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One of the biggest impressions I was left with after my 111S test drive was how the car behaved while making turns at a decent clip over a bumpy road surface. WOW. I sure felt the bumps in my butt and my teeth, but the car's attitude and line were rock-solid steady. The car just kept tracking along exactly as I wanted it to. My Audi TT, by comparison, gets upset by that stuff. At a similar speed, it will start tracking off of the intended line and require small corrections.

Somewhere along the line, I picked up the idea that a firmer suspension should get MORE upset by a cornering on a bumpy surface. How can this be if the Elise took in stride what my softly-sprung Audi has problems with?

Would a more firmly sprung Elise (LSS) be better or worse at holding a line on a bumpy road?

My n00b guess would be that for cornering in general, firmer == better as long as you are able to keep the tires on the ground. At some point, firmer == less able to keep the tires on the ground?

Just trying to understand the theory here.
 

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As a generalization, firmer is better. The purpose is to maintain full contact with the road. A full race suspension though can be VERY tiresome on the street. You can tell well set up cars at a track as the body of the car will be smooth and straight while the suspension does all the work.
 

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Lotus is know for developing road cars that handle well and still have rather soft* suspensions. I'm thinking of the Elan, Elan M100, Cortina, Carlton, Impulse, Esprit, and even the Elise.

*soft is a subjective thing. Compliant is a better description of the way the suspension works.
 

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Some generalization.

Stiffer is better on a perfect surface. As the surface becomes less perfect, you need compliance. When the tires are skittering over the surface because they get unweighted, the suspension should be softer.

It is a common tuning mistake to make car's suspensions too stiff.

The other issue is the stiffness of the car. It is easier to work with a car that is stiff and dial in compliance with the suspension. You want the wheels to have a certain compression/rebound. But you would not be fighting the body flex also.
 

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Having ridden in an Elise S1 Sport190 I completely agree. I was very surprised in how smooth it felt on the freeway compared to the sports suspension on my Box. Turn-in was *immediate*. Can't wait till next year and compare it at the track with my friends 190. All his Lotus (Loti) are RHD so it saves me airtickets back to the UK :)
Every now and then I still walk to the wrong side of the car at gas station etc.
My wife thinks it's hilarious.
 

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strawtarget said:
How can this be if the Elise took in stride what my softly-sprung Audi has problems with?
The dampers on the Audi are probably not matched properly to the spring rates. A softly sprung car can be uncomfortable if it's over- or underdamped.

There are very different schools of thoughts on what spring rates are best for maximum performance. Some people believe that things go downhill if you go too stiff. Others believe that stiffer is better, even on fairly bumpy surfaces. For a car that you still drive on the road, I think the limit is mostly given by your tolerance level.
 

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Adamant - you'll be carrying over 400lbs more than your buddy's 190. Keep that in mind when doing comparisons.

To go faster - add lightness. :D:D
 

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Hmm, I thought I responded to this (damn, probably just hit Preview and not Submit).

Anyway, I think it's important to separate the concept of "stiffness" into it's components - spring and shocks. I would bet that the Audi has a higher spring rate (due to the weight of the TT) than the Elise. I would also bet that the Elise dampers are "stiffer" than the Audi (because of the GT-nature of the TT and the more comfort-oriented audience). The result is an underdamped suspension, which leads to the tracking issues you describe. Especially with the inertia of the TT (weight). I had the exact same issues with my S4.

But it doesn't need to be this way. With my S4, even though I'm now running spring rates nearly twice the stock rate, the selection of the proper dampers means that it maintains sufficient comfort but has new found levels of lateral grip. And it is absolutely amazing the differences that shocks alone can make.

In any event, I expect that the Lotus suspension engineers are much better at striking the spring/damper balance than Audi and that stock and LSS will be well balanced. I would expect that the real difference between the two is the lesser wheel travel of the LSS becoming an issue.
 

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Randy Chase said:
Some generalization.
It is a common tuning mistake to make car's suspensions too stiff.

