Wilster at Work

What is it about damp roundabouts, Scoobys and understeer. Seems to be a perennial problem. Its taken me a while to get over/admit to this one, 'cos I thought I was just a crap driver :

The other day in good 'ole Milton Keynes was zooming up dual c/w in early morning, no traffic, steered into damp roundabout no problem, went through the 'apex' and the front just let go giving me no chance, so up the kerb I went. Dunno how fast was too busy contemplating the motorway barrier. Luckily the beast stopped in time. Now I know its all my fault but:

The car does seem to let go surprisingly easily, so whats the most likely root cause? (Car is MY99 4dr, no mods, yet).

1. Tyres - Bridgestone Potenza RE10 (205R16 4mm tread i.e. 50% wear)
2. Suspension set up
3. Suspension design/components
4. Wheel size (16 inch)
5. Tracking
6. All of the above
7. ?

Any help/suggestions much appreciated.

O'h yehh, the damage:

Bent lower suspension arm
Knackered shock
Minor paintwork
Buckled wheel/damaged tyre

Grand total of £1000, no Christmas pressies for me
On the positive side, although the steering was a little bit out of alignment, the car was still solid as a rock at all speeds. Amazing 'cos I did hit the kerb bloody hard and almost square on!!

Paul.

[Edited by Wilster at Work - 12/9/2002 8:26:58 PM]

SiCotty

Some better tyres, I had the RE010 on mine when it was new and soon replaced them with SO2PP and now Goodyear F1 GDS2 which are much better. The RE010 are just such a pile of crap.

Oh and you should notice that at about 70% wear they tramline like F***

Si

[Edited by SiCotty - 12/9/2002 8:32:50 PM]

SiCotty

ROFLOL

(Roll On Floor Laugh Out Loud)

Si

[Edited by SiCotty - 12/9/2002 8:49:44 PM]

CrisPDuk

PS: One is always equipped the best Kevlar-Lined Flame Suit money can purchase

Editted because even the best pubic (sic) schools omit grammar these days

[Edited by CrisPDuk - 12/9/2002 9:35:16 PM]

LG John

And with a bit more luck onto the other side of the road and straight into the side of your car!!!!

[Edited by Saxo Boy - 12/9/2002 10:11:16 PM]

Wilster

Mr Evo, OK point taken; Next time I'm in town can I book some lessons please?!!

Now, if I've got Goodyear F1's on the front and Bridgestone RE10's on the back.......

Anyhow, when I dropped my car off for the repairs last week the salesman let me have a spin in a PPP'd MY00. Wot a hoot; makes a mad noise compared to the mellow std Scoob. When I pick mine up sometime this week (can't wait, miss it) they might let me go in the P1......

Ps. I've got a Fiat Cheapo as a courtesy car - now I've finally arrived home (note its "Wilster" now, not "Wilster at Work" clever huh?) guess what I managed to do as I breezed onto the wet A38? Yep, you guessed it, oversteer!! Whoop Whoop!!! Learning.

Paul.



[Edited by Wilster - 12/10/2002 12:37:38 AM]

roee

I find the real one to watch for it the front snapping back after oversteer! Picture this, your powering out of a damp turn and the backend steps out. You feed in the opposite lock and enjoy your sideways moment Then - I'm assuming diffs shift more power back to the front - the front end gets power with the front wheels pointing to the opposite side of the road and the car snaps back the other way and tries to catapult you off the other side of the road 4WD, tisk - not always a bed of roses

Well well well.
You have to LEARN driving AWD before you do such things, don't you?
Snapping back into line is one of AWD greatest features! That means that given enough road and engine power you almost can't make an AWD car spin, unlike a RWD.
To properly drift a AWD car you need to do the following:
1) Get into the corner, provoking the tail (trail braking would do, you can combine a nice flick if you're on gravel etc.)
2) Feed power (ideally use left foot braking to overcome the turbo lag, so you'll have instant power)
3) Back end is sliding under power? now straighten the front wheels completely and keep the power on. The front wheels will now have minimal understeer and will act as a nice pivot for the car to revolve around.
Generally, at this point more power = wider turn (drifting more), while easing off the throttle will make the corner line tighter.
You can add little opposite lock just to stop it from rotating around, but then straighten again to keep it drifting nicely and evenly.
4) Had enough fun? Now put on opposite lock, and just hold it using generous throttle - the car will gently straighten.

If you miss on step 3, all you get is a car going sideways a bit, and then jumping back to the other direction nervously. Which is nasty.

Saxo Boy, about the Noble - I guess that you just need to apply opposite lock and balance the car through the turn. Tricky, but fun.

