PsychomIKE wrote:Hmm ok Lauren, but can you comment on the castor adjustment at all
? Most people who change it seem to state they increase it to 6 degrees.
.
.
as though this maybe some sort of adjustment max
(no more thread to wind!)
is this the case? Just had a quick look for Laser track rental but no luck, know of anywhere this might be possible?
And one final thing
(i think;)) Have you ever tried using roll center adjusters? I've got the same springs as you had
(30 mm drop iirc) though im not sure these are needed until you start getting into the 2" area.
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Sorry for all the questions, just interested in hearing about it all
Cheers
Mike
With the castor you may be able to get more but you have to be realistic about how much pressure you want to put the lower arm mount under i guess.
6deg is really about the most you'd want.
steering gets heavier to turn at speed.
Don't think its worth putting roll centre adjusters on, particularly for a drop of 30mm.
I understand the logic behind it but you can still have a very well balanced car without them.
Coming back to the setup TRD settings are the best to go for IMO.
I tried a few different setups followed by some track time
(i did the geo adjustments with the car half in the back of bookatrack's artic!).
I even tried an elise setup with very slight 0.2mm toe-out but this wasn't as good as the 1.6mm toe-in as in the TRD set up.
I'm sorry i don't know where you can hire a laser tracker.
I borrow bookatrack's set when i do
geo setup, though i normally borrow their garage.
Changing the toe makes the biggest difference IMO.
If you want to know more read this, its a post i wrote last year when i did some testing:
I thought i'd pass on some stuff I found out from playing with the geo on track.
Have just got back from a very good weekend at Anglesey, had two days on track with today being a bit special as it was private so only had to share with 8 other cars.
Obviously this gave me the ideal opportunity to experiment a bit with setups and to try and build a picture of how the car handles on the limit.
I started off with what was a bit of an experimental setup I had been using.
Basically set front Toe to 0.2mm toe-out
(stock is 1mm toe-in) with the rear being 3.9mm toe-in
(stock is 5mm toe-in).
It should be remembered that stock is within 1mm of the setting so my setup wasn't miles different.
Camber was maxed out and is approximately 1.5deg neg on front and a little more on the rear.
Due to
'McCrapson' struts the camber isn't very well controlled and will tend to move toward positive camber as the strut compresses.
To some degree this is also evident with toe and particularly so on the rear when the track rod passes the horizontal less toe-in will be the result.
so as you can see the geommetry will affectively change both in toe and camber as the suspension compresses when cornering, so really the static settings are not necessarily where the suspension will be under load, but all you can do is try a static setting out and change it according to how the car feels.
I was concentrating on the toe settings as this seems to make the biggest differences.
Just to give some background the car is an SC running 195/50/15s
(Yoko Advan Neova LTS).
It has poly bushes and Koni shocks with Fensport 20% uprated 30mm lower springs.
Tyre pressures are: 24front and 30 rear
(cold).
Anyway onto the track stuff.
A lot of you know Anglesey from the fairly recent IMOC day.
I tend to use School Corner as a test for the handling as its very fast and quite long so you can feel the car load up, balance the throttle and get a really good feel for whats going on particularly so as theres a bit of change in elevation which tends to highlight the handling characteristics.
First few laps out and the car really felt like it was almost
'skipping' at the front so it just wouldn't turn-in cleanly and was really understeering quite badly.
The front would bite mid-corner but really you had to trust that it would because a slight lift in the middle of School corner always leads to some immediate lift-off oversteer purely as a result of weight transfer.
Obviously you can correct this
(as long as you are quick) but its not what you want to be doing really!
After a few more laps and an obvious increase in front tyre temperature it was better but still frustrating to feel that the car wasn't biting at the front end.
In the slower corners of the circuit the understeer wasn't too much of a problem as to some extent it was possible to drive around it.
However, though MK1s do tend to understeer
(its really a result of the chassis design as far as I can work out) minimising it is desirable for track work.
So day 2 and I was determined to have another crack at the geommetry.
I opted to try out pretty much the TRD settings, so set front toe to 1.6mm toe-in and at the moment have left the rear as it is at 3.9mm
(TRD is 3.2mm)toe-in.
So off I went and for the first couple of laps there was slight decrease in the understeer turning into School.
Though what became apparent that after 5 laps or so the front end did bite a lot better on turn-in and this really helped me carry more speed through the first third of School corner.
I would guess this is a result of the front tyres getting more heat into them due to the effect of having more toe-in.
Lap after lap it was just getting better and better and it was becoming really nice through the mid speed corners as it was simply a matter of steering on the throttle and getting the steering wheel completely straight way before the apex and just drifting the car through the apex with my right foot right to the exit and onto the straight.
This is what track driving is about and I have to say after a long absence of driving the car this year I reckon I fell in love with it all over again! It really is a lot of fun on track and this year i've been lucky enough to drive a lot of different cars
(Caterham Superlights, RX8s, Elises, Single seaters etc) but though these other cars impress in a lot of ways and are fun, I still think the MK1 is such a hoot on track and was easily enough to keep me entertained all day and is such a good challenge to drive quickly.
It has taken me a long time to get the car how I want it, but after a three years I think i've got there in terms of how it performs both down the straights and more importanly round the corners.
So i guess i'd be looking at a fast road setup with the occasional track day when funds allow.
