Some Limited Slip and Traction Control information from Lotus - Page 3 - LotusTalk - The Lotus Cars Community
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post #41 of 118 (permalink) Old 10-30-2005, 01:11 PM
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We're talking autocross here.

Our "great pumpkin" elise has a Limited Slip too, which we struggled to install for Nationals....we felt it was THAT important.

Mike "Junior" Johnso co drove our car this year, and he too is a National Champion and Evo instructor, and he too agreed, it NEEDS a limited slip for autocrossing.

We ran our great pumpkin elise at Nationals this year, and if Junior had not tipped over a silly cone in a slalom, he would have WON the class. For someone in England who isnt familiar with superstock or SCCA solo II, you probably dont know how significant that is for the elise.


Before we went to the LSD we spent an entire year with some of the best minds/drivers in the field, trying to make the "stock" car work. We've tried a multitude of set up's, shocks,swaybars, adjustments, etc.


Simon, I think "what gives" is that you speak to us as if we're rube's who haven't thought of your ideas first.

The dynamics of setting up a car for autocross ( or in general ) are fairly fundamental. So the fact you've roadraced an elise for 6 years and we've only autocrossed an elise for a year and half, doesn't really weigh in here.

As I said we ( and by WE I mean a multitude of people in the US driving the elise) have spent a year and a half working with top drivers and suspension experts trying to get this car up to the level of a Super Stock competitor. All the ideas you've thrown out to us HAVE been looked into and tested. The limited slip does make a difference in autocross situations.

Frankly I really dont care if nobody else ever buys a limited slip for their car, especially if they're autocrossing. By all means, leave your car open diff if you're competing against us.

We arent just a group of people with loads of cash who thought "hey I need a limited slip" and didnt give it any thought or put effort into set ups etc. The people involved in "project autocross" are well respected people in the autocross ranks.










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post #42 of 118 (permalink) Old 10-30-2005, 01:12 PM
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By the way, Simon, you can make all the changes in the world in the not stock category in autocrossing. But then you are running with car with huge horsepower advantages.


Again, in Stock Classes, the changes allowed are extremely restrictive and you need the LSD. You don't need the TC, but Lotus has decided that they are both needed, so any stock class car equipped with the LSD also has to have the TC (although it can be turned off).

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.




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post #43 of 118 (permalink) Old 10-30-2005, 01:23 PM
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Originally Posted by Simon S
you honestly think cct racing is not about shaving fractions of seconds off lap times?

you think you have the monopoly on tight corners?
I brought that up because you SHOULD know what it's worth to save that much time. If you could spend 2-3k$ and shave .5 seconds a lap, would you?

You don't see tight corners on a track like there are in an auto-x. Simon, you obviously don't know what these courses are like. I wouldn't be telling you what to do or not do on the track.

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post #44 of 118 (permalink) Old 10-30-2005, 02:47 PM
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We raced today, and I'm running a very stiff front bar. I STILL had inside rear wheel spin and had to feather in the throttle coming out of a number of 1G+ turns to keep the car accelerating. The bar helps a lot, but does not solve the problem.

In addition, all the adjustments to keep the rears planted have had adverse effects on other handling characteristics, like turn-in and overall feel. The car is less nimble in this state. I cannot wait to get the factory LSD installed and be able to dial back down the bar.

A half second in autocrossing is HUGE; it was the difference between 1st and 4th today.

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post #45 of 118 (permalink) Old 10-30-2005, 04:23 PM
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In an autocross..


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post #46 of 118 (permalink) Old 10-30-2005, 04:38 PM Thread Starter
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Amusing thread.

I certainly wish that an LSD did not make a significant difference.

And just my take, but I bet it helps on the track too, given the parameters of the Elise set up using SCCA Stock Class rules.

I can't really add more.. I am on the way to SEMA for a week. But there are a lot of very good and knowledgable drivers and tuners that agree that the LSD helps and makes the car a C5 Z-06 killer in autocross.

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post #47 of 118 (permalink) Old 10-30-2005, 05:56 PM
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Originally Posted by Simon S
Have to ask, What the hell do you want traction control and an LSD for? ..... if you are spinning one rear wheel, then sort out the suspension
Simon...in the US, the most common form of entry level racing is called Autocross. Most of the Elises that autocross do so in the stock class. No...stock is not actual stock out of the showroom, but many of your suggestions cannot be performed for stock class competition. They'd be illegal. But they could be added to cars running in other classifications.

