StanS

iTrader: (3)

I am running Prodrive-ish geometry (1 deg neg on front + 1mm toe in F+R) on UK98 5 door. Had it done before I knew about bumpsteer. Will I notice any improvement getting the bumpsteer mod done - would it be worth another £100 ?? Anyone done a comparison ?
Cheers
Stan

[This message has been edited by StanS (edited 08 October 2000).]

DocJock

Stan

I went from Prodrive settings on UK97 5dr to PS settings + bumpsteer removal. IMHO it is the best £100 I have ever spent on a car.
I believe most people with the mod agree.

DJ

sickboy

Can someone enlighten me as to what bumpsteer is (have a vague understanding) and how one goes abou removing it?

DocJock

When the front springs are in compression the toe-out increases, in rebound the opposite occurs (toe-in)

Take a right hand corner as an example;
front left is in compression and toe out increases ie wheel tends to point more to outside of the corner. Front right is in rebound and tends to toe-in ie wheel tends to point more to outside of corner.
Both wheels are tending to point more to left than steering input = understeer.
Obviously it is not as simple as this but you get the idea I hope.

Adjusting the position of the steering rack so that the track rods are horizontal at rest removes the bumpsteer. My car has zero change in toe with two of us compressing the front springs, same with us lifting.

DJ

SDB

Hi sickboy...

Go to

psyg

Simon,

Within a copple of weeks I come to the UK for the bumpsteer-removal (and to Mira );

question: after the b.s.-rem, is there some effect on driving with very high speed? The car f.e. a bit more nervous?
(every week I drive on german Autobahn with 145-155 mph )

grt Geert

SDB

Hi

At High speed the front end feels much more planted. Whilst in a straight line, the car is much more stable.

The only problem that would occur would be if you started wiggling the steering left and right (for some strange reason ), because the front end would react much more positively.

Cheers

Simon

James_Harvey

How does the bump steer mod sit with uprated suspension? I have Eibach Springs / Koni Shocks.


James.

Stef

Most of you know how happy I am with my bump-steer mod (if you've forgotten, look at

SDB

Stef

I was reflecting this morning (on the bog! - sorry, but it's true) on driving your car round MIRA yesterday...

I have to say (although I took it really easy and only did a couple of laps) it was probably one of the most fun cars I've driven round there.

The tyres made it VERY slow, but the handling was really nice.

I would guess it would be really quick round there on S02s, but there is no way of being totally sure.

The main thing is, the set-up is incredibly driveable.

Cheers

Simon

Stef

Thanks mate!
As I already said, I've just stuck those part-worn RE010's on for the 'Ring and Brands. It'll be back to Toyo's when I get my new wheels, then we'll have to go again.

Stef.

Robb

Getting my bump steer sorted by Powerstation on Saturday - can't wait!!! If that doesn't sort out the understeer I'll disconnect the drive from the front wheels and go back to having a RWD car (now there's a thought - anyone ever driven a Scooby with RWD only?)

Cheers

Rob

simo

Stef

What wheels are you getting?

simon

StanS

iTrader: (3)

Thanks very much for all the info. I much prefer a very positive front end (if you know what I mean) so I wish I'd heard of this before spending the £*** at Elite for Prodrive settings - which did make the front a lot more +.
Still - older and wiser !
Cheers.
Stan

Stef

Simon.
I have just bought a set of second-hand 17" wheels for £100, with tyres!!!
They are in great nick, but I'm having them powder-coated a different colour as we speak.
As for the style.....they'll be on for Brands.

Stef.

Trout

iTrader: (1)

Stan,

was out on a very, very wet Castle Combe yesterday (more suited to a U-boat)

One of my passengers was a guy who had punted Formula Ford and Zetec cars around there. His comment - unprompted - was that he thought the front end grip was 'incredible'.

I had Prodrive settings and the anti-lift kit - and moved to PS Bumpsteer/Anti-lift. Tyres were S-02s - the car gripped like glue. Only a Skyline was faster which is a combination of bigger cahonas and some electronics!

Experience would suggest the PS Bumpsteer mod provides real clarity in steering AND provides awesome front end grip for a four wheel drive car.

R

PS Stef you would have been proud - there was a Cossie there - I passed him!

PPS I also passed a Ferrari 550 Maranello driven by Pete Gethin (ex-F1) - but I guess he can't of been trying - all THREE times

PPPS By late afternoon the Evo VI driver had learned how to exploit his AYC and so he was faster

[This message has been edited by Rannoch (edited 10 October 2000).]

JamieR

Can I ask a newbie question here?

I read up on bump-steer on

SDB

Hi Jamie

You've mis-understood mate. It may be how I've written it, I'll review...

The bump-steer does not reduce steering, it effectively make the wheels toe-out (meaning the left one points left and the right one points right).

This effect is increased the further you compress the suspension.

To compensate for the prodrive, set the front geometry to a toe-in position so that the fronts are *more* parallel when braking.

This can only be a rough improvement though as the wheels will only be parallel at a certain suspension postition.

What the Powerstation bump steer removal set-up does is set the fronts to parallel and remove the bump-steer so that they stay parallel the whole time, no matter what the suspension does.

Cheers

Simon

PeteT

is this mod a Power Station exclusive or does anywhere else do it? (i.e. north of Watford?)

