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Lets talk Difs.

Posted by D's GS-T, Apr 26, 2011

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  1. DSMReviver

    DSMReviver Proven Member

    810
    75
    Joined Mar 4, 2008
    Little Rock, Arkansas
    Cusco is geared towards the rear so it will deinitely wip out :thumb:

    I haven't put mine on yet cuz i can't decide if i want to tear my transmission down or not. How hard is it to put it in?
     
    Last edited: Jun 12, 2014
    DSMReviver

    1K  0

    1995 Mitsubishi Eclipse GSX
    manual · 2G DSM

    Showcar Build 809  0

    1998 Eagle Talon TSi AWD
    manual · 2G DSM
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  2. Scott McIntyre

    Scott McIntyre DSM Wiseman

    287
    38
    Joined Mar 15, 2002
    Halifax, NS, Canada
    You technically could install a Cusco Tarmac with the trans still on the car, but I'd recommend pulling the tranny so that you can properly measure & set your case preload & end play.

    It's not all that hard to do, just time consuming.
     

    2K  0

    1997 Eagle Talon TSi AWD
    manual · 2G DSM
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  3. ZeGaNe69

    ZeGaNe69 Proven Member

    30
    0
    Joined Jul 18, 2011
    Tallinn, Europe
    Did anyone measured the length of inner EVO LSD or 2G Non-LSD axle cup?
    Teeth count and diameter.
    And what has EVO/Eclipse tripod inner teeth count and bearing diameter.
    I know that, 2G open diff and 1G Outlander rear diff`s internals are exactly the same (except gear ratio).
    Here is a image for an example. This image is from 1G Outlander 02-06 rear`s. Metric scale.
    Thanks.
    s260.png
     

    Street Build 1K  0

    1991 Mitsubishi Eclipse GSX
    manual · 1G DSM
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  4. ZeGaNe69

    ZeGaNe69 Proven Member

    30
    0
    Joined Jul 18, 2011
    Tallinn, Europe
    Anyone?
     

    Street Build 1K  0

    1991 Mitsubishi Eclipse GSX
    manual · 1G DSM
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  5. ACM

    ACM Proven Member

    678
    55
    Joined Dec 11, 2002
    Jamaica Plain, Massachusetts
    Based on the various replies, the non-LSD DSM is functionally identical to the Evo as far as the diff is concerned. Since people build Evo cups onto DSM LSD axles it would appear that the spline count is the same however we will have to wait for someone who's actually done this, to comment on the tripod/bearing comparison (but this may be in one of the axle threads, I'm not sure). It's already well-documented that LSD and non-LSD inner joints are completely different - spline count, tripod bearings and outer dimensions.
     
  6. kchaazz

    kchaazz Proven Member

    1,125
    66
    Joined Oct 2, 2002
    PENSACOLA, Florida
    I measured the Evo and 1G tripod bearings with a micrometer before swapping my Evo cups onto the 1G 4 bolt axles. The spline count of the evo and DSM tripod is the same, and the bearing rollers themselves are identical as well, if thats what you are asking.
    Also, I dont know where you found that picture, but couldnt you find one for the Evo as well?
     

    5K  0

    1993 Plymouth Laser RS Turbo AWD
    manual · 1G DSM
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    tsiboosted likes this.
  7. TheCrazyDSM'r

    TheCrazyDSM'r Proven Member

    94
    1
    Joined May 11, 2003
    Atlanta, Georgia
    I'm really sorry to bring this discussion back to the for front but I have some questions that I'm not really getting the answer for yet.
    For the guys running around with a 1G non-abs, what is the best option for the rear LSD?

    Will an EVO III rear differential work as a direct drop in without changing the pumpkin?
    Does the gearing match OEM?

    Sorry to ask like this I just am hoping for a few simple answers.
     
  8. Canadian_CD9A

    Canadian_CD9A Proven Member

    428
    115
    Joined Feb 10, 2012
    Winnipeg, MB, Canada
    It drops in, but the gearing is wrong; 3.909 for the Evo vs 3.545 for the 1g AWD DSM.
     
  9. TheCrazyDSM'r

    TheCrazyDSM'r Proven Member

    94
    1
    Joined May 11, 2003
    Atlanta, Georgia
    So, I guess my next question is, I'm sure it has been answered somewhere but I can't find it, what is a good option that will just drop in?
     
