VR4 Handling really loose rear end

[Davezj]

Hi all,
just wanted to canvas opinion on this very odd handling issue.

standard VR4 in carpark,
try and do a doughnut in the dry, car will grip well and rather than spinning on the spot like a rear wheel drive car the VR4 will try and scrable for grip and push on forward which will start it understeering then it will start to loose a bit of traction on the rear end, and it will slide a bit, but you need a lot of space to get it to do this on dry surface.

Odd handling VR4 (no engine mods that i know of, auto gear box, standard facelift boost) in same carpark, same conditions.
the VR4 i was in would let go on the rear very easily and slide round as if the rear wheels were on ice, no hint of understeer, the front stayed almost stationary, proper doughnut action. this all occurs with half throttle in second gear from a slow rolling forward start and also form standstill in first, turn steering wheel to the right not full lock half throttle and car rear end spins round on the spot. scarey handling when you are not expecting it.

VR4's are not meant to do this, does anyone have any ideas as to what would cause this type of handling?
get the comment flooding in,
i can't get head round what could cause this, i am stumped.

[fassi1]

Disabled or not working AYC and warning bulb taken out.
That's what I had when I bought my Legnum.

[adaxo]

We disable ayc by takin fuse out in known good vr4 and try to lose back end with no success. This was a really scary and funny experience, it literally behave like very powerful rwd.

[Ghost_2008]

Low grip compound tyres, over inflated and no power to front wheels? I would assume no ayc..... I tried to spin the back round / u turn and my ayc diff blew up!!

I've currently got hankooks on the rear and I have found them to slide on occasion.....

[adaxo]

Car has falkens at the rear so good grip and we check 4WD and it seems like front wheels are connected tbh that was my first thought that someone disconnected front wheels.

[Davezj]

One thing we did not check was tyre pressure.
The were 225 40 18 fallen ZE914 I think.

I will drop him a pm and ask him to check the pressures just to rule it out.

[Davezj]

Green Ayc light on the dash while spinning the rear end round. As you would expect.

[adaxo]

One thing we did not check was tyre pressure.
The were 225 40 18 fallen ZE914 I think.

I will drop him a pm and ask him to check the pressures just to rule it out.

I didn't push tyre pressure check as i take wheels off and 'drop' them on the floor during this day and they 'bounce' normally I know it's not very accurate but they not been flat

[Davezj]

Before the car was looked at the owner mentioned the symptoms of the car being quite easily provoked into loosing the rear end. But we thought it was just him being overly enthusiastic on a wet roundabout. Which you can do if you really give it some.
But not on bone dry Tarmac, at only half throttle while moving in 2nd gear in an auto.

So this surprised us when the rear end just snapped away.
It was not a progressive slide either, you could grew the car accelerate as you turned through about 90 deg then woof the car had turned 180 in a fraction of a second as if there was zero traction at the rear end.

[Davezj]

Is it possible the alignment of the rear wheel could influence this issue.

[Colin Wiltshire]

Diff seizing? like the drifters weld the rear dif to slide the rear more easily.

[Davezj]

We check both front and rear diffs by jacking the car up at each end on turn put car in neutral, and spin a wheel by hand. The other wheel turned in the opposite direction. Them we turned both wheels in the same direction and the wheels that were on the floor dragged the car along. So the drive train seemed to be operating as it should.

[adaxo]

Diff seizing? like the drifters weld the rear dif to slide the rear more easily.

that was our thought too so we lift car up and turn wheels and they behave normally ie one turning forwards other turning backwards at front and rear.

This one its really odd one, I driven about 10ish vr4s in various state of tune/working or not working ayc/state of the car overall and NEVER experience anything close to this yesterday one. Its really scary BUT huge fun if you somehow manage to master it. I hoping to find out what casing this and it could be done to mine for a bit and then reversed to normal when I get bores of drifting.

[Ghost_2008]

What are the springs on the rear and front? Different spring rates? Could cause issues with the handling, also are the pistons in the rear struts moving as they should?

[swinks]

Is it possible the alignment of the rear wheel could influence this issue.
Very much so! If geometry is ****ed up, then you will get very happy loose tail in rwd style. :)

[Davezj]

maybe swap front tyres for back tyres and try again. that would prove the or disprove the tyre possibility. the fronts were a different brand i can't remember what type.
unfortunately it was late when we went out to test the the car, and after a long day and of work. So we did not have a lot of time to check things out.

the seems to sit flat and level, there was no lean to one side or anything like that.

i did cross my mind that one of the rear springs could have snapped previously and the snapped bit just removed, normally it is only one coil that snaps on a spring if it does snap. i mention this as it has happed twice to my dad in his mondeo both front springs at different time have snapped and each time it was just the top coil that broke off, i think this is due to the large speed bumps in his road.

but i thought i would have noticed if the spring were different heights the surely the car would sit on slant and it would be obvious. i didn't actually look at the suspension while i was under the car doing the rear diff fluids and bleeding the AYC pump. i didn't have any reason to.

[Davezj]

Very much so! If geometry is ****ed up, then you will get very happy loose tail in rwd style. :)

this is something that is easy to check and most alignment places will give you a free check to see if it needs to be adjusted, it usually does to certain degree, but it would be a good thing to get check.

i will start a list of the reasonable things to check.

i did not notice any kind of adjustable suspension links on the back, or anything other than stock suspension, we did think it was lowered slightly but not exsesive maybe 20mm.

