Rum*

Arron, have you had the bump steer sorted?

If so, hows it handling?

and what was the final cost?

cheers Tom

ARRON BIRD

Tomorrow Tom(Tuesday)
PS Can you sort out some trackday cover for my mates Skyline?
How much?
PPS Have you got the PIAA`s yet and if so what do u think?

PhilHulse

Aaron, Tom,
Hi guys How the P1.s going? What the heck is Bump Steer? How much did you pay for the Prodrive backbox and is it really that good? Been offered a new Scoobysport box but based on what I've heard the Prodrive is s**t hot. The standard P1 box(STi) is too darned quiet

Cheers

Phil

Rum*

Aaron,

Will look into trackday cover - tho I think cheaper via specialist broker. I will try and speak tomorrow.

Please advise when bump steer sorted...I am interested!

Re the PIAA's - bought them...fitting tomorrow (Tuesday) - Graham Goode....real Goode ...very helpful, informative etc. Will try them before upgrading the spots.

Phil, P1 is fine, going really well thanks. The prodrive backbox is excellent - tho I have heard equally good reports for the Scoobysport. I think the Scoobsport box is £50 cheaper...tho can't be sure.

Anything is better than the standard one.

Phil, I think you know what I'm chasing - any joy yet??? Will no doubt speak later in the week.

Night night...

Tom

Rum*

Phil,

Sorry - Prodrive back box is meant to be £350.00 incl VAT I believe.

Cheers Tom

PhilHulse

So what's this Bump steer then? or is another bum steer (sorry)

Tom check your E-Mail

Phil

Rum*

Phil....I take it you mean my work email ....

and not the one I'm on now. If so I will see it in the morning.

Cheers

Bum(p) Steer - well I'm still learning...will mail something to you tomorrow.

All the best - Tom

Hos

iTrader: (1)

lol i'm nowinterested in what bump steer is after seeing 2 threads about it ,but no one knows? what is it?
Ian

Stef

OK, in the absence of any techie replies, I will try to explain what I know....
Bump-steer is the movement that the front wheels go through whilst undergoing normal driving conditions. For example, when you brake, the wheels both want to toe-out due to the extra weight transfer. This makes the car more stable in extreme conditions, and so is what most manufacturers put into their cars as standard.
Likewise when you turn, the wheel on the outside of the car naturally wants to turn the opposite way, and does so to some degree. In other words, there is a degree of movement in the wheels that is supposedly there to offer a safety margin under certain conditions. By removing this feature, the front wheels will always point in the direction you want them too, regardless of what the car is doing at the time. It makes a HUGE difference to the way the car responds to your actions. As you can see at

IWatkins

Stef,

So much easier to understand in those terms

Hos, Phil,

Much longer, more technical (but no more valuable explanation) see:

Hos

iTrader: (1)

Stef, Iwatkins..
Thankyou very much

ARRON BIRD

Much better now.
Car responds crisper to turn in and all I need now is the original STI rack and I`ll be happy.
Power on PS dyno with backbox 258bhp.
Make of it what you will.
Car not run in especially easy and 2100 miles.
ALWAYS 97 RON fuel

[This message has been edited by ARRON BIRD (edited 15 August 2000).]

Stef

Aaron.

Haven't you got a P1??
If so, what was PS's explanation for the low figures? Temperature?

Stef.

ARRON BIRD

I dunno Stef sure feels pretty quick!
To be honest I`m not too bothered with pub bull**** power figures.
Much more interested to see the power curve etc.
Handling is better now.....not perfect.......but better.
Tyres next when these are shagged so any recommends greatly recieved.
Can I go 215/40 next time?
I did on my 5door and it seemed better?

Stef

Aaron.
Hmmm...I guess you're right. Just seems low that's all. I went out in a P1 with Dave Clarke (racing driver) today, and he actually thought it felt slower than an STi.
Regarding tyres, I believe Pirelli are the only company to make 215/45 tyres so it will be OK to switch to 215/40's. TOYO Proxes T1-s and Bridgestone SO2's seem to be the favourites, with the TOYO's being more preogressive and cheaper!
Call Mark at TYRES NORTHAMPTON on 01604 588599 for a good deal.
Gives you an excuse to drive up the B645 as well!

Stef.

Geoff M

My two penn'orth of theory on the original title of this thread - bump steer. I know it as the effect of vertical wheel movement on the steering angle while turning. If the design geometry is not correct, as the wheel moves up and down (ie over bumps!!) it changes its steering angle without any change in steering wheel position. This means that a bump in mid corner can make the car move off line without any loss of grip, simply by the road wheel turning in a different direction. It's usually when the length of the tie rod from the steering rack universal joint to the wheel hub is different to the lower suspension control arm, or the pivot points are in different planes. Then when the hub moves up and down in an arc defined by the radius of the lower control arm, the corresponding movement in the steering arm describes a different arc, changing the relationship between the outer ends of the control arm and steering arm, thus pivoting the hub. I don't think there's much you can do with wheel alignment to fix this. It's a design issue to do with the relative vertical location of the inner pivots and outer pivots. If the two arms are similar in length and move in parrallel arcs, it won't be a problem. Also variable because the amount of lock wound on will move the inner pivot point of the steering arm, while the lower control arm pivot point stays fixed.

jwhitton

Ahmed Bayjoo modified my RS Turbo to reduce the bump steer by moving the steering rack.
Cannot remember if the rack was raised or lowered.

How is the Scooby bump steer modified?

jon

Stef

Jon.
It is modified the same way. I believe they shim the rack up, or is it down? Oh, well it works whichever way!

Stef.

psyg

After reading sometime about the bump-steer adjustment I'm very interested in it.
Overhere in Holland, till now, I didn’t find a place that have experience with it.
Though before comin’ to the UK & Powerstation to have done it, I/we have some questions:

* the b-s adj, is it just for once (not like 'normal' geo-adj., that you have to re-adjust after a period of driving)?
* is the adj a problem, when the car has Whiteline swaybars & AntiLiftKit, and is 30 mm front-lowered?
* when in the future the car get’s some other suspension-adjustments (for example Leda or other springs or dampers, or removal of the ALK) the b-s adj must be done again?
* somebody knows which geo-settings (camber & toe) goes together with the bump-steer adjustment?

Thanks for replying!

grt Geert
Holland

DocJock

psyg,

Under normal circumstances it is a one time adjustment as long as you dont change the ride height of the car afterwards. there are also guys running cars with ALK fitted.
It is tailored the each car individually so your suspension mods should be no problem.

I know it would be an expensive trip for you but IMHO it really is so good that you would find it worth it.

Geometry on my printout reads;
Front-camber = -0~45' total toe = 0
Rear -camber = -1~14' total toe = 0

Hope it helps

DJ