It's been a long time, but hopefully worth the wait!

This is where I want to track the changes to the setup of the car, and more important, why the changes are made and what effect they had!

I think it's important to say that this car is a regular track and drift car - normally these set-ups are quite contradictory.. so this could be a bit of a challenge!

But first an introduction to the car...

This is the roadster in question, a 1992 Mk1 1.6



As you can see its not quite standard, so here are the important mods (trust me, there are many more!)
Aragosta coilovers - 10kg/mm FR, 8kg/mm RR
extended strut towers
Racing Beat antiroll bars
16x6j wheels, equiped with 205/45 Falken FK451s
Suspected Cusco 1.5way diff
Full Roll Cage
And Supercharged...

other things of note - no power steering, and extended final drive

The set-up I started with was as follows (nothing too extreme here)

LEFT / RIGHT / Average
FR Toe :2.1mm / -1.8mm / 0.15mm
FR Camber :-1.85deg / -1.6deg / -1.77deg
Castor :3.56deg / 3.72deg / 3.64deg

RR Toe :1.2mm / 4.1mm / 2.65mm
RR Camber :-2deg / -1.5 / -1.75deg

Comments...
So virtually parallel toe at the front, a healthy amount of toe in at the rear for stability.
Camber was surprisingly even (on average).
and Castor is pretty average.
One thing I wish I had measured was ride hieght... Looking at these numbers the odd thing that stands out is the LH/RH offset. It makes me think that with a driver in the car the numbers would be almost equal! (I might start a separate post about this one - it could be a whole can of worms

This setup had mild amount of understeer, and handling was fairly predictable.
However when drifting I found myself without enough lock! so this was something I wanted to change.

After chatting with Tony, this is what we opted for as a baseline set-up for future development.

LEFT / RIGHT / Average
FR Toe: 0mm / 0mm / 0mm
FR Camber: -2.3deg / -2.3deg / -2.3deg
Castor: 3.0deg / 3.0deg / 3.0

RR Toe: 1.0mm / 1.0mm / 1.0mm
RR Camber: -1.0deg / -1.0deg / -1.0deg

Comments...
Toe & Camber set up to make the car more neutral and balanced
Castor was taken out to increase Toe-out on turn, to give me that little bit extra lock. Also had the bonus effect of making the steering lighter.

So how did it go?

On track - The car handled beautifully through medium/high speed corners, going from neutral in medium speed corners to gentle O/S through high speed corners (maybe not ideal for everyone, but great for me Oversteer could be easily induced with an 'assertive' turn in. The down side was a lot of understeer through slower corners, I had to be quite agressive on entry to counteract the U/S. My theory here is that the loss of castor has had quite an effect on castor jacking, i.e the tendancy of the inside rear wheel to lift off the ground. At lower speeds with less weight transfer, the rear wheels are more evenly loaded - combine this with my aggressive diff, and the net efect is more 'push' from the rear wheels, leading to U/S!!

On Drift - Once I'd sussed out some reasonable tyre pressures, the car was very well balanced, and easy to both initiate and hold a drift... However in transitions, it wouldn't wind itself from lock to lock quick enough - leading to some pretty embarassing spins. Also any extra lock from the TOOT effect had little noticable effect.

So what next?

Well, firstly I need to out some castor back in, and find another way of adding extra lock. Captain Sideways - who used to run a Drifty MX5 has given me some cunning rack mods to try out, so I'll get them done and then go for maximum castor for know - I subscribe to the motorsport theory of only changing one thing at a time to appreciate the effect it has!

Tony, I'll be back in to see you soon, and then I'll be back here to let you know how it goes.

If any one has any comments, then please throw them in for consideration!

First thing I must say is surely the pic you have posted of your car is a Mk2 not a Mk1

I'll dig out what my settings are as I found that on track & road the car is really holding itself down well & even at high speed there is no lightness of the front as there usually is, but it just takes a quick power on/off to initiate the start of a drift when you want it

Keep getting the tips from Declan (Cpt Sideways) too....but start sharing them

Don't let the lights fool you! its definately a MK1! (unless you know of any MK2s built in 1992?