About the understeer through roundabouts - To get a AWD car cornering neutrally without diff magic (eg. Suretracks) you need to provoke it into drifting. Again, trail braking, flicking, will all be useful for cornering effectively. Applying power won't solve anything by itself, you need to balance the car to oversteer before you do that.
Think of your tires as a bonus - crappy, low grip tires can make for wonderful practice sessions on airfields and such.
If you want to just stop the casual understeer, without turning each commute into a slide frenzy, just apply VERY GENTLE brake while turning, will help the fronts bite in. Too much brakes and you get more understeer (fronts locking). You can also feather them mid understeer, less effective than balancing the car pre-corner, but still good enough.

Hope that helps

[Edited by roee - 12/10/2002 10:12:21 AM]

MorayMackenzie

Saxo Boy,

Re: "I guess its like someone giving you 300bhp and saying only use 250bhp, it ain't easy "

Guess its also like suggesting that its a good idea to drive appropriately for the prevailing conditions.

Any car, F1 and WRC's included, can be made to understeer if you provoke it, the trick is not provoking it.

Moray

[Edited by MorayMackenzie - 12/10/2002 1:48:42 PM]

dhorwich

i did the same 2 months back and im still off the road, well gutted.... mine just kept understeering to i was not happy...

I snapped my wishbone and bent/broke my bumper, wing, suspension subframe, hub, 19" wheel..!!! and more..!!

I had nearly new pirelli p7000's

Dan

MarkO

You sure it wasn't fuel surge?

Wilster at Work

Mark, now I bow to your superior number of posts, experience etc etc but wouldn't that cause oversteer?

(OK this is a dig at Saxo, right?)




Ps. ROFLOL = ?

scooby_si

i'd ask whether uve had a play with the amount of throttle action thru the corner as if u lift off mid corner then u shud get a bit of oversteer? Tyres definately a factor in wet & while i cant say as i've herd of yers but i did have crappy dunlops on the original 15" & actually span it in an oversteer style when i lifted off under duress but set of toyos & 17" wheels eternally better in the wet stuff but anyway i still get understeer if i plough into a corner with foot down so it's important 2 no how the car handles dependant on the gas pedal application either way
just a fort as even if largely rubber dependant the right foot still a key factor
Si

Scooby555 2

I got it in the dry the other day
Could it be anything to do with a heavy right foot ????

And ..... I dont want to appear dumb .... BUT what is this fuel surge thing ??? And where can I buy some ???

LG John

You know, one day someone is going to push it too far on a corner with low fuel go backward through a hedge and then the jokes will all stop

The solution to your problem is simple my friend. Get the bumpsteer mod The bumpsteer mod and geometry settings to go with it cost me about £115 at falkland and is easily my favourite mod to date and also one of the cheapest (excluding dawes). Understeer is massively reduced and the car is far better balanced and more predictable. I did 70 miles of twisties today, c-class roads with some mega tight hair-pins. I came into one corner fairly quickly and realised it tightened so I turned in more. It tightened even more, so I turned in more and then it tightened again and I crapped my pants!! Most of fagotnet would claim I'd panic and lift off here but I put my faith in the old girl and maintained my speed and turned in some more and she held on I'll remeber that corner next time There is no doubt in my mind my car wouldn't have made it at the speed before bumpsteer and would have understeered to the otherside of the road potentially risking myself and others.

It really does make a massive difference IMO. As does good tyres as has already been suggested

Josh L

I live in MK, and don't really have any problems with understeer on the doughnuts. If you're ploughing through fast enough to understeer though the roundabout like that, it would have happened in anything. However, a bit of power as you feel the understeer, will often drag the nose round. As someone recently pointed out, 4WD cars only really corner when the wheels are under power.

A number of points though......

1. Make sure your geometry's correct (not just tracking)
2. For MK I'd always recommend at couple of extra pounds in the tyres.
3. Put some decent tyres on.
4 Always remember the cardinal rule of 'Slow in, Fast out'. Drop it down a cog on the entry.

Josh

CrisPDuk

I'm sorry chaps but every time you start talking about understeer I PMSL, If you are getting understeer on public roads in one of the best dynamically balanced production saloons available you are driving like a rock ape

Until you have hooned an XR4x4, which has tyres better suited to a 1.1 popular, and an engine over the front wheels that weighs more than a Scoobs entire driveline, you do not know what true terminal understeer is.