I've learned this the hard way. A car that's too stiff has great turn-in and feels good in transition, but just has no grip. My feeling is that autox requires a pretty soft setup compared to road racing. The faster and the smoother the track, the stiffer you can run the car. A soft (relatively speaking) car with about 3-3.5 degrees of roll on the DOT R tires seems, IMO, to be a good autox setup. Assuming you can get enough camber in the car, the grip will be there.

Does anyone know if Lotus typically designs in enough suspension adjustment to get -3 degrees of camber??

Cheers,

Jeff
 

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Tripledigits said:
Does anyone know if Lotus typically designs in enough suspension adjustment to get -3 degrees of camber??
I doubt that it will need that much. I think you've spent a lot of time in strut-land! A stock Miata on DOT competition tires needs less than 2 degrees, and leans a lot more than the Elise will. Unless the Elise's double-wishbone setup provides less camber compensation than the Miata's, it shouldn't require as much static camber.
 

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Maybe it's my car. The Supra is 3300 lbs and has double wishbone suspension. I ran the first autox season with -1.75 front camber and couldn't get the front to grip. I went up to 3 degrees late this season, and now the front end is hooking up so well I'm having to make the rear stick better. I never would have thought I'd need that much camber. I'm run both Kumhos and Hoosier A tires. Car is developing lateral Gs of 1.25+ sustained and 1.4 instantaneous on the autox events, according to my GCubed unit. I would imagine the Supra's body roll is less than a stock Elise on the same tires. I'm on wheel rates of roughly 550 front and 500 rear, about 2.5 times the stock springs.

Jeff
 

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Tripledigits said:
Does anyone know if Lotus typically designs in enough suspension adjustment to get -3 degrees of camber??
An Elise S2 can do about -1 degree at the front and -2.5 to -3 degrees at the rear.

That's when you have removed all the camber shims.

If you want to go further (but that's not very common if you get sports suspension with an uprated ARB) then you need to start shaving the hub carrier or top mounting plinth (or both)

Bye, Arno.
 

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Thanks, Arno

That doesn't sound like much camber up front. Lightweight adjustable upper a-arms anyone? That is, assuming it needs it. I've never seen a car optimized for the track at -1 degree front camber. Sounds like a tire saving street setting.

Jeff
 

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Tripledigits said:
Thanks, Arno

That doesn't sound like much camber up front. Lightweight adjustable upper a-arms anyone? That is, assuming it needs it. I've never seen a car optimized for the track at -1 degree front camber. Sounds like a tire saving street setting.

Jeff
When you're not overweight you don't have to cheat the tires inward with camber to allow them to roll over and make a good contact patch:D
 

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Tripledigits said:
Thanks, Arno

That doesn't sound like much camber up front. Lightweight adjustable upper a-arms anyone? That is, assuming it needs it. I've never seen a car optimized for the track at -1 degree front camber. Sounds like a tire saving street setting.

Jeff
I must admit I've never driven a car as light as the Elise, much less set one up for the track. I suppose it would be a better comparison to my 125 shifter kart days. Didn't need alot of camber in those machines.

I always welcome enlightenment.

Jeff
 

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Tripledigits said:
Thanks, Arno

That doesn't sound like much camber up front.
Just keep in mind that the normal road settings for the Elise pretty much mean *no* front camber (0°) and only a tiny fraction of toe-out (0.02°)

Going to -1 is a pretty big jump and very noticable.

A track-oriented setting that's often used here in europe is to set the front between -0.5° to -1° camber and about 0°15" toe out at the front and -2° camber and between 0°30" to 1°00" toe in at the rear.

These values differ if you fit solid wishbone attachments to the chassis (eg. made from nylon or going to spherical bearings). In this case there is much less front/back motion in the wishbones, so you can run less toe.

Camber settings also depend on the type of tire you're running, but to find te right settings thee you need to do some laps and then check the temperature of the tread surface to see if it heats up more in certain areas.

The S1/Exige could go a little further on the front camber range, but not that much before you also need to start modifying stuff..

Bye, Arno.
 