In stock class, we have to run at stock achievable ride height, use stock or stock size wheels within +/- 1/4 inch on offset. Any DOT-R tire that will fit on those wheels and the car. Any (or no) front sway bar. Shocks close to the stock overall length, but with the spring perches set to match the stock dimensions on either end. So the popular (outside the US) Nitrons would not be legal as-is: since Nitron moved the spring to allow for the rebound adjuster. Yes, moving the spring coaxially does nothing for performance. And stock springs would have to be used, not sure if they fit a Nitron modified for stock class or not. You can use a larger front sway bar to help the back of the car gain acceleration traction. But at some point the inside front lifts off the ground hence 100% of the front weight is carried by the outside front and no more help for the back of the car is possible from the sway bar. Engine mods such as another panel air filter and a cat-back exhaust are okay. Interior items stay mostly stock. You can't change the seats....add stiffer suspension bushings...bump steer the suspension...add a faster steering rack...machine bits to gain more negative camber up front (we even have to leave in the last camber shim since it holds the ABS wire ~.7 degrees of negative camber is often the max achievable with these limitations)....bore and stroke the engine, add cams or port work...change to an aftermarket clutch...add a supercharger...add an accusump...baffle the oil pan...add better brake calipers...convert to a sequential gearbox, etc, etc.

Compared to the open track note that Autocross is primarily a 2nd gear sport with few if any shifts once you hit 2nd gear. So at times the car is vulnerable if caught off the cam in certain parts of a course. Can't change the gearing to deal with that. But on the open track you'd not spend much time in 2nd gear...so the torque to the ground is often lower on the open track - being in the higher gears reduces the likelihood of wheelspin. As opposed to Autocross where you are generally in 2nd, but sometimes in 1st or 3rd (very rarely).

An LSD can be added since that was a 2005 option. So then by definition it is a stock part. If we could do some of the mods you suggest, the need for a LSD would plummet or maybe even go away. We have to use the options open to us in this setting though. It is this setting with which you might be less familiar.

Take a look at some of the autocross videos hosted on this site or Randy's Chase Cam site. A great deal happens during a one minute autocross run. Giant, rapid transients. No long, steady cornering forces like a long sweeper on the track. Generally way, way more than in one minute on the track. It is very intense and you can routinely push harder than you can on the open track because: there are only cones and your pride to knock down...there are no other cars running with you so you won't have to deal with them. Think of it as a more intense, lower speed version of the old F1 qualifying sessions. In F1 you see the same tracks each season, model them on the computer, practice and test there on non race periods. In autocross the venue (huge, flat, unobstructed parking lots or airfields) is the same..but the course never is the same. Most of the time you show up at an event, see the course for the first time, walk it a few times and then get as few as 3 chances to compete on it to the thousandth of a second. No practices. No dial in time to get the car perfect for that course. No videos to watch before you get there. After that event, the course is gone forever. Many excellent open track racers just cannot handle autocross. They can't do well in it.

Check out the tires used in Autocross. They are so sticky and gummy that they can overheat in a few one minute runs with generous cool down between them! Often the competitors rush to spray water on their tires to cool them back to ambient just before an upcoming run. They use pump up portable water tanks intended for garden insecticide spraying. That's not an open track thing either. You'd have to come in every lap for a cooling down and watering session!! BTW the autocross tires allow just amazing amounts of lateral and longitudinal grip...a few clicks higher than typical track day tires...this also tends to increase the inside rear wheelspin issues. Since even more weight can transfer away from the inside tires. The tires are way stickier than A048s or A039s.
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Last edited by Stan; 10-30-2005 at 06:35 PM.
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post #48 of 118 (permalink) Old 10-30-2005, 06:25 PM
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Originally Posted by Simon S
I am really struggling to understand this, so I think I will leave you to spin you wheels LSD or not (and BTW, the Lotus spec LSD will not stop it as it's a torsen, un-load the wheel, it will still spin!)
Simon, are you implying that unloading a rear wheel is the same as the wheel being off the ground? I understand that if the inside rear tire is off the ground with a torsen LSD, the torsen effectively becomes an open diff and the inside tire will spin. If the driver tends to be a curb hopper (as shown by the pics you posted) the torsen isn't going to do anything to stop inside wheel spin. There is no curbing to get a tire airborne in autocross.

If both rear tires are on the ground when exiting a corner, the torsen LSD will transfer torque to the outside tire with about 1/5 or so of the remaining torque to the inside wheel (depending on the torsen setup). As long as the tires aren't spinning with the torsen, it has the potential to be faster around a track when compared with an open diff. Add more power as many of us plan (turbo or S/C) and the chance of spinning an inside tire with an open diff becomes greater.

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post #49 of 118 (permalink) Old 10-30-2005, 06:44 PM
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Thanks for the info Randy...going to bash my dealer over the head with that info and see if we can get them moving.

