View Full Version : Diff's...... Tip owners look away now
Right, as i can't be arsed raking through the reels of info on dif bits and bobs im looking for some definitive answers.
Firstly, has anyone fitted any mechanical diff's to their car? Im looking at changing the rear for just now, but unsure what to go for. I know you can get cusco or Kaaz, for the evo4 gsr's and the RS's. but do we definately have the same rear diff? Does anyone have the part number? Also, does anyone know how you would install one to the original casings? Would it have to be a rs casing (ie no ayc)?
The same also goes for the front and centre viscous. Are they both situated in the transfer box? If so can you change them both in the transfer box, or do you instal the front one in the gearbox, remove the one from the tx box and replace the VC?
Not sure if anyone will be able to answer the specifics, but can we clarify exactly what boxes we have? Is it identical to the evo 4 apart from the bell housing?
Sorry for all the questions, but as it looks like im about to head into the world of major investment yet again, i need to get it right first time!
Kenneth
05-10-2009, 12:11 AM
Front diff and viscous coupler are both in the transfer case, centre diff is in the gearbox.
That is fact, if anyone tells you different steer clear.
My understanding is that the EVOs usually break the spider gears in the front diff due to wheel hop on launches.
I haven't researched centre diffs a huge amount, but I haven't heard of the centre diff causing any issues.
Kenneth
05-10-2009, 12:38 AM
Oh, and while I am thinking about it...
If you have the transfer case out and are putting in a stronger diff (or anything really) you might want to shore up another potential weakness.
Apparently Evos blow the transfer case due to the bolts not holding it together well enough and allowing movement of internal components, which then results in damage.
The solution is to re-drill and tap the holes and use bigger bolts. IIRC this makes quite a significant difference to the durability of the transfer case.
Yeah i was just reading that the changing the centre and the front means you can do away with the vc. may have to do it if i keep braking the vc. This is why i need to know exactly what we have in the boxes.
But of more concern is the rear diff at the moment, and how the diff is fitted in that.
Kenneth
05-10-2009, 02:02 AM
Short of having done the conversion myself, I believe the diff can be placed in the AYC housing.
Put it this way, if it were me I would go for it, but giving advice to another without being 100% sure just doesn't work for me.
Of course the benefit of using a RS housing is that you reduce the weight some. Down side is you would have to have different length half shafts.
I am not sure what you want the car for, but personally I would go with a helical (Torsen) LSD over plate.
In saying that, it seems quaife do a LSD called a wavetrac which is essentially both. It is a helical in operation, but has a binding disc which gives it positive lock up like a plate, should things get out of hand (or you lose 100% traction with one wheel)
Adam.Findlay
05-10-2009, 04:52 AM
Hmm my AYC blew up and from all the research I have done it I have come to the conclusion that the gears are not the weakness its the fact that the casing is made from a alloy which is weaker then the cast iron casing of VR4 type V open diffs and evo RS VC LSD'S, this weakness in the AYC casing caused the casing to twist under heavy load (launches, increased horsepower) which means the pinion moves away from the crown wheel causing more torque to be exterted on the base of the gear teeth (Torque=force*distance. Increasing the distance for a given force increases the torque at a point). Having said this it may seem a bit off topic but my point is dont use a AYC casing for any LSD rebuild.
Furthermore changing the rear diff to a VR4 Type V open diff is easy enough (and Gwof I am Sure you are capable having seen your work on the intercooler thread).
Now we both know that ayc from evo and VR4 are the same right?
they have 3 bolts on either side of the pinion part that bolt to flanges which connect to the subframe, and two subframe bolts at the back as shown in the link below.
http://www.lancerregister.com/attachment.php?attachmentid=72007&stc=1&d=1159037961
The Vr4 type V diff has the cast iron casing with the exact same bolt patern as an AYC diff so all you have to do is change the half shafts to different lengths and bolt the new diff up :).
I beleive it to be the same for a evo rs rear diff (where some people say the evo rs subframe must be swapped in to fit the rs diff), BUT the wings on the rs diff that use the 3 bolts on either side of the front of the diff, ARE different in a evo compared to a vr4, this is because evo's have different subframe mounts. so just use the vr4 wing mounts and you are away laughing.
Here is a evo rs lsd for comparison sake
http://zevo.se/temp/RS_Parts.jpg
But saying that I dont know if the rs diff has the rear two subframe bolt holes like the VR4 Type V diff has.
One last thing I know you can get LSD packs for the evo rs diffs to replace the VC but am unsure if these kits will fit the type V diff, I think they will fit both evo RS diff and VR4 Type V diff but am not sure as I have never had the two diffs apart to compare.
