Is it possible to change AYC for mechanical LSD?

[Brunty]

When I originally had my AYC fault RogerRally stated that many EVO owners ditch the AYC/electronic LSD and replace the whole unit with a mechanical one.

There seem to be a number of current threads abour AYC lights/pumps and problems and also most of the ebay VR4 seem to be advertised with non-working AYC.

1. Would it be possible to swap in a mechanical LSD?
2. What would be the likely cost of the unit+labour?
3. What would the running costs/considerations be?
4. What could you wire the AYC light up to?

[richy rich]

1 yes
2 will look in to it
3 shouldn't be any difference IMO
4 sound system

[d3x]

considering my position, I may look into this... love the idea of the ayc lights rigged up to the sound system rich..

[amsoil]

Three types really Hewland powerflow which is ramps and clutches , the Quaiffe style with lost of little gogs set at funny angles and the old Cam and Pawl . Yes sure there are hyro electric ECU controlled etc but if you actually want to do it rather than dream about it ....... Hewland is well into 4 figures but the best and you will need to know / guess ramp angles, Quaiffe (so good I changed one of these for a Hewland) about 2/3rds the cost of a Hewland but .... and its operation varies with wear and the oil used ; Cam and Pawl yes well. Lets go onto something else. A firm called Gripper use the hewland idea but only put the ramps and clutches in at one end (clever) and so are very much cheaper. Andy Robinson Racing import these if its any help to any one.

[Brunty]

Response from Roger Rally

I have an advert on Ebay at the mo, so that should help solve a few problems!

Once the pressure has droped off that much adjusting the switch setting down means that when full wheelspin control is needed, then there wont be enough strong fluid to keep things in check, and the warning light will come up again anyway!

A new pump with refreshed motor is about £450 fitted, but a Cusco LSD, which goes into the rear casing, and does away with the AYC pump and pipes ( saves a bit of weight!) is £1000 inc assembly, Then its just Diff removing and then re fitting back to under your car ( I do this last bit for free, if I can have your old pump for refurb!) and a couple of liters of Oils.

[Axeboy]

Interesting...

[RogerRally]

3. What would the running costs/considerations be?

Having recently fitted a cusco LSD to a Legnum rear diff, I can vouch for the handling characteristics.
Going round a bend/ or roundabout the front scrubs wide,you need to lift off or break to get the grip.This is the same as non ayc working car would be,

but back under gentle power though, the front definatly now turns in sharper, ( causing less wear/ scrubbing on the outer edge of the tyres).

If the corner tightens up and you need more steering angle, just boot the throttle and the back steps out in a controlled diff angle, and you can wind off the steering lock, and get ready for the exit of the bend, and roar off in a straight line. weired sensation in a big estate car!. With a bit of practice ( and an empty roundabout) you can adjust the steering without touching the steering wheel, just using the throttle ( abit like a capri etc!)
The diff clonks though, only at low speed round supermarket carparks, as the rear wheels dont like turning at different speeds.
Fun to be here, methinks!
Running costs would be less wear on the fronts, but more use of the back pair

[flyboy]

RogerRally what lsd center did you use? I cant find any ones that match..

[RogerRally]

Ive just taken delivery from CoOrdsport (After a 3 month shiping wait!), a new cusco LSD unit to go inside the rear diff of a VR4, instead of the AYC pump set up.
We be built up complete next week into a good empty casing.
Cost will be £1,000, on an exchange basis.

I can also offer help fitting, if needed in Southern UK area, ( for free if i can keep the old pump, for refurbing)

[Kieran]

Roger - on a slight tangent, based upon your experiences with Legnums so far, how close is the running gear to the EVO, and which flavour?

[RogerRally]

The back end on a type s, ois the same as evo 4, with active diff to speed up or slowdown the right wheel to match the left, but the front end runs an open front diff, which doesnt proportion power evenly if there is front wheelspin. Thats why the Cusco LSD in the back works so well in Vr4s as a handling upgrade, compared to in an evo, where the 4 wheel drive is under better control to start with,
The biggest difference is the extra weight over the front wheels, causing the front to run wide whilst pressing on round bends. The other problem is the brakes are under powered for hard use, and a brembo upgrade works well, if you change the wheels aswell.
personally, i just love the extra tourque the vr4s turbos have lowdown, makes for effortless overtaking!

