Back End Slipping Out

[dobboy 231 2 Cars]

Wondering if anyone/everone else's car does it, why, and what can be done to stop or reduce it.

 

I don't remember my last standard GTI from 20yrs ago doing this at all.

 

It seems to be happening a bit much for my liking and sometimes just at moderate speeds. It definitely feels like gentle slipping and its not bouncing at all.

 

My set up is all more or less brand new

 

Quaife Diff

205 B4's on Eibach -30mm

Grp N top mounts

Upper strut brace

 

Xsara VTS B4's on rear

Refurb'd beam

Group A torsion bar bushes?

New OE sandwiches

 

Nearly new toyo T1R all round, which I find to be good in dry, crap in wet.

 

I've no problems or understeer at all with front of car.

 

The first time it slid I checked all tyre pressures, which the tyre fitter had at 35psi, I reduced them to 29in front and 28 on rear, and have since dropped them by another 1psi. I would say this has helped but the improvement is minimal.

 

A few examples of where it has happened:

 

Today joining a motorway and giving it full pelt on the big long bend on the slip road, I could feel it every so slightly slipping out as i went round the bend. Dry weather

 

Giving it good throttle round big roundabouts. Dry and wet weather.

 

On one occasion going 60/70 on a B road, I bottled it going into a corner, braked heavily and I thought it was the end but fortunately controlled it, but it calmed me down for the rest of the day as I shat myself, but I blame this one on bad driving.

 

Generally braking on bends, or decelerating on bends.

 

I had the car on the track a few weeks back and I didn't notice it so much if at all, but obviously on the road it's a totally different environment.

 

Does everyone's car do this, and you just need to live with it?

Is it safe to just let it do it, give some gas, and rely on the front pulling the car round, especially with having the ATB diff?

Is there something fundamentally not right with my set up/combination of parts?

If this is typical back end behaviour, does the back have to be really out before there's a risk of loosing all back end grip and going backwards?

 

It's by no means the car going sideways but its enough for me to be aware of it happening, it feels like the back is 3 or 400mm wider out than it should be, and I don't like it, and it's noticeable from a car behind.

 

Any comments/suggestions?

[Slo 283 1 Cars]

This the one with the boat anchor in it?

[dobboy 231 2 Cars]

Boat anchor? If you mean GTI6 then yes.

[dobboy 231 2 Cars]

Something else to add that may or may not be relevant.

 

When the car was MOT'd the guy said he thought a rear wheel bearing was suspect, he said it wasn't gone enough to warrant an advisory but thought he'd mention it to me.

[Slo 283 1 Cars]

Mmmm thought so, i have cti with gti front suspension which is already heavier than gti due to reinforced sills etc and cast iron roof + roof pump at the back. Add to this turbo engine, same cast iron boat anchor as gti6.

 

From my own experiences......

 

Going round bends in dry is pretty good but can get skippy, handbrake sometimes helps.

 

In the wet can be a bit worrying have to slow down a bit.

 

Roundabouts in the rain might as well forget it as the car just carries straight on as if driving on ice, this is particularly bad on roundabouts that have a petrol station next to it.

 

Its all in the weight mate, I dont have any of that uprated stuff on mine but does any of this sound familiar?

[dobboy 231 2 Cars]

No, not really, but yours may be a bit like my CJ. It bounces/judders at the front on bends if the road surface isnt perfect, Think its called scuttle rattle? h

 

Yours sounds predominantly like under steer issues?

 

The front end grip on my GTI is excellent, no issues at all, the diff is immense, its just this back end thing. It's difficult to explain it, you can just feel something happening at the back. I imagine it would feel similar to having bald tyres on the back in the wet, but having good tyres on the front in the dry, at the same time.

[Slo 283 1 Cars]

But i have gti suspension at the front and its all brand new too not 27 years old and worn out. Of course theres scuttle shake/roll but were talking about traction here not driving around in a space hopper lol.......aren't we?

 

Basically you've got a s*itload more weight on the front and virtually nothing on the rear in comparison to the original light ally engine anyway.

 

Are your rear shocks new? BTW whats a torsion bar bush?

Edited September 6, 2014 by Slo

[dobboy 231 2 Cars]

Space hopper lol

 

I remember mines with no fancy diff and the 1.9 was murder on round abouts on the wet, I though it was cos it was too light to get the power down or s*it tyres.

 

Reading the net, its not the weight that's my issue, its the weight transfer that's my problem, ie decelerating means less force on the rear tyres and less grip. Think I just need to put the foot down (and pray).

 

The torsion bar bushes ( I think that's what they're called) are part of the rear stuff BBM do, the white nylon things in their kit?

Yeah everything's new

[Slo 283 1 Cars]

Yes weight transfer that's what I was getting at, poke it np slow down np even quickly, but poke it on a roundabout or slow down quickly on a roundabout and the weight digs in at the front and the rear puts in an appearance n sez how ya dooin.