Hope that helps? :)
Well... As just said the RS diff is heavier due to the casing than a gsr diff apopting a mechanical set up. They dont have issues that i have heard of through the rally world. Now, changing the rear diff is not what i was on about, as bolting a diff on isnt exactly difficult ( i think ive done a fair bit more than bolt intercoolers on in the past.) butwhat i need to know is how to install in the casing. Are they pressed in? or can the assembly be easily placed in without the need for pressing new bearings on etc.
Ken, Its going down the strip in some savage fashion, so a plate is really what i am after. I know what your saying though, as the helical's are a lot more friendly and pretty much maintainance free.
Just spoke to coordsport. Can get a cusco rear ayc replacement for just over £1k. They will do me a deal on them if i buy all 3 diffs. If only i had more than 20p left! Looks like i may have to put a standard diff on and see how long it lasts, place your bets now!
elnevio
05-10-2009, 10:14 AM
Just spoke to coordsport. Can get a cusco rear ayc replacement for just over £1k. They will do me a deal on them if i buy all 3 diffs. If only i had more than 20p left! Looks like i may have to put a standard diff on and see how long it lasts, place your bets now!
I think the diff will look at the car, and just break out of fright in your hands before you even fit it! :beerbang:
Its odd that you say that, When i arrived at my car's resting place last night it did let out a sigh, as though it was thinking, not again
Louis
05-10-2009, 10:30 AM
Roger Rally, puts cusco etc diffs in VR4 casings, (removing all ayc bits etc) someone on here has one. (£1k)
The evo centre will shear the bolts when pushed, you can replace these with higher tensile steel bolts (of the same size), available on the MLR forum.
S-AYC is a totally different internal set up and much stronger, (looks nore like an LSD when removed)
Evo RS is cast iron and very durable, but, very expensive second hand bout £2k.
A russian guy has fitted a 6 speed evo box, by drilling a couple of holes in the bell housing, and is mates to the V6 VR4 block.
The plan is eventualy to have a dog box in there, with plate lsd's all round. Will make it oversteery as hell, but awsome in a straight line. At the end of the day, sideways is the new forwards anyway
miller
05-10-2009, 10:59 AM
sideways is the new forwards anyway
Style, as always Gowf!!!! :guitarist love it!!
Rubbing is racing......
well you know, for those 13s or more... Im free
White Lightning
05-10-2009, 11:59 AM
If you are going to just fit another standard diff for now, does it not make sense to fit one from a Type V if they are stronger?
They are open dif's though, so not going to help with traction issues
psbarham
05-10-2009, 08:26 PM
get a type 'V' one and weld it you pussy /Steeringw
Kenneth
05-10-2009, 08:33 PM
get a type 'V' one and weld it you pussy /Steeringw
Agreed! If straight line or sideways is your motto, this is as good an idea as any and the cheapest by far!
psbarham
05-10-2009, 08:36 PM
Agreed! If straight line or sideways is your motto, this is as good an idea as any and the cheapest by far!
yup, it works perfectly on the rear diff of our pug 205 (yes rear diff /bananaroc )
Nutter_John
05-10-2009, 08:36 PM
And how many type V diffs are there for sale in the uk at this point in time ?
White Lightning
05-10-2009, 08:37 PM
And how many type V diffs are there for sale in the uk at this point in time ?
What happened to the one on your old car John?
Nutter_John
05-10-2009, 08:39 PM
Don't know what happened to mine but I assume Ben never kept it
the only other type V I know of is Big Pauls ( cashianvr4)
Adam.Findlay
05-10-2009, 10:40 PM
Good point just locking the type v diff by welding the spider gears will be by far the cheapest and most effective way of stopping wheel slip, I want to put a SAYC in my car when i can afford it so when I do do that in the future some time i can dismantle my type v diff and bring it to Jap Racing Supplys and compare the insides to the evo plate LSD paks
zedy1
05-10-2009, 11:33 PM
i may have a non ayc diff somewhere, but i think its out of a v624 or a gdi will have a looky
Good point just locking the type v diff by welding the spider gears will be by far the cheapest and most effective way of stopping wheel slip, I want to put a SAYC in my car when i can afford it so when I do do that in the future some time i can dismantle my type v diff and bring it to Jap Racing Supplys and compare the insides to the evo plate LSD paks
Have you ever driven a car with a locked diff? Fine for the straight line and a good bit of oversteer, but the already ****e turning circle becomes outrageous. Totaly no use for the road
Adam.Findlay
06-10-2009, 02:37 AM
yeah I know locky's are a asshole on the road thats why i made my point about getting the LSD's. haha alot of my mates have drift skylines with lock diffs. but i do think Researching the compatability of evo internals with the vr4 cast iron casing is worth wile.
bradc
06-10-2009, 04:26 AM
All 4wd Legnums that don't have AYC, ie Type V VR-4's, ST-R's and Viento's all have the same rear diff.
d-rek
06-10-2009, 07:36 AM
Just ripp the ayc out,weld up the centre diff,put a diamnte diff in the back and go rwd its so much fun...