[bradc]

So do EVO's have an LSD at the front then?

[RogerRally]

They have an open diff in the gearbox, that evenly splits the drive to front and back, but then goes through a viscous coupling in the transfer box, to prevent different speeds between axles, the front then goes through an open diff in 4-5 gsr, or through a helical geared diff to prevent wheelspin ( and make steering heavier!) on some evo 6 GSRs, and all RS variants.
latest ones (7-9 )have an active control over the center viscous, that has on dash adjustable different release lock times, depending on condition.
Tarmac:, quick release of center diff after wheelspin or diference in front to back ratio detected and cured,
snow: diff stays locked on for a few secs after wheelspin detected.

BTW, I also now have a stronger EVO 8 rear diff, with upgraded SAYC plated lsd diff fitted, and all hydraulic parts removed (for sale too, if needed).
not as agressive as a cusco type, but used in my Evo 4 as a demo play thing.

[Kieran]

Roger - what's the going rate on refurbished AYC pumps?

Also, how long do the clutch plates in the AYC diff last? Must say I've never heard of one failing through wear (pumps excepted).

[RogerRally]

click on my user name, and that will allow you to view "my home page".
I have a refurbed pump off a VR4, (NOT THE DIFFERENT SORT FROM AN EVO)with an uprated 12v motor, and an upgraded improved pressure switch, all for £450, less £50 if i can have you old faulty one back. fitting is a couple of hours of yuck trickling down your arms!
As with brake disks, and clutch disks, any moving parts that are forced to rub against each other for traction will eventually wear out. evos used top be a safe reliable 280 bhp, but dealers sell them speced up at 340 bhp, with no thought for the wear further down the line. the newer evo 8s come with stronger rear diffs, and its those that i prefer to fit to VR4s that are being put to hard use.

I no longer repair AYC internal clutch packs (it was at least 4 hours work £120 plus parts), but would rather sell a complete working AYC pack (£250) removed from a car that I know worked fine, as its all fiddly inside. Better still just removed the whole let and get some LSD into your blood stream!

[ritch_w]

Roger - can u refurb knackered AYC pumps? if so how much? I have a knacked one in my shed which could be handy to have as a spare (one of the solenoids has "parted" ways from the pump)

cheers!

[Kieran]

I no longer repair AYC internal clutch packs (it was at least 4 hours work £120 plus parts), but would rather sell a complete working AYC pack (£250) removed from a car that I know worked fine, as its all fiddly inside. Better still just removed the whole let and get some LSD into your blood stream!

Good grief - I never knew you could - is this something within the realms of a enthusiast with a good set of tools and a workbench or is it rather more specialist?

Also Roger (and I apologise for the incoming thread hijack)- Had any dealings with the W5A51 gearbox we have? My understanding is that it was also used on some JDM Lancer EVO VIIs.... just wondered if you'd ever played with one?

[Brunty]

I have a refurbed pump off a VR4, (NOT THE DIFFERENT SORT FROM AN EVO)with an uprated 12v motor, and an upgraded improved pressure switch, all for £450, less £50 if i can have you old faulty one back. fitting is a couple of hours of yuck trickling down your arms!

Just like to say that Roger installed a refurb AYC unit on my car on Saturday, after checking that the AYC equipment was working as it should (bar the old pump obviously).

As agreed Roger took my old pump (although I doubt he'll be able to refurb it to any worthwhile condition) and only charged for the quoted two hours despite the job taking quite a bit longer than anticipated.

If a pressure switch doesn't cure your AYC problems then you need to speak to this man. Looking back through old posts I see that I was originally quoted twice this amount by Xtreme for a replacement pump.

Thanks Roger.

[Josh2xsv]

Is there anyone that would fit the cusco LSD into the casing in NZ? Hopefully for less than an arm and leg! I would love to get that in my bloodstream!!!

[bradc]

Gary Capper regularly fits LSD's to evo's, I would imagine he would be able to do it to VR-4's as well