 

When i drove my 2nd cti home it was a big shock to experience the crapness of the original front setup again (how far can you get one to lean over?) particularly with no pas which i realised at the the first roundabout lol

 

Yet the handling was awesome, so light and nimble and even dare i say it powerful but no weight to dig in and pop the back end round loads better.

 

Ive not seen the bbm torsion bar kits thats why i asked

[allanallen 528 2 Cars]

The rear wheels do 'slip' during turning, it's sort of how it works. You will notice it more on fast bends.

The rest of what you describe is lift off oversteer which as I'm sure you're aware these cars are famed for. You need to adjust your driving style to suit the cars characteristics.

 

You can make the rear end more stable/predictable by fitting solid rear beam mounts and trailing arms with toe in.

 

What are grpA torsion bar bushes??

[allanallen 528 2 Cars]

Ahhhh so you've got solid mounts at the front of your beam and rubbers at the rear?? That's bad practice IMO, you shouldn't mix and match the bushes.

They're called beam mounts not torsion bar bushes

Slip the solid rears mounts in and see what you think.

[dobboy 231 2 Cars]

Allen, the white nylon things here

 

http://www.bakerbm.com/205.php?data=suskit205a

 

Malc also suggested solid beam mounts.

 

Thing is, just now my beam mounts are brand new OE, so I imagine there isn't as much play in them at the moment.

 

I think I notice the slipping most on longer sweeping bends, at 50+, probably when I've been accelerating then ease off slightly, then I can feel isomething happening and get a bad feeling. It probably happens just before and after the Apex of the bends.

 

When you say adjust driving style, what do you mean? Slow down or put the foot down or make sure I'm on the inside of the bend to have room for the back end to go out etc?

 

I won't be surprised if its down to my driving as ive not driven the speeds I'm driving at recently for a long long time.... If ever!

 

Would a dodgy rear wheel bearing make the car feel like its slipping?

[dobboy 231 2 Cars]

Yeah Allen, rubber sandwiches and a set of they nylon things.

 

Can the solid mounts be fitted without removing the beam?

[allanallen 528 2 Cars]

Your current driving style provokes oversteer. Accelerating then lifting during a bend will make the rear end light and it'll want to come round on you. So either stop doing it or embrace it and get used to it. I personally love it and with an LSD it's a very useful trait on fast twisty stuff for adjusting direction quickly.

 

If your on a long sweeping bend you either want to be holding speed or accelerating, lifting off before you're used to what the car does can be a recipe for disaster.

[welshpug 1,655]

Whats the ride height like ?

[dobboy 231 2 Cars]

Thanks Allen.

 

WP, its dropped slightly, nothing major.

[welshpug 1,655]

specifically the difference front to rear. how much rake is there from sills to floor and what are the wheel centre to arch measurements?

[Matt Holley 11]

Just sounds like classic lift off oversteer to me.

[Simes 248 2 Cars]

Don't lift off mid corner.

[2052NV 24]

Don't lift off mid corner.

 

 

NAILED IT

[dobboy 231 2 Cars]

 

NAILED IT

Yesterday i made a conscious effort not to approach corners as fast, and just kept a gentle bit of gas on through the corners, and the back end felt fine.

 

I'm gonna change these beam mounts anyway, but i'm not sure if i should be going for GrpA or GrpN (if i can get them).

 

I intend to use the car for the odd track day, but it's used regularly on the road.

 

Is there much difference in the normal ride quality between these two?, and are both alright to use with the front mounts i have?

[Henry 1.9GTi 36]

I had a 306XR completely standard on 175 tyres and that thing would go sideways without fail wet or dry. Wheels at the rear had alot of play in and out. Suspect under load was causing toe out. Was oh so fun to drive but car was shagged.

 

So maybe look into your rear wheel bearing. Is the behaviour consistent left and right? Getting the car to rotate is fun anyway. Just stamp on the loud pedal if it gets silly

[dobboy 231 2 Cars]

Cheers Henry, i think i've only ever noticed it slipping when i'm turning left, but on the road i seem to try to go faster round LH corners for some reason.

 

Is slipping (or the feeling of it)consistant with a dodgy bearing? (i think i can hear an ever so slight whine from the OS rear, until the noise is overcome by exhaust noise, and incidently, it was this side of my beam that was knacked.

 

Just checked the price of a bearing.... Gulp!

 

Do i need a kit or just the bearing?

[Henry 1.9GTi 36]

The bearing will come as part of the hub assembly.

 

Changed mine recently and was about 60quid a side for decent bearings. Not too bad. It can be a pain getting them on an off however. Make sure you retain the spacer (big washer) behind the bearing assembly and refit it. Or just leave it in place making sure its definitely present!

 

and replace the hub nut. The kit may or may not come with the hubnut.

Edited September 8, 2014 by Henry 1.9GTi

[dobboy 231 2 Cars]

Thanks Henry, where did you get the kit and what manufacturer is it? The SKf ones I'm looking at are £90 ish to £120.

 

I'll phone my local place and see what and how much they are.

 

I wouldn't know a good from a bad one.