Adam.Findlay
07-10-2009, 02:11 AM
could try this
http://www.trademe.co.nz/Trade-Me-Motors/Car-parts-accessories/Mitsubishi/Diffs-axles/auction-245851109.htm
looks exact same as the type v diff, dont know about the ratios though
bradc
07-10-2009, 08:57 AM
Ratio should be 3.3ish, not 3.9
Ratio should be 3.3ish, not 3.9
So the rear diff ratio is 3.307? would be nice if it was........
Also, ive now been to guildford and had a proper look at the car. Diagnosis is rear diff. Drives like a slipping clutch, but pulls away from the handbrake. But then coasting with engine off you can hear and feel the rear making some bad noises.
elnevio
07-10-2009, 02:22 PM
So will you be fitting a borrowed spare (i.e. test) rear diff to confirm this and that the rest of the drivetrain is ok?
Something like that.... worst case scenario il need to get my hands on a propshaft
bradc
07-10-2009, 07:04 PM
vr-4/evo 4 3.3125 53/16
evo 5-9 3.307692308 43/13
So yeah, 3.3ish if you are looking for a replacement that isn't out of a VR-4 or EVO 4-9. I don't know what the X's are, but they are most likely 3.307
I was looking at a MK2 GTO, but as ive been reliably informed, the uk and JDM ones share the same rear diff. So, it means that they are only the USDM option (dodge Stealth).
Now as these came with lsd's and not much else, and Ben has not managed to break one yet, it seemed the logical progression (if of course i can get one cheaply enough) to see if they can be mounted to a vr4 subframe.
Aparently the US boys want the JDM ratio's, so there is maybe a market to get one.
Is that slight difference in ratio's acceptable? I know a lot of people do run the later diff's.
elnevio
07-10-2009, 07:14 PM
Is that slight difference in ratio's acceptable? I know a lot of people do run the later diff's.
I think there was a post not so long ago where the effect of the ratio difference was notably less than the effect caused by having a few millimetres tread difference between the tyres.
bradc
07-10-2009, 07:27 PM
Yep, I did the maths, the difference at about 1250rpm in 5th would have the front wheels turning at 47.476kmh and the rear wheels turning at 47.545kmh.
so shave some off the rear tyres then yes?
bradc
07-10-2009, 07:36 PM
Not really important. The rear tyres to match a front size of 255/40/17 would need to be 255/39.8/17, or change in diameter (or height if you will) from 635.80mm to 634.78mm, about 1mm in total diameter, or shave 0.5mm from the tyre tread itself.
Over the life of a set of tyres you will get more uneven wear than that anyway!
Yeah i know, i was only taking the piss. Its good news though, all i now need to do is find one!
Louis
08-10-2009, 07:05 PM
Whole load of info here on rear diffs if you can be arsed trawling through it, all useful stuff and links though :)
http://www.clubvr4.com/forum/showthread.php?t=23198
Kenneth
08-10-2009, 09:11 PM
Gowf, where did you get the 80/20 torque split from?
AFAIK, you will only get this if you use a open planetary centre diff in conjunction with the standard VCU. i.e. the cusco tarmac gears.
If you are talking a plate or helical LSD, surely you should have a 50/50 split?
Hmmm, it was the kaaz plate diffs. We currently have an open centre diff with a vcu, and its more like a 60/40. I did read it somewhere, but i can't remember exactly.
Kenneth
08-10-2009, 10:08 PM
Yeah, it is 60/40 bias to the rear, but that comes from the planetary gear in the VCU not the diff.
Yeah, but that is removed when fitting a centre lsd. Just looking aparently the cusco's are a 65/35 split, I definately did read it somewhere but like i said i may be totally wrong.
I can see why the 50/50 split would be thought of, as would that not also be the same as welding the diff's? Which when thinking about it is what a plate diff would do anyway? hmmmm, im now on a mission to find that
Kenneth
08-10-2009, 10:46 PM
Cusco tarmac gear is 65/35, but that is an open diff which uses a planetary gear arrangement. It is definitely not an LSD. Not sure if you are supposed to run it with the VCU.
With the diffs you have to be careful to differentiate between torque and output speed. Welding the diff locks the torque split to 50/50, but also the output speeds, which is what causes the handling issues.
