Some Limited Slip and Traction Control information from Lotus - Page 4 - LotusTalk - The Lotus Cars Community
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post #61 of 118 (permalink) Old 10-31-2005, 05:03 AM
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Again, to use my Spyder with its open diff and large amounts of inside-rear wheelspin as an example...here's a pic of me at an autocross spinning my inside-rear wheel. My Spyder has a stiffer aftermarket front swaybar, aftermarket dampers and autox rubber on it.

Clearly, lifting the inside front wheel is not sufficient to prevent the inside-rear from unloading in a Spyder...so I tend to believe that same story can apply to the Elise.
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post #62 of 118 (permalink) Old 10-31-2005, 05:07 AM
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There aren't too many people (any at all??) that think that they need the LSD for the track - only for autocrossing in stock classes.[/QUOTE]

Actually, you need LSD, preferably Torsen type, in any class
where it's legal for Autocrossing. If Simon were to try our sport,
I think he'd agree.

dan wasdahl

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post #63 of 118 (permalink) Old 10-31-2005, 05:45 AM
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Quote:
Originally Posted by iwilson
Ding, question is what is the back inside wheel doing? Can't see it well in that shot.
In the yellow Elise pic previously posted above and again just below, the inside rear is still on the ground, barely. The car has a light weight custom tubular front sway bar with aluminum arms. It is stiffer than stock.



Below are some PICs I took of a stock Elise with Hoosiers from last year. It shows a particular corner every 1/3 of a second.









Last edited by Stan; 10-31-2005 at 06:23 AM.
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post #64 of 118 (permalink) Old 10-31-2005, 05:59 AM
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Quote:
Originally Posted by iwilson
Stan, when I first got started I did run the car completely stock standard. I did OK normally in the top 3 but never 1st. I was always up against other Elises with a 40hp advantage and/or Nitrons. When I swapped to Nitrons, I started winning on a regular basis despite the power difference. Of course the driver is a major factor in any Motorsport event. The S2 suspension was a major improvement over the S1 and many S1 owners have upgraded their cars with the S2 bilstein dampers and springs, Nitrons are an incremental improvement over these. But all this is fairly meaningless to your situation. What really needs to happen is for you guys to get friendly with Lotus USA and try and encourage them to produce a factory option specifically tailored to AutoX requirements. They would be stupid to ignore this important market segment. After all win on Sunday sell on Monday...
Out here, very understandably, I think that Lotus is trying to establish itself and get off the ground. Most people in America have never heard of or seen a Lotus car. Lotus has the '06 cars coming out and many dealers have inventories of available '05s to move.

Clive or Clyde came out to the SCCA (Sport Car Club of America) National Finals this past September. Apparently he had no idea! Lotus did add the LSD option and in a way that is legal for '05 and '06 cars. Else serious types would have to ditch their '05 and run an '06 in order to use the LSD. Even though the car's are fundamentally the same, the model year is different and you can only run bits that could have come on a new car. The rules are sorta vague..but I gather that you can run bits that came on a car or could have but didn't come on a car. For example if a BMW had a sunroof delete option available...but noone bought one...someone could add the nonsunroof roof to their car. Something like that.

So..a big factor is HOW stuff becomes available. Lotus can help '05 and '06 cars if they add choices via TSB or service manual changes. For example a competitor can revise the settings on his brake pedals because that is now Lotus approved and 100% legal, although no parts changed.

It would be nice if Lotus did some TSB or servive manual changes. Such as allowing an alternate front ABS wire holder: so that we could remove the last camber shim if that was desired. Such as reducing the occurance and severity of ABS ice-mode which turns down the braking power to all four wheels if one decelerates "too quickly" for the ABS computer. See here for actual data logs showing what happens to your braking power when ice-mode kicks in:

http://www.elisetalk.com/forums/showthread.php?t=16703

Black trace = ABS Ice Mode:



At the moment, Lotus says it's a nonissue. Well, it's not, IMO. Ironically...the LSD may help the Elise with braking! See...if we can run a softer front bar...because the LSD allows power to be fully put down at corner exit...corner entry may benefit...since the softer front bar may help reduce the intrusion of ice-mode at that time. This stuff is all interrelated.

Last edited by Stan; 11-01-2005 at 05:02 AM.
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post #65 of 118 (permalink) Old 10-31-2005, 08:22 AM
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Quote:
Originally Posted by Stan
In the yellow Elise pic previously posted above and again just below, the inside rear is still on the ground, barely. The car has a light weight custom tubular front sway bar with aluminum arms. It is stiffer than stock.



