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Center Diff Options?

Posted by Th3ory, Mar 10, 2019

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  1. Th3ory

    Th3ory Proven Member

    179
    25
    Joined Aug 6, 2015
    Centralia, Washington
    First off, I am admitting I have very little drivetrain knowledge. So please be patient if my questions :)

    Questions or input needed:

    I have a 98 gsx, 350bhp,300 torque and running a ACT2600. Nothing impressive, however I just discovered 2step a few weeks ago, when using 2step off the line, I have a nagging feeling I am on borrowed time with the center diff/trans/axles...

    I have only launched the car a handful of times (practicing on an old abandoned road). The 2step is set around 4500rpms, the FP Green I am running builds about 10psi, and I feather the clutch out. I will never dump the clutch, just feather it, and the car hooks and pulls like I have never felt before. I can feel the car want to break all 4 tires loose, so I back off in fear of damaging the drivetrain.

    I have since been trying to research the weak points of the 2g drivetrain and found most say its the Center Diff, I read through a good amount of information, however most the threads are from 6 to 8 years ago. After reading, I came to the conclusion that I wanted the strongest Center Diff I can get without welding it. I found a lot of people used to run a 4 spider center diff from Speed Design, however I cant seem to find there site, I am not not even sure they are still in business?

    I also found this: https://www.tmzperformance.com/shop/custom-4-spider-hardened-chromoly-cross-shaft-for-1990-1999-dsm/

    I seen TMZ has a sale on there Center Diff options. Looks like the have a fully assembled center diff for sale, something that appels to me because I do not have the knowledge or time to pull out my center diff and piece upgraded parts into it. I would like to drop in or have the local transmission shop drop in a new fully assembled unit.

    Is anyone running a TMZ center diff? Is Speed Design still in business? Is there any other option that I should be considering; another company, welding the center diff, or anything else I am simple missing or misunderstanding? Thanks for any help guys
     

    Street Build 664  0

    1997 Eagle Talon TSi AWD
    automatic · 2G DSM

    2K  7

    1998 Mitsubishi Eclipse GSX
    347.3 whp · 300.4 lb/ft · 2G DSM
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  2. DSMPT

    DSMPT Proven Member

    633
    275
    Joined Jun 12, 2014
    Japan / Mexico, Arizona

    Drag Race Build 2K  3

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM

    Street Build 1K  4

    1998 Mitsubishi Eclipse GSX
    awd · automatic · 2G DSM
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  3. Canadian_CD9A

    Canadian_CD9A Proven Member

    498
    188
    Joined Feb 10, 2012
    Winnipeg, MB, Canada
    From the above list, go with the TMZ or White Shed Speed. I don't trust a machined OEM center diff cross-shaft as much as I trust the aftermarket part.
     
  4. Th3ory

    Th3ory Proven Member

    179
    25
    Joined Aug 6, 2015
    Centralia, Washington
    Thanks guys, the White Shed Speed unit looks very nice. Also has been proven on his car for 2 race seasons at 650whp, wow! Thanks for the info guys.
     

    Street Build 664  0

    1997 Eagle Talon TSi AWD
    automatic · 2G DSM

    2K  7

    1998 Mitsubishi Eclipse GSX
    347.3 whp · 300.4 lb/ft · 2G DSM
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  5. jdxnc

    jdxnc Proven Member

    164
    57
    Joined Sep 15, 2009
    Stanstead, Vermont
    I run the Beyond Redline cross shaft from TMZ as well as extra machining for double thrust washer as per Tim's specs, has held everything I've thrown as it and is 10x more enjoyable to drive than a welded center diff. It has gone 1.52 60' in a 3300lbs with driver car and gone mid 10's. I've also added oil scoops to the housing to make sure everything is well lubricated.

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    fGRSVyO.jpg
     

    Street Build 4K  20

    1997 Mitsubishi Eclipse GSX
    10.456 @ 136.87 · 2G DSM
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    mitsubishikid and Th3ory like this.
  6. bastarddsm

    bastarddsm Proven Member

    4,485
    1,037
    Joined Aug 26, 2003
    Mendota, Illinois
    I don't want to be a bearer of bad news, but unless you have a junk 4 bolt rear diff I can harvest parts out of, I can't do a center diff right now. I can't even find some spares for myself.

    I'm trying to learn/figure out how to make my own cross shafts, but I'm also doing 6 million other things too, so It's on a long too do list. My brother needs one for his galant, so that might push it along a little bit.
     

    Showcar Build 6K  1

    1991 Eagle Talon N/T
    9.805 @ 144.00 · 1G DSM
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  7. Th3ory

    Th3ory Proven Member

    179
    25
    Joined Aug 6, 2015
    Centralia, Washington
    Gotcha, thanks for the heads up. I send you an email, but you just answered my question :)
     

    Street Build 664  0

    1997 Eagle Talon TSi AWD
    automatic · 2G DSM

    2K  7

    1998 Mitsubishi Eclipse GSX
    347.3 whp · 300.4 lb/ft · 2G DSM
    Loading...
  8. Th3ory

    Th3ory Proven Member

    179
    25
    Joined Aug 6, 2015
    Centralia, Washington
    Thanks for the info, another well proven setup!
     

    Street Build 664  0

    1997 Eagle Talon TSi AWD
    automatic · 2G DSM

    2K  7

    1998 Mitsubishi Eclipse GSX
    347.3 whp · 300.4 lb/ft · 2G DSM
    Loading...
  9. ThunderChild

    ThunderChild Supporting VIP

    2,639
    783
    Joined Jan 5, 2012
    Rathdrum, Idaho
    Is it possible to use a 3 bolt diff cross shaft? I haven't had one apart to check it's particular internals.
     

    Street Build 402  3

    1990 Plymouth Laser N/T
    fwd · manual · 1G DSM

    502  8

    1987 Toyota Pickup/Hilux
    awd · manual · Misc Vehicles

    Street Build 1K  7

    1997 Mitsubishi Eclipse Spyder GST
    fwd · manual · 2G DSM

    1K  0

    1992 Eagle Talon TSi AWD
    manual · 1G DSM

    Street Build 2K  10

    1992 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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  10. bastarddsm

    bastarddsm Proven Member

    4,485
    1,037
    Joined Aug 26, 2003
    Mendota, Illinois
    Not really. The pins are a different size than a 4 bolt and won't work. I did do one with a 3 bolt cross shaft, and it was a bunch of extra work, and not worth the liability.
     

    Showcar Build 6K  1

    1991 Eagle Talon N/T
    9.805 @ 144.00 · 1G DSM
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  11. ThunderChild

    ThunderChild Supporting VIP

    2,639
    783
    Joined Jan 5, 2012
    Rathdrum, Idaho
    Bummer, I was thinking the abundance of discarded 3 bolts might make it easier for parts. Oh well!
     

    Street Build 402  3

    1990 Plymouth Laser N/T
    fwd · manual · 1G DSM

    502  8

    1987 Toyota Pickup/Hilux
    awd · manual · Misc Vehicles

    Street Build 1K  7

    1997 Mitsubishi Eclipse Spyder GST
    fwd · manual · 2G DSM

    1K  0

    1992 Eagle Talon TSi AWD
    manual · 1G DSM

    Street Build 2K  10

    1992 Eagle Talon TSi AWD
    awd · manual · 1G DSM
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