Let's talk about limited slip differentials - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Race Prep Miata race-only chat.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 10-26-2010, 11:15 PM   #21
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,372
Total Cats: 1,333
Default

Quote:
Originally Posted by Splitime View Post
When considering bang for the buck... still the same opinion? Did you ever run with one that was rebuilt?
Same opinion. Mine was preloaded to 110ft.lbs initially, no idea what it dropped off to after it "broke in". The car would NOT turn in, even with the RSB attached, and then it would spin the inside rear HORRIBLY on corner exit. This was all at 200whp. Less/more preload would have exasperated one problem or the other - having both problems at the same time quickly convinced me that the Rx7 diff is the wrong way to go. Kotomile has my Rx7 diff now, even despite my warnings about how shitty it was. He said he wanted something stronger than the Torsen, and the Rx7 diff is definitely that. I swapped back to a Torsen and all of those problems went away - nice predictable turn-in, nice smooth power application on exit.

At 270, the Torsen starts to get a little crappy, and it's really holding me back now that I'm at 350. I have the power to spin the inside rear even if it's not completely unloaded, and once it begins to spin I have to pedal it until everything hooks back up again. It's really bad at some tracks and not too bad at others. As Bob said, it's really bad when you are coping with bumps or pavement undulations, like exiting the Omega at WSIR or turn 11 at Thunderhill. For instance, Laguna Seca doesn't cause an issue, except in turn 11, since the track falls away from the apex to the trackout point. If I get into the throttle when I want to, the IR spins and I have to pedal it.

I borrowed an OSG from Emilio for RTA last year and it's absolutely magical. The car turns in properly, and it just hooks up and goes on exit. Even if you have a little slip angle on the way out, it will just haze both rear tires without even putting up a fight.

As far as RSB vs. no RSB, it helps a little on exit but my car needs the RSB to be balanced everywhere else - if I can't get the car rotated correctly there's no hope of getting away from the apex with any sort of drive.

Last edited by Savington; 10-27-2010 at 12:05 AM.
Savington is offline   Reply With Quote
Old 10-27-2010, 09:43 AM   #22
Elite Member
iTrader: (2)
 
fooger03's Avatar
 
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,133
Total Cats: 188
Default

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.
fooger03 is offline   Reply With Quote
Old 10-27-2010, 09:48 AM   #23
Elite Member
iTrader: (12)
 
GeneSplicer's Avatar
 
Join Date: Sep 2009
Location: Birmingham, AL
Posts: 2,006
Total Cats: 147
Default

I wish I could tell ya how amazing it was to swap from a Torsen to an OSG.... but I went straight from a viscous to OSG - now THAT was a change. I'm only at 225 too, but I'll take Sav's word that I'll be glad I've got the OSG once I put in my built 1.8 at the end of the season. It's awesome fun coming out of #5 and #8 at Barber, very predictable.
GeneSplicer is offline   Reply With Quote
Old 10-27-2010, 10:21 AM   #24
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

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.

It's my understanding that when you unload the inside wheel on a Torsen, it turns-into an open-diff. If the high-speed valving is right, the inside wheel stays on the pavement and never unloads the inside wheel, it won't spin.

I bet a real diff in my car would be epic.
hustler is offline   Reply With Quote
Old 10-27-2010, 10:34 AM   #25
Junior Member
 
Join Date: Jan 2007
Location: EXTREME Southern Illinois
Posts: 281
Total Cats: 0
Default

Quote:
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.
That is what a Torsen R is. I believe they come stock on S2000's?
I blew up my stock '99 Torsen autocrossing it. Lifted the inside rear, got on the throttle, it spun up the wheel, and ate some teeth off of the worm gears when it landed. Switched to a Cusco Type RS. Turn-in suffered compared to the torsen, but exiting the turns is much better.
DammitBeavis is offline   Reply With Quote
Old 10-27-2010, 10:58 AM   #26
Elite Member
iTrader: (2)
 
fooger03's Avatar
 
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,133
Total Cats: 188
Default

Quick note because I didn't know: Per Torsen's website, the Type A (Torsen T-1)differential is superior to the Type B (Torsen T-2) differential for getting power to the wheel with traction. IIRC, the Type A Torsens were found on 94-95 cars, and the Type B Torsens were equipped on 96+ Cars.

