S2 111S understeer

Author
Discussion

stuart1969

Original Poster:

335 posts

278 months

Monday 21st October 2002
quotequote all
Can someone help me with reducing the understeer in the front end of the S2 111s. My last car was a TVR Tuscan RR which had a tremendous front end, I find the tendency to "hairdresser friendly" understeer a little dissapointing and am keen to sharpen things up.

Arno

349 posts

279 months

Monday 21st October 2002
quotequote all
First have a full geo check so everything is checked out. May be off at the moment (even from the factory they come with weird settings)

Then set to (courtesy Simon Scuffham):

Front toe: 0°15" OUT (total)
Front camber: -1.7° (each, or as far as it will go)

Rear toe: 1°15" toe IN (total)
Rear camber: -2.5° (each)

It will wear your front tyres faster, but should help with the understeer.

Bye, Arno.

Chorme Orange

140 posts

258 months

Thursday 21st November 2002
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Your fault for buying a car with pram wheels at the front. No wonder it has'nt got any front end bite.

Swap it for an S1

bert

36 posts

284 months

Thursday 21st November 2002
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Last weeks I had more understeer than I was used to in my s2. First I tought it was due to the wet and slippery conditions on the roads. Last week I checked the air pressure in the tyres and found that there was 100 grams difference in the front tyres. After setting them equal to 1600 grams the understeer was gone !

hungryjim

883 posts

266 months

Thursday 21st November 2002
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Chrome Orange if you knew anything about the Elise S1 and S2 you would know that the S2 has bigger and wider wheels and tyres for loads more grip and sharper turn-in also the S2 has a sharper turn in and the car is less likely to go wide with the new set-up.
The S2s suspension is probably off in this case and can easily be rectified!

simonel

6 posts

259 months

Thursday 21st November 2002
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the pram wheels stop the rear end snap which can be a tad hairy , I wonder how many elise s1 owners have exceeded the limits of the car with unforgiving consequences, or been lucky to survive unscathed from a pretty steep learning curve? after all were not all Mr Schumacher.

Chorme orange

140 posts

258 months

Friday 22nd November 2002
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Hungry Jim, me old mate. In response -

"if you knew anything about the Elise S1" - I've owned one for years and have done 30,000 miles in it.

"you would know that the S2 has bigger and wider wheels and tyres" - Larger radius, but narrower at the front actually.
S1 has 185/55 R15 front, rear 205/50 R16 S2 has 175/55R16 front, 225/45R17 rear.
Narrow front tyres as a rule will generate less grip. Simerly wider rears will generate a tendency to understeer resisting oversteer for longer. Which is why the S2 has more understeer.

"S2 has a sharper turn in and the car is less likely to go wide with the new set-up" - I think not. For example, Autocar slated the S2 111s at this years handling challege for too much understeer amongst other things.

stuart1969

Original Poster:

335 posts

278 months

Friday 22nd November 2002
quotequote all
Thanks Arno, the new setup has made a very significant difference. No longer does it just keep trying to push wide at the front. Dear Chrome boy! despite all the bickering and the "mine is bigger than yours" banter the understeer on my car has now been banished and that realy is the only issue here. To any other S2 111S owners I would recomend it, to all S1 owners they are just different models of the same car, lets vent our energy on Mr Prescott rather than each other!!!

hungryjim

883 posts

266 months

Friday 22nd November 2002
quotequote all

Chorme orange said: Hungry Jim, me old mate. In response -

"if you knew anything about the Elise S1" - I've owned one for years and have done 30,000 miles in it.

"you would know that the S2 has bigger and wider wheels and tyres" - Larger radius, but narrower at the front actually.
S1 has 185/55 R15 front, rear 205/50 R16 S2 has 175/55R16 front, 225/45R17 rear.

AS STANDARD

Narrow front tyres as a rule will generate less grip. Simerly wider rears will generate a tendency to understeer resisting oversteer for longer. Which is why the S2 has more understeer.

Actually the wider wheels generate more grip and a better ride quality and the s1 slid to easily so they changed it. The Tyres on an elise can be varied wheather you want high accelearation/Grip track us/Road use and the widths and compounds can be varied as required!

"S2 has a sharper turn in and the car is less likely to go wide with the new set-up" - I think not. For example, Autocar slated the S2 111s at this years handling challege for too much understeer amongst other things.

I TOO BOUGHT THAT EDITION OF AUTOCAR AND IF I RECALL IT CAME 4TH OUT OF ALL THE OTHER CARS ABOUT 11 IN FACT AND I DONT RECALL ANY REAL PROBLEMS WITH UNDERSTEER PLUS THE ELISES BASIC SET UP [GEREMY CLARKSON SAYS ON HIS VIDEO] IS MILD UNDERSTEER !




Roadrunner

2,690 posts

268 months

Saturday 23rd November 2002
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Having mainly come from the porsche and general forums, to your lotus section more recently, I find far too much arguing and not enough light hearted banter and helpful exchanges etc.

Chill out hungryjim - you loon, always harassing arn't you mate.

Do you lotus peeps ever meet up in the south east at all?

Chrome Orange

140 posts

258 months

Monday 25th November 2002
quotequote all
Hungry Jim,
"Actually the wider wheels generate more grip and a better ride quality " - Only the rears are wider on the S2, the fronts are narrower. Wider tyres invarible negitivly effect ride comfort incidentally. Fact.

"s1 slid to easily so they changed it" - The S1 had a tendency to break away in to snap oversteer in extremis. The Wider rears and slimmer fronts allow the S2 to have more rear grip and less front. This effectivly repositions the center of grip rearwards, increasing the tendency over the S1 to understeer. Which was my point.

