CR new Front sway bar - and its the simple things that are often the problem.

[Gav]

Originally Posted by beauies

Ian may not be aware of the problems, may think it has only been a random shock failing

I have had randomly 3 of the four fail, and so have many others!

[DaveW]

Kanga,
Which Koni's have you got, I've priced 8211's and the alloy 8212's from the US, very competative pricing to AVO's purchased here.

Dave

[Kanga]

Dave

I think that they are the 8212, from the states, there are better shocks around but at the price these are far and away above the AVO. I wouldnt waste time and I would go with the konis, some things you just have to fork out the big dollars for, in the end by the time you add up the rebuilds with the AVO, its better just to buy the Konis.

steve

[Mando]

Originally Posted by beauies

Ian may not be aware of the problems, may think it has only been a random shock failing

Beauies, you must be joking.

Regards.

[stephen low]

Keen for a bit of shocker education if someone can help. Noted Kanga's comment above about having bump and rebound on front and bump only rear.

What is the advantage of single versus dual acting shocks and can you get away with different front versus rear options like suggested here.

I'd be looking to upgrade my shocks down the track as one of my first enhancements, assuming I get the car back on the road in the near future of course.

Was thinking Koni's myself, but went to an SA club meeting at an engineer's shop and he was sold on GAZ branded shocks in the cars.

Any advice appreciated.

Steve

[sambo]

Slowy, it's not that 'single' acting shocks only provide damping in one direction, it's that they're only adjustable for different rates in one direction. As I understand it, all shocks act in both directions. I guess with a nose heavy car such as the Cobra, you might be more interested in controlling the rebound at the front rather than the rear (hence dual adjustable up front), but I'm only taking an educated guess here.

With the AUD at better than parity ($1.02 today) I'd be ordering some QA1s or similar from the States.

[Aussie Mike]

Here's how I like to think about it...

The spring's job is to keep the car off the road and keep the wheels in contact with the road. Like any spring the energy of your cars movement will travel back and forth along the suspension spring. The damping in your shocks stops this energy moving back and forth by dissipating it through a controlled resistance (oil moving through an orifice). That's their basic job. The heavier the vehicle the heavier the spring required to support it and the stronger the resistance required to damp the springs oscillation.

Cars being a machine that likes to change direction accelerate and generally carry on means that the weight carried by each corner of the vehicle changes due to the cars inertia. The shocks adjustability lets us have some control over how quickly that weight moves from corner to corner.

Shocks usually have damping that works in both directions of travel.

Compression damping is the resistance to the shock compressing i.e when your suspension loads up.

Rebound damping is when the shock is relaxing or when the load comes off the suspension.

A Single adjustable shock has one knob that changes the overall resistance of both sides (compression and rebound). A double adjustable usually has two knobs that let you adjust the resistance levels of the compression valve and rebound valve separately. It's usually done by changing the size of the orifice the oil is forced to travel through.

Most non adjustable shocks are fixed from the factory with 50/50 each way i.e the same resistance in both compression and rebound.

As basic example of how shocks can be used to move the vehicle weight to where it's wanted, drag racers often like running 90/10 shocks on the front. That's 90% compression damping and 10% rebound damping. They do this to help move the vehicles weight onto the back wheels. As the car accelerates the front lifts. The 10% rebound damping allows the front suspension to easily relax and the front quickly rises. That moment of instant acceleration passes and the car starts moving down the track but the 90% compression damping slows the rate at which the front suspensions settles and keeps the front up in the air and the weight on the back wheels.

In a Cobra the loads are not only in acceleration but lateral cornering loads and deceleration. So under brakes the weight transfers to the front and in the corners it transfers to the side. The load is usually greatest when the car is first thrown into the corner so increasing the compression damping on the outside corner will slow the rate at which the suspension compresses on one side keeping the vehicle's weight on the other tyres. Increasing the rebound damping on the suspension on the inside wheels slows the rate at which the suspension relaxes and keeps the weight on that side of the vehicle.

This is a very simplistic view but it helps me understand what's happening.

Cheers

[Kanga]

Thanks Mike,

A very comprehensive explanation, I would have preferred bump and rebound on all four corners however cost was an issue, and as such I wanted to have more control over the front than rears.

What spring rates are you running in your mike? Do you have rear sway bar.

steve

[stephen low]

Thanks Mike and Paul a good start.

What shock brands are suggested? Note QA1's rate regularly, who make these? Ans what about Koni's and Bilsteins, how do they compare?

Obviously need an adjustable coilover set up but am looking for street practability, keen to hear what is suggested?

Steve

[Aussie Mike]

http://www.qa1.net/

Cheers