As for the "do you really need it" discussion:

I autocross a 2000 MR2 Spyder (open diff) in C-Stock against Miatas that have LSDs equipped and have nationally competitive drivers (top placers at national tour events, etc). On courses where there is less call for putting down power mid-corner, I am able to compete with (and sometimes even beat) the Miatas. However, on courses where I'm spinning my inside-rear all over the place I have trouble getting anywhere near the Miatas. On two occasions, I have driven an LSD equipped car back-to-back with a non-LSD car and found the LSD car to be more fun AND faster.

OK...so much for the Spyder. What about the Elise? I have autocrossed Elises a few times on street tires and found that their inside wheel spin is similar to the Spyder's.

As for me and my house, we will desire an LSD.

Thanks again Randy.

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Last edited by Nochmal; 10-30-2005 at 06:47 PM.
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post #50 of 118 (permalink) Old 10-30-2005, 09:13 PM
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you all seem intent on missing the point.

It's not about changing the dampers to some after-market (ALA Nitrons/Ohlins/etc) it's about getting the wheel travel and limits right.

FYI, the two pics are NOT kerb-hopping, that's steady state cornering, what I was trying to show, (and clearly failing) is that you need to get the car to lift the front wheel BEFORE the rear, if you don't, the rear will unload.

In stock form, this is what happends, its supposed to do this as it's safer like that for 99.9% of numpty drivers.

the way to change the damper lengths is to move the damper mounts if you can't change the dampers themselves, by either new brackets (and there are several Lotus ones as well as many non-lotus ones) thus changing the static point in the stroke of the damper (you can also use droop limiters if allowed).

you then change the springs to suit so that the static ride height is back where you started etc (there are more then one rate of Lotus spring if you feel you *have* to stick with Lotus stuff), in any case you telling me that you are going to have the springs inspected at every event? (and who here can tell what a spring is by looking at it?)

Also, comparing the use of an LSD on an Elise vs. a Miata (MX5 to us) is dumb, the MX5 is Front engined and not transverse, so it will suffer torque reaction to the rear end, hence an LSD is essential (much the same for the Caterham etc).

Last point,

you clearly have no idea what cct racing is about, and think I don't understand autocross, Look, which country do you think invented it? do you not thing we have the same sort of competition here?

it's irrelevant what the event is, if your getting wheel spin in tight corners, it's the same wheel spin, and required the same solutions.
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post #51 of 118 (permalink) Old 10-31-2005, 01:00 AM
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post #52 of 118 (permalink) Old 10-31-2005, 01:44 AM
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Quote:
Originally Posted by Simon S
you all seem intent on missing the point... is to move the damper mounts if you can't change the dampers themselves, by either new brackets (and there are several Lotus ones as well as many non-lotus ones) thus changing the static point in the stroke of the damper (you can also use droop limiters if allowed).
You cannot change brackets in stock class. Or droop limiters

Quote:
Originally Posted by Simon S
you then change the springs to suit so that the static ride height is back where you started etc (there are more then one rate of Lotus spring if you feel you *have* to stick with Lotus stuff), in any case you telling me that you are going to have the springs inspected at every event? (and who here can tell what a spring is by looking at it?)
You can't change springs in stock class. You can use only the stock spring sets with no mixing. You can only use the sport pack springs with the sort sized wheels. You're not advocating deliberately cheating to cut wheelspin issues are you?

Quote:
Originally Posted by Simon S
Last point, you clearly have no idea what cct racing is about, and think I don't understand autocross, Look, which country do you think invented it? do you not thing we have the same sort of competition here? it's irrelevant what the event is, if your getting wheel spin in tight corners, it's the same wheel spin, and required the same solutions.
Autocross setups don't work well on the open track. Autocross is large and very competitive out here. I don't see autocross tires widely sold overseas, nor stock class rules similar to ours. I think you'd run into the same wheelspin issues if you ran US style autocross.

Last edited by Stan; 10-31-2005 at 01:49 AM.
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post #53 of 118 (permalink) Old 10-31-2005, 02:00 AM
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look, way I see it Stan, an LSD and TC are banned, but you seem to have no problem cheating by using them?

as for spring changes, there are several factory springs for the Elise, are you saying that they are not legal even though they are fitted as std to Elises?

think about what you are saying here.

you last comment about your events, I would strongly suggest you might want to actually look at what motorsport we have in the UK before you start to imply that your competion is nore compatative/different/etc...

You might just want to have a chat with Ian when he is over there about what sort of competition he does with his road car, you may just be a little supprised...
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post #54 of 118 (permalink) Old 10-31-2005, 02:26 AM
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look, way I see it Stan, an LSD and TC are banned, but you seem to have no problem cheating by using them?
They are not banned because you could order a 2005 Elise from the factory with them on. That is what enables us to use them, and it's not cheating. Stan was pretty comprehensive about suspension rules. He did not mention LSD because it is allowed---as long as you get TC too. You couldn't order an Elise with LSD and not TC, so that's what we have to add.

