zilspeed
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| posted on 7/5/05 at 02:38 PM |
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Geometry
Having been through the mill somewhat recently it has become increasingly apparent to me how important it is to have all four wheels pointing in the
right direction.
As it came to me, the GTM had an alarming tendency to be extremely tail happy when turning left. Turning right was fine, but turning left was scary on
the limit.
I didn't realise this to start with. The car was an unfamiliar layout to me and I wanted to slowly creep up on it's limits, not just jump
right off the edge of the cliff.
In the last week I have learnt that as well as positive camber on the OSR it also had toe out on the same wheel. So every time I wanted to turn left
at any sort of speed at all, that wheel wanted to go straight on.
I have now rectified both problems and it is difficult to put into words how much of a difference this has had on the car. It is now equally benign
whether going left or right.
This all sort of got me thinking. All these MK Indys with fully adjustable rear alignment and camber. How do you all go about this ?
Are there any other evil handling cars out there that would benefit from a look at with a string line, a home made camber gauge and a flat surface ?
I reckon that todays adjustments will have easily bought me a couple of seconds at Kames sprint track.
All for free.
I could have chucked a couple of grand at a new engine and not gone any quicker.
Any thoughts, anyone ?
[Edited on 7/5/05 by zilspeed]
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Peteff
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| posted on 7/5/05 at 03:54 PM |
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Spend the money you've saved on the engine now  .
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Mark Allanson
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| posted on 7/5/05 at 04:01 PM |
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I used to run X19's, a similar layout, and used shed loads of toe in at the rear to keep things nice and tidy, although you could still force
the back out if the need overcame you
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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zilspeed
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| posted on 7/5/05 at 04:01 PM |
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What money - the hypothetical money that I would spend in an ideal world ?
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Volvorsport
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| posted on 7/5/05 at 04:17 PM |
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the best compromise we found on track darrians , was about 1 degree negative camber with about 3mm toe in.
we did have big slicks tho and it was semi trailing we were using , so you might want to discover what actually happens during , bump, rebound etc
with varying amounts of toe and camber .
you may find the wheels will toe out further the more bump and roll you have , or vice versa .
get a copy of mitchell software , or the 'string' computer to give you an idea of whats going on .
www.dbsmotorsport.co.uk
getting dirty under a bus
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zilspeed
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| posted on 7/5/05 at 05:02 PM |
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I've done a 'wee' bit of that so far.
The camber goes negative in rebound and obviously positive in bump.
I've been thinking in relation to that : The advice I was given by a.n. Other to lower ride height to get rid of the positive was in fact
completely wrong.
I do want to keep the car supple, don't want to have to limit travel just to try to control camber change 
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Volvorsport
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| posted on 7/5/05 at 05:24 PM |
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really ?
so this is with the metro front suspension at the rear ?
should be the same as the front in geometry terms ?
if not a wishbone relocation may be needed!!!!!!!
www.dbsmotorsport.co.uk
getting dirty under a bus
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zilspeed
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| posted on 7/5/05 at 05:42 PM |
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Exactly the same as the front, yes.
That's why I think I need to start off with a fair degree of static -ve camber at normal ride height. So that it goes into neutral at worst
when loaded at the outside. This was how metro cup racers did it.
I'm learning 
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britishtrident
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| posted on 7/5/05 at 05:55 PM |
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First thing is to try and get some measurements of the wishbones and heights of the pivots and ball joints.
Re your earlier mismatched ball joint it seems that the balljoint used on the late Metro/Rover100 suspension varies with tyre size --- I presume
because of ride height and camber angle issues.
155 tyres
Track rod end QR2381
bottom ball joint QSJ1147
185 tyres
Track rod en QR2382
bottom balljoint left QSJ1146S
bottom ball joint right QSJ1148S
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