Any recommendations? I was planning to go with the inokin monoball spherical bearing and NITRON 46MM RACE PRO 1-WAY default rate. Should I look for custom rate? Would a uniball be better?
For the nitrous they stopped doing the 46mm road ones so for the 40mm go for Elise S2 TOYOTA 05 onwards
TOYOTA is the key here.
Street series is a good upgrade to the adj bili’s but you are still stuck with single rate springs.
The front/rear weight is approximately
Front Rear
976.5. 1813.5
Front left 488.25
Front right 488.25
Rear left 906.75
Rear right 906.75
So the fast road would be shock of choice, they are not cheap but you are aiming for they sky at less than standard replacements. You need 900lbs to hold up the rear. I’d want the helpers to be 30% of the main springs so 270/630 but 250/650 is more realistic or 300/600 depending on road conditions.
Fronts need more for braking and rough surfaces and roll control. 700lbs is recommended.
The club sport have helpers on the front and rear so for the front 210/490 200/500 would be a great start. You can adjust the height but the nose sits higher slightly anyhow I’d personally like a little more stiff at the front so 200/550 may be better or 150/550 as 150 is 30% of the static weight and you want that gone in a corner or braking but present in normal road driving.
The small difference in fast road to club sport would give me fully adjustable springs in all 4 corners and if I got a chance I would have the corner weights adjusted. The single adjustment it perfect for the enthusiast as 3 way shocks need hours of track time to set up and to be honest few people know what they are doing with them. True race teams would think long and hard at using them so we should stay well away. Antiroll bar upgrades would make far more sense at that point.
I would also ask Nitron to what they think is a good setup remembering it’s a heavy car, they may suggest more spring? I haven’t worked out their spring rates on a stock Lotus but I’m betting it would be pretty close.
The other thing would be the spring height, obviously shorter springs would result in a higher spring rate but it also lower ride height, the helpers are just there to seat the main springs and take up the slack if you are lucky/unlucky enough to get full extension on the shock. I would want maximum travel throughout the main spring while maintaining road height so you have to have adjustable spring platforms and therefore you have to use helper springs to keep everything seated. A quicker reacting shock needs a stiffer helper spring to keep everything where it should.
I question the validity of 46mm v 38mm pistons on a road car that has to react with much worse surfaces than a track. If the valving is competent to take on a heavy car then I think the more reactive smaller piston would be a better choice depending on location.
I feel like Tesla just increased the spring rate to compensate for the additional weight and as a result we see a rear end dependably on the spring, not the shock to control the rear wheel.
The Nitron roadster package seems to either be poor shock choice (not the Toyota shock) or in my opinion a shock that is way to short requiring the spring platforms to be all the way to the top. If they have done this by shortening the piston rod and leaving the body the same to ensure the shock will coil bind before the shock bottoms out then that is perfectly reasonable to protect the valving, but I have not done that many measurements or comparisons.
This is pretty much my opinion and may or may not be the same or similar as anyone else’s. My entire knowledge comes from 30 year old technology and the immortal work of Herb Adams and his chassis design books. It worked for the Jaguars, Porsche’s, Cosworths and the Corvettes I’ve worked on over the years but newer materials and cars that carry this much weight are pretty new to me.