Actually, we are snippy, and we are RIGHT when it comes to the Evo drivetrain.

If you had bothered to look at the diagram of the Evo's center diff, you would have realized that it already has 4 spider gears, no wonder TRE doesn't offer a 4 spider gear center diff for the Evo, it doesn't need one!!! As a matter of fact, the Evo's center diff design wouldn't even work if it didn't have 4 spider gears.

And your point about there being an upgraded center diff available for the DSM is about as relevant to this disgussion as a stroker kit for a 350Z. It simply doesn't matter, the Evo is not a DSM and the drivetrains are nothing alike, and nothing is interchangeable!

I've known all along that TRE offers that diff for the DSM, the entire drivetrain in my Evo was built by Jon, I've had extensive disgussions with him about drivetrain designs and possible upgrades beyond the standard off the shelf parts. As well as long talks about just how different the DSM and Evo drivetrains are.

- Steve

 

A Detroil Locker is not a welded diff. A welded diff is most closely related to a "Spool", a Spool being significantly stronger than a welded diff. A Spool locks both axles together forcing them to rotate at the same speed in all conditions. If you locked your front and rear wheels together by putting a spool in the center differentials locations it will have severe negative impacts on handling and tire wear. The front wheels follow a different path than the rears in a turn and want to rotate at a slightly different speed. If locked to the rears, the car can understeer, oversteer, and generally behave very iradically all while destroying your tires. But as said before my Miami DSM "Who said anything about turning, wezz drag racin mista". So if you live in that world, a welded or spooled center diff is just fine for you.

A detroit locker is a ratchet type LSD that locks and unlocks depending on axle load. When the axles try to turn at different speeds and the force is being applied from the wheel/axle into the diff, it unlocks and allows the axles to turn at different speeds. This is what happens in a turn, and why you'll hear a distinct clicking sound from the rear as it ratchets around a turn. When the torque load is applied to the carrier assembly through the ring gear, the ratchet locks up and it ends up acting like a spool.

- Steve

 

Appreciate the input, it's nice to see a picture of the actual parts.

If you look at this thread that is stickied at the top of this forum, it pretty clearly shows every component of the drivetrain (minus the rear) and how it all works.

- Steve

 

Wow! Thats super nice. Is there any chance that you did one for the trasmission parts? One showing 1-5 gears, syncros, fork locations, etc. would be nice to see. Sorry for going OT.

 

Yea, I'll either do one for the tranny or update that one to show all the components specifically.

I also want to do a DSM version to clearly show the differences between the Evo drivetrain and the DSM drivetrain. But as you said... this is all off topic.

- Steve

 

" Down in Jamaica they got lots of pretty women; steal your money and they break your heart"
but i digress:
Anyways we have a multitude of JDM EVO 7 & 8 and few 9's ranging from 2001 to the present. All come with the active drivtrain. Down here the cars are used for anything and everything, shopping to ralley.
One guy with an EVO 7 pushing 550+ whp kept breaking the CENTRE DIFF launching much too aggressively and had to order an uprated ACTIVE CENTRE DIFF from cusco jp.
Needless to say he trashed that too, but i tend to believe that he just abuses the shyt out of it and withthat kind of torture anything would break!
My EVO7 makes more hp than his and I have quite a few ,more civilized, launches on my active diffs and its still going strong [knock wood], but then again i do have the ralliart active diff ECU and ATS tri carbon clutch.
The active stuff can take power but like with everything else if you abuse it it will break; and you can get uprated active stuff from the jap market. It is out there!
Mark

 

Was he breaking the Diff itself, or the ACD unit? And no, they're not the same part...

From your description it sounds like you're talking about the ACD unit, since Cusco makes LSD's and not carrier assemblies with spider gears, etc. I just want to be as clear as possible

- Steve

 

sorry, a lil off topic, but how much is typical labor to install front LSD for '04? and what does front helical Quaiffe run if u get a realy good price, $1000-1200 or so? i would love to do the install myself, but i wouldn't tackle it alone, rather have a knowledgeable person helping.

 

Are you talking about install price for you driving your car to a shop and they do everything, from dropping the TC to the actually LSD install? Or are you talking about bringing/shipping your TC somewhere and having just the LSD installed?

- Steve

 

This was a disgussion about the Evo Drivetrain, you mentioned an upgraded transfer case with 4 spider gears instead of 2, at least for the DSM. And IN my post...

Which I admittedly typed out the conclusion I logically came to without going over every step that went through my mind first. Those logical steps while reading your post were...

You mentioned a TC with an upgraded center diff... well the center diffs in both the Evo and DSM are in the tranny... so that just sent a flag to me that you weren't all too familiar with either drivetrain. So I treated it as such, someone who didn't know exactly what they were dealing with. Sue me.

If you had looked inside an Evo Tranny, or at a diagram of one you would have noticed that the Evo tranny's center diff already has 4 spider gears, so again I logically thought, maybe you thought the Evo Tranny and DSM Tranny had the same parts in them, well, they don't.

You shouldn't need to specifically mention the Evo in an Evo forum! I guess every post by everyone else here about front mounts, injectors, turbos, clutches, and everything else is about totally random cars. When people post in an "EVO Engine Turbo Drivetrain" forum you tend to assume they're talking about EVOS. If that was a bad assumption of mine, I am sorry.

You know what? Crower makes rods for small block Chevy's and Evos, but I bet you they don't interchange those Rods. If you did more research with TRE you'd realize that the Evo gears and Evo shift forks that they put in their DSM trannies are out of the Evo I - III, not the IV - IX. The earlier Evos had a drivetrain layout that was VERY similar to the Evo's. The Later Evo's are COMPLETELY different from a DSM. Hell, they moved the front diff from the Tranny to the TC for one. Call Jon at TRE, ask him for yourself since you obviously won't believe me. And please don't come back with "Well what about the Evo I-III, the original poster could ahve been asking about them, and then my point is right". The I-III didn't have an ACD and that was the original point of this thread.


You're absolutely right, not everyone knows what I do, and when I try to share, I get people like you starting a pissing contest. And I don't claim to know everything, but I know a LOT about drivetrains, it's what I do for a damn job. I'm a design engineer, working with aircraft gearboxes on tiltrotor aircraft which are WAY more complex than an Evo gearbox. I think I know quite a bit on this subject.

- Steve

 

Miami DSM = UMiami80?

 

????????


I used to live in Miami, but recently moved if that is what you are asking? I live Right by South Florida Performance so I had great DSM influence not to mention Miami DSM club, that was a bunch or wrench turners.

 

If there ever was a time for a "arguing on the internet is dumb" picture, this would be it. I lack the motivation right now to go find one. Sorry.

SuperHatch, be the bigger man for the sake of this thread, and let it go.

 

Ok,

My concern was essentially that with high Tq loads the center diff would begin to slip under heavy load (hi lateral g's, or adversely disproportional rear load)

 

My experience with broken transfer cases and Diffs is basically caused by sudden drivetrain shock. Basically revving the hell out of it and then dumping it. Sure this gives you crazy 60 foot times and all but is hell on the drivetrain. IMHO the proper way to lauch it is to sorta "half lauch" it, not give the full power and just a nice controlled slip and then when the car is rolling then dump it. This IMHO relives a lot of stress from the sudden shock of a all out launch. But this will also net you slower times, but hey atleast you can drive home afterwards, I get myself 1.7 60's myself with little or no drama.