  10. Canadian_CD9A

    Canadian_CD9A Proven Member

    428
    115
    Joined Feb 10, 2012
    Winnipeg, MB, Canada
    Why not just change the crown wheel on the E3 diff to your stock gear?
     
  11. Canadian_CD9A

    Canadian_CD9A Proven Member

    428
    115
    Joined Feb 10, 2012
    Winnipeg, MB, Canada
    Alright guys, I'm hoping someone can come up big for me here. I need to know if anyone has ever experimented with initial torque settings and/or disabling clutch plates for grip. I came across this article - http://www.motoiq.com/MagazineArtic...-Improving-Grip-by-Tuning-a-Cusco-RS-LSD.aspx - and started to worry.

    I have a 1993 Evo 1 RS that I autocross and want to start lapping with (very similar to a 2g DSM powertrain-wise). Recently I acquired an Evo X Ralliart Super Traction rear LSD (yes, I'm pretty sure it works in my car), it's a 20-plate unit vs. my original 12-plate (it's like the E8/9 but all of the plates are active and it's 2-way vs 1.5), and I'm guessing it really changes dynamics. I also have a Ralliart front LSD and Cusco MZ front LSD to choose from, both with very different characteristics; I believe the front diff's initial torque settings will be the most important. I also got my hands on an Adelia Magic mechanical center coupling, but its settings are anyone's guess.

    If my setup matters, my car's suspension is fully sorted; 10k front/12k rear springs on big-buck dampers, front/rear camber and toe fully adjustable, every bushing done, roll center corrected, etc. I want the car dead neutral on handling, but slight rotation on the throttle - and I want it to bite very hard coming out of tight corners, but without understeer. Power is about 375whp right now, aiming at 450-500whp in the future. Tires are wussy 215/45R17 Dunlop Z1s, hoping to go to 255/40R17 Bridgestone Potenza RE71Rs once I chop my quarters up. It's not an R-comp car, probably never will be.

    That being said, has anyone experimented with initial torque on their clutch-type LSDs (either front, rear or center) to match a specific tire, or driving condition? If so, what happened?
     
    Last edited: Apr 7, 2015
  12. Canadian_CD9A

    Canadian_CD9A Proven Member

    428
    115
    Joined Feb 10, 2012
    Winnipeg, MB, Canada
    As a payback to the DSM community for any help I get on the above, I'll supply the following key information (geez, feels like a video game saying this).

    If you want to convert your 1.5-way Evo rear LSD to the 2-way rear LSD found in the Evo 1 RS for mad acrobatics, the cam housing part number is MB290983.
     
  13. TSiAWD666

    TSiAWD666 Supporting Member

    2,109
    511
    Joined Aug 15, 2003
    Herndon, Virginia
    I commented quite a while ago in this same thread on this topic, posts 65 and 107. TL;DR:
    - Evo 8 rear diff with 12 discs modification (oem is 8, edit - looks like it's 10 from the FSM), redline hw shockproof + 1/4 bottle redline friction modifier, on 285 street tires had way too much power oversteer for my liking in mid/high speed turns (did not confirm lap times were affected, was just too scary for me). I made it more driveable by adding a lot more friction modifier and staying out of the throttle a bit in the problem areas of the track, but that's not fun when you have awd.
    - Evo 8 rear diff with 12 discs, redline hw shockproof, 1/4 bottle redline friction modifier, on 315 Nitto NT01 r-compounds, just the way I like it with slight power oversteer for extra rotation on acceleration on low/mid speed turns. High speed turns the rear tucks on full throttle and gives me incredible grip.
    - same as before, but without any friction modifier, results in slightly more power oversteer for low/mid speed turns, but this feels overall better. high speed wasn't really affected. This is how I am running it now.

    If I were to bet money, I'd bet a lot that a full 20-plate diff, completely activated, on street tires, is going to be a power oversteering nightmare. It's pure speculation though based on my small experience with a single diff + what I've read on lsd clutch-type diff tuning. I suspect the only thing you can do here is try some combination of disabled plates and pre-load (assuming you can adjust your spring plates or anything else) and tweak from there. The big takeaway from my experience is that evo 8 with 12 discs on bigger street tires than yours is dangerous, and friction modifier alone didn't cure it but it does help and thus can be used as a tuning aid.

    Evo 8 rear diff is a 1-way isn't it?
     