Below are some PICs I took of a stock Elise with Hoosiers from last year. It shows a particular corner every 1/3 of a second.

this one shows the problem best

the car is pitched over way too much, the rear right is out of droop travel and must be almost completely un-loaded.

you need to stiffen up the front end MASSIVELY to stop the opposing front corner (front left in this case) nose diving down, this will in turn stop the rear rising, and thus reduce the un-loading at the rear.

this said, you can't dramatically change one end without the other or the balance will be well screwed up, so the rear will also need stiffer springs in simmilar proportion to the front.

to put some numbers to this, we tend to setup S2's here with 400/550Lbs F/R springs for starterts, this with a VERY much stiffer ARB will stabalise the car no end, then all you have to do is get the open lenghts of the dampers to make sure the front is out of droop before the rear,.
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post #66 of 118 (permalink) Old 10-31-2005, 08:32 AM
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Quote:
Originally Posted by Simon S
this one shows the problem best the car is pitched over way too much, the rear right is out of droop travel and must be almost completely un-loaded. you need to stiffen up the front end MASSIVELY to stop the opposing front corner (front left in this case) nose diving down, this will in turn stop the rear rising, and thus reduce the un-loading at the rear.
this said, you can't dramatically change one end without the other or the balance will be well screwed up, so the rear will also need stiffer springs in simmilar proportion to the front. to put some numbers to this, we tend to setup S2's here with 400/550Lbs F/R springs for starterts, this with a VERY much stiffer ARB will stabalise the car no end, then all you have to do is get the open lenghts of the dampers to make sure the front is out of droop before the rear,.
The grey Elise is an LSS/sport pack car runing sport sized wheels and Hoosier autocross tires with no tread except two thin grooves. That is how the US Elise behaves with the more performance oriented of the two options.

The suggestions you forward are not stock class legal as far as the springs go.

So maybe we are really saying about the same thing. Those that must run the car as delivered plus a bar more or less cannot make the beneficial changes you suggest. Your ideas would help the car in a class where such mods are allowed. SCCA stock class rules do allow the length of the shock to vary from stock. They can be +/- one inch of the stock fully extended lenght. Note that if you lengthen the shock to gain droop, the springs can unload as the car uses a low preload design. The springs need to be mounted with the same distance to the end mounts as the stock shock. Since there is little preload, the car cannot be set for much increase in droop without running out of spring. No we cannot use helper springs or non stock longer springs or something like that.

I'll see if I can find more of the yellow car with stiff front bar pics. Here's one..elevation change in progress though.
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Last edited by Stan; 10-31-2005 at 08:45 AM.
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post #67 of 118 (permalink) Old 10-31-2005, 01:23 PM
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So Simon, do you know of anyone running a Torsen LSD on the Rover engine S1 or S2 Elises' in Europe? How about the Vauxhall VX220, 220T or R models?
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post #68 of 118 (permalink) Old 10-31-2005, 07:09 PM
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The S2000 with a torsen differential is subject to wheelspin. Fixes include using a clutchpack lsd. S2000 Inside Wheelspin

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post #69 of 118 (permalink) Old 11-01-2005, 04:56 AM
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[QUOTE=Prolene]The S2000 with a torsen differential is subject to wheelspin. Fixes include using a clutchpack lsd.

If you unload the inside rear enough (like, off
the ground) a quaife will spin the inside rear.
Clutch types may avoid this problem (with enuf preload).
Some say the early gleason type 1 diffs wouldn't
spin an inside rear even when lifted off the ground,
but I can't testify to this personally.
The point being,you not only need lsd, but you also
need proper suspension setup. As Stan points out, this
stuff is all interrelated.

dan w

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post #70 of 118 (permalink) Old 11-01-2005, 05:14 AM
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[QUOTE=danwasdahl]
Quote:
Originally Posted by Prolene
The S2000 with a torsen differential is subject to wheelspin. Fixes include using a clutchpack lsd. If you unload the inside rear enough (like, off the ground) a quaife will spin the inside rear.
Clutch types may avoid this problem (with enuf preload). Some say the early gleason type 1 diffs wouldn't spin an inside rear even when lifted off the ground, but I can't testify to this personally. The point being,you not only need lsd, but you also need proper suspension setup. As Stan points out, this
stuff is all interrelated. dan w
\