Kenneth
08-10-2009, 10:48 PM
I have done a fair bit of research into the different diffs etc... I plan on getting my drive train setup to my specification before going for more power.
I plan on having the following drive train arrangement
Cusco Tarmac Gear centre
Wavetrac front
S-AYC rear
Just talked to a friend of mine who works at MML and apparently they recon that no ayc diff will cope with 500lbft. They also say, that just firing an lsd in the ayc casing is not the way to do it. So now it looks like im in rs uprated to GpA territory. Awesome, all i need to do now is sell a kidney
Nutter_John
12-10-2009, 10:05 AM
Just talked to a friend of mine who works at MML and apparently they recon that no ayc diff will cope with 500lbft. They also say, that just firing an lsd in the ayc casing is not the way to do it. So now it looks like im in rs uprated to GpA territory. Awesome, all i need to do now is sell a kidney
Sorry they only accept kidneys without 20 years worth of alchool abuse :P
Apologies for intruding with my techno-peasant brain but what sort of diff was Valmes using and how many did he end up going through?
This i do not know. I have an sayc sitting here waiting to go in, but i dont want to put it in if its just going to go pop as soon as it goes up the strip.
bradc
12-10-2009, 07:11 PM
I'm fairly sure Valmes had the normal AYC diff.
Think about this though. I'm making around 440lbft at the engine. In first gear this equals a massive peak of 5280lbft. I have a much longer first than stock which helps reduce that peak. Gareth's car still has the short first gear in it, meaning with the same torque output as me, he would make 6030lbft. Now he makes even more torque than me, so clearly his diff would have to handle much more torque.
In 2nd gear (again I have a longer ratio) we are at 3520lbft versus 3810lbft. Less of a difference, but a much lower overall value.
Perhaps changing to the ultra long RS 1st gear ratio like Kenneth has in his car is a good option? That would limit your 1st gear torque output to 5040lbft.
bradc
12-10-2009, 08:17 PM
Perhaps yes, but then if you launch in 2nd you will have to be very careful with the initial shock load if you are revving the engine up fairly high to get a good jump off the line.
Limiting the boost in 1st would make the most sense to me.
limiting the boost? It makes a bar on the line!!!!
bradc
12-10-2009, 08:20 PM
Make less then :)
Where's the fun if there's no launch control? Its all about the popping and banging. I can totally see what your saying though, but im still thinking that an rs diff is the way, the only downside is the price, and obviously the driveshaft issues im going to have
Louis
12-10-2009, 08:35 PM
Surely there must me a few Evo's with standard S-AYC running big bhp numbers?
Nope, they get rid and put proper diff's in. Same as all the rally cars do not run ayc. And if you look at Norris, he runs a skyline rear diff
bradc
13-10-2009, 05:37 AM
Actually a lot of Rally, Targa and Track use EVO's over here are running SAYC now. All of those classes are limited by throttle body size or whatever and therefore don't go over 350hp or so. All of them love the handling advantage AYC in general gives, especially on gravel
Turbo_Steve
13-10-2009, 09:41 AM
Same as all the rally cars do not run ayc
True, but don't they run monstrously complicated active centres and rears?
The Subaru WRC car had some mechanical triple plate thing covered in electro-hydraulic actuators and sensors when I looked a few years back. Not sure if the rules have changed again (again again) since then. They seem to dip in and out of fashion with teams - possible due to changes in designer / philosophy, or maybe just down to driver.
It all depends on whether you are running GpN/A/WRC.
Subaru developed bits and bobs and had them implemented in certain versions of the road cars (having the diffs locked for 3s after the handbrake is used for example) in order to get this stuff into GpN.
But for the majority of competitors a decent mechanical system will be used for GPA, and its only at £500,000+ that you see the s****y active everything. Even then when you buy a used WRC car you really dont get the same car that was competing for the manufacturers.
Turbo_Steve
13-10-2009, 01:49 PM
Can't agree more there: the active stuff only seems to turn up in the million pound headline WRC cars.
Today was quite exciting. Spent the afternoon touring round what was ralliart and is now MML. The development evo x is stunning, but not just that, all the older cars that were there were just so impressive, not to mention the fresh GPN/A builds.
I suppose the most impressive bit was the price you can now pick them up for, i was totally amazed. £160,000 for an ex-works WRC car! Cheap as chips, when you compare that to the likes of the the fords that are going around the £400k mark.
Anyway, back to business, i am now in possession of Harri Rovanpera's rear diff from his recce car used on the '05 WRC Monte Carlo. Along with new brackets and the like and a set of evo 7 shafts. All for a price of around £1600. Sounds ludicrous i know, but what i dont use goes back (like the shafts etc). Which isnt bad as the diff alone (not including casing) retails @2750+vat.
