I was always surprised at how small the Esprit front ARB is, and the fact it doesn't even have one in the rear.
None of the actual X180R (Type 106) full blown race cars I've seen have a rear ARB either. When I inquired with one owner he said it doesn't need one. This is apparently confirmed by the fact they won championships.
TBH I wouldn't mind just a bit less body roll in spirited driving. But I trust the Lotus engineers and test drivers did their job, and wouldn't trade less body roll for less tire/ground contact. Of course I don't doubt it would be fun to try...😏
Interesting. I've seen dozens (well, probably more like hundreds) of different and innovative ARB designs on race cars. But in the final analysis they all end up twisting a solid or tubular bar that basically functions as a cross-connected torsion bar. And the adjustments are traditionally made by either changing the mechanical advantage of the lever arms by moving their attaching links, or by rotating blade lever arms that vary in stiffness relative to their orientation WRT the ARB.
But more recent designs seem to take a completely different approach. This example has a conventional front ARB (middle pic), albeit with very long connecting links. But the rear (bottom pic) has instead the links are connected to a pivot mechanism.
Most of these I've seen have the pivot mounted solidly, usually to the transaxle. But this one has the additional feature of the pivot being carried on some type of piston or damper. Still trying to wrap my head around how these things function. Intuitively it seems almost the opposite of a conventional ARB.
EDIT: OK as usual good old YouTube has some answers. This has an explanation of the rear "T-bar" which is for anti-roll, and the piston/damper device which is for vehicle heave control:
Back to analyzing the picture - as asked..............the shotgun side front tire seems to have a smaller contact patch than would seem advantageous. Stiffer front springs to solve that? Shock adjustment? Both? Take the donut out?..........after all we're looking for thousandths in an Auto-X.
The car in question is mine and is running r-compound tires and Protech shocks at their stiffest setting. I wouldnt have minded going stiffer but it did feel under control on course. I was within 2s of the fastest Elise/Evora GT which isnt too bad for a 30 year old car.
Stiff chassis with body roll is pretty much the Lotus way and may be exaggerated at autocross where the transients Gs can be pretty high as there is no penalty for messing up. Here are some pics of an S1 and S2 Elise at a WCLM autocross.
Such a sweet machine! A few more of the X180R suspension mods from the standard road cars (I'm sure @Erik L will be incorporating these or something similar on his hotrod in no time...😉😀👍).
Note the reference to spring frequency changes. I've always thought of it in (probably more simplistic) terms of spring rates. The topic is discussed in some detail in the autocross setup link above (see post #9).
Very Interesting, I have not noticed any strengthening to the spring towers in photos of the X180R. I wonder if that is actually the roll cage, although I dont believe it connects through the front fire wall. Have to look more carefully.
Also, I am shocked to see the Delco Moraine system listed for the brakes. I thought that came later.
Why do they talk about an increase in spring frequency instead of spring rate?
I couldn't see spring bearings surviving road grit, but found some Teflon washers I could use between the spring and perch, allowing bit easier adjustment. Hadn't thought about reducing spring compression torsion.
I was remembering that drawing of the cage from the parts manual. That picture does not make it obvious that it ties in to the front out riggers/chassis horns. Those actual pics however do look like it might. I bet that is what the add is talking about. I am going to have to do a cage.
I reached out to Safety Devices a while back to see if they would make that same cage. They said the buck or whatever had been destroyed and they did not have a way to make it.
They were a little testy about it, I got the feeling they had been asked quite a few times, or there was some back story.
I have talked to a couple shops locally that seemed to be open to making a bolt in cage - similar to the factory item shown above. I think I have figured out how to do it with out butchering the body up too bad.