rear diff upgrade?

[Scanny]

is there any way of having a bulletproof rear diff built by a specialist? i know they are a weak point and there are only so many sitting around waiting to be given new homes. is it possible to have them strengthened in some way?

[Nick Mann]

You mentioned you had found a non-ayc diff. They are supposed to be stronger anyway, and easier to make into limited slip which some say is more desirable than AYC as well as being stronger.

[Scanny]

http://www.clubvr4.com/forum/showthread.php?63078-Breaking-FL-1998-VR4-%28WHOLE-CAR%29

i know there are a few diffs around Nick so now you can see all the information that i have so far. my original diff will be scrapped by now but that case cracked which is not the case with the diff that is currently on the car. i am wondering if that casing could be strengthened to prevent a repeat of the original problem and then have the internals replaced with some kind of upgraded components.

im not sure whether the AYC is worth worrying about as it didnt work anyway so its not like i will miss it. on the other hand, mitsubishi produced it for a reason and have managed to build a hell of a reputation with it so maybe it is worth coming back to this eventually and putting another AYC diff in. i am just playing with theories and opinions just now to see what is possible before choosing a route to take

[Nick Mann]

This thread has some good general info - Adam summarises in post 1, I comment a few posts later and Carsten a few posts after that. Don't know if you have read it or not, but if not it's worth a read.
http://www.clubvr4.com/forum/showthread.php?63408

[Gly]

think you have llinked the wrong thread Nick??

these are worthwhile looking at aswell...

http://www.clubvr4.com/forum/showthread.php?63831-AYC-LSD-comparison-please!

http://www.clubvr4.com/forum/showthread.php?63232-another-cheaper-option-for-the-people-wanting-to-go-LSD

[Adam.Findlay]

In saying the st-r diff/lsd conversion has been covered a hundred times im still intrested in an even stronger option as im hunting 600+hp with my planned engine build and stock driveline wont take that, maby there are some evo CWP (crown wheel and pinion) sets that will bolt into the st-r casing?

[Scanny]

for a road car doing one track day a year i am better off with an EVO8 AYC diff?

[Nick Mann]

That's what I am running and I'd choose it again. I'm not aware of an SAYC diff failing in a VR4, although the Evo lads say that the LSD unit is stronger.

[Scanny]

i have just collected the new diff and he says it is not an AYC diff but may be LSD. he doesnt know!

[Gly]

Easy way to tell look through the shaft holes. If its a clear view, its LSD of some sort.
Then if the cv cups pin are matching length, its plate LSD.
If one is longer than the other its viscous LSD.

If there's a bar obstructing the view its open diff.

No 8th gen rear diff came LSD factory. They are all open,
Evo rear diffs had an option for LSD or ayc.

[Scanny]

it is an open diff based on that information. The casing does look different though. The garage was concerned about that but i am assuming that this is down to being a different type of diff and not needing room for the AYC components

[Gly]

Yes it is smaller .
Make sure you use the non ayc shafts as well as the are longer to reach the smaller housing

[Scanny]

no-one said i need different shafts. Anything else?

[Gly]

it was said in my cheaper lsd option thread a few times,

yes you need the non ayc rear diff matching shafts with the CV's .

nothing else, unless you want LSD you get the plate LSD center from a evo 1-9.

[Scanny]

matching CVs? Are they part of the shafts or separate? I am getting the shafts for the diff tomorrow

[Gly]

they should be on the shafts as long as they haven't been removed.

you cant use the original inner cvs from the vr4, i think the outers are the same.

[Scanny]

they have the shafts that came from the same car as the diff and i should have my car by friday. They need the room and i want rid of the hire car so we are all aiming for a fixed problem