The Racemaster (Torsen T-2R) was designed to provide the higher bias found in the type A Invex gears while using the newer T-2 Equvex gear style.

Food for thought.
fooger03 is offline   Reply With Quote
Old 10-29-2010, 04:23 AM   #27
Junior Member
 
Join Date: Jun 2005
Posts: 166
Total Cats: 11
Default

at 300ish whp, the torsen started acting up, at 400whp, it is useless, feels like an open diff. The osg is without doubt the best diff i have tried ever no chatter og clunking when driving on the streets, cant really tell there is a racing type diff in the car as it feels more like a stock mazda diff. Compared to lets say kaaz diffs, well.. it cant really be compared(kaaz is klunky and terrible all the time).
when accelerating, the car would wander from side to side as the torsen struggled to find grip all the way past 80-90mph. with the osg, it just feels planted, much more stable..
Turn in is also great. we are building another 400whp miata now. and were putting a osg unit in it from the start. no point even running the car with the torsen. Better of selling it before it breaks(like mine did)
hf-mx5t is offline   Reply With Quote
Old 10-29-2010, 06:52 AM   #28
Newb
 
Join Date: May 2008
Location: Europe
Posts: 18
Total Cats: 0
Default

I've been thinking about the Quaife LSD. Does anyone have experiences on the Quaife?
http://www.horsepowerfreaks.com/part...ip_A.T.B/16679
The price of the Quaife LSD is about 800 euros in Europe and the Os Giken LSD is about 1500 euros.

Last edited by Marko; 10-29-2010 at 11:50 AM.
Marko is offline   Reply With Quote
Old 10-29-2010, 09:24 AM   #29
Elite Member
iTrader: (2)
 
fooger03's Avatar
 
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,133
Total Cats: 188
Default

Quote:
Originally Posted by hf-mx5t View Post
at 300ish whp, the torsen started acting up, at 400whp, it is useless, feels like an open diff. The osg is without doubt the best diff i have tried ever no chatter og clunking when driving on the streets, cant really tell there is a racing type diff in the car as it feels more like a stock mazda diff. Compared to lets say kaaz diffs, well.. it cant really be compared(kaaz is klunky and terrible all the time).
when accelerating, the car would wander from side to side as the torsen struggled to find grip all the way past 80-90mph. with the osg, it just feels planted, much more stable..
Turn in is also great. we are building another 400whp miata now. and were putting a osg unit in it from the start. no point even running the car with the torsen. Better of selling it before it breaks(like mine did)
Was this on a stock Torsen(R) unit, or were you using an aftermarket gear bias differential (such as the Kaaz)?

It's strange to think that you would be breaking individual tires loose - I would expect that the coefficient of static friction between a tire/asphault is less than 2 1/2 times the coefficient of kinetic friction - especially a sticky race tire which tends to have a significantly less frightening transistion from "stick" to "slide"

I could see it rolling out of a corner
fooger03 is offline   Reply With Quote
Old 10-29-2010, 11:08 AM   #30
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

kaaz is not a gear bias diff, it's all clutch.

and it's not all that terrible on a street car. I've had mine a long time and it's only clunky if you're trying to zip through U turns. not anywhere else.

the biggest issue I have with it is how it straightens the car out when you get on the gas in turns.
y8s is offline   Reply With Quote
Old 10-29-2010, 01:16 PM   #31
I'm Miserable!
 