    Last edited: Apr 7, 2015

    Road Race Build 13K  12  371

    1999 Mitsubishi Eclipse GSX
    384 whp · 400 lb/ft · 2G DSM
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  14. decathect

    decathect Proven Member

    196
    7
    Joined Mar 5, 2009
    Denver, Colorado
    Isnt' it true that autocross cars are better set up looser than road course? Tight turns, oversteer at lower speeds much more controllable and helpful.
     
  15. cioc

    cioc Proven Member

    190
    33
    Joined Aug 2, 2006
    Sparta, New Jersey
    I have an Evo 8 12 disc in my 1g and can confirm what Tsiawd666 is saying. Street tires are 255's and there is a hair too much on throttle oversteer. 275 Hoosiers are just right. I use Diaqueen with a 1/4 bottle of friction modifier. I believe the Evo 8 is a 1.5 way diff. I wouldn't want a 2 way for fear it would be way to skittish.
     

    3K  0

    1992 Eagle Talon TSi AWD
    manual · 1G DSM
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  16. Canadian_CD9A

    Canadian_CD9A Proven Member

    428
    115
    Joined Feb 10, 2012
    Winnipeg, MB, Canada
    Fair enough, thanks for your experience guys. I'll knock it down 20% each side (disable 2 clutches in each direction) for the rear and run it on the 1.8-way cams, and probably run the front normally. A diff with a higher plate count will lock a lot faster and wear out slower, I'm just hoping to find a happy medium and never have to touch it again.
     
  17. Canadian_CD9A

    Canadian_CD9A Proven Member

    428
    115
    Joined Feb 10, 2012
    Winnipeg, MB, Canada
    I have the Ralliart EvoX rear LSD in now. It's set at 1.8-way with 80% of total lockup, so far so good.

    I got one of these for the first time ever - Cusco 35/65 Tarmac. It wasn't too far from me, and the seller was a member here too.

    7axnb9z.jpg

    I'm deciding whether to run it or not. A few people have asked me for one, but I'm at a crossroads trying to figure out if I want outright grip to be faster, or a loose rear-based center diff to help the car rotate and be more lively on the tail. I do think I would run a stock viscous along with it so it doesn't spin endlessly, though.
     
    MJcanada likes this.
  18. kchaazz

    kchaazz Proven Member

    1,125
    66
    Joined Oct 2, 2002
    PENSACOLA, Florida
    Did you ever happen to play with a locking setup in fron rear and center, or locking front and rear with the stock center and an adelia magic coupler? Ive been thinking about trying to get a Kaaz center or the adelia magic coupler and i know youve had all of these in your possession at some point. I have a feeling that a clutch type center is geared more toward loose surfaces and rally stuff. I will say that i did have my Kaaz front set to 30 percent because i was worried about understeer, but Ive since changed it back to full lockup and its actually given me more grip when accelerating out of corners with the evo rear, so it would seem that stiffer swaybars (Ive got RM bars, nothing compared to Whiteline or RRE but still bigger than stock) and stiff spring rates probably unload the inside front wheel enough under hard cornering to avoid understeer caused by having a locking front diff, yes?
     

    5K  0

    1993 Plymouth Laser RS Turbo AWD
    manual · 1G DSM
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  19. Canadian_CD9A

    Canadian_CD9A Proven Member

    428
    115
    Joined Feb 10, 2012
    Winnipeg, MB, Canada
    I would think that stiffer bars and springs keep the inside tire loaded so that it won't understeer. They would make the most difference with an open diff, seeing as weight is the only thing keeping that tire from spinning. The front LSD eliminates understeer unless you have a 1.5-way or 2-way, then you might get a bit on corner entry but not exit (Kaaz is 1.5). A 1-way shouldn't have any negative effects, but it might affect racing line; it's just a matter of learning to drive with it. One of the time attack guys from Australia is adamant that a good front LSD and lots of caster will do more to reduce or eliminate most of the understeer problems we face, and I do think he's right.

    I never got my transmission out to rebuild it (I do need a new clutch and synchros too), so I can't comment just yet. The Adelia coupling is a 1-way, so it only acts on acceleration, and can allow for some slip. Cusco and ATS centers might be 1.5- or 2-way, I'm not sure which, so they can affect driving on good surfaces if they're set up tight. If you have well-sorted front and rear diffs, the car would behave ok with a stock center diff, since it wouldn't have to do too much. Adelia, same thing, but it's going to be active immediately in the situations where the stock viscous center might slip. It's when you get into poor diff setups that the biggest changes occur by changing one out.