Im also now in the possition of getting hold of various ralliart bits a lot less than the price you would pay if you went to the dealers. The only thing is that they would have to be in stock there, so basically stuff from the later evo's, but you never know whats in stock.
The likes of seats and harnesses that have been in crashes can be got fot very very cheap. (seat's arnt damaged, but not able to be put back in a rally car), as long as you dont mind various well known names embroidered on them.
Anyway, was just to let you know if you have any requests i can see what i can do about getting stuff.
But with relataion to my car, the weekend will tell if this fits or not
scott.mohekey
14-10-2009, 09:00 PM
This is very exciting news. Both for you and your rear diff woes, but also the thought of named seats and the likes getting about in vr4s in the future!
I hope this isnt too premature as its only been round the block, but I now have a car with a rear end that is full of the spirit of competition.
Managed to get the EVO7 RS diff to fit today. The mounts were no use as it the mounting points on the evo's must be totally different, so a little bit of welding here and there and some polyeurathane spacers made and job's done. I was amazed as to how easily it mated to the propshaft (which was always the big concern.
The driveshafts were an interesting one, as it didnt look like the short shaft was long enough (it should have been 3mm longer than actualy required) but caution was thrown to the wind and the shafts assembled and fitted (the longer one is a wee bit too long, but the extra is taken up in the inner cup.
The only downside was that my ayc pump fell apart when taking it off. Was going to sell it, but nevermind these things happen.
So time to take it out for some abuse tomorrow to see if there is anything else in the drivetrain thats expired.
A big thankyou to paul for today though, cheers for all the help, your a star.
Pics will be up tomorrow
scott.mohekey
18-10-2009, 01:28 AM
The mounts were no use as it the mounting points on the evo's must be totally different, so a little bit of welding here and there and some polyeurathane spacers made and job's done.
Do the RS evos have a different rear subframe to the regular evos then? As far as I can recall, fitting the SAYC only requires a couple of spacers.
psbarham
18-10-2009, 07:54 AM
No problems Gowf, it was a pleasure, i'm just glad it worked.
still pissed about the ayc pump, i can't believe how brittle the ally has become on those pressure switches, i suppose it can still be sold as the pump is ok, it just needs a bit of jiggery pokery to get the broken thread out. in fact bring it over and i'll have a play with it.
i have to say it was a bit of a :dance: moment when you pulled away and we heard the boost kick in and the car kept going :2thumbsup
Do the RS evos have a different rear subframe to the regular evos then? As far as I can recall, fitting the SAYC only requires a couple of spacers.
yeh, the RS diff came with lots of fancy very expensive bracketry to fit it into the subframe, the front mounting points are the same, and the rear ones must be 100 mm narrower, but luckily its the same length as a standard diff :2thumbsup
miller
18-10-2009, 09:58 AM
Wow so far so good! Fingers crossed
yeh, the RS diff came with lots of fancy very expensive bracketry to fit it into the subframe, the front mounting points are the same, and the rear ones must be 100 mm narrower, but luckily its the same length as a standard diff :2thumbsup
As Paul said, they do have different mounting possitions to ours, all the evo diff's do, when your changing to the sayc, your not changing the mounting bracketry. But the RS is different to the GSR mainly because the diff is a a good bit smaller so doesnt need a mahoooosive subframe to mount to, so they use some s****y aluminium bracketry thats only £1000.
Here's some pics:
Old Diff:
uploaded/3977/1255859765.jpg
Close up of the badness inside the old diff:
uploaded/3977/1255859815.jpg
This shows the RS diff dry mounted in place, looking promising
uploaded/3977/1255859859.jpg
Then the bit that was the most important, how does it line up with the prop shaft:
uploaded/3977/1255859942.jpg
The driveshafts were the next issue, so again a dry build of them showed where the shaft would sit in the cup:
drivers side:
uploaded/3977/1255860033.jpg
Passenger side:
uploaded/3977/1255860077.jpg
From that it felt like the passenger side was too sort so a hunt ensued for a shaf of the correct length. That came up with nothing, so then, for curiousity, tried it with the joints attacted:
uploaded/3977/1255860218.jpg
uploaded/3977/1255860260.jpg
It can be seen then that the n/s is fine and the o/s is a wee bit long, but the cups seem to be able to handle it.
So from there it was a case of making the diff fit the standard subframe with some drilling and welding it was done.
uploaded/3977/1255860371.jpg
uploaded/3977/1255860402.jpg
Apologies for the picture quality, its a new phone and realised when at home that i hadnt taken the lens protector off
Nice work & its looking good. Hope it holds up for you.