Had Lotus kept the original width front tyres and widened further the rear the same balance could have been achived, but the negative effects of tramlining, aquaplaning, and poor ride would have been probably unbearable/dangerous.

"I TOO BOUGHT THAT EDITION OF AUTOCAR AND IF I RECALL IT CAME 4TH OUT OF ALL THE OTHER CARS ABOUT 11 IN FACT AND I DONT RECALL ANY REAL PROBLEMS WITH UNDERSTEER PLUS THE ELISES BASIC SET UP [GEREMY CLARKSON SAYS ON HIS VIDEO] IS MILD UNDERSTEER" - Clarkson however also distroyed the S2 in his Times column. Why? Understeer as I recall.
His opinioin though, not yours. Personally I adore the way my car turns in and hangs on.

You clearly love your car. Good. I Like mine too. But choosing a Lotus over a default choice Porsche/slk/TT etc.. is an act of interlect over reason. You have made an insightful buying decision, but your enthusiasm cannot change the fundemental physics of the cars basic geometry.

Both the S1 and S2 suffer naturally from a 60% rear weight bias, so all will want to oversteer if asked. Polar moment of inertia as it used to be called. In effect the Elise has a rear-mid engine instalations - pure mid engine cars having a more balanced 50/50 weight distrobution.

Your S2 has modifications to grip behavior to best diguise this natural tendancy.

Oh, and chill out man!

Captain Muppet

8,540 posts

266 months

Monday 25th November 2002
quotequote all
Now I know I'm going to regret this but...
The reduced width of the S2 front tyres would definitely lead to increased understeer if all other factors remained equal. But they didn't. The contact patch is longer (due to the increased diameter)and the compound is softer. The S2 tyres also benefit from more flexible sidewalls as they were designed to suit the low weight on the front of the car, unlike the S1 tyres.

HJ - You would get a lot more respect on this site if you told us what car you drive, if it's an Elise then your comments will carry a lot more weight. I don't have an Elise - owners please feel free to ignore anything I say.

fergusd

1,247 posts

271 months

Tuesday 26th November 2002
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One thing that is common to S1 and S2 is the sensitivity to suspension geometry changes and tyre pressures . . . you can go from twitchy as h*ll, scariyly oversteery, understeer tedium all with a few very subtle changes . . .

IMHO it's very worthwhile having the geo properly set up once a year (or more) as rattling the car over potholes and track kerbing tends to take it's toll. I do this and every time I comment to myself that the car feels so much better following the setup . . .

It's also worth saying that, depending on your use cases, the standard geometry settings are not all that are worth trying . . .

Fd

Nightmare

5,188 posts

285 months

Wednesday 27th November 2002
quotequote all
out of interest, what sort of place would you take your car for a full geometry check...and more to the point, would you necessarily trust them?!

N

fergusd

1,247 posts

271 months

Wednesday 27th November 2002
quotequote all
Ah well, that's the difficult part, you really need to ask around and find somewhere that actually knows what they are doing, as opposed to charges a lot/has the machine/say they know what they are doing . . . usually personal recommendations at the only way to get this info . . .

Fd

Chrome Orange

140 posts

258 months

Friday 29th November 2002
quotequote all
Sinclaires of London offer this service. £120 if I remember correctly.

roulli

175 posts

270 months

Friday 29th November 2002
quotequote all

Nightmare said: out of interest, what sort of place would you take your car for a full geometry check...and more to the point, would you necessarily trust them?!

N


If you have a place with a flat floor, you can set toe-in very precisely with fine ropes put up @ the level of wheel hubs. Measure distances front/back of each rim with caliper gauge equipped to measure deepness of a hole.

The most important here is to align car and the ropes left and right of car in parallel. This might take some time as you have to adjust the fixatures of the ropes until:
a) distances of both ropes are same in front and behind the car
b) delta distance front/rear wheel hub to rope must be the same for both ropes on each side of the car
c) steering must be on center of course

As fixatures for the ropes I use 4 buckets upside down, put 4 bricks on them to hold the rope (wrap them around). Missuse anything as shims to adjust the rope to hub-height.

Camber of each wheel can be checked in a similar way with a weight hanging on a rope, placed in front of the wheel hub.
Measure distance from rope to top and to bottom of rim.

During the measuring procedure with the gauge, pay attention to touch the rope only very gently, in order to prevent it from oscilating.

Sounds a bit complicated, but it's rather foolproof and you don't need to trust anybody to set up the geometry of your pride.

Cheers
Patrick

>> Edited by roulli on Friday 29th November 17:02

>> Edited by roulli on Friday 29th November 17:06

sllimr

33 posts

258 months

Friday 29th November 2002
quotequote all
Hate to say this (I'm going to get a bashing I know), but watch Topgear this sunday (I was there for filming on Wednesday), Jeremy C has the same problem, then the Lotus chasis engineer explains that in actual fact he's not driving it properly and goes on to prove it (watch the VT), apparently they do a different damper pack and wider front wheels for the 111s to stop it for people that have the problem and prefer not to drive it like they took their brain out to solve it.

/R

Nightmare

5,188 posts

285 months

Friday 29th November 2002
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Cheers All - Patrick, I will follow your instructions faithfully and see what happens!

Night

kelvyn

83 posts

261 months

Monday 2nd December 2002
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After watching jemery Clarkson on top gear last nite driving the s2 111s then the geezer from lotus driving it, me dont thinks its the car understeering, me thinks its driver problem??????
Little more of the right foot needed

>> Edited by kelvyn on Monday 2nd December 19:42

>> Edited by kelvyn on Monday 2nd December 19:43