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MG MGF Technical - Handling problem...

OK, time to ask the gurus... ;-)

Recent history:

Stage 1 gas flowed head fitted
ITG Maxogen fitted

Therefore more power to wheels...

Ride height pumped up 5mm (now running at approx 325mm)
New rear tyres fitted
Re-tracked to 0/5 toe in

Problem:

When i accelerate hard, the rear for all intents and purposes digs in unevenly, resulting in what feels like mild power oversteer, but is unpredictable.

Some of this is the sharper steering response from the revised tracking settings, certainly the wheel feels hyper-sensitive at the moment, resulting in some minor course corrections under braking conditions.

I suspect that the tyre place has set up the tracking incorrectly, maybe a little too much toe in, giving the hyper-sensitive steering, some of it is also down to the new tyres bedding in.

My current plan of action is to get it re-tracked ASAP (probably monday am now) as i am worried that it will surprise me at the wrong moment. Certainly i feel it is dangerous at the moment, occasionally i just feel out of control behind the wheel.

Any other suggestions as to what it could be would be appreciated.

SF
Scarlet Fever


Hi ,
think I know whay You mean - my "stock showroom " F was like that many years ago before all the fiddling with tracksettings / new bushings started. IMO the problem is that during driving the rear is constantly "going thru parallell setting" on the rear wheels. The reason for this can be enough slack in tie-bar bushes or even subframe bushes.. As described in an earlier thread : Open the rear boot. Park on a level surface and pull the handbrake hard in neutral gear.Grab the rear boot and rock the car fore and aft. Any movements of the rear wheels inside the wheelarch despite pulled handbrake ? Any abnormal slack will show up in this test.
Another good test is when at the company doing the tracking : Get it set at correct settings, take the car for a short spin and find out if the previous settings are still present when You return !
Hope it will be sorted ASAP , others will no doubt also give their clues to what to do.

BR, Carl.
Carl Blom

Sound advice Carl, one thing that did occur to me is that maybe after all these years the rear shock mounts had gone. I doubt it's bushes as i had them replaced with a full set of polybushes just over a year ago, but movement at the top of the shocker mounts could produce these symtoms.

SF
Scarlet Fever

>My current plan of action is to get it re-tracked ASAP (probably monday am now)

and Carl said,
>Get it set at correct settings, take the car for a short spin and find out if the previous settings are still present when You return !

Andrew,
hope you read before you leave for the tracking job.
Rock foreward and backwards with engaged handbrake is almost the best idea to check the rear axle.
You may do another test when the car is standing on the 'sliding plates' of the track measurement place.
If possible then rock the car yourself strong up and down while it's up there.
Strong grip to the rear from below with spot on the slide plates one after the other.
Notice, the front circular plates allow movement of each wheel in any direction and the rear move sidewads only. So take care that you don't through 'her' from the slide tables. Talk with that craftsman in advance that you would like to see whether there is any uneven play in the suspension sections of each wheel.

The probabble fault due to hard accelerating can also have it's reason at the front suspension !
Please remember that the front lifts up when you accelerate and the toe angles must change equal on both sides. If not then it steers without moving the steerung wheel.
See pictures below on this site.
http://www.mgfcar.de/tracking/ebspur.htm

Dieter
Dieter Koennecke

Thanx for the advice guys.

Current plan is to spend Friday getting it sorted out (day off work). I am not driving Scarlet at the moment as i have access to mum's Freelander and Dad's Jag - it's a hard life! ;-)

SF
SF

Any update Andy?
Rob Bell

Its intersting that you mension the handling problems. I had an MG Metro in the eary 80,s that was on 155 tyres and handled great. Than about 6 years ago i brought a Metro GTI, it was bloody awrful! I wonder if Hyrogas works well with low profile tyes?

2,000 miles in the Honda "R". No return to dealership/no Problems. If you buy the right car first, you get to spend more time in the Pub.

Mega.
Mike MEGA

Mega,

Come back in 6 years time (Scarlet's that old?) and we'll compare your Type-R's problems against that of a new car and conclude you made the wrong choice....

Darren.
Darren

UPDATE TIME

OK, first things first, got it sorted out today - woohoo! :-)

Turned out to be as i expected, not very well set up from a tracking point of view.

Was reading:

Drivers side front 0
Drivers side rear 7
Passenger side front 3 (toe in)
Passenger side rear 8.5

Now reads:

Drivers side front 0
Drivers side rear 7.5
Passenger side front 0
Passenger side rear 7.5

On the surface of it, it wasn't that far out - but boy did i notice the difference after it had been done!

Scarlet is back to her old self again, only this time she is riding between 5 and 10mm higher.

Incedentally i finally figured out why the tracking is affected by adjusting the ride height (d'uh, it's only taken me 6 years!!!!) ;-)

For those in the same fog of non-comprehension, the toe angle is measured in 2 ways, one of which is between wheels on an axle, ie across the width of the car. When the ride height is adjusted it is done one side at a time, ie along the length of the car, with each adjustment affecting the left or right hand side independantly of each other. Therefore it is impossible to adjust the two sides exactly the same and this, affects the relationship between the wheels on each axle, one of the tracking readings.

SF
Scarlet Fever

This thread was discussed between 28/07/2002 and 02/08/2002

MG MGF Technical index

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