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post #55 of 118 (permalink) Old 10-31-2005, 04:11 AM
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[QUOTE=Simon S]look, way I see it Stan, an LSD and TC are banned, but you seem to have no problem cheating by using them?[QUOTE]

They are not banned. They come on cars of the same model year. So you can run a car that came that way, or add them to a car of that year. You must add associated parts if you retrofit. So we need to add the Lotus TC if the Lotus LSD is added. Even if we'd just turn it off all the time.

[QUOTE=Simon S]as for spring changes, there are several factory springs for the Elise, are you saying that they are not legal even though they are fitted as std to Elises?[QUOTE]

No. For US cars you can run either spring. But full sets only. And associated bits must be run with them. So to run the slightly softer base springs, you'd need to run the narrow front wheels...the OE ones actually...as there are not many 16 x 5 1/2 width wheels around. Many with base cars buy the ~$200 sport/LSS springs, run nonLSS shocks and aftermarket sport sized wheels with the 6 1/2 inch wide front wheel. No you can't run wider and/or lesser diameter wheels.

Quote:
Originally Posted by Simon S
you last comment about your events, I would strongly suggest you might want to actually look at what motorsport we have in the UK before you start to imply that your competion is nore compatative/different/etc...You might just want to have a chat with Ian when he is over there about what sort of competition he does with his road car, you may just be a little supprised...
Well I bring it up because something must be different about US Autocross and the events to which you refer. Any suggestions?
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post #56 of 118 (permalink) Old 10-31-2005, 04:12 AM
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Originally Posted by Simon S
look, way I see it Stan, an LSD and TC are banned, but you seem to have no problem cheating by using them?
They are not banned. They come on cars of the same model year. So you can run a car that came that way, or add them to a car of that year. You must add associated parts if you retrofit. So we need to add the Lotus TC if the Lotus LSD is added. Even if we'd just turn it off all the time. No you cannot use a different type of LSD, modify the one you have, adjust the TC in some manner, etc.

Quote:
Originally Posted by Simon S
as for spring changes, there are several factory springs for the Elise, are you saying that they are not legal even though they are fitted as std to Elises?
No. For US cars you can run either spring. But full sets only. And associated bits must be run with them. So to run the slightly softer base springs, you'd need to run the narrow front wheels...the OE ones actually...as there are not many 16 x 5 1/2 width wheels around. Many with base cars buy the ~$200 sport/LSS springs, run nonLSS shocks and aftermarket sport sized wheels with the 6 1/2 inch wide front wheel. No you can't run wider and/or lesser diameter wheels.

Quote:
Originally Posted by Simon S
you last comment about your events, I would strongly suggest you might want to actually look at what motorsport we have in the UK before you start to imply that your competion is nore compatative/different/etc...You might just want to have a chat with Ian when he is over there about what sort of competition he does with his road car, you may just be a little supprised...
Well I bring it up because something must be different about US Autocross and the events to which you refer. Any suggestions? Is Ian running his Elise in these events, in stock form?

Last edited by Stan; 10-31-2005 at 04:15 AM.
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post #57 of 118 (permalink) Old 10-31-2005, 04:37 AM
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As I understand it, to run the Elise in a *stock* class the car must remain essentially stock. *But* you can bolt on any factory option Lotus offers. So if for example Lotus produced a handling package for example that greater increased the range of adjustment for camber, this would be ok.

Although it would be possible to cheat a dramatic improvement in times would not go unnoticed. And having read lots of AutoX threads here, some competitors will go to any length to protest the smallest infraction even if it brings no performance benefit.

Given the popularity of AutoX in the States, I think Lotus has listened to some degree by bringing in the LSD, although I think developing a factory option geared towards AutoX would be more productive i.e. sorting out the dampers/springs and increasing the range of camber adjustment.

My car which has run in a lot of AutoX type events here in Europe does not get a lot of wheel spin if any from tight corners due to the back wheel lifting - what wheel spin there is tends to come from a lack of control with my right foot.

This photo I guess shows what Simon means by the correct setup. The car is running stiffer springs, nitron dampers and a 3 x stiffer ARB. Front wheel is lifting but the back wheel is still hanging in there.



An even better example is here.



Just a little unforturnate I'm going backwards at the time

Here's a vid of a run at a Dutch AutoX - Clicky
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post #58 of 118 (permalink) Old 10-31-2005, 04:46 AM
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post #59 of 118 (permalink) Old 10-31-2005, 04:50 AM
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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...
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post #60 of 118 (permalink) Old 10-31-2005, 04:51 AM
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Ding, question is what is the back inside wheel doing? Can't see it well in that shot.
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