The Gazman
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Posts posted by The Gazman
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The reasoning is correct IMHO, who as a "responsible" manufacturer would want to be seen as producing fast turn in cars.
Not going to happen in this compensation culture society we live in.
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The Lance set-up will give you a nice safe understeer but if you want the car a bit more pointy without damaging tyres you might like to consider the following options.
1) What sort of ride height are you running and is the rear 10/15mm higher than the front?
2) To cure understeer and make the car more pointy consider the following.
Front
Caster=4.5 degrees
Camber=1.5 degrees neg
Toe= Parallel
Rear
Camber=1 degree neg
Toe= 3mm overall toe in
This should not have a detremental effect on tyres.
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The front springs are 65mm, i've height adjustable coilovers so length tolerances don't need to be exact.
The rears are taper spring, 70mm-100mm. Trust tein to be awkward. There's a group buy going on ksport inverted coilovers which works out cheaper than getting mine revalved so i'm not sure what to do currently, i'm trying to find out damping rates on them.
If you need to borrow an sw20 for testing you can have mine, i rarely use it!
I usually keep 65mm in 8", 9" and 10" at 325lb .
I will probably take up your offer of a borrow of the car
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Infact I notice from your website you offer springs. Can you provide me with the uprated front? Might as well keep it in the family and give you some feedback. Shame you don't offer a kit for the SW20, at those prices i'd imagine it would be quite popular.
I also notice your name probably isn't Gaz so sorry for earlier.
Funnily enough I have the OEM kit but I haven't got around to making a prototype.
I have just chased up the factory and told them to get a kit underway for spring launch.
I don't know exactly what length and dia you currently have on the car but I can get pre-stresses springs made to any spec in 10 days and stock about 1000.
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Righto. I'll go up to around 320 on the front and leave the rear as it is just to save cost and report back. I'll also redo my geometry to something close to the discussed settings with Tonys input.
I'll also be throwing on +20 section tyres front and back (eg 245 rear instead of 225), perhaps i'll save that mod so i can judge what's doing what. Nothing worse than bolting on X mods at once and not knowing what's helped.
Also, i don't mean to be rude but what's your background Gaz? Tony rates you and you came to some sensible geo settings very quickly so you obviously know your stuff, the next question is how?!
I front a company called Absolutely Shocks and we specialise in developing bespoke fast road and trackday kits and geo for popular sports cars.
Between my R&D and me(mostly him) we have 35 years experiance setting up everything from road rally to grasstrack, formula 3000 cars and saloon car racers. We don't know everything but we have a good all round knowledge of basic set-ups and track geo.
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Hi Gaz,
Funny you put that geo up, that's pretty much what i was moving to next (i currently run just about that toe but -2 camber front and -1.5 rear).
I agree the ratios are all wrong on the current setup but would you really recommend spring rates that low? Bearing in mind i run a really soft bar might something like 400front and 525rear make more sense for track only work?
When you say soft bar ar you talking standard, if so I would stick with our suggestions.
I also take it that we are taking fully adjustable Tein shocks with standard valving?
I would only run your existing camber on a front engined rear wheel drive car, we think you are right to move the other way.
I think the front will feel soft, you will be surprised what a difference 75lb on the front will make on such a light car.
We don't think you will have much compliance on the back with those current spring rates, we would run a bit lighter on the springs and turn the dampers up until we felt they were working properly, its possible you could be running on the springs with no control.
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Hi Gaz,
Funny you put that geo up, that's pretty much what i was moving to next (i currently run just about that toe but -2 camber front and -1.5 rear).
I agree the ratios are all wrong on the current setup but would you really recommend spring rates that low? Bearing in mind i run a really soft bar might something like 400front and 525rear make more sense for track only work?
When you say soft bar ar you talking standard, if so I would stick with our suggestions.
I also take it that we are taking fully adjustable Tein shocks with standard valving?
I would only run your existing camber on a front engined rear wheel drive car, we think you are right to move the other way.
I think the front will feel soft, you will be surprised what a difference 75lb on the front will make on such a light car.
We don't think you will have much compliance on the back with those current spring rates, we would run a bit lighter on the springs and turn the dampers up until we felt they were working properly, its possible you could be running on the springs with no control.
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Hi Gaz,
Funny you put that geo up, that's pretty much what i was moving to next (i currently run just about that toe but -2 camber front and -1.5 rear).
I agree the ratios are all wrong on the current setup but would you really recommend spring rates that low? Bearing in mind i run a really soft bar might something like 400front and 525rear make more sense for track only work?
When you say soft bar ar you talking standard, if so I would stick with our suggestions.
I also take it that we are taking fully adjustable Tein shocks with standard valving?
I would only run your existing camber on a front engined rear wheel drive car, we think you are right to move the other way.
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Hi again
I put this into the pot at the R&D meeting at the factory today and the general consensus was"too hard on the back and too soft on the front".
We recomend you try 300lb front and 375lb rear.
On a trackday car we would start at the following geo (just as a point of interest)
Front
Caster=4 degrees
Camber= 1.5 neg
Toe= parallel
Rear
Camber=2 degrees neg
Toe= 1.5 per wheel
After testing we might run a tad more toe in on the rear and maybe a tad more neg camber on the front, we would be looking to provoke a tiny little bit of understeer.
All IOHO
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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.
Testing
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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.
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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
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.
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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
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?
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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
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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
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Hi
I haven't had a play with an MR2 yet but my initial thoughts are that uprating springs is a much more controlled way of stiffening up the front end than arbs, your front springs sound a bit soft to me.
Tein do tend to run harder valving and softer springs which do work well on road cars but come unstuck as soon as you really start to push them, Nitron and Ohlins also have the same problem.
I favour a more agressive geo and pumping up tyres to stop the fronts rolling over and I will have a think about this and pass on my ideas to Tony next week.
By design all domestic cars under-steer!
in Geometry
Posted
Yep
but we are quite often talking about cars specifically designed for the US market and we seem to follow their geo settings.