LSDs are not LSDs. None are perfect and they behave differently. Quaifes come with tuneable belleville washer packs. You need to set those *before* you install the lump. This provides a mild clutch action to help a Quaife equipped car if one drive wheel gets off the ground. With a quaife, just a small amount of rear traction at the inside sends lotsa oompth to the outside. Full clutch LSDs tend to introduce corner entry understeer, which the Torsens and Quaifes tend not to do as they act open at such times.
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post #71 of 118 (permalink) Old 11-01-2005, 05:23 AM
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[QUOTE=Stan]
Quote:
Originally Posted by danwasdahl
\

Quaifes come with tuneable belleville washer packs. You need to set those *before* you install the lump. .
This is news to me. If true for the quaife I use in the
porsche 901 transaxle in my europa, this is good news
for me. I may be able to use a bit of preload in that car.
I'll call quaife. Thanks.

dan w

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post #72 of 118 (permalink) Old 11-01-2005, 05:28 AM
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[QUOTE=danwasdahl]
Quote:
Originally Posted by Stan
This is news to me. If true for the quaife I use in the porsche 901 transaxle in my europa, this is good news
for me. I may be able to use a bit of preload in that car. I'll call quaife. Thanks. dan w
On my M3 besides adjusting the belleville washer stack, I used a softer rear sway bar and made up the stiffness back there with springs with long travel. That way the rear suspension is "more" independent, and can still load the inside rear during times when there is suspension droop related to body roll. Sway bars work by lifting on the inside wheel...not a great idea if you have a Quaife (see the pics showing the Elise lifting and inside front...I realize that you probably have not added a rear sway bar to your Europa). So you tune the car accordingly to get the most good and least bad. You cannot properly evaluate a Quaife plopped into a BMW where a clutch diff lived, if no other changes are made. For an Elise with LSD my suspicion is that the car will respond well to softer front sway bar settings than are presently used in autocross. Other stuff too I suspect.

Sorry for the OT tangent, see item 2 below:


Last edited by Stan; 11-01-2005 at 06:18 AM.
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post #73 of 118 (permalink) Old 11-01-2005, 03:39 PM
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Theory

And here you find the theory: Vehicle Dynamics

http://homepages.fh-regensburg.de/%7Erig39165/

Everything’s clear? Questions left?
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post #74 of 118 (permalink) Old 11-02-2005, 12:13 AM
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Quote:
Originally Posted by Ruediger
Everything’s clear? Questions left?
Ya, auf English bitte.
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post #75 of 118 (permalink) Old 11-02-2005, 03:37 AM
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Vehicle Dynamics

Quote:
Originally Posted by GabbaGabbaHey
Ya, auf English bitte.
The script titled VEHICLE DYNAMICS there

is in English, though many of the Elisians writing in this Thread and to whom I would recommend to read it might think that it is Chinese.

Perhaps it’s Germane English but give it a try please in case you want to understand your Elise better.
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post #76 of 118 (permalink) Old 11-02-2005, 04:08 AM
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Ruediger, thank you very much. I have some late night reading for certain to cure my insomnia.
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post #77 of 118 (permalink) Old 11-02-2005, 11:18 AM
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Quote:
Originally Posted by Ruediger
The script titled VEHICLE DYNAMICS there

is in English, though many of the Elisians writing in this Thread and to whom I would recommend to read it might think that it is Chinese.
Danke..
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post #78 of 118 (permalink) Old 11-02-2005, 01:25 PM
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LSD and Traction control for the street

So, all this discussion centers around Auto-X and to some degree road-course racing. What I would like to know is what effect LSD and traction control would have for me in wet and cold weather in my daily commute.

Randy, Have you had a chance with yours to compare before and after street driving in those sort of conditions?

Scott
SY / LSS / Touring / Hardtop
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post #79 of 118 (permalink) Old 11-02-2005, 01:44 PM
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Quote:
Originally Posted by Terminus
So, all this discussion centers around Auto-X and to some degree road-course racing. What I would like to know is what effect LSD and traction control would have for me in wet and cold weather in my daily commute.
If you haven't already, I would get a second set of wheels and street tires (not 48's) before getting a LSD, which also should help in cold and wet.

I would think that a LSD will allow one to run stock springs instead of having really stiff springs / bars; therefore a more forgiving ride with a LSD vs. optimizing the springs / shocks to maintain traction for extreme cornering w/o a LSD.
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post #80 of 118 (permalink) Old 11-02-2005, 02:34 PM
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FVMC got back to me today concerning LSD parts. According to them (Don P.) the part numbers exist but actual parts (and prices) do not yet exist. I was told that the ETA for prices is 3 weeks.

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