It'll be cool to find out your settings... I find that the back comes around easy enough at speed without lifting off - in fact I'm being quite gentle on the throttle application to stop the back coming around too much (except when drifting of course!)

I also find that tyre pressures are really important too. I run 30/32psi FR/RR when set hot. This makes the car neutral on the road, but on the track when the temps get up it becomes nicely oversteery!

LOL Yes I did see you had put '92 (mines a '93) just that I have never seen a Mk1 with a Mk2 front before

I'll dig out the settings when I get home

DAZZASPEED..... Your situation is complicated to say the least since you combine two challenging Motors ports with one set-up. The positions could only ever be partially successful within sections of the requirements.

Your Castor position as you say requires much thought at high speed, but a blessing on a drift lock... The over-steer corner off for some is an absolute requirement, jon here in wim would beat me up if i dialed this out of his set-up ..... I'm looking forward for you to come back in..... Lets explore that Castor position.... and the toe

LOL Tony how did your post get there ??

Right settings as follows

Front: Rear:
Toe: L & R: 0.8mm = total toe 1.6mm L: 0.9mm R: 1.0 total toe = 1.6mm
Camber: L: -0deg 31' R= -0deg 34' L: -1deg 48' R: -1deg 45'
Cross Camber: 0deg 04' -03 deg 03'
Caster: L: 5deg 04' R= 5deg 03' --------
Cross Caster: 0deg 01' --------
King pin: L: 10deg 11' R: 10deg 57' --------
Includ angle: L: 9deg 40' R: 10deg 23' ----------
Thrust angle: -------------------- 0deg 01'

Interesting you are running on 30/32 psi is that for drift too ?
I'm finding I need 36/8 to really get anywhere but then I am running 1.6 n/a so haven't got the power that you have

Just missed out on the double post

Are you running the same toe in front and rear? does that give you mild understeer or still quite balanced?

Also you're running almost the opposite to me on camber, far more on the rear than the front. I must admit I've seen quite a few Roadsters running camber like this... whats the reasoning behind this? is it something unique to roadsters/5's or a set-up trick I'm missing out on? hmm, this is making my head hurt

As for tyre pressures, I was running 32/34 on track, but settled on 30/32 for drift (as the rears were overheating and giving up all the grip, so I dropped them by 2 to get some grip back). I'm going to try this next time I'm on track and see how it goes, hopefully when I get the castor back to near what you're running it'll help prevent it from becoming dangerously tail happy!

I guess is also depends on tyre width and profile hieght. I might be wrong, but lower profile tyres need less pressure to achieve good wall stiffness - what size wheels/tyres are you running?

I think I could quite happily live without Lift-off oversteer - why on earth would you want to lift mid corner anyway? thats just slow I need to play with the rack first and try a few things out - and then on with the Castor!

LOL your head hurts....mines starting - I'm having to think

mild understeer, but I hardly notice any difference from before


You will have to ask Tony about that one, I originally had stock settings all round and then fitted
-45mm springs which completely changed the rear camber which felt good & planted, so Tony worked with that, & all I can say is that its 10x better than stock


Possibly - I'm not too up on tyres Running on 185/65/14's so dinky toys

DAZZASPEED actual comparisons are not wise... read this thread.
http://www.wheels-inmotion.co.uk/forum/ind...p?showtopic=181
Small changes mechanically or within the chassis will conclude very different set-ups.... Also janey's current set-up is for the ring, look at the Castor position, and deliberately i set the car to under-steer.

Currently janey is mastering the art of Drifting, should this continue the we will need to manufacture the cars abilities Geometrically to suit.

That explains a lot - my head hurts less now

Good ..... If your head hurts because things are difficult to read then i have failed A Geometry forum could could never be easy reading but it needs to be easy to understand.....

Some further set-up tweeks (courtesy of Tony):

Front Castor changed from 3.0 degrees to 4.0 degrees. Camber and toe unchanged.

The intention was to leave the Rear unchanged, but a few tweeks were needed to remove an unwanted rear thrust angle!

So rear camber changed from -1.0 to -1.5 degrees (both sides equal)
Rear toe changed from -1mm to 0 (parallel).