Turbo_Steve
18-10-2009, 01:29 PM
Well done guys: really glad you were able to get it in: must be a weight off your mind Gowf (and weight IS the enemy :D )
Well here's something to make you laugh, have a look at the old diff
uploaded/3977/1255892781.jpg
uploaded/3977/1255892840.jpg
uploaded/3977/1255892902.jpg
uploaded/3977/1255892968.jpg
uploaded/3977/1255893054.jpg
uploaded/3977/1255893108.jpg
So there you have it, 4 teeth or so off the crown wheel and every tooth of the pinion shaft. Not a bad effort for 1 launch
psbarham
18-10-2009, 09:07 PM
tee hee /Devil5
you weren't wrong when you said it was impressive.
at least you have a casing to sell if someone wants to do the cusco conversion
bradc
18-10-2009, 09:15 PM
Carsten's diff did the exact same thing....twice!
scott.mohekey
18-10-2009, 09:18 PM
The phrase 'much gnashing of teeth' comes to mind.
miller
18-10-2009, 09:41 PM
Thats a mess allright! a heroes mess.....
The oil that came out was quite interesting, obviously the stuff out of the diff was silver in colour, but the stuff out of the pump was odd. And it was only changed a week before that happend.
You've got to be impressed that it still drove with the diff like that.
scott.mohekey
18-10-2009, 11:54 PM
I seem to recall that the cause of this is flex in the case, causing the gears to be pulled slightly apart, meaning the power is being run through a smaller contact area. Would it be possible to reinforce the casing in some way?
This is what MML have also said to me. The only way round it is to use a steel casing (ie an RS diff). Even though they are steel, they are so much lighter than the AYC's. The only problem with them is the cost. But at least now the options to do this have been proven, and your not just restricted to evo 4 stuff
scott.mohekey
19-10-2009, 12:03 AM
So you don't think there's any way to run high power through the AYC system? Would it be fair to say that with your setup, the problem was a massive initial spike of torque that killed it? I.e. if the initial torque was tamed somewhat to stop breakages, do you think the AYC would handle higher peak outputs?
Its totally possible, but then i recon that its been going for a while, and thats why it showed the flucuation of torque on the ramp up as the VC was trying to compensate, which then killed the transfer box.
But yeah, it was totally decimated after a launch.
Bear in mind, that the car has been run for about 18months at about 400bhp/430lbft of torque, so its quite possible that they just cant cope with this for any long period of time.
Having said that the SAYC may be better.
But i have been 100% assured that there is no way that any AYC diff will take 500lbft at all. Now i can not argue with them and dont really see the point as no one on here has the extensive experience of these things like the works world rally team. So it does indeed look bleak for big power and duribily of ayc
scott.mohekey
19-10-2009, 12:20 AM
Ok, here's something of a tangent then. Given these facts, would AYC be able to handle circuit racing? Or is the power needed there too much as well? I'm guessing it will come down to class.
Im assuming that itd be totally down to how much power you are putting down. But at the end of the day, if you were doing it properly you'd want a plate diff anyway's
scott.mohekey
19-10-2009, 12:28 AM
Ok, and why exactly a plate diff?
Because you have much more feel with it. The AYC is really really good at what it does, but i've never been a fan as it takes away from the driving experience. Your when they eventualy let go, you are way over the edge and its a nightmare to recover. Whereas with a plate diff, no you cant just point and put your foot down as it wont just go round, but it will allow you to have maximum traction where needed with maximum feel.
An ATB diff would do the same, its just that plate is a bit more severe at what it does. For a start, it allows you to continue driving with a snapped shaft.
I should also add, A VC style diff will work fine on the road, but on track they become a little unresponsive. Whereas a plate diff is responsive 100% of the time. However it is down to you how you want it by setting the preload of the plates and the ramp angles. The ramp angles will set how the diff works (1/1.5/2way) and the preload sets how 'locked' the diff is. For example, a 100% locked diff will get you away with a snapped shaft, but would be a nightmare to manouvre in slow tight spaces, but for track would give you total predictability.
scott.mohekey
19-10-2009, 01:09 AM
I think I need to do a bit of research on diff types. I've only ever driven an AYC.
Like i say, AYC is good, but its just not as fun as a proper mechanical diff!
Adam.Findlay
20-10-2009, 01:27 AM
Yeah like I said earlier the weakness in ayc is the casing flexing. a plate lsd would be wicked, i would love to know if there is a kit that can be fitted to the type v diff as that is what i have in at the moment as my ayc popped in a ver similar fashion.