[CANDEE]

My old Legnum was really loose on most tires I had on the back under throttle. It used to act like a rwd and the rear end came out really easily.

I put it down to alignment(never did it the whole time I had it) and the crap/touring tires I had on it.

[Z-Kev]

I'm betting suspension geometry, do the rear wheels
seem to shift when seen from the outside when this happens?

[Davezj]

Had we thought about it at the time one of us should have got out of the car and videoed it to see what was actually happening. There was no screech of tyres when the back end snapped round , it was just a violet 180 ish. This is why I say it was just like the back end hitting a patch of Ice and complete loss of traction was the result.

Very odd indeed.

When looking from the back of the car I could not see any noticeable negative camber on the rear wheels. I have seen much worse negative camber looking vr4 at the rolling road days I have attended and no reports of anything like this.

I hope it is tyre related or geometry/alignment issue as this will be relatively easy to fix.

I am waiting to hear back from the tyre pressure question I have asked and the fingers between the tyre and arch test to get a little more info on this topic.

[bungle]

I have some bad news.....I think this issue is fixed. :sad3: I had 4 new falken ziex put on the car today the same as the ones on the rear and the car feels completely different. No loss of grip at all really although I wasn't caning it too much due to having fragile-ish bits in the car. But still giving it enough to cause the drifting previously. If it is sorted I'm gonna be sad to see it gto as I had some fun in it yesterday./HappyBD Think there is definitely a tracking/alignment issue as the car does vibrate at high speeds, especially when pushing it past the limiter./thumbsup
Thanks again for the service adaxo Davezj, the brekkie was muchly appreciated. Gonna have to disconnect the battery again in the morning I think as all the eratic driving Wednesday/Thursday has not taught my gearbox very well/Elmo

[Nick Mann]

So what were the tyres that were replaced?

[bungle]

The rears were falken ziex they were worn right down to the limit and evenly worn. The fronts were just economy tyres put on to get through an mot.

[Confused]

I'm not really surprised having read through the thread - the ZIEX 914 are very much a budget/eco tyre - they are designed to be hard and long-lasting, which is the exact opposite of what you need for decent grip.

It's entirely possible that the mismatch of tyres - the hard, eco Falken on the rear, and I'm guessing a softer, grippier one on the front, caused this inbalance of grip levels.

These are, at the end of the day, £35,000 high performance vehicles, and they benefit from putting decent, high quality tyres on them.

[Davezj]

I'm not really surprised having read through the thread - the ZIEX 914 are very much a budget/eco tyre - they are designed to be hard and long-lasting, which is the exact opposite of what you need for decent grip.

It's entirely possible that the mismatch of tyres - the hard, eco Falken on the rear, and I'm guessing a softer, grippier one on the front, caused this inbalance of grip levels.

These are, at the end of the day, £35,000 high performance vehicles, and they benefit from putting decent, high quality tyres on them.

that is a surprise because elnevio has given them great reviews after using them at the ring and other various track days.

[Davezj]

The rears were falken ziex they were worn right down to the limit and evenly worn. The fronts were just economy tyres put on to get through an mot.

the front had budget tryes and gripped well but did not try and drag the car forwards out of the spin and the rear tyres a much better brand/make loose traction very easily on dry tarmac.

it does not ring true with me unless as the tyre wares the rubber left on the casing the low levels is really crap rubber and should not be driven on at all.

by the way what were the tyre pressures on the rear before you had the tyre changed?

[bungle]

the front had budget tryes and gripped well but did not try and drag the car forwards out of the spin and the rear tyres a much better brand/make loose traction very easily on dry tarmac.

it does not ring true with me unless as the tyre wares the rubber left on the casing the low levels is really crap rubber and should not be driven on at all.

by the way what were the tyre pressures on the rear before you had the tyre changed?

I'd blown them up to 35 psi all round about a week before at a local garage.
There's definitely no complaints from me with these tyres so far. They may not be prestige but they are far from budget, only fault is a slight increase in road noise but you have to be really trying to hear it over the exhaust. It's like with anything you get what you pay for. But these tyres have felt solid so far on a few different road conditions. It is really strange the difference they have made as before the car used to scare me ( which I quite liked) where as now it feels like a train. I took her out for a good stretch last night down some nice windy roads, and large roundabouts and never once felt the same looseness I felt since first owning the car.

I dont know whether the abs light issue could have anything to do with it as Ive read somewhere that an abs fault can throw out the ayc system?

[Davezj]

glad to hear you have that loose sorted. with a tyre change.

i would still get the 4 wheel alignment tested as a check to see if this correct can be a good thing to know for the future.

[bungle]

Its next on the list fella. Had the front pads replaced with the padgid ones while the tyres were being done and the grinding sound has been massively reduced, the back ones were the wrong size though(too big), so hopefully will be gone completely once this is done. Then for the cambelt in the next month or so. I'll keep u posted once alignment has been done.

[Nick Mann]

ABS faults can be common with AYC faults. However that is only because they both use the same sensors. If you have an AYC fault as well then the red AYC light would be on the dash too.

[elnevio]

Yes, I quite liked the ZE912s that I had on the car for a set a few years back. They were really good on the Leon too.

Either way, my view is that as long as all four are the same, you'll have pretty much equal grip all round. :)