Rear Differential

[Mr.Salas]

Hey dude's

Well today I went to test my car with the new clutch setup
and guess what, bye bye differential

Dont know what broke yet, but its leaking oil all over. But I still can drive the car.


What are my options????


Evo 8 differential?
Stock one again?

?????


Thanks

[Adam.Findlay]

evo 8 or evo rs like what gwof did. infact gwof is selling his i think,
stock ones are to crap haha i broke mine too

[Mr.Salas]

Yeah suxx meng . I was driving back home after some racing well, it did made a bang sound and that was it.
Jammy gear oil came out
lol

[Adam.Findlay]

Yeah suxx meng . I was driving back home after some racing well, it did made a bang sound and that was it.
Jammy gear oil came out
lol
yeah mine gave up when i was doing everyday road driving. but made quite an impressive bang.
hope you can get it sorted tho man

[Mr.Salas]

What all is needed to swap the evo 8 or 9 diff?

[Nick Mann]

A few washers for the rear mounting points and swapping the propshaft flange.

That's it!

The RS diff is MUCH harder to put in.

[Wodjno]

As Nick says /yes

[steelie600]

if your quick i have a standard ayc diff for sale, make me an offer

[Mr.Salas]

HMMM, just a orig diff neh, planning for more track use so , i want to put something good that can hold some hp

[djb160]

As a cheap quick fix while you get a good idea of what diff you want I'm sure you can disengage the AYC by pulling a fuse and just make do with an open diff. More knowledgeable members will be able to correct this if anything's wrong.

[bradc]

You can yes but his diff has exploded

[VR4WGN]

Open diff!!!!!!
Stronger and ivnever had 1 blow(yet), theyr good diffs IMO

Brad werent we just discussing the Blown diff thing last night?? well Scott Kreil's Evo 8 S-AYC gave up today!!!

[bradc]

How much power does he have and was he launching?

[VR4WGN]

700hp and no he was super lapping.....

[Mr.Salas]

Hhahaha damnn 700hp damn lol im not even close to that hehe

[Mr.Salas]

Dudes, can the car drive without the rear diff???

[Adam.Findlay]

not unless you want to roast your viscous coupling

[Mr.Salas]

Hey dudes,
Whats the best option, that wouldhold good power and would not disturb daily driving?

an Evo 8 RS rear differential or a normal S-AYC diff?

I got a good deal on the RS diff, will it fit? and what all do I need to have to fit it?

[bradc]

RS diff's are virtually indestructable, but won't let the car corner quite as quickly as a car with AYC.

SAYC is the grail imho.

[Mr.Salas]

OKies meng, hmmmmm to fit the RS differential what DO i need to buy?? or what mods do i need to do to fit it??

[bradc]

The driveshafts are going to be your big problem. You are probably best to get in touch with gowf and see what he has done.

[Mr.Salas]

Oh okies I will contact him to see if this is worth it , or i would just buy a regular S-AYC of a ev0 8

[Gowf]

RS diff's are virtually indestructable, but won't let the car corner quite as quickly as a car with AYC.

SAYC is the grail imho.


Wont corner as quick? Think it will! Ive had both and i know what i prefer. You've actualy got to be able to drive with a lsd/plate diff at the rear though, rather than relying on the car doing it for you. But you certainly can corner just as quick, and on loose surface there is no contest!

[bradc]

I've driven various VR-4's with open rear diffs but never an LSD so I may not have the best experience here.

However assuming you aren't sliding the car out sideways, ie driving it near the limits but cornering steadily like what would at a race track, the wheels aren't going to be spinning or sliding anyway, so I don't see how an LSD would make a difference.

The AYC (as we all know) helps move the power to the outer wheel to negate the VR-4's natural tendancy to understeer. There are a few pdf's from Mitsi showing the cornering speed from having an LSD vs AYC vs SAYC and with AYC there is a massive improvement, with SAYC there is another improvement but much smaller, maybe 40-50% of the gain that AYC offers.

