Earlier last year, I became increasingly aware that my Bilstein shock absorber were deteriorating. I've been more than happy with the standard Bilsteins over the years (having replaced them once before), but I couldn't find anywhere that had them available. Tried Vauxhall (discontinued), Autovaux (discontinued), Bilstein (discontinued but will refurb).
Considered the refurb route (it was cheap at £80 per shocker), but really wanted a new and viable replacement.
Read about Nitrons/Ohlins etc on this forum and didn't want the faffing about with clickable adjustments and height settings, I just wanted a quality fit and forget replacement for the Bilsteins, that would do the same job. Plus I'd read all about people having hard ride issues on Nitrons etc. My car has been a daily drive for the last 90k miles and the Bilsteins provided a good compromise between comfort and handling.
So looking around I spotted the Quantum Zeros. From the Elise Parts website:
"....giving the performance previously only available with adjustable mono-shocks, but in a simple fit and forget package without any confusing adjustments."
".... it has been designed as a performance road damper that offers much better handling without compromising OE comfort levels too much."
"Spring rates are optional, we can offer either 200/400lb or 220/550lb rear progressive springs, front springs range from 275lb to 400lb depending on usage and what rear progressive spring is installed."
They sounded ideal, so I phoned Ian up at Elise Parts and discussed my requirements.
I requested 'Road Preference' over 'Track Preference' and was expecting the 200/400lb set. They supplied me with 375 Front and 220-550 Progressive Rears
I spoke to Ian at Eliseparts, who said that because of the heavier turbo engine, they would only supply the 220-550's on the rear. The alternative 200-400 would be compressed too much by the turbo engine thus losing much of their progressiveness.
He said that the 375s on the front could be slightly softened, but there has to be a balance with the rears ultimately.
I fitted them and set the ride height to 130 rear/125 front.
I found the suspension to be way too hard. The car was skittish all the time and felt like it was being shaken to pieces. The harsness of the ride couldn't be good for the car, never mind my back.
I chatted to forum member Lou-m who also had fitted Quantum Zeros. He originally ordered 325 fronts and the 220/550 progressives for the rear. He found the rears to be much too hard. So he swapped for the 200/400 progressives on the rear and found them to be too soft, i.e., he had to wind the preload on the spring up so much to get the correct ride hight, that the spring was partially coil bound. This meant that the rear springs would run out of travel very quickly. He went for 400lb non progressive rear springs after advise from Matthew Bentley. He was so much happier with the ride of the car afterwards.
I chatted with Matt Bentley, who advised not going below 350 on the rear, as the turbo has a tendency to dig in at the back on hard cornering. He also advised a difference of not more than 100 front to rear. He said that Bilstein knew what they were doing when they designed the turbo shockers, but that they just didn't last long enough and deteriorated.
I wanted to get as near as possible to the original Bilstein set up (because I was happy with the standard set up for daily driver), which is 275 front, 315 rear. So I phoned up Ian at Eliseparts again, who was very accommodating. He advised that he would supply whatever springs I wanted without cost, to sort my issue out. Very nice man.
I decided to go 275/375, so same fronts as original but stronger rears (Matt Bentley's input). All linear (non-progressive). Ian said that they'd never supplied springs that soft for the Quantum Zeros, but was happy to do so, and was interested to know how I got on.
So I received and fitted the new 275/375 springs. To get a ride height of 125f/130r I had to leave the springs fully extended without any pre-tensing, but the car settled nicely once dropped off the jack.
This resulted in the car being slightly more compliant, and not as shocking to drive. I still felt that it was harder than I wanted it to be, even knowing that the Quantums are a performance shocker and therefore the damping qualities will be firmer (regardless of spring rating).
I tried it for a couple of weeks to see if I could live with them. I might have gotten used to the deterioration of my Bilsteins, and the car gradually became softer. So I felt that I'd potentially lost my point of reference.
However, I simply couldn't live with the harshness as my daily drive.
I phoned Ian up again, and told him I was still not happy with the harsh damping properties of the Quantum Zeros. He very graciously agreed to have me return the Quantums for a full refund. Top bloke!
So there's my story. Make of it what you will. My personal conclusions:
- Quantum Zeros are too hard for a daily driver turbo, regardless of spring ratings
- Ian and Eliseparts are a top notch company, who offer excellent advice and who put their customer first.
- Go buy stuff from Eliseparts
