jameswwt

Hi Guys,
just wonder will it worth to go for LSD for my DD & Occasionally Up Hill Runs + Tracks?

Hope to have better Handling during hard cornering.

Which should i go for 1.5 or 2 way? Rear only or the Front Differential?

Thanks

RS200

iTrader: (1)

A front clutch-type 1-way LSD would make the biggest difference. Unless you have an RS, you'll have AYC, and aftermarket AYC diffs aren't as effective as the purely mechanical setup.

Handling is mostly suspension and tires, diffs have less of an effect mid-corner.

Evo8cy

Evo4-6/TM cars have a ViscousCouplingUnit (VCU) controlling the centre diff (the VCU is in the transfer and controls the centre diff. (it’s a regular open diff. which is located in the gearbox).


TM Editions are slightly different, as some had bigger bearings in their transfer casings, similar to Evo7s.


The OE front diff. is either an open diff. or a Helical Gear Diff (torsen/worm drive).
The OE rear diff. is a plated LSD on the RS, or the ActiveYawControl diff. on the GSR.


You need an LSD unit that can be fitted with your VCU as the VCU is better for tarmac.


For tarmac, especially smooth stage/circuit, it is an ideal starting point to have strong/tight diffs at the front and the rear, along with a softer centre diff. setting.



My reccomendation is the Cusco front diff. with their tarmac setting of Viscous Unit (50Nm – can be rebuilt to 200Nm)– these come as a set, LSD+VCU. They are available in RS Type, using small coil springs for initial preload, or MZ Type, using Belleville Spring Washers (Cone Springs) for initial preload.





Front:

RS type (as I prefer this over the MZ type)

Cusco 1,5:1

LSD147CV115




Rear:

RS type

Cusco 1,5:1

LSD448L2 (for gsr models with ayc)












Marios

nemsin

iTrader: (19)

What exactly is the car doing that you do not like in hard cornering? Your car can likely be sorted out with some combination of alignment, new bushings, sway bars, coilovers, spring rate changes, and/or tires.

A new differential is not going to magically make your car handle better. Its just one piece of the puzzle. Try to replace/dial in the less expensive parts first.

Just throwing on an aggressive differentials can make the car handle worse if the rest of the components are left stock.

If you have not replaced your stock bushings, I would start there. Also, check all your control arms to make sure none of them are damaged.

If you are set on a new diff, here is a good overview http://www.coordsport.com/blog/2012/...commendations/

P.S. If you car has AYC, consider swapping to an RS or USDM Evo 8 rear diff and ditching the AYC. The 5/6 AYC pump is prone to failure and might be your problem.

Evo8cy

The recommendations from Co-Ordsport are very good, on my post I have used their site for reference.



On the rest of the suspension components he needs to be more specific of what he has changed/left stock and ask the appropriate questions regarding each suspension/handling part if he wishes to do so.



I am also as much in favor as I am against getting rid of the AYC, both setups with or without the AYC have their pros and cons.










Marios

nemsin

iTrader: (19)

The 5/6 AYC is fine when it works. But it is a know weak spot that will fail eventually. You can find used Evo 8 rear diffs cheap enough and the swap is pretty straight forward. There are how to threads on lancerregister.

I am convinced you can make a non-AYC 5/6 handle as well as (or better) as one with AYC. So why lug around the time bomb?

Also, I really like Quaife diffs (mainly because they work just as well and are less noisy than Cusco). OP could email them and tell them his intended use and see what they recommend. They have products and support for the Evo 5/6 https://shop.quaife.co.uk/contact-us

LetsGetThisDone

iTrader: (1)

I concur. Race guys even put the 8/9 diff in the X. Or guys that are just tired of the AYC failing.

Evo8cy

I do not know how much experience you have with diffs, but I have about 20 years of experience. As far as the evo diffs are concerned, I have seen all 3 of them brake, of any oem type and not just. I have seen evos with 400hp, brake both RS and AYC rear diffs.



It is easy to replace an AYC with an RS one, there is no need for a how to do thread, atleast not for me, but yeah I am sure there are enough on the net and they are very helpful. I do use though such kind of threads myself, either to remind me of something that I have forgotten or to solve a problem I might encounter, but changing the diffs is a straightforward procedure.



Yes you can do an RS diff handle like an AYC one, or at-least very similar to it, especially on Gravel. On Tarmac surface, I have yet to see an RS diff handle like an AYC as it lacks the "smoothness" of the AYC setup.



I do not see it as a time bomb at all. If my ayc pump needs servicing then , no worries, I'll take it off and service it. On the other hand if you can't be bothered to do that, then changing to the RS setup eliminates that action. Another point is the price of the RS setup, as you may already know, it is not just the diff itself that needs to be changed but the whole assembly, hanger, shafts, etc and it costs a considerable amount of money in relation to just servicing the pump.