Join Date: Feb 2010
Posts: 584
Total Cats: 0
Default

On diffs…note that it can be misleading to just swap and choose the "best". For the best results given very different diffs, you should also tune your car setup and driving strategy a bit. Some that "promote" understeer will perform better if other things are also changed to accommodate that tendency. They can also affect brake setup as the nature of any rear lockup characteristics can become more or less pronounced. Which can be a big thing for those that like a lot of rear brake (retaining stability) as I do. On some cars I've setup, a diff swap could allow a few hundred more PSI at the prop valve's knee point. This stuff is all interrelated...
sjmarcy is offline   Reply With Quote
Old 10-29-2010, 03:42 PM   #32
Junior Member
 
Join Date: Jun 2005
Posts: 166
Total Cats: 11
Default

Quote:
Originally Posted by fooger03 View Post
Was this on a stock Torsen(R) unit, or were you using an aftermarket gear bias differential (such as the Kaaz)?

It's strange to think that you would be breaking individual tires loose - I would expect that the coefficient of static friction between a tire/asphault is less than 2 1/2 times the coefficient of kinetic friction - especially a sticky race tire which tends to have a significantly less frightening transistion from "stick" to "slide"

I could see it rolling out of a corner
coming out of sharp, high grip 3rd gear corners on a track, using 225 R888 tires, it would spin the inside tire like posessed.. it simply was not able to transfer enough torque to the outside wheel to break it loose before the inside started spinning, atleast thats what it feels like. And then i had to get of the throttle a bit, find grip, and easy back on the throttle again, just like running a open diff This was when using the stock mazda torsen diff. When opening the diff to install the OSG unit, there was massive wear on the spider gears inside the diff, on the sides trying to transfer power to the outside wheel. This had happend in just a few months use (it did display the same issue from day one when running 400whp), and the unit had no problems at all when running lower whp settings. seems that there is a point where the stock torsen just is not up to the massive task it is being dealt.

i must sound like a OSG sales rep . but it absolutly transformed the car.
hf-mx5t is offline   Reply With Quote
Old 10-29-2010, 04:33 PM   #33
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,372
Total Cats: 1,333
Default

Seems like EVERYONE that's tried/owns an OSG diff sounds like a sales rep. Speaks volumes for how badass that diff is.
Savington is offline   Reply With Quote
Old 10-29-2010, 04:38 PM   #34
I'm Miserable!
 
Join Date: Feb 2010
Posts: 584
Total Cats: 0
Default

In case some missed the article…while the test used an S2000, the details are still interesting:

http://grassrootsmotorsports.com/articles/whats-diff/
sjmarcy is offline   Reply With Quote
Old 10-29-2010, 05:48 PM   #35
Senior Member
iTrader: (3)
 
Join Date: Jun 2008
Location: Port Orchard, WA
Posts: 620
Total Cats: 4
Default

Quote:
Originally Posted by Marko View Post
I've been thinking about the Quaife LSD. Does anyone have experiences on the Quaife?
http://www.horsepowerfreaks.com/part...ip_A.T.B/16679
The price of the Quaife LSD is about 800 euros in Europe and the Os Giken LSD is about 1500 euros.
Quaifes work similarly to a Torsen, get the inside tire light and it acts like an open diff.
Rennkafer is offline   Reply With Quote
Old 10-30-2010, 01:34 AM   #36
I'm Miserable!
 
Join Date: Feb 2010
Posts: 584
Total Cats: 0
Default

Quote:
Originally Posted by Rennkafer View Post
Quaifes work similarly to a Torsen, get the inside tire light and it acts like an open diff.
Although…at least some Quaifes have a preload adjuster set via belleville washers…you have to open up the unit to get at them. I got a few Qs cheap after I helped them out with a lawsuit. Put one in an E30 M3 and another in a boosted Lotus Europa with nitrous antilag. I haven't compared a Q to an Giken but they were better than the usual BMW diff setup for racing. Those smear some understeer over the turn-in process whereas the Qs feel open at that time.
sjmarcy is offline   Reply With Quote
Old 10-30-2010, 10:47 AM   #37
Senior Member
iTrader: (14)
 
