M12 Rear anti roll-bar to help rear STICK to tarmac:-)?

[georgeo]

I'am trying to make the rear end stick to the tarmac a bit better as it can be skitish, so just thinking about fitting a rear anti roll-bar. Has anyone already done this? If so does it make much difference and where did you obtain it from OR did you make it? OR has anyone a spare?

[chillidog]

Have you tried adjusting the rear wing? It's easiest to try this first.
--
Richard

[ThatPhilBrettGuy]

If we're talking about road driving it's just going to make things worse.

[georgeo]

chillidog said:

Have you tried adjusting the rear wing? It's easiest to try this first.
--
Richard

Good point thanks. I've tried increasing rear wing, which did not appear to make much difference? Is the wing very effective at medium cornering speed? as I would not like it to cut down top end to much:-) Is it best to adjust right to max?

[georgeo]

ThatPhilBrettGuy said:

If we're talking about road driving it's just going to make things worse.

Road and Track in partic as thats the best place to drive it as intended:-)

[chillidog]

georgeo said:

chillidog said:

Have you tried adjusting the rear wing? It's easiest to try this first.
--
Richard

Good point thanks. I've tried increasing rear wing, which did not appear to make much difference? Is the wing very effective at medium cornering speed? as I would not like it to cut down top end to much:-) Is it best to adjust right to max?

On my setup it makes a huge difference at speeds as low as 30 mph. I've added a gurney onto it and have larger endplates both of which seems to make it work better - see http://tinyurl.com/4gqge9

--
Richard

Edited by chillidog on Thursday 16th October 10:40

Edited by chillidog on Thursday 16th October 10:40

[ThatPhilBrettGuy]

georgeo said:

ThatPhilBrettGuy said:

If we're talking about road driving it's just going to make things worse.

Road and Track in partic as thats the best place to drive it as intended:-)

Problem is if to stiffen up the back, which this would, on the bumps it'll be worse. If you want better brakes on bumpy roads in an M400 for example, take the ARB off. On the same tyres I've seen a 3R out brake an M400. Lee always said that the only reason he put the ARB on the M400 was the marketing people said it'd sell better with one.

When you say the back is moving about what sort of speeds are we talking about and what exactly are you going?

[RobP]

georgeo said:

I'am trying to make the rear end stick to the tarmac a bit better as it can be skitish, so just thinking about fitting a rear anti roll-bar. Has anyone already done this? If so does it make much difference and where did you obtain it from OR did you make it? OR has anyone a spare?

Nobles should not be 'skittish' at the rear end
Tyres and pressures OK and correct?
dampers/springs OK?
Checked camber/alignment and integrity of rear suspension components? (See my comments and pictures on the 'vibration' thread)
Getting the up-rights machined will allow you to alter camber at the rear and good suspension set-up (with corner weighting etc) should do the trick nicely.

[NobleGuy]

RobP said:

Nobles should not be 'skittish' at the rear end
Tyres and pressures OK and correct?
dampers/springs OK?
Checked camber/alignment and integrity of rear suspension components? (See my comments and pictures on the 'vibration' thread)
Getting the up-rights machined will allow you to alter camber at the rear and good suspension set-up (with corner weighting etc) should do the trick nicely.

+1 on that. My 2.5 was all over the shop until I crashed it. Would light up the rear at the smallest opportunity. Skittish as hell. My replacement 3.0 is so well behaved it's like a different car altogether. Never did find out what the difference was. My first thought was check tyre pressures.

Has yours just started doing this or has it always?

[georgeo]

chillidog said:

georgeo said:

chillidog said:

Have you tried adjusting the rear wing? It's easiest to try this first.
--
Richard

Good point thanks. I've tried increasing rear wing, which did not appear to make much difference? Is the wing very effective at medium cornering speed? as I would not like it to cut down top end to much:-) Is it best to adjust right to max?

