Hi. I would like to sense check what I'm thinking of doing at the rear of my late 1996 De-Dion car.
To cut a long story short I wanted to replace the dampers and springs on all four corners. All were OE from 1996, so non-adjustable Bilsteins. As they are 23 years old, it seemed the most sensible option. I was tempted to keep the car OE, so new Bilsteins with adjustable platforms. In the end I decided to treat me and the car to Nitron NTR R1 1 way adjustables. I exchanged e mails with Simon and received some very useful advice at the same time. I took Simon's advice on the spring selection for road use (200 ib/in front and 130 ib/in rear, but decided eventually that I would obtain the set direct from Nitron, I will come back to that point though.
When I specified the kit (Narrow Track De-Dion), I looked at the car first and as the rear mount for the damper on the de-dion tube seemed to be in the centre, I asked for that option. Bassically there were two options, lower mount or mid tube. Of course, that was incorrect! The lower mount of the rear dampers is welded to the underside of the de-dion tube. About 30mm above it is where the dampers used to be mounted, up to, I think early 1996. So on my car, in the event, I have the later de-dion tube, with the wider triangular gusset and mount for the A frame. This has two possible mounting positions for the rear dampers.
As a result, I have ordered, and been provided with, dampers that fit the top to centre mount dimension. Dampers were mounted in this way on the early de-dion cars, then the lower mount was moved, I think to allow Bilstein dampers with increased gas capacity, in 1996.
Going back to Nitron NTR RI dampers. It seems to me that the only difference between those specified for the centre mount, and the lower mount, is the length of the lower mounting eye. The damper body, and therefore the piston travel, is the same. There is only 30mm difference in overall length between the dampers specified for the two positions. See photographs:
The above photograph shows the unused centre mount and the currently used lower mount, viewed from the rear of the car.
The above photograph shows the Nitron damper specified for middle mount fitting. The lower mount, just below the adjuster ring, is shorter that the mount for the lower position would be. Nitrons mount 'upside down' depending on how you define that!
The above photograph shows the lower mount in close up.
I now have a dilemma, of sorts. I have fitted the front dampers with no apparent issues. It seems as though, once I have obtained the correct 1/2" UNF x 5" tensile bolts, I can fit the above Nitron dampers and springs to the centre mount in the de-dion tube. Alternatively I could ask Nitron to change the lower mounts for the longer ones and then continue to use the lower mounting position.
I am though attracted to the centre mount option. There will be no change, I don't think, in suspension travel, and the centre mount seems potentially stronger, given that over the years there have been some failures of de-dion tubes and damper mounts. The drawback might be, though, that if the de-dion tube ever needed changing, the newer tubes do not have the centre mounting hole, and a wider triangular gusset. I dare say that Arch Motors could help with that though, if needed.
What I am after, if possible, is reassurance that I haven't missed something obvious?!
I said above that I would return to how I obtained the Nitron damper set. I did ask Simon (Rogers) for advice, and I'm certain that Simon would know the answer but as I didn't obtain the kit from him I haven't asked directly. My thinking there is that when I have had chance to use the car with the new dampers and springs, there will at some point be a need for either overhaul of the dampers of maybe modification. If that eventuates I will no doubt be asking Simon.
Any advice gratefully received!!