is a plate diff, with a similar 2:1 bias and no preload so in terms of action it mimics the Torsen closely."
By the way, I datalogged the bejesus out of many Elises and my own…with all sorts of drivers from myself, to noobs, to Aliens, half a dozen National Champs, etc. An interesting thing about the open diff on that car…although it is slightly slower than the LSD version, it feels better as Lotus notes, and this can be measured in the steering data too, you can see it in the various driver inputs. When you spin up an inside rear on an Elise (mostly RR), you get some "extra" acceleration back as it spins back down, lol. Another thing about autocross is that you tend to use / need larger front sway bars than other uses require. In racing it does not matter if a part is 1 second or 0.001 quicker since it is competition. The LSD does not do much to help the Elise, nothing like what it does for pony cars for example.
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Old 10-30-2010, 10:31 PM   #45
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Originally Posted by fooger03 View Post
Is a preloaded torsen possible? Is it possible to squeeze a small self-contained viscous or clutch unit inside the torsen and attach it at the center of the output gears? How much room is in there? It wouldn't have to provide for the full strength of limited slip, it would only be preloading the torsen unit. If it put 50 ft-lbs of preload on the torsen, then the torsen would treat a wheel in the air as having (0+wheel inertia+50 ft-lbs) of torque, and would use that to apply torque to the grounded wheel.
No, there is no room inside a torsen. We use one on the FSAE car because of the very tight turns we have.

Also to note, you won't have to service a Torsen, unlike a clutch pack. (No clutch plates to wear).

I would say Torsen style for the street, clutch for the track.
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Old 10-30-2010, 10:46 PM   #46
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The Torsen T2R is preloaded
http://www.torsen.com/products/T-2R.htm

By combining the patented Equvex gearing from the Torsen T-2 with a coil spring pre-load and/or friction enhancing plates, the Torsen T-2R can remain locked, providing torque to both wheels, under low torque inputs. The addition of the friction plates allows the Torque Bias Ratio (TBR) to be tailored to differential design needs.
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Old 10-31-2010, 06:00 AM   #47
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Originally Posted by cardriverx View Post
No, there is no room inside a torsen. We use one on the FSAE car because of the very tight turns we have.

Also to note, you won't have to service a Torsen, unlike a clutch pack. (No clutch plates to wear).

I would say Torsen style for the street, clutch for the track.

bullshit the torsen doesnt need service. it wears as much as anything else, even more, with the proper amount of power applied to it
OSG for street and track : its better at everything, period
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Old 10-31-2010, 12:51 PM   #48
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True the torsen does have wear parts, they look something like the conical springs in a clutch type but are much smaller and there is one for each of the helical gears.
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Old 10-31-2010, 01:59 PM   #49
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Originally Posted by hf-mx5t View Post
bullshit the torsen doesnt need service. it wears as much as anything else, even more, with the proper amount of power applied to it
OSG for street and track : its better at everything, period
Yeah sure everything wears. But if you have a properly set up clutch pack, it will need servicing far before a torsen.

P.S - the T2R is slick.
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Old 10-31-2010, 02:42 PM   #50
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Has anyone here tried the S2K diff swap in there miata? I thought about it but couldn't find the stub shafts that you need out of the S2K cheap enough so I just went the RX7 route. Those Honda dont let parts go cheap.
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Old 10-31-2010, 05:41 PM   #51
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Quote:
Originally Posted by cardriverx View Post
Yeah sure everything wears. But if you have a properly set up clutch pack, it will need servicing far before a torsen.

P.S - the T2R is slick.
my torsen lasted less than 3months at 400whp and track use. The helical gears were the parts that wore out.. the osgiken has lasted twice that already I would say that the giken unit is properly set up too.

no point in arguing, osgiken diff= best diff for our miatas :P Please find someone that has tested one, that disagrees .
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Old 10-31-2010, 06:06 PM   #52
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hf-mx5t tracks his car a bit so I would def tend to believe what this guy is spouting.
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Old 10-31-2010, 07:13 PM   #53
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Has anyone every used a Carbonetic clutch type diff? I know they make one for the S2000 so you could use it in an MSM. Might be an interesting comparison to the OSG.
I don't think Wavetrac makes a miata LSD do they?
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