On my setup it makes a huge difference at speeds as low as 30 mph. I've added a gurney onto it and have larger endplates both of which seems to make it work better - see http://tinyurl.com/4gqge9

--
Richard

Edited by chillidog on Thursday 16th October 10:40

Edited by chillidog on Thursday 16th October 10:40

Thanks for info. looks great, so would you say it does not effect top end speed to much:-)

[chillidog]

Georgeo: I haven't tested it so don't know but if you just do a standing start then I'd be surprised if it didn't reduce your Vmax.

It does help improve laps times in the wet but as RobP has mentioned there are numerous other things that contribute ... which is why getting a good race setup isn't easy which in turn is all part of the fun (unless you crash of course).
--
Richard

[georgeo]

ThatPhilBrettGuy said:

georgeo said:

ThatPhilBrettGuy said:

If we're talking about road driving it's just going to make things worse.

Road and Track in partic as thats the best place to drive it as intended:-)

Problem is if to stiffen up the back, which this would, on the bumps it'll be worse. If you want better brakes on bumpy roads in an M400 for example, take the ARB off. On the same tyres I've seen a 3R out brake an M400. Lee always said that the only reason he put the ARB on the M400 was the marketing people said it'd sell better with one.

When you say the back is moving about what sort of speeds are we talking about and what exactly are you going?

Slow tight corners say about 30-40m/h and medium bends at 70-80m/h

[Adrian W]

georgeo said:

ThatPhilBrettGuy said:

georgeo said:

ThatPhilBrettGuy said:

If we're talking about road driving it's just going to make things worse.

Road and Track in partic as thats the best place to drive it as intended:-)

Problem is if to stiffen up the back, which this would, on the bumps it'll be worse. If you want better brakes on bumpy roads in an M400 for example, take the ARB off. On the same tyres I've seen a 3R out brake an M400. Lee always said that the only reason he put the ARB on the M400 was the marketing people said it'd sell better with one.

When you say the back is moving about what sort of speeds are we talking about and what exactly are you going?

Slow tight corners say about 30-40m/h and medium bends at 70-80m/h

Do you know how much lateral G your making when you think it's moving about?

[AMG Merc]

Agree with previous - never heard of any Noble to be skittish! Suggest something's up.

[Adrian W]

AMG Merc said:

Agree with previous - never heard of any Noble to be skittish! Suggest something's up.

They all are on the limit

[node]

Georgeo,

If you dont have any onboard measuring equipment, why not go for this to start with.

It should tell you what G's you're pulling at a given speed.

http://dynolicious.com/index.php

[RobP]

Adrian W said:

AMG Merc said:

Agree with previous - never heard of any Noble to be skittish! Suggest something's up.

They all are on the limit

Should be more progressive than skittish

[daddysumo]

Maybe you should find out the geometry settings and ride height you are running at the moment as a good base line before you touch anything and what suspension set up you have ?

The tolerance in the standard setup from the factory allows for quite a bit of leaway.If for example you rear camber is like mine was then it was almost upright and hardly any negative at all, but still within spec.

Steve

[Jenx]

I think my 3R is the only one with a front ARB from the M400 (I wait to be corrected) It snapped mid corner while pushing on...the front turned in like a barsteward, I let go of the loud pedal much to quickly, and it all ended up in my traveling backward down one of Berkshire's finest lanes at about 80 mph and doing a J-turn a la Jim Rockford. Only problem was the road was so narrow the front went over the grass verge and pulled the original spoiler off

Anyway, after driving it without I've not bothered putting it back as I hate understeery cars, and that is what it was designed to do...induce slight understeer. I cannot imagine a rear ARB improving anything either, just changing it for the worse, as the car was optimised to find the best compromise for speed and comfort.

I think that if the car is skittish then you have a problem...perhaps you could grab a pax ride in someone elses, car or or give another owner one in your car, to see if it's any better/worse?

Martin.

Martin.

[F.C.]

I had some issues with my M400, after having the uprights machined for more adjustment; I had the geo sorted at Plans.
The car was so different (in a good way) when it was done I wouldn't hesitate to recommend the modification to anyone.
F.C.