Turbo_Steve
20-10-2009, 07:26 AM
Casing flex can be fixed with a bracing kit? (usually a few biggish bits of milled ally and some big bolts).
miller
20-10-2009, 08:51 AM
Havent i seen a thread on MLR where they reinforce the casing? hmmmm let me go trawl again!
scott.mohekey
20-10-2009, 09:01 AM
Havent i seen a thread on MLR where they reinforce the casing? hmmmm let me go trawl again!
Much appreciated.
miller
20-10-2009, 09:17 AM
http://www.lancerregister.com/showthread.php?t=111208
Here it is, but it is with LSD inside the AYC housing as far as i can gather, unsure if it works on current models
Well this is the thing, are the CWP's being destroyed through case flex, thus allowing different spacings between the CW&P, or is it the CWP themselves?
When changing for an LSD inside the AYC you retain the stock CWP and so maybe wouldnt help you at all, oh and they are a little bit over 1k just for the diff.
This is why i went for the ralliart plate diff, as they are in a steel casing (RS) and have a beefier CWP, not to mention the diff itself.
All things being considered you may be able to put an RS diff inside the type V casing, but no idea what the tolerances would be like
Adam.Findlay
20-10-2009, 10:01 AM
yeah but rs diffs are viscous arent they? but i think that the rs parts may be interchangeable but like i said i would be intrested to know if they are, and if so can you buy plate lsds to suit.
There seems to be some confusion with regards the term Viscous here. The RS diff's are not as i am aware viscous, they have a mechanical LSD, now whether or not thats an ATB im not sure, but more than likely so. The casing is the important bit as if you want a plate diff for them you can pick them up for about £600, but they ONLY fit the RS casing. Whereas the replacements for the gAYC are over £1000 but you still have the weak casing issue.
The Due to the RS being a smaller diff, you also need shafts at £500ish each and to modify your stock subframe to suit.
Basically your not going to see change from £1500 for an RS diff conversion or a £1100 for the ayc swap. At the end of the day, its expenditure that few can justify, i just didnt want to be replacing diff's every other week.
Adam.Findlay
22-10-2009, 12:07 PM
Oh i stand corrected, I was told by a few people tht rs's have VC's. hmm i guess its a matter of waiting and seeing for me. Im saving for a rs diff but there are alot more things of higer priority to do first. Wonder if the type v shafts can fit the rs diff as the casngs are very very smilar
thy are similar but doubtful. It depend's on the joints as they are also different. Your better getting hold of an e4 rs rear end, but good luck with finding that.
Adam.Findlay
22-10-2009, 11:55 PM
theres a E6 rs rear end for sale here but its $2000 which i cannot afford
Eurospec
23-10-2009, 01:51 PM
Hey, for all you diff destroyers, there is a guy in a scrappy up north selling an xfr box with cusco front diff in it on ebay at the mo.
I'm told it has 200 miles on it.
I believe he wants a grand.
Cheers,
Ben.
elnevio
23-10-2009, 02:11 PM
Hey, for all you diff destroyers, there is a guy in a scrappy up north selling an xfr box with cusco front diff in it on ebay at the mo.
I'm told it has 200 miles on it.
I believe he wants a grand.
Cheers,
Ben.
That'll be this one then: http://cgi.ebay.co.uk/EVO-4-5-6-CUSCO-LSD-Transfer-box-Road-Rally-Track_W0QQitemZ200396741236QQcmdZViewItemQQptZUK_C arsParts_Vehicles_CarParts_SM?hash=item2ea8939a74
Don't know who it is - but he is in Chesterfield! :thinking:
So, if necessary, the CVR4 postal service is available (i.e. me!) and I'm sure I can look after it for a little while if needs be.
Plus I reckon whoever bids for it is likely to get it for £800 too.
Im good for front Diffs at the moment. Finaly got round to driving it tonight, and oh my god, what a car!
Non of this gayc keeping you going round the corner, more look at where you want to go out of the passenger window! Totally epic, absolutely love it, but it is a wee bit of a handful.
Oh and the 'noisey' diff really isnt, so there is a possibility that its had a rebuild before i got it, so happy days!
psbarham
24-10-2009, 08:12 AM
feckin excellent news mate, I'm really chuffed its worked OK.
I take it there is no sign of the centre diff winding up due to the potential difference in ratios that we did wonder about?
Is it a controlled animal? or a "drive it half asleep and you'll be arse first into a ditch on "sort of animal?
Madhav
01-12-2009, 12:43 PM
Great thread, I have been doing a lot of research and it appears without a doubt that the alloy casing on the AYC diffs both in our VR4's and the evos cannot withstand much power.