So the new setup is…..
LEFT / RIGHT / Average
FR Toe: 0mm / 0mm / 0mm
FR Camber: -2.3deg / -2.3deg / -2.3deg
Castor: 4.0deg / 4.0deg / 4.0

RR Toe: 0.0mm / 0.0mm / 0.0mm
RR Camber: -1.5deg / -1.5deg / -1.5deg

Toe could have been preserved at the cost of camber, but it was decied to minimise any change to camber. Its also worth noting out that due to how low the car is, I'm now running minimum camber and maximum toe out at the rear as allowed for in the standard adjustments (eek!).

Tyre pressures were set to 32FR / 34RR hot (as before).

The first things I noticed was how much easier transitions are - the increased castor really coming into effect helping the car steer itself quickly and easily.

However the car seemed to grip up mid drift and switch into understeer, making the longer 180+ degree corners quite difficult.

A play with the pressures: 30FR / 34RR hot, sorted that out.

The initial breakaway was still very easy and controllable, (I guess due to the reduction in toe) and then when the camber kicked in I had more grip through the drift.

Slowly I got the hang of the increased mid drfit grip levels and it allowed me get back on the power earlier - previously I was waiting to see if I span out on the entry before bringing the power in, but now it was a much more fluid slide.

Interestingly, I've checked out photos from the day (thanks to dori-stars.com!) and you can see that the outside rear wheel is vertical mid drift - confirming the above theory.

All in all an improvement - for drifting..., but I think the tendancy to oversteer might make very difficult to drive safely on track. Right at this moment I'm thinking I might have to develop a separate track setup for the rear wheels. I'll see how it goes….

Next steps...
eccentric poly bushes (to give a bit more room to play around with the settings, especially rear toe and camber)
Steering rack mods are almost ready to go on.
See if there is any way to increase the castor even more!

I am reasonably happy with your feed-back for those positions, as you know the toe positions concerned me but this concern needed to be tested by the driver.. i feel we can now act on those positions and generate a better 'mid' compromise.... the under-steer if so detectable needs aggressive action from us.

Hi
I have yet to get the heat gun and tyre probe on the 5's but my trackday set-up is veering towards yours.
Front
Caster=4.5degrees
Camber=2degrees neg
Toe= parallel (toe out .75mm wet)
Rear
Camber=1 degree neg
Toe= 3mm overall toe in

Ride height and rear damper settings are critical on this set-up, 10/15mm higher on the back and loads of rebound required on the dampers, oh yes and getting hot tyres up to about 38psi is good

One more thing, If I go to the Brands indy circuit, I put even more camber on the front 3 degrees or so, unfortunately the Max 5 rules state max 2 degrees on the front so the race car will understeer on druids etc

Can you define the 38psi and why it's good?... Is it pneumatic slip? http://www.wheels-inmotion.co.uk/forum/ind...p?showtopic=572

With these soft walled tyres that everybody favours these days they do tend to roll over if under inflated and we have found that higher hot pressures of around 36/38 work better on track

What steps have you taken to address the under-steer. By this i mean it's quite easy to develop over-steer elsewhere Geometrically to assist the corner, or do you feel the corner benefits will belay the straight line gains?

We have put preload on the offside rear damper but with rule limitations on front camber on the race cars we may have to look at another solution like caster perhaps, probably have to wait for weather to dry up and get some heat in the tyres so we can see what the tyre probe and heat gun say. Might be an interesting day Tony, fancy comming down?

Yes, when is it?..The future me should be free to be involved in this sort of experience. Is this the test day you was talking about or a track day....

This will be a test day for a couple of race MX-5's and 2 or 3 TVR race cars that run on Gaz. Good time to meet Dave Lyon my track guru and R&D man who has set up just about everything on the track scene over the last 35 years.

Yep i'm up for that.. Learning is something i enjoy... Hopefully Mark@wim and Sam@tdi could attend as well?

You are all more than welcome Tony, I have a list of people as long as your arm who want to attend these clinics but I have to get the race cars prepped before calling in the trackday stars.

What is the exact principle of the event.... Are we talking a training day? testing day? or something else? I am extremely keen to advance my knowledge regarding suspension and the track but i need to know the format.

Testing

Excellent....