Lotac Bilsteins with standard springs - fitting guide (and comparison with Nitrons)

[dclare]

After a brief flirtation with Nitrons on my v8 (which I found a little to harsh for my kind of use) I decided to change over to the Lotac Bilsteins, however, I didn’t see the point of the Eibach springs as they are the same rate as the standard springs and my original springs are in good condition, so I only ordered the shocks. Fitting the standard springs to the rear Bilsteins needs an adaptor LOTAC05449, so be sure to order this if you are retaining the standard springs.

See pic for the order the bushes and washers need to be assembled in – note that the two rubber bushes/isolators and their respective (thinner) cupped washers go on either side of the top spring platform. There are other bits and bobs in the box which can be discarded.

While I was waiting for the Bilsteins to be delivered I had the old springs blasted to remove the old paint and crud and re-painted with primer and blue Plasti-Dip flexible “rubber” paint. I also removed the front ARB and loosened the wishbone bolts to take the stress out of the bushes. Next job was to assemble the fronts and once this was done I spent a lot of time swearing while trying to get them bolted up onto the car. In the end I used the following Heath Robinson method (don’t try this at home folks!!!) to take some compression out of the springs while I levered the assembly in place against the shock’s gas pressure. Don’t know if it was just me but this was a ball-ache to do (as it was for the Nitrons) so maybe I’m missing a trick here.

I couldn’t get any of my spring compressors to fit with the spring/damper unit in the car, so the ratchet straps were the only way I could find to help with this (see pic) – not recommended, but a last resort, just mind your fingers when you release the tension on the straps!

Next job was to fit the rears which was much easier because they can be offered up with the heavy duty spring compressor in place. Note that the Esprit parts bible is incorrect and shows a rear upper spring “Insulator, 12mm alloy, road spring to chassis” – part A082D4122F. This does not fit, and my car originally was fitted with rubber isolators, not alloy. The only place I could find the correct part was from SJ Sportscars, so kudos to them for knowing their stuff!!

 Ride Height

First things first. My car runs 245/35 18s on the front and 295/30 19s on the rear so the front diameter is 9mm larger than standard and the rear is 3mm larger on the rear, so this needs to be factored into the ride height measurement.

With the new assemblies fitted and the suspension settled (drive back and forth a few times) the ride height with the spring seat circlip in the TOP position was 188mm at the front and 180mm at the rear, so too high against the spec of 170/164mm (admittedly this was with 2 x 60kg ballast and half a tank rather than the recommended 2 x 75Kg). Because the springs are the original “used” springs I don’t anticipate them settling at all, so I regard this as representative. To my eyes the car also looks like the ride height is too high at this setting, and I know this has already been debated endlessly, but I decided to see what it was like on the lower circlip setting. Its not hard to change the circlips with the suspension in place – use the spring compressor on the rear and you should be able to lift the spring platform enough to get to the circlips. They aren’t very strong, so pretty easy to drop in to the lower slot. Again the front is more of a challenge so I made up a timber yolk that went around the lower wishbone and located under the spring seat and I used a jack from underneath to compress the sprint/damper unit enough to expose the circlip. Again the switch to the lower slot is pretty easy once you can get to the circlip.

With the spring seats at the lower setting the ride height was 174mm (front) and 166mm (rear) ..….so pretty close to spec given the 4.5mm and 1.5mm increase caused by the larger tyres on my car. My garage floor isn’t perfectly flat (although not bad) and moving the car around leads to small inconsistencies so this is close enough for me, and to my eyes the stance of the car looks much better without appearing “slammed”. I’m not going to be looking for a ‘Ring record with this car (although it has been there), so for me this is the best compromise compared with the Nitrons which allow you to run a much lower ride height (but with associated bump steer problems if you go too far). Pics below for reference between the top and bottom circlip settings. Maybe the purpose of the two circlip settings is to use the top for the new Lotac Eibach springs and the lower one for the standard original springs, although I have never seen that written anywhere.

The last job was to tighten up the suspension and shock mounting bolts at the final ride height, so I ran her up on four small wheel jacks, raised her up (with the weight still fully on the wheels) and tightened everything up. Job done.

How Does It Drive Now? Definitive Bilstein vs Nitron Conclusion

The car is definitely quieter riding than with the Nitrons, but not as “cushy” as the old Monroes. So, on an NVH scale of 1-10 with the Monroes at 10 I’d put the Nitrons at about 6 and the Bilsteins at 8. This isn’t surprising given the Nitrons have solid mountings with no rubber bushes in their bottom mounts and the Monroe’s had done about 70k miles!

From a handling perspective its hard to tell on the road without going to a track. The Nitrons could be adjusted to give a quicker turn-in by going a click or two harder on the front, but at the expense of understeer. With no adjustment on the Bilsteins you get what you’re given (and what Lotus intended), but overall I’m pleased with the change and there is no doubt the car is still epic in the twisty bits! Of course, if you are intending to turn your car into a road-racer or regularly heading to the track then the Nitrons are probably the best bet becasue of the adjustability.

Hope this helps if anyone is contemplating changing their springs/shocks.

 

[Mightymetro]

Hi Dave, I’d be really interested in having a ride out in your car.  I’ve got the full Bilstein and Eibach set up and also the Lotac bushes and find the ride pretty crashy and unsubtle on anything but the smoothest roads.  I don’t track the car (anymore 😂) and wouldn’t mind dealing a little bit of softness into the set up

[dclare]

10 hours ago, Mightymetro said:

Hi Dave, I’d be really interested in having a ride out in your car.  

You're very welcome to come over any time, just PM me when youre thinking of coming.

If you are looking for something more compliant I think the Monroe's are hard to beat. Ive got some spares if you're interested in them.

[Vulcan Grey]

Love that Nautilus Blue color!