A little education in springs and shocks here. Shocks do not hold the weight of the car. The springs do. Shocks are dampers, i.e. to slow down the compression and extension of the springs.
The two must be matched in order for them to work well. Stiff shocks and soft springs = sag + bumpy. Soft shocks with hard springs = bumpy and bouncy.
When I first got my Hot Bits street spec shocks, the general opinion was that they were too bumpy, and indeed they were. Because...
a) They were wrongly installed. Springs must be marginally preloaded to take away the initial "holding" effect before they compress. Preloading compresses the spring marginally allowing them to compress further smoothly.
b) They were wrongly matched. The front coilovers were ok. The spring rates and absorber stiffness were within tolerance. Front coilovers are easier to match and tune because the engine places a huge load on the assembly thereby allowing a very large margin for error.
The rears were another story completely. They were bumpy, tended to compress under load, and bounced on the highway. After sending them to be serviced, the characteristics remained just as bad.
Two weeks ago, after getting rather fed-up of having my arse bounced around all over the place, I took them off and went back to speedworks. I wanted a smoother ride and less compression. The springs were obviously too hard, and the absorber too soft. The general consensus was that I would have to change to softer springs if I wanted a smoother ride.
But I did something exactly opposite. I instructed Speedworks to HARDEN the absorber by approximately 15%, my estimate of the degree of mismatch.
The final result...no more bumpiness, no more compression under load, no more bounce, and generally, a smooth but tight suspension feel.
Some recommendations for the A32/33. To handle well, the car MUST be lowered at least 1.5" - 2" all around.
1. Stock+Eibach Prokit. If you want the exact same comfort, then the stock shocks are usable with Eibach Prokit springs. The uppermost edge of your mudguards will sit almost exactly 27" from the ground.
2. Uprated shock + Eibach Prokit. The Eibach Prokit, by virtue of being rather soft, is preloaded quite a bit by the weight of the car. This provides a larger margin for error when matching with a shock. Tokiko gas will probably not hack it as this is only slightly better than stock. Koni 3-way adjustables are some of the best shocks you can find for this application. However, as the Prokits are only about 10% stiffer than stock, expect your rear to sag when the car is loaded. Remember...springs carry the weight, not the shocks.
3. Coilovers. An expensive option, but necessary if you really want to solve the problem.
Hot Bits street specs are ok, but you will need to instruct for the rears to be tuned like mine to correct the mistake made by Speedworks in their initial calculation (they never took into consideration that the A32 weighed 1.45 MT).
Titan are not bad. My only reservation is that they are hand made and lack the precision of the international brands. Expect the seals to leak earlier, but then again, they are cheaper to service. Also, the fact that they can be infinitely tuned makes them a rather nice option.
There are an infinite number of coilover options on the market, but except for the purely Japanese imported stuff, the rest are local manufacturers licenced to assemble, and they match according to their own "experience". I have yet to see one of these actually calculate spring vs damping rates. You can use any one of them, as shocks technology is no longer "rocket science" but be sure that they are easily and cheaply serviced, the shop you buy from is going to stay in business for some time, and you have the time to find the right match by trial and error since, in the absense of any sort of scientific matching methodology, this is what they will be doing.
Forget about the so called "experience" they spout as it is highly unlikely that anyone has driven every vehicle in the market and knows the handling characteristics of every vehicle in the market. Test a properly tuned car to know how it should feel. Then, find a coilover shop and start testing combinations of shocks and springs.
First, find a spring rate that doesn't sag under load, but don't over do it as too much and you will be running on steel rods, not springs. My springs from Hot Bits are rated "30". I have no idea what this matches up to in Kg/mm. And neither do they.
Then, find tune a shock to handle the high spring rate. Also, don't overdo it because you WANT the spring to compress when you hit a bump.
Good luck!