Scott J Davies

Currently running Prodrive Geom its Ok wasn't as a dramtic effect that I was hoping for. Changing to the Bumpsteer on the 24th just before Brands

I'll let you know what its like if you are there.

gregh

Does the bumpsteer mod ever need repeating, ie can it dial itself out?

Also can the dealer **** it all up at a service etc?


and lastly where are Powerstation?

greg

StanS

iTrader: (3)

Thanks Rannoch and all.
Have booked in at PS on 21st.
I thought the Prodrive settings made a great improvement so I can't wait to drive it with the bumpsteer corrective surgery.
(Car has Eibachs but std shocks, 17's + SO2's).
Stan

[This message has been edited by StanS (edited 10 October 2000).]

RichS

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by Simon de Banke:
<B>Hi Jamie

You've mis-understood mate. It may be how I've written it, I'll review...

The bump-steer does not reduce steering, it effectively make the wheels toe-out (meaning the left one points left and the right one points right).

This effect is increased the further you compress the suspension.

To compensate for the prodrive, set the front geometry to a toe-in position so that the fronts are *more* parallel when braking.

This can only be a rough improvement though as the wheels will only be parallel at a certain suspension postition.

What the Powerstation bump steer removal set-up does is set the fronts to parallel and remove the bump-steer so that they stay parallel the whole time, no matter what the suspension does.

Cheers

Simon[/quote]

Simon

Am I to understand then that the wheels remain parallel even when turning?

Surely this will create excessive tyre wear?

Rich

SDB

Rich

no ackerman (sp?) angles are not neutralised, but...

whithout this set-up, the ackerman angles change depending on the load on the wheels.

Think of it this way....

Without the bump-steer set-up....

Turning right, the left suspension will be compresses and right extended...

This means that the left wheel will be pointing slightly more left than it would if the suspension was less compressed and the right wheel will be pointing slightly more right than it would if the suspension was less extended...

When you go over a bump as you are cornering, the suspension compresses an extra amount quickly, this will again throw the geomtery out the window as the wheel that hit the bump will toe out as it compresses the suspension.

There is no way a competition car could be driving on the limit consitently with bump-steer (IMHO).

Cheers

Simon

gregh

Call me stupid, but I can't find ANY info about this mod on the Powerstation web site, so my questions above still stand

Greg

IWatkins

Greg,

I'm working on updating their website at the moment.

To answer your questions:

1) No, it will not dial itself out, but the geometry changes made at the same time can be dialled out by hitting kerbs, bricks etc.

2) Again your dealer could mess the geometry changes up, without a doubt, but the hardwired changes would require major surgery to mess up.

3) Powerstation are in Cheltenham.

Advice, talk to Powerstation about this mod. if you want further info.

Cheers

Ian

[Edited for a zillion typos]

[This message has been edited by IWatkins (edited 11 October 2000).]

Airmiles

Simon, Stef,

I checked the driving techniques website, and they had this to say:

"Almost all 4WD cars are prone to ‘lift-off oversteer’. When you lift off the throttle or brake, you load up the front tyres with weight and therefore grip and take the same away from the back tyres. If you are turning at the same time, the chance of oversteer is very high. Subaru must have taken a decision that the majority of drivers can cope with understeer more than oversteer (which is very true), and in the interest of safety spend time and money tuning out the majority of the ‘bite’ of lift-off oversteer by playing with the bump-steer settings."

So, is this neccessarily such a wise move to make? Does it make LOOS worse? What are your experiences? What's the impact of Prodrive settings on LOOS?

Not that I'm paranoid (much)

Ta
Airmiles

SDB

Hi Airmiles

The word "worse" is a subjective one...

In my view, making a standard subaru's lift off oversteer "worse" would be to make it oversteer LESS.

I assume you mean, "make it increase"...

Understeer is the bain of the life of a skilled driver. Lift-off-oversteer and also Trail-braking (which just has a greater effect than lift-off-oversteer) are the two most powerful tools in the AWD armoury of handling. Without them (if that were possible) they would be the most undriveable cars on the planet.

As I have always said, the bump-steer removal is not for everyone. If you are not fairly skilled behind the wheel, but like to push beyond your abilities anyway, then it is undoubtedly not the set-up for you, but...

If you ARE skilled, or just don't push beyond your abilities, it will (IMHO) improve the handling no end, by providing more bite to the front end. This will inherrantly (sp?) mean more oversteer or less understeer. In my book, this is GOOD as scoobs suffer terribly from understeer in standard trim.

*off topic slightly*
It is important to note also though, that a skilled driver will VERY rarely encounter big understeer, unless experimenting. The reason for this is that understeer is almost always driver error. The reason for THIS is that a good driver will drive within the limits of the car, and if the car understeers a lot, he should do something about it (drive around it or slow down).

*back on topic*
The best thing to do, is go to powerstation and tell them how you want your car to handle. They can then make suggestions to find the best compromise for you.

Cheers

Simon

PS. The prodrive settings increase lift-off oversteer also. Just not as *consistenly* as bump-steer removal.

[This message has been edited by Simon de Banke (edited 11 October 2000).]

Triggaaar

Simon,
Since we're discussing understeer - have you had much experience of the anti lift kit (eg at Mira)?
While the bump steer mod does wonders for the scoob under breaking, on turn in, it hasn't done enough (MHO etc) to reduce understeer when on the power. So... is it worth getting the anti lift kit as well as having the bump steer mod?