Suspension set-up

[Bodger Bedge]

I have a 4.2 Cerbie that has had AVO shocks fitted to both front and rear. When origianally fitted the ride height was far too low and I had to jack-up the springs a little to lift the car. It currently rides at about 670mm rear and 610mm front from ground to under wheel arch (no one inside). It runs on standard 16" wheels. Now that I have finally got around to driving the beast I have been a little concerned with the handling and ride. The rear tends to bounce a little whilst the front is skittish and wonders on poor road surfaces. I believe I have dampening adjusters on the shocks but should I be making them softer or harder? The Avon tyres are in good nick and correctly adjusted so I have ruled them out. The rest of the running gear is fine therefore I can only assume its the shocks. Please can anyone advise if this is the likely case and suggest the best set-up for AVO's?

[jesfirth]

dont know the best set up for avos but check the 4 wheel geometry caber toe in/out etc that makes a huge difference to how a car feels

[carl_w]

I'm no expert, but if the front is skittish it suggests it's too hard. If the rear is "bouncy" then it suggests the rear dampers are knackered.

On the other hand, maybe your car is a Porsche 911 pretending to be a Cerb?

>> Edited by carl_w on Monday 27th March 19:01

[the gazman]

Do I take it that you have inherited this suspension?
Or that you have had it recently installed and are not in agreement with the set-up.

If you have inherited the system, I'd go and see a specialist and get the car set up properly, it could be a bit high at the back and dampers and geo could do with checking and re-setting if necessary. (I'd go to the Midlands and see Mike at Horizon or Guglielmi)

If you have had the suspension fitted and are unhappy,I'd take the car back and tell them what I was unhappy about. Check what spring rates they used, commonly 400lb front and 325Lb rear with Avo IIRC and take them out in the car to explain the problem.

[jensena]

I might be wrong but the rake (diff betweent front and rear)seems wrong, it should be 35mm - ie rear is 35mm higher, I am not sure what the ride height of the car should be, but altering the ride height alters the camber of both front and rear wheels, so it is important to get the ride height set correct. When correct all lower wishbones should ideally be parallel with the ground.

Any suspension experts out there, I'll be happy to be correctd if I'm wrong.

[the gazman]

jensena said:

I might be wrong but the rake (diff betweent front and rear)seems wrong, it should be 35mm - ie rear is 35mm higher, I am not sure what the ride height of the car should be, but altering the ride height alters the camber of both front and rear wheels, so it is important to get the ride height set correct. When correct all lower wishbones should ideally be parallel with the ground. Any suis not spension experts out there, I'll be happy to be correctd if I'm wrong.

You are not wrong but the rake is only there because the rear suspension is softer than the front, and under power the car would ideally be level. However, measuring from the wheel arches is not the best way to measure ride height, maybe a quick measure either end of the outriggers to the ground is the easiest.
Keeping wishbones about level is a good move.
I don't however think that ride height is the entire problem here and think it could be a combination of dampers and spring rates needing checking and Geo.

[Bodger Bedge]

Thanks for all of your thoughts. I inherited the front AVO's but had the original TVR shocks replaced last year my Mike at Horizon. (Dam good fella too) He set-up the geo's when fitted but when there are 4 of us in the car, it constantly grounded out. For this reason I took advice through this forum and raised the height of the car slightly. I think taking the measurements from the wishboans is a better idea and I will check that they are sitting horizontal. I believe the springs are the original TVR ones (green in colour if I recall) and I don't know if these are ideal for the shock's. I am sure Mike would of told me if they were wrong for the set-up. In my mind, it is the damping that is suspect so I guess I need to play with this. Can anyone advise how many clicks work best for normal driving? All four shocks have done no more than 2k miles, the car is 6 years old and only done 33k miles. The tracking is spot on so I have ruled these out.

[t8rus]

ive recently had avo's fitted, the fronts were set at 10 clicks & and the rears were set at 8 clicks. the car now rides a lot better.

[Bodger Bedge]

I have managed to tinker with the back dampers and turned them anti-clockwise (so they became looser and hit the end stop) I then wound them clockwise about 8 clicks. I notice the dial got stiffer the more I turned it clockwise. I assume that this means the dampening is getting stiffer?
The front damper adjuster does not seem to do anything but just keep clicking around and around! Both sides are the same but these shocks are just over a year old and done no real work. How do I check they are working? I have taken one of the front units off for further inspection / testing.
The springs for the front are red Eibach 30/98 units whilst the back are green coils with only the number 0117 printed on them. How do I determine which are fitted? I suspect the front springs are replacements whilst the rears are original. Any thoughts would be appreciated.

[huddscerbie]

i am not an engineer but feel competent with most aspects of vehicle maintenance.
i would seriously bite the bullet ad go to a local indie to get the suspension set up. from what i understand, failure to do so can have disasterous results.

[jesfirth]

topcats in aylesbury set up mine and its superb

[bodger bedge]

Just spoke to a techie at AVO suspension and he was very helpfull. He has advised what the best settings are for normal driving of the Cerb and what the best overall set-up should be. On AVO shocks you wind the damper adjuster fully in then back out about 10 clicks. There are 16 clicks in total. Over compression of the springs can cause problems or even old units where the springs are weak. Just as said by a few people on this forum. I intend to remove, clean and reassmble the units then have them set-up professionally. It seems the safest option. Thanks for all your help.

[dean_ratpac]

jesfirth said:

topcats in aylesbury set up mine and its superb

I concur – Topcats did a superb job on the Nitrons on mine...

[purpleheadedcerb]

Did he say that the rears nbeed re-springing from the standard green springs? I only ask as I have some going on soon and haven't bothered with springs yet.