I know it's probably just a matter of time till my stock AYC diff dies, so I am trying to organise a stronger solution now, so my car won't be off the road for too long when it does happen, i.e. have the parts on hand.
First question: Does anyone know whether you can fit a cusco LSD diff centre to the type V VR4 diff? The casing on the type V is cast iron and should be stronger right? This could be a fix?
The other solution is to fit an evo RS diff, and from what I read on other forums, the USA has cheap and plentiful supply of EVO IX RS diffs, as all evo 9's over there had them stock, unlike the JDM versions which are rare and expensive.
Second question: What parts exactly will I need to do the conversion?
I have access to a great welder/engineer the same dude who did all the custom work to fit the KKR 280's, so the welding wont be a problem, just need to start sourcing the parts.
Yep, it should all be in this thread. But you will need shafts, now the shaft lengths are different for all the different evo's and so a 4 would be the best, however if you are going 9, you may have an issue as the length of those shafts are a lot longer, i also dont know if the 9 diffs are any different, i have a feeling they may well be, i know the 10's certainly are (with respect to mounting and the like).
Also, the stock rs diffs arnt all that either, so you really would want to swap the internals. I run the Ralliart plate diff, which then obviously allows you to have the adjustable preload.
Madhav
02-12-2009, 12:58 AM
Thanks for the reply... I really need access to a mechanic locally that has worked on a lot of evos and VR4's. From what I read on other forums the evo 9's have a longer rear wheel base than the evo 4s, so probably no joy there.
So you are saying that if you buy an RS set up from the evo 4, then all the shafts will bolt right up? and from there you just replace the centre and problem solved?
The one below is from an evo 9, but I am using it as a reference of parts needed. Is this all you need?
There is a dude on trade me selling the diff kits (http://www.trademe.co.nz/Trade-Me-Motors/Car-parts-accessories/Mitsubishi/Diffs-axles/auction-257667221.htm) for evo 4's for NZ$1675 here
Right you need not worry about the all the bracketry as it wont fit. You modify your existing subframe to take it. the diff from the 4-9 should fit (im using a 7). Im using shafts from a 7, which are longer than we need them to be (cant remember by how much but the drivers side is a lot more than the passenger). Dont just go on the wheelbase as the shaft lengths changed from 5-6 but the wheelbase didnt.
It will also mate to the propshaft ( an area of huge concern when first looking at them in purely diagramic form) but you need to swap the flanges over ( they changed them on the 7's onwards not that it matters as youd be changing them anyway).
You will also find that you will also be running a slightly different ratio, but ive had no transfer box issues yet.
The obvious advantage of this set up, apart from the stronger casing, is that if you manage to get a standard diff, an uprated plate diff internals arent all that bad if you go for the likes of cusco or KAAZ
bradc
07-12-2009, 05:36 AM
I've got an ST-R/Type V diff on my garage floor for Madhav now ;)
Adam.Findlay
07-12-2009, 10:52 AM
I've got an ST-R/Type V diff on my garage floor for Madhav now ;)
OOhhh exciting hope one of you can solve the evo lsd into vr4 casing question :):)
bradc
07-12-2009, 07:22 PM
I might take it down to Ralliart one day and see if it looks similar or identical to some of their LSD's
Adam.Findlay
07-12-2009, 10:46 PM
wicked that sounds good becuause I really miss the AYC in my car, cos The open type V diff that had to replace my ayc with just doesnt cut the mustard handling wise.
Why did you have to replace it with a type v? Also, if you miss the ayc a plate diff is not what you are after at all.
Adam.Findlay
08-12-2009, 03:04 AM
it was all i could afford at the time man. yeah and after learning how the weakness in the ayc is in the casing im opting for a mechanical lsd
Madhav
08-12-2009, 09:12 AM
I've got an ST-R/Type V diff on my garage floor for Madhav now ;)
Purchased for the grand sum of £60! Absolute bargain!
I might take it down to Ralliart one day and see if it looks similar or identical to some of their LSD's
Do it!!! :sweethear Take it there before you send it to me! I have nobody to ask here in perth that really knows, so it's up to you.... help us Brad, you're our only hope.
Like I said I am in no hurry, need the diff to arrive within 6 weeks, and even then, my current diff is working fine, but I have a buyer waiting for it, and his diff is whining a bit, so it's life span is limited.
bradc
08-12-2009, 09:22 AM
I was down there today, enquiring about AYC line pressures when cornering, which turned into an ACD and Motec conversation. I also sat in a rare rally spec Escort ;)
Anyways, I had a look at both an EVO X RS and EVO 8 RS diff on the ground as well as an EVO 9 RS diff (in an EVO 9) and they are quite different unfortunately.
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