VR4 - Rear Diff upgrades

[Boostin21]

The APC EVO II drag car is using an MKIV Supra rear diff. you need to make a custom cradle for it... i have already started drawing out/forming a cradle for my car. and if i remember correctly its dead on or very close for the gearing.

 

[vr4play]

I do not have the 4ws. I took it off because it makes the car very unpredictable.

 

[DSMTurbo2]

Has anyone been able to fit a Torsen into their car? I really like some of the plus' to this unit. have never been ready to even look into it.

 

[Telecaster]

Quoting vr4play:
I am using an Evo 9 rear diff and rear inner axle joints. Bolts right into our rear end housing no mods. Seems to work pretty good. Much better than the viscous. Got it from a wrecked car. If you could find axles from a newer evo the inner joints should work with any of the mechanical diffs incl. the Kaaz. You do have to use 4 bolt axles.



Do you have any pictures?

 

[Lonewolf64]

Quoting vr4play:
I am using an Evo 9 rear diff and rear inner axle joints. Bolts right into our rear end housing no mods. Seems to work pretty good. Much better than the viscous. Got it from a wrecked car. If you could find axles from a newer evo the inner joints should work with any of the mechanical diffs incl. the Kaaz. You do have to use 4 bolt axles.



I think a comprehensive write up of the installation procedure should be written up in the "How-To" section. This is a pretty significant and awesome mod that I would place right up there with transplanting the evo suspension to the vr4.

 

Quoting vr4play:
I am using an Evo 9 rear diff and rear inner axle joints. Bolts right into our rear end housing no mods. Seems to work pretty good. Much better than the viscous. Got it from a wrecked car. If you could find axles from a newer evo the inner joints should work with any of the mechanical diffs incl. the Kaaz. You do have to use 4 bolt axles.



let me make sure im understanding you correctly. you used a newer evo rear diff and 4bolt axles?

Bolts right up?

 

[Dialcaliper]

I've been suspicious that it would work for a while, but this is the first confirmation that it actually works (I've never been able to get my hands on one).

It's definitely not "bolt-in" but close. Install exactly as you would an an Evo 3 diff (bolt the clutch-type insert into the VR4/DSM pumpkin). Use the stock VR-4 ring gear just like you would swapping a 4-bolt.

For the axles, it requires taking apart the tripod joint on both sets to make hybrid axles using the JDM/Evo tulips (stub-axles, halfshafts, whatever you want to call them) Insert the rest of the 4 bolt axle (the tripod bearings), and at the same time, fit on a new CV boot. Basically, its like rebuilding the inner CV joint using the Evo tulip.

You can use 3-bolt axles if you're willing to replace the small tripod bearings with the larger 4-bolt style (which are the same ones used on the front axles I believe)

I agree, definitely worth assembling a VFAQ/How-To if someone has the chance to take pictures while doing this.

 

[bazeng]

I have had confirmation from a few workshops that this works.

EVO8 MR (AUS SPEC) were the only mechanical diff lancer evo's released. The rest were AYC. Part numbers are the same from mitsu also.

As mentioned, you will only need the lsd diff and stub shafts (tulips)..

 

[gtluke]

i'm also using evo innards and inner axle cups, but from an older evo.
i have the housing and axles laying around here somewhere. i'm using the 3.909 gear ratio too

 

[Dialcaliper]

All USDM Evo 8's and 9's were given the mechanical LSD (apparently from the older Evos), presumably to keep the cost down in case the Evo wasn't as big of a hit in the US as they were expecting. 2003 and 2004 Evo 8's didn't even have the ACD or front helical diff - they were sold with viscous couplings and open front diffs. (Except the 04 RS which had the front diff)

They also didn't release the Evo 8 MR here until 2005, at which point all 2005's had the ACD and front helical. Also in 2005, the RS model was given the lightweight mechanical diff from the Evo 7 RS. Mitsubishi dipped its toe into the US market rather slowly, since the main demographic interested in the Evo in the US is much younger (and poorer) than in Japan and Europe - The rest of the world learned of the Evo through watching WRC, and most Americans found out about it from playing Playstation video games, which are much more popular than actually watching WRC here. (Rally is still not exactly a mainstream motorsport in the US and WRC doesn't really even have a race here, except for the more recent "X-Games" special stages.)

That being said, I guess in the US there is a better opportunity to get ahold of an Evo mechanical rear than in the rest of the world, because Mitsubishi cheaped out on us. (wamp wamp)


Quoting bazeng:
I have had confirmation from a few workshops that this works.

EVO8 MR (AUS SPEC) were the only mechanical diff lancer evo's released. The rest were AYC. Part numbers are the same from mitsu also.

As mentioned, you will only need the lsd diff and stub shafts (tulips)..

 

[H05TYL]

RS evo's all have mech rear diff's rather than ayc too.

Though whether they were availible new in aus and the US, i've no idea.

 

[bazeng]

OK

Update guys.

My VR4 MONTE CARLO 4bolt rear was an OPEN DIFF. So FYI, 4bolts do come open!

Now I managed to fit an EVO3 Rear diff into the VR4 4bolt pumkin without any issues whatsoever. The only difference would be the loss of 4WS since the evo3's don't have the gear to run the pump.

As for the axles, the open 4bolt had the correct axles to use with the EVO3 LSD. Spline count was the same, length was the same.

Very happy with it.















Open diff axle on the left
LSD diff axle in the centre
viscous diff exle on the right

LHS axles are the same

 

[gtluke]

do you still have the ring and pinion from the evo 3 rear end?

 

[bazeng]

Yes I do,

They are the same as the vr4 RS 3.909 obviously.

 

[curtis]

Nice but looks heavy if you want to chunk it I'll pay shipping. /ubbthreads/images/graemlins/grin.gif

 

[RedTwo]

Hah, now I've got some proof for the missus that sometimes I am right /ubbthreads/images/graemlins/laugh.gif
Did you pay a shop to swap the diff internals over or do it your self?

 

[bazeng]

I did it with a frend at his workshop.

It can be easily done at home.

I can get more evo3 rear diffs for you guys if interested.

With the exchange rate as it is, I can do it for about $500.00 USD shipped at an estimate.

 

Hi.
I've just bought an USDM rear diff (viscousLSD, 3.545) that I planned to put instead of my JDM rear diff (evo3, 3.909). This is because I bought a new VR4 tranny from Sheptrans without knowing I had a evo3 rear diff, so i got a USDM tranny. To make things better I have 4WS on my Galant, and the rear diff I bought doesn't have that..

So I'm wondering about what's going to be the best option for me to do. Look for a evo3 rear diff w/4WS and 3.545 ratio? Or just mount the USDM rear diff and plug the 4WS-circuit? And if I choose to do that, will bothe the rear axles fit or do I have to buy a new for one of the sides..

All answers are very appreciated.. There's almost noone up here in the cold north that know anything about this. /ubbthreads/images/graemlins/smile.gif

 

[Dialcaliper]

To complicate things, there aren't any 4WS Evo 3 diffs (and noone has ever seen a VR4 with both a mechanical rear and 4WS), and so far as I can tell, the clutch diff unit is shaped differently (larger) and won't accept the 4WS ring gear. There might be a workaround, but there's no good solution.

Basically, your options are to run the USDM viscous diff and pinion inside the stock housing, keeping the 4WS, or to remove it and run the Evo 3 unit, with the 3.545 ring gear bolted to it instead of the 3.909, and put it inside the USDM diff housing.

 

So then I guess it would be the easiest to just remove the differential together with the 4WS and block off the lines up front, and then install the USDM differential without 4WS?
That should be the easiest fix, anything I'm forgetting? Axles will fit?