Marios

nemsin

iTrader: (19)

I do not have anywhere near 20 years of diff (or evo for that matter) experience. But I think the main reason to eliminate the AYC is so it does not fail at the track, potentially ruining your track day and/or creating a dangerous situation.

OP could likely do the whole RS or USDM Evo 8 rear diff swap for less than he would spend on a single Cusco diff.

Personally, I have owned a stock Evo 9, a TRE max lock rear diff, and an Evo 6 RS (with stock rear diff). I understand its not exactly apples to apples, but the stock Evo 6 RS rear (mechanical) diff has done everything I need it to. And is why I suggest OP look to the other suspension components 1st to dial in handling. I suspect OP is complaining about understeer when cornering. Adding an aggressive rear diff might make him think his car is handling better (because oversteer "feels" fast) but it doesn't mean his lap times would improve.

Evo8cy

It is a misconception that the AYC system, apart from the pump, has a higher braking rate than an RS one, this is what my experience tells me. I have even seen groun N rally cars run the Cyprus Rally stages with AYC diff setup.

Also hillclimb cars.





I have owned my evo 8 since 2003, it is a jdm evo 8, one of the first 8s produced, and I have been running the same 6 speed gearbox and AYC setup since then. The car went from stock to 400hp(stock 8gsr turbo) when I first got it, and in the same year I increased the power to 440hp. Then I ran an fp green gen 1 with 392 @ the wheels, then an fp red, now an fp black with around 700hp.(relate the above flywheel figures to a low reading dyno, not DJ high reading one).I have not put the car on track, there is only one on the island which was built very recently, but I have done through the years between 350-400 hillclimb 1hr sessions on mountain twisty roads.





Regarding your comment on aggressive rear diff, it is one of the reasons I mentioned the "smoothness" of the AYC setup. Also bare in mind that the aggressiveness in "locking" is greatly depended on the preload settings. A 1,5 way diff with the appropriate settings accordingly and in relation to rest of setup/type of driving/type of surface/tires used/driver style of driving, along with the AYC system can become an awesome combo/setup.









Marios

nemsin

iTrader: (19)

I think we agree on more than we disagree. If you have the know how to self service your own AYC pump (or a Group-N team to replace it between races) then sure keep it. For us normal occasional track day evo drivers, we want to eliminate parts (like the AYC pump) that are prone to fail. I feel like moving from the AYC setup to the RS mechanical rear diff is a reliability mod.

Evo8cy

Of course we do, there is no actual disagreement on these matters. I merely point out the differences according to my experience, and stating my personal preference.


Since you feel better with not having to deal with AYC and as you said you have already used an ev6rs diff and you have no complaints regarding it , than by all means go with what keeps you happy about your setup.










Marios

nemsin

iTrader: (19)

I still think OP's handling complaints have nothing to do with his diffs. My money is on 16+ year old stock struts and bushings. And/or cracked rear upper control arms http://www.lancerregister.com/showthread.php?t=503492

Both my Evo 6 rear upper arms had cracks at the seams before 40k kilometers. The good news is the Evo 8 rear upper arms are a direct replacement.

RS200

iTrader: (1)

The major complaint from Japan is that the RS differential is more predictable than the AYC, you'll notice that most of the period circuit cars from Japan ditched the AYC. The whole conversion costs $1500+ - you need both diff braces, the pumpkin with RS diff and the axles. It's tricky to find everything together.

On JDM 789s you can buy a conversion kit to run the RS diff in the GSR pumpkin, like this: http://www.ebay.ie/itm/151663821336 but I don't think there is anything available for the 456. Cusco does make AYC-compatible diffs, but I don't think they're very effective considering the hydraulics still do a lot of work.

As for the front, the stock center diff is alright, so just get something compatible with the stocker. The 'tarmac' center and front for the 456 runs $4000+ last time I saw, pretty pointless. Just run a good 1-way front clutch-type (Cusco RS as mentioned previously) and it will be fine.

That said, for the guy who has a street car and won't spinning the inside front tire on a corner, do suspension and tires. Spend the extra $1200 of an LSD towards a set of Ohlins and some bushings. Maybe get Cusco sway bars, but remember that stiff springs and stiff sway bars are redundant. Choose one, not both.

If you feel like the AYC isn't keeping up, or don't like its handling vibe, you'll have to make the choice to convert to RS-spec stuff.

My Evo 1 with 30,000 miles on it (hard ones mind you), all of the bushings were shot. No diff in the world would have saved it from sucking (and clunking when anything got loaded up).

Evo8cy

For sure, he needs to address all the handling components in the proper manner, and see it as a whole, as everything is interrelated, from bushings to anti-rolls, struts, springs, camber/castor kits, diffs, etc. Anything that is worn out must be replaced first either with an upgrade or new oem part and then move on.




The AYC/Cusco RS type 16plates combo works great on group N rally cars.










Marios