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Arno said:

Camber settings also depend on the type of tire you're running, but to find te right settings thee you need to do some laps and then check the temperature of the tread surface to see if it heats up more in certain areas.


Bye, Arno.


Speaking of tires, Arno, what track tires are typically used in Europe on the Elise/Exige?

The Hoosiers that are popular in the States for autocrossing and road racing recommend 3 degrees of camber. I had been running -1.75 in front on my Supra, with tire temps a little warmer on the inside of the tread. When I increased the camber to -3, the front grip went up substantially. I was surprised considering what the tire temps had been with the lower camber setting. On a higher speed track, I think a lower camber would be tolerable (no slow corners). By the way, the Supra is a double wishbone suspension as well.

Thanks again for the input.

Cheers,

Jeff
 

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Hoosier is trying to give recommendations that apply to a wide variety of customers, including all car types, classifications, and both road racing and autocross. In the section on pressure recommendations, the document says that the recommendations are for front-engine, rear wheel drive cars, and implies that you can reduce the pressure if you have an independent rear suspension and "proper geometry up front". Those conditions might also apply to the alignment recommendations.

With Hoosiers on the Miata, I corded the inside edges of the tires first. That was at -1.8 degrees rear and -1.3 degrees front.

The top notch stock S2000 drivers (with Hoosiers) don't run -3 degrees either -- they don't even max out their camber. Typical numbers are closer to -1.5 front and -2.5 rear.

It could be that if your car is lowered, it's in an unfavorable position on the camber compensation curve, so you need more static camber than you'd need otherwise. I don't have any experience with Street Prepared suspensions, so that's just a wild guess.
 

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Tripledigits said:
Speaking of tires, Arno, what track tires are typically used in Europe on the Elise/Exige?
Depends a bit if it's sprinting or real track use with many laps.

On a track (during events or track-days where the track is open to the public) for the S2 with LSS and the Exige you're usually seeing Yokohama A048. The Exige used to run A039's before these came out.

S1 elises (15"/16") either run Yokohana Advan Neova tires in specific 'LTS' compound (very good 'all round' tyre for road use too, also known at Yokohama as 'AD05/AD06' types) or A038's.

Then there are several people running other types of cut slicks like Dunlop R01 or 89's, but most of these are a bit of a compromise as the sizes are not always correct.

In the UK quite a few people also run on re-covered tyres from MaxSport. Very good value for money, although not very useful for the road as they can be very noisy and hard to balance properly. Avon is now producing properly sized full slicks for the S1 Elise.

Full slicks are not used that much unless someone brings their Elise to the track on a trailer and doesn't need to drive it home again on the same tires. Most people don't have that luxury.

With either full or cut slicks you must upgrade the rear toe link construction though, as the normal road version can't handle the additional load generated by the much more grippy tires.

Sprints and hillclimbs are often done on road tires (most of the time because of regulations not allowing slicks) and because of the short nature of these events people use tires that warm up quickly like the Toyo Proxes. You could legally use Yoko A048's as they are road legal, but they take some time to get up to temperature (probably 1 to 2 laps of a GP circuit) and as such are not that useful in these events.

Bye, Arno.
 

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Getting back to the topic at hand, there is another way to ruin a car’s handling over lees-than-perfect roads: sway bars. I spent this year progressively softening the sway bars on my CSP Miata, starting with big aftermarket bars at the start of the season. Early on I put the OEM bars back on, and never looked back. After the season was over, I disconnected the OEM bars on a whim, and the behavior over back roads was transformed. What was once a fidgety uncertain car over even familiar roads became much more confidence-inspiring, with huge grip levels that really surprised me.

OK, I added a bit of travel back in to, but even when I dropped the car back down the difference was palpable. I do run fairly stiff spring rates - even without sway bars my wheel rate is considerably higher than the OEM setup - and I have no desire to reconnect the bars for road use. At all.

Didn’t I hear that the Elise has no rear bar? If so I would wager it has a fairly small front bar, and that can only be a good thing for back-road handling, in my experience.

George
 
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