    I have a Ralliart front to go with the Ralliart rear in my car, and I try to keep the flow of Ralliart diffs going in North America. In the event that a Ralliart isn't available, I'd advise people to take the hit and buy a new Cusco RS. I also have an Adelia coupling in my private stock and a long line of buyers who want one, but it's doubtful I'll be able to get another. The downside of that part is also shelling out money for a really good 4-spider.
     
  20. RipperXX

    RipperXX Proven Member

    3,144
    115
    Joined Feb 23, 2003
    Royston, Georgia
    I wish I knew more about these things to figure out what to do with mine. There expensive and I don't want to just toss that money out there on something that might not last a long time or perform in a way that will make the car easier to drive fast & faster.
     

    Street Build 2K  9

    1990 Eagle Talon TSi AWD
    13.476 @ 105.48 · 1G DSM
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  21. ACM

    ACM Proven Member

    678
    55
    Joined Dec 11, 2002
    Jamaica Plain, Massachusetts
    If the Adelia only works on acceleration it will be the perfect partner for the Cusco Tarmac. The one failing of the Tarmac is standing-start acceleration - ProSolo / drag strip launches. We were rarely quicker off the line than the typical pony car - I don't remember exactly what times we were cutting, but they were pathetic, they are still on the SCCA's archives if anyone cares.

    Using the stock VC with the Tarmac makes the car behave like it has the OEM diff, so that's a waste of time, but running without anything makes the car as slow off the line as a typical FWD vehicle.

    Jon@TRE started on a Adelia-style clutch-pack replacement for the OEM VC years ago, but since I was the only person pestering him for it, total sales volume of 2 didn't encourage him that much :)
     
  22. Canadian_CD9A

    Canadian_CD9A Proven Member

    428
    115
    Joined Feb 10, 2012
    Winnipeg, MB, Canada
    Whoaaaa, can you walk me through how the Adelia would work with the Tarmac?
    The Adelia is a quicker-reacting version of the stock viscous; it only locks on acceleration and unlocks as soon as the throttle is off.
    Since the Tarmac only does something when torque is applied, and the Adelia is locked when torque is applied, the front and rear speed outputs would have to be the same. Unless the planetary setup splits torque when speeds are the same, I can't see how it would be anything but a 50/50 split on throttle..
     
  23. 94awdcoupe

    94awdcoupe Proven Member

    1,174
    185
    Joined Nov 6, 2004
    tampa, Florida
    I am doing some axle research for the wagon LSD conversions which I dont think has been done yet. I have a couple of 2G axles questions I hope someone can answer.

    1. are left and right axle bars same length on 2G?
    2. what is collapsed length of axles after evo 8 cups are installed?
    3. rock auto has one rear axle listed under 95 eagle talon. the info on the axle is conflicting as it says it fits left and right. but it lists dimensions as having the double inner splines on the cup. has anyone ordered one yet? what axle is it actually?
     

    Street Build 3K  0

    1994 eagle summit wagon JDM RVR swap
    automatic · 4G63t Swapped

    Street Build 3K  0

    1993
    manual · 4G63t Swapped
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  24. pksystems

    pksystems Proven Member

    192
    108
    Joined Nov 9, 2003
    Calgary, AB, Canada
    Can anyone confirm what this is? Bought it thinking it was a Kaaz. KaazUSA says the casing looks like their's, but the clutch plates/grooves are wrong. Looking at the assembly diagrams, the casing looks different to me.

    kaaz01.jpg

    I *think* this is a Cusco plated center diff. Not the open diff tarmac one.

    Looking for a model# if anyone has it. Hopefully rebuild parts are still available.
     

    5K  25

    1997 Eagle Talon TSi AWD
    awd · manual · 2G DSM
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  25. kchaazz

    kchaazz Proven Member

    1,125
    66
    Joined Oct 2, 2002
    PENSACOLA, Florida
    Not sure about it being a Cusco mechanical. Theres another manufacturer but the company name eludes me at the moment. Ask Canadian_cd9a, he will know as hes had just about every dif availible in his possession at one point or another.
     
    Last edited: Jan 11, 2016

    5K  0

    1993 Plymouth Laser RS Turbo AWD
    manual · 1G DSM
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