Here is one http://www.mitsubishi-motors.com/corporate/about_us/technology/review/e/pdf/2003/15E_11.pdf

That isn't the one I was actually thinking of, I will search at home tonight for the one that really goes into the development of it, but basically having AYC increases cornering speeds. What it may not do is help out when the car is sliding, whether all 4 wheels are sliding or just power oversteer. Personally though I don't drive like that very much at all, I drive up to the limits and stop there :)

I guess that if the car had it's suspension tuned very well to eliminate the cars understeering that you wouldn't need AYC at all and that an LSD may be ok. I did run my car with a larger 24mm cusco rear anti roll bar and stock AYC diff and that did make it feel very neutral, similar to how it feels now with larger bars all around and the SAYC diff, but with only the larger rear it did feel a bit twitchy, especially coming into corners, probably due to the closer under/over steer balance that the car then had.

I would prefer the car to have a slight tendancy to understeer and to not feel twitchy at all when coming into the corner, but to have the ability to keep on track while exiting the corner and I think that having SAYC offers that, while suspension tuning can make the car a bit scary to drive to get the same result.

[Mr.Salas]

Oh okies, well my car has Tein suspension and the roll bars are not stock.

[Mr.Salas]

Hmmm but those SAYC dont hold up right?

[elnevio]

SAYC is much stronger than AYC.

[Mr.Salas]

Yeah but how strong?
Don't wanna invest in something that would break in a few hard lunches.

And just was wondering, by upgrading the rear diff, then we eliminate one weak point, how about the gearbox and the transfer box? Are they going to hold up?

[elnevio]

Probably, but ultimately depends on what power you're putting out.

[bradc]

The next thing most likely to die with hard launches is the front diff gears. Lots of EVO's kill them.

[Adam.Findlay]

the weakness in ayc is the casing, it flexes under launching and the crown wheel and pinion come apart causing the teeth to come flying off the gears, however with s-ayc they upgraded the gears but NOT the casing, so if you do plan to give the car some "full beans" launches do not get s-ayc, yes it is stronger then a factory ayc diff but ultimatly it has the same weakness as the factory diff,
Bradc is correct, any ayc powered car will out handle a lsd, (in saying that i mean the same car with the same driver, if the car had ayc it will pull round a race track faster then a plain lsd diff)\
but again Gwof is also right, with a better driver behind the wheel a plate lsd will be a better diff.

in short if you want to launch or shock load your diff avoid ayc like the plauge,
if you want to put power to ground well but not launch S-AYC = :thumbsup
want to launch it get a rs rear end

In my opinion youy shouldnt be launching unless you have the money to be replacing drivetrain bits quite often. ayc breaks then the hollow output shafts in the center diff then transfer cases and from there on you can do a center diff, strip a cv joint or pop you entire gearbox,
only really need to launch on a 1/4 mile run
ive lost my ayc advantage to being a knob and launching wayyyy to much, now i am stuck with a open diff that makes my wagon handle like a bag of s**t

long story short rs diff :)
good luck

[bradc]

The EVO 5 onwards diffs do have less teeth though, they have 13/43 rather than 16/53 as on EVO 4 and our diff's. The thinner teeth react much worse to the flexing than the thicker teeth. You are right though, it still isn't cured completely.

Watching best motoring a while ago they had a few evo's going around a track one with an LSD and one with SAYC. The drivers both loved the SAYC and said it made the car much better

[Adam.Findlay]

The EVO 5 onwards diffs do have less teeth though, they have 13/43 rather than 16/53 as on EVO 4 and our diff's. The thinner teeth react much worse to the flexing than the thicker teeth. You are right though, it still isn't cured completely.

