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MG MGF Technical - Anti roll bar swap

Hi guys,

Has anyone swapped the anti roll bars from a TF onto a F?

I was thinking about trying a stiffer front anti roll bar on my F to see if this reduces the oversteer.

I have tried Spax adjustable dampers, compliance washers, different rear toe in settings, various tyre pressures and track day tyres. The car doesn't understeer even round the hairpin at Knockhill and I can not keep up with a friends new MX5 through the twisty bits, quicker in a straight line, but still oversteery on the way into corners.

Any ideas?

Thanks
Alastair.
Alastair McLeod

On my old "F" (97) it made a dramatic change to get solid bushings for the front subframe. Before it was "panta rei " (sp?) = everything is floating....
The balance now is perfect and can be easily altered into wanted behaviour with the throttle. Apart from that I donīt think it is a straight roll-bar swap between the TF and the F. Remember that there was something about it when we first saw the pictures from below of the then new TF.
But others will certainly fill in....
PS. Found during slalom event this weekend that slight "trailbraking" with ABS thru a multi cone-chikane will stiffen up the "F" considerably and improve time! / Carl.
Carl Blom

Not trying to be funny but have you tried driver training? The F is set to understear quite badly and if you are provoking overstear all the time then you may have foot trouble!

A stiffer ARB will make the front loose grip faster, but you are after speed, and cutting the grip is not the way to acheive faster times.
Will Munns

Alastair,

Have you changed front tyre width.

Although there may be a slight loss of grip by uprating arb, (dependant upon control of camber angle), it is not on a driven wheel. Uprating front bar will increase weight transfer to front from rear so its balancing grip.

Paul
Paul

Carl, I have thought about solid subframe bushes & poly bushes, but it looks very difficult to do myself and expensive to pay someone. I have checked the suspension bushes which look OK but are probably past their best at 80k, and I replaced the top ball joints all round.

Will, I have done several courses at Knockhill, the best was driving my own car with the instructor commenting round the lap. Since then I have done a few track days, but always felt the car to be nervous as you turn into the corner. Just to check it wasn't me, I let another friend who has a MR2 turbo, do a couple of laps and he also found the car harder to drift than the MR2, and spun it. I was able to catch a couple of TF's that were at the same track night, but you don't know how hard they were trying.

Paul, I have used 15" F 185, R 205, and 16" F 195, R 215, different tyres but the same handling.

Thanks
Alastair.
Alastair McLeod

Alistair, the TF roll bar might be stiffer, but I don't believe the change will overcome the play from wobbly rubber parts in the wishbone bearings.

Means, better save this costs for a later bushes upgrade or other dampers.
Dieter K.

Alastair, you need to switch to 205's on the front to kill the understeer - but then beware oversteer :-)
jt
John Thomas

Dieter, I have been using Spax adjustables to try and reduce the oversteer. The reason I haven't changed subframe bushes is that the small bolts don't look like they will undo without breaking them or the captive nuts. Have you been able to remove subframe bolts?

John, wider tyres on the front will make the Oversteer worse.
Alastair McLeod

Alaister,

I think you are describing a transient handling oversteer, so on turn in you are decreasing braking and increasing steering, weight is being transferred outside and rear, so the outboard rear damper moves in bump and the inside front damper moves in rebound. To increase understeer in this situation try harder front rebound and reduce rear bump. I doubt whether with Spax adjustment this is possible so probably need very hard front damper set up.
A larger front anti-roll bar increases understeer in steady state cornering.

The polyflex will help firm the suspension.


Paul
Paul

Oops, sorry Alastair, I didn't read it closely enough, I assumed it was the traditional understeer that was the problem.

So you're saying that if you find a decent sized deserted round-about and go round it faster and faster (without getting sick/dizzy) you end up with the backend breaking away rather that having to lift off with the front tyres objecting like hell?

john
John Thomas

> The reason I haven't changed subframe bushes is that the small bolts don't look like they will undo without breaking them or the captive nuts. Have you been able to remove subframe bolts?

Subframe bushes change would be after changing the lower arm bushes to PU.
The 4? small subframe bolts are a minor problem. But the big bolt is an ar*e to remove cause splashed with Loctite before they did them in.
I didn't get it off without heating it up with a acetylen flame (carefully)

Anyway, you need to lower the subframe by 2"? if you like to change the front lower arm bushes with polybushes.
Support subframe, undo the mentioned 4? bolts, steering column from steering rack, and notice aircon pipes if you have.
Dieter K.

Paul, setting the front dampers harder than the rears did help the handling, front 14 and rears 6 this was in the wet.

Dieter, I went round the Front subframe bolts, the 6 rear bolts all turned no problem, but the 4 small front ones wouldn't move, they felt like shearing or breaking the captive nut weld. I haven't tried the rear subframe bolts yet.
I had wanted to fit solid subframe mounts first, then poly bushes later, but it looks harder to get apart than I though.

John, yes faster round a roundabout and the backend will break away, but that is predictable. The problem is when you just turn into the corner the back tends to come round, with no understeer warning.

Alastair
Alastair McLeod

Hi Alastair

I have a pair (front and rear) of TF ARBs that I intend to fit to my MGF. The front ones are a direct swap - the rears are not however.

The TF ARBs are 1mm thicker in diameter: how much of a difference in terms of resisting rear oversteer remains to be seen. I'm planning to fit the front ARB later in the year and see how things go at a track day. It should be quite instructive... :o)
Rob Bell

This thread was discussed between 15/08/2004 and 19/08/2004

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