Join Date: Jan 2007
Location: Murfreesboro,TN
Posts: 1,279
Total Cats: 53
Default

Quote:
Originally Posted by Savington View Post
Seems like EVERYONE that's tried/owns an OSG diff sounds like a sales rep. Speaks volumes for how badass that diff is.
You'd think that, but two of the top CSP cars run a stock Torsen and RX7 diff. I know its not track, but diff problems seem to exaggerated in auto-x. I've driven two different cars with OS Gikens (a CSP Miata and X Prepared S2000) and I couldn't tell you there was difference between it and the Tomei diff I used in my old Corolla (AE86) in terms of performance. Maybe its just because I'm cheap, but I think I'll stick with a Tomei/Kaaz diff when the time comes.
Midtenn is offline   Reply With Quote
Old 10-30-2010, 11:01 AM   #38
I'm Miserable!
 
Join Date: Feb 2010
Posts: 584
Total Cats: 0
Default

Quote:
Originally Posted by Midtenn View Post
You'd think that, but two of the top CSP cars run a stock Torsen and RX7 diff. I know its not track, but diff problems seem to exaggerated in auto-x. I've driven two different cars with OS Gikens (a CSP Miata and X Prepared S2000) and I couldn't tell you there was difference between it and the Tomei diff I used in my old Corolla (AE86) in terms of performance. Maybe its just because I'm cheap, but I think I'll stick with a Tomei/Kaaz diff when the time comes.
Maybe those two CSP cars had the "whole package" tuned to work well together…quite often, LSD swaps need setup changes to max out potential.
sjmarcy is offline   Reply With Quote
Old 10-30-2010, 11:23 AM   #39
I haz no trubo
iTrader: (2)
 
Oscar's Avatar
 
Join Date: Jan 2007
Location: Bolton, UK
Posts: 3,021
Total Cats: 114
Default

Quote:
Originally Posted by y8s View Post
kaaz is not a gear bias diff, it's all clutch.

and it's not all that terrible on a street car. I've had mine a long time and it's only clunky if you're trying to zip through U turns. not anywhere else.

the biggest issue I have with it is how it straightens the car out when you get on the gas in turns.
Mine's only clunky when cold and quiets down after a couple of minutes driving. I do change the oil religiously though. Importing those cans cost me a fortune every time.
Oscar is offline   Reply With Quote
Old 10-30-2010, 11:37 AM   #40
Elite Member
iTrader: (12)
 
GeneSplicer's Avatar
 
Join Date: Sep 2009
Location: Birmingham, AL
Posts: 2,006
Total Cats: 147
Default

Quote:
Originally Posted by Rennkafer View Post
Quaifes work similarly to a Torsen, get the inside tire light and it acts like an open diff.
Speaking of Quaife, AWR and Flyin no longer carry the gearsets for the 5spds... new US distributor, bad sales, Quaife stop making them? I know it was crazy expensive - but the wideratio was temping with the 5spd. - not trying to change the topic, but I'll be needing something to handle 400rwhp (I'm serious) - been researching a various swaps - finding something with proper shifter location being a problem.

My OSG should not be a problem at that power level.

Last edited by GeneSplicer; 10-30-2010 at 11:59 AM.
GeneSplicer is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
1994 Spec Miata Race Car SM/SM2/SSM For Sale Quinn Cars for sale/trade 6 10-23-2016 08:58 AM
[CT] 1999 Mazda Miata 10th Anniversary Edition - $5800 Jike Spingleton Cars for sale/trade 3 09-20-2016 05:33 PM
Momo Supercup seat jpreston Miata parts for sale/trade 2 05-17-2016 01:51 AM
Which moderator should I talk to? unplugged92 Meet and Greet 4 09-16-2015 07:20 PM
Mystery Engine Trouble. Halp, mt.net! vehicular General Miata Chat 12 09-14-2015 04:17 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 05:09 AM.