Watching best motoring a while ago they had a few evo's going around a track one with an LSD and one with SAYC. The drivers both loved the SAYC and said it made the car much better
yeah i know the gears have had the number of teeth reduced to make them beefier and stronger,
but as mentioned above its the casing that is the weakness, no matter how strong you make the gears the casing will still flex and eventually it will fail. my casing cracked into 3 pieces causing catostrophic failure of the gears.

it angers me so much to know that If i put a s-ayc in my car it will be nearing 2 grand to put one in and if i go horsepower hunting in the future it will be 2 grand down the drain, i really really do miss my ayc :(

[Mr.Salas]

yeah i know the gears have had the number of teeth reduced to make them beefier and stronger,
but as mentioned above its the casing that is the weakness, no matter how strong you make the gears the casing will still flex and eventually it will fail. my casing cracked into 3 pieces causing catostrophic failure of the gears.

it angers me so much to know that If i put a s-ayc in my car it will be nearing 2 grand to put one in and if i go horsepower hunting in the future it will be 2 grand down the drain, i really really do miss my ayc :(


that's why im thinking to go with the LSD evo 6/7/8 Diff



Any buddy knows who has one for sale?? Need to Diff plus the axles?????!?!?!

[Nick Mann]

the weakness in ayc is the casing, it flexes under launching and the crown wheel and pinion come apart causing the teeth to come flying off the gears.....

Are you sure about this? It is certainly one way that makes sense. I destroyed my casing too when I launched last year. But I have seen them with destroyed teeth but an intact casing. (Was Elnevio one of these?) It made me wonder if the teeth go first, and then the broken bits of teeth force the crown and pinion apart, leading to casing destruction. Cause and effect would be back to front as compared to your statement then.

I'm not trying to correct you - I don't know myself. I have just been thinking about it. If the casing is the weak point, then there is not much point upgrading to SAYC for strength. If it is the teeth that are the weakness, then it does make sense.

[bradc]

I think both can happen, the casing can flex without blowing apart which can chew up the gears

[elnevio]

My casing was definitely goosed! I've theorised that the casing flexed slightly, sufficiently to allow a tooth or two to get snapped off, but without breaking the casing (although possibly fracturing the internal walls between diff and AYC). Then a few miles later, those loose bits got in between other diff parts, shredding some more internal bits and forcing the casing apart.

[Nick Mann]

So it wasn't you then Nev. I'm sure I have spoken to someone who destroyed the teeth but not the casing. Who was it?

[elnevio]

Yes, definitely not me! (http://www.clubvr4.com/forum/showthread.php?t=44954)

[Turbo_Steve]

Casing flex is comparitively easy to cure : you just need some big milled bits of ally.

[Gowf]

So it wasn't you then Nev. I'm sure I have spoken to someone who destroyed the teeth but not the casing. Who was it?


That would be me Nick. Casing was totaly fine, not even a drip of oil out of it, but crown wheel lost 4 or 5 teeth and the pinion shaft lost them all

[Nick Mann]

I knew someone had done it!

I hate my memory sometimes....

[Wodjno]

Mine was the same Nick.. Plenty of Teeth mashed up inside.. But no damage to the casing.

[bradc]

Carsten did that at least once, mashed up gears but casing was fine. However the gears were probably wrecked by the casing flex.

[Mr.Salas]

Just found out that in the US the Evo 8/9 didnt come with the SAYC,they came with an RS model differential. But by reading more they say that the Japanese RS model diff better is then the one from the USDM evo's what do you guys think?

Any one has a SAYC diff or a RS diff (With evo 7 shafts )for sale

[Gly]

the diffs i blew were in the same casing,
the casing is still fine (uncracked) but the gears are rooted

my current (3rd) diff is in its own original casing,
as it had been rebuilt at some stage, so left it as is.

[Mr.Salas]

Hmmm dudes. i'm in need of some evo 7 rear axles...
Does someone have them up for sale?

[Mr.Salas]

Does anyone know if there is a difference between the USDM Evo 8 RS differential and the Japanese evo 8 RS differential?

[bradc]

No there won't be any at all.