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Discussion Starter #1
What does the Elise's front suspension camber curve look like? Is it very aggresive? The stock camber settings for the car are very mild and teh caster isn't too crazy, so I'm assuming the upper arm is rather short and the suspension has a short virtual swing arm. Anyone care to comment on the lack of fron static negative camber? Was it chosen for saftey reasons (ie under-steer inducing)?
 

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00 scrub said:
Anyone care to comment on the lack of fron static negative camber? Was it chosen for saftey reasons (ie under-steer inducing)?
Probably, not to mention the fact high camber angles mean increased sensitivity in the steering making the car twitchy, also you would need to increase the rear camber to balance and the overall effect would also have high tyre wear. Remember this is a road vehicle.

I think I have a copy of the bump camber curve at work, I'll have a look next week.
 

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Discussion Starter #3
Would the tire wear really be all that bad with higher amounts of negative camber? The car is light and has rather wide tires for its size. I was under the impression that excessive toe caused tire wear (constant slip angle).
 

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In "Lotus Elise - The Offcial Story" it is stated that as the car was developed they kept finding an excess of front grip over rear grip. Front negative camber stock is around 0.3 degrees. You can run a bit more than 1 degree negative camber and not hurt tire life too much. Lotus did things like this to try and get the car balanced and controllable for most people. Ignoring wheels and tires, it looks like you can increase front grip via some more negative camber along with a stiffer front sway bar. The contact patch improvements from a stiffer bar look like they would offset the usual understeer increase due to more heavily loading the outside front, but this needs to be tried out. That would also affect tendencies toward wheelspin from the inside rear .
 

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Stan,
Have you noticed a lot of wheel spin from the inside rear? Have you had a chance to take some really windy roads? I went to the dragon's tail for the second time this weekend (in case you haven't heard of it, it's 318 turns in 11 miles - very intense) On the way back on the dragons tail there are a bunch of right hand switchbacks with major elevation changes. I noticed the inside rear wheel hopping a lot when I got back into the gas. I love the balance of this car as I found I can cause understeer or oversteer with ease. The loss of traction came about even below v-tec so I was a bit surprised when the car didn't just whip around when in a corner, in v-tec. I am learning this car carefully as I've never owned a mid engine car.
 

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>>>Stan, Have you noticed a lot of wheel spin from the inside rear? Have you had a chance to take some really windy roads? I went to the dragon's tail for the second time this weekend (in case you haven't heard of it, it's 318 turns in 11 miles - very intense) On the way back on the dragons tail there are a bunch of right hand switchbacks with major elevation changes. I noticed the inside rear wheel hopping a lot when I got back into the gas. I love the balance of this car as I found I can cause understeer or oversteer with ease. The loss of traction came about even below v-tec so I was a bit surprised when the car didn't just whip around when in a corner, in v-tec. I am learning this car carefully as I've never owned a mid engine car.<<<

I have quite a bit of fast driving, autocross and open track experience. My Elise just got the A.S.S. last week (after sales service) so now I can fully excercise it. I did autocross it beforehand gently and with a roughly 4000 RPM limit. I didn't find any real vices and note that the LTS doesn't like it if you enter a turn to hot. Really, no car does though. At the limit, mild understeer. Great turn-in and steering feel. Incredible brakes that allow you to trailbrake quite easily. Any oversteer I could provoke was mild and controllable. It absorbed bumps and could corner well on rough surfaces. As far as wheelspin goes I really didn't find that to be an issue at all. Of course that is at lower revs and without the step-up transition to Lift. On the type of road you describe, it sounds like the elevation changes can be a big factor. In that case a good line and lots of experience with those corners would help a great deal.
 

