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Discussion Starter · #1 ·
Check out this X180R at an auto X

Tire Wheel Vehicle Car Automotive tire


At first I was shocked at the amount of body lean. Then I noticed how the contact patches of the tires look perfect. Am I missing something? Amazing.
 

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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...馃槒
 

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Discussion Starter · #3 ·
Yeah - I am afraid I cant help my self. I hope I dont screw it up too bad. My thoughts exactly. I just did not have confidence on the track - maybe its something you have to get used to.
 

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No rear bar. The front bar diameter varies by year and model with the SE, X180-R, and Sport 350 having an 17mm if I recall, and the others slightly smaller.

Not sure what shocks @rnr had on there, but the originals were specially valved Monroe's.

My car has double adjustable JRZ race shocks, and you can get it fairly flat, but in both the X180-R photo, and mine you can see the inside tire lifting and not actually flat.
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Discussion Starter · #5 ·
nice! yeah yours looks much flatter Travis. The inside is lifting but the outside contact patch looks perfect.
 

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Generally rear ARB equals more oversteer than many drivers like. I used to totally disconnect it in the Formula Ford
 

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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.
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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:
 

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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.
 

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Fairly interesting discussion of auto-x suspension setup here, down to the excruciating detail of installing bearings on spring seats to eliminate twisting friction 馃槸.
Note the mention of chassis flex in the equation, which is not an Esprit strong suit. So don't forget the roll cage, which the X180R does have...馃槒馃榾.

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Erik's picture reminds me why I don't autocross/solo our Esprit any more.

The car likes high-speed sweepers MUCH BETTER!
(Not to mention the turbos coming up when you least expect it...) :oops:

Racetracks, not parking lots.:love:
 
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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.
https://flic.kr/p/fy9a3N https://flic.kr/p/fxTUr8
 

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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...馃槈馃榾馃憤).
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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).
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Discussion Starter · #14 ·
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?
 

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It appears the roll cage ties into the front chassis and the rear, assuming the road-going homologation cars are the same as the race cars in that area.
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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.
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Couple shots of a road-going X180R. Appears that the cage fwd diagonal tube passes through the dash and almost certainly ties in to the front chassis near a suspension pickup point.
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Discussion Starter · #18 ·
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.
 

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Discussion Starter · #20 ·
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.
 
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