Your Scoob is a precision instrument, it must be respected & treated as such One must breeze gently into a corner, easing the hammer down prior to the apex thus giving it time to get it's house in order, before sliding broadside out of the exit making you look like a god

P1Fanatic

I had this the other day. Slightly damp small roundabout only in 2nd. Went to put the power down and woah understeer - the front just slid towards the kerb. I just eased up and luckily I avoided clipping my wheels on the kerb. Thing is Ive done that roundabout faster before and after that day. Running 1,500 mile old Toyos on the front.

Could possibly be a layer of grease or something slippery but Im not sure.

Think the bumpsteer will be one of my next mods as its got a lot of happy punters. Is it worth waiting until I get new tyres (will go for F1's all around next I think) before I get the bumpsteer done or not?

Simon.

astraboy

I was behind a bloke in a scoob at silverstone this year as he looned it into the bottow hairpin. the understeer was shocking. He was on almost full lock but still flying forward.
astraboy.

CrisPDuk

AB I hope you showed him th correct approach in the 3 door

LG John

In my experience doing this is an absolute lottery! Sometime I find the car will dump power to the rear with a little the front and you'll, as you say, pull the front round and be set up for power oversteer on the exit if you wish

HOWEVER!!!!

50% of the time I find the power stays up front and you spin the front wheels with the rears pushing you even more off track

Therefore, you can apply power and potentially sort it or equally make it 10 times worse. Unfortuantly, I just can't seem to figure out exactly what the car is going to do so I guess avoiding understeer in the first place is the way to go

CrisPDuk

And if you're really lucky the fool surge will bring the back round to compensate

LG John

BTW, I'd say my scooby can turn in at similar speeds to the VTS now with the bumpsteer and geometry. This is quite impressive given that extra weight of the scooby and the fact that relative to the cars weight the VTS has wider and more low profile rubber. Thank you boxer design

SCOSaltire

u should try it in the snow on normal tyres

i got major understeer @ 15 mph... was funny

another time i got oversteer at same speed

it seems the difference was the balance of the car before i turned...
when it understeered... i was *trying* to turn...
when it oversteered, it was a gradual turn at first.. then it settled a bit, and then i turned more and the back went out

both were not under power

its easy to do doughnuts on ice n snow... it it is easy... if the wheels are turned and power down... so guess its all to do with the rate of turn and lateral forces...

this is all imho and without warranty, on a std suspension uk turbo

hades

If you've gone into the corner too quick: Shut the throttle and ease off the lock to get the front gripping and induce some lift-off oversteer. When the back starts to come round re-apply the throttle/and or use opposite lock to stop the slide. Understeer solved! Don't try this out for the first time on a busy/tight roundabout though! And it's always better to not induce it to start with

Having driven a vauxhall for four years, a scoob doesn't have a lot of an idea about how to really understeer. The above technique - induce lift off oversteer, then hold it with the throttle - was the only way to make it corner quick.

Geometry, good tyres, bumpsteer etc will always help lots.

Puff The Magic Wagon!

iTrader: (2)

RE10s are notoriously cr@p, so bin them to start with....

Then get the Prodrive settings (see SIDC FAQ ) or the Bumpsteer Mod, which is the Prodrive settings + ickle shims in the steering to take out the slack & provide more feed-back.

That will make the car better in the roundabouts, but slow in fast out will make even more difference

LG John

Question: I remember top gear saying the Noble was near resistant to understeer and that if you chucked her into a corner with too much momentum the front would tuck in and the back would let go. I've been wondering!!! What do you do then? The back end is already coming round cause you've gone too fast so you can't use more power. If you back off the gas it'll change to lift-off oversteer but is still oversteer and you're still likely to spin and die! What do you do? Is this where the ejector seat comes in useful?

davyboy

How about slowing down when its damp/wet?

The best mod you can get and it's free!

Wilster at Work

He he

LOL Saxo

OK am getting the picture,

BTW F1's are on order already

Last thing I would do is attempt to accelerate out of it; therefore expert lessons are in order if I'm ever going to try that one. Its slow (breeze?) in, fast (slide?) out for now then Saxo.

Have investigated the "bumpsteer" mod further as there are some quite polarised views on this one. Seems it could all simply be down to having a top-dog mechanic eh? Seeing as Scoobs are undoubtedly ??

Hades, You're absolutely right, but I would have been upside down on the M1 before I got round to all that!!

Cheers,

Paul.

Ps.

PMSL = ?

LG John

PMSL = Pi$$ing Myself Laughing

P1Fanatic

SB & Wilster - know what u mean. Everyone says ooh power out of trouble - that is all well and good when you have room to drift wider but if your pride and joy is heading towards something hard the last thing you want to do is feed more power in. I just eased up and straightened the wheels a bit then prayed.

Simon