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Stan said:
In "Lotus Elise - The Offcial Story" it is stated that as the car was developed they kept finding an excess of front grip over rear grip. Front negative camber stock is around 0.3 degrees. You can run a bit more than 1 degree negative camber and not hurt tire life too much. Lotus did things like this to try and get the car balanced and controllable for most people. Ignoring wheels and tires, it looks like you can increase front grip via some more negative camber along with a stiffer front sway bar. The contact patch improvements from a stiffer bar look like they would offset the usual understeer increase due to more heavily loading the outside front, but this needs to be tried out. That would also affect tendencies toward wheelspin from the inside rear .
To run higher camber will increase tyre wear, not to mention you need to play around with the toe settings as you increase camber to get the best out of it, again affecting tyre wear.
I run over 1 degree on the front of the Exige, but have almost 3 degrees on the rear, not to mention a lot of rear toe in, and a touch of front toe in. This is running on AO48's and a lot stiffer springs than the Std Lotus ones (400lbs front and 475lbs rear). I still run the standard S1 LSS front ARB all be it on it's stiffest setting. With std springs/dampers I never run at stiffest as it made the understeer worse.

Stiffer front ARB will give more grip on initial turn in but will then tend to understeer as the loads/cornering speeds increase as the stiffer bar overpowers the front tyres. Running stiffer springs (Front & Rear) along with a touch of toe in helps reproduce that inital turn in response while reducing the roll effects without increasing front roll stiffness excessivly over the rear.
 

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I'm assuming that the LSS cars have different stock alignment settings than the nonLSS cars. Has anyone gotten their factory alignment checked at their dealer after delivery to check it's accuracy?
 

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What is possible as far as camber/caster adjustment? How much camber can be had in the front/rear? Is caster adjustable at all?
 

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del105 said:
What is possible as far as camber/caster adjustment? How much camber can be had in the front/rear? Is caster adjustable at all?
The caster is adjustable via small washers either side of the front upper wishbone.

Camber is adjustable by the spacers at the top of the upright.

On my car (rear) I am at Max negative before I need machining (to get extra camber it has been known for people to have some material machined off the mounting face). On the front I still have a few spacers so probably go as high as 2 deg before it needs machining.
 

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Mark A said:
The caster is adjustable via small washers either side of the front upper wishbone.

Camber is adjustable by the spacers at the top of the upright.

On my car (rear) I am at Max negative before I need machining (to get extra camber it has been known for people to have some material machined off the mounting face). On the front I still have a few spacers so probably go as high as 2 deg before it needs machining.
That is excellent news. What is the max caster you think you can get stock without modifing anything?
 

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Do you have a sense of about how much caster / camber change with their respective shims as they are removed or repositioned? How much toe change per turn too.

The manual seem to indicate optimal caster is at about 3.8 degrees but most US cars for which I have seen numbers were at around 3.1 degrees, still in range but below optimal.
 

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Mark A said:
On the front I still have a few spacers so probably go as high as 2 deg before it needs machining.
That's true for an S1/Exige.

The S2 can reach a maximum of -1 degree front camber. Then you need to start shaving the mounting plinth.. I suspect that the 111R/Fed-Elise are similar.

Bye, Arno.
 

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Thanks Arno. That is the number I was looking for.

I will go to 1 degree, but I am not sure it will be enough for our applications. But it has to be better than zero for these Hoosier tires.

Unfortunately for us that compete in SCCA, you can not machine anything to get more camber.
 

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Randy Chase said:
Thanks Arno. That is the number I was looking for.

I will go to 1 degree, but I am not sure it will be enough for our applications. But it has to be better than zero for these Hoosier tires.

Unfortunately for us that compete in SCCA, you can not machine anything to get more camber.

Unless it says you can in the shop manual.
 

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del105 said:
Unless it says you can in the shop manual.
True, there is that slim possiblity. Wonder if Lotus would be willing to change the shop manual? :)
 

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Zero said:
If you run -1 up front what would be an appropraite setting for the rear?

-1.5 or -2
We need more negative camber up front because the tire wear characteristics of the Hoosiers. We corded the outside corner in 20 runs. The rears are okay I think. So I think the rear neg might be fine as it is.
 
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