NO LSD for 2-eleven

[freaking]

Why?

http://www.grouplotus.com/car/car_te...s.php?id=6#top

[codymac]

Variable TC?

[sandsmuseum]

I respectfully suggest you search this forum on the subject of the benefits and problems with a limited slip in a car. There are benefits which most people can list. How about the problems, and why Lotus for a long time, did not offer limited slip differentials in a track purpose car...

Search is your friend,

Michael

[Bgwilly31]

You can search...Basically its a bunch of non-sense.

Some people like myself and yourself. LOVE the LSD. And others dont hate the LSD> But are fine with going without it.

I think its rubbish Lotus at least wouldnt give you the option with the 2eleven.

[Patricko]

What does Lotus know about cars anyway

Lotus are the best suspension and chassis engineers in the world. We should give them a bit of credit, they might just know more than we do

[SteveLevin]

While I give Lotus plenty of credit, the truth is that there's not a single authoritative racing source in the world that doesn't say "limited slip is better." This comes from not only well-accomplished drivers such as Mario Andretti (who, no disrepect to the Lotus testers, but let's face it...he's Mario Andretti), engineers such as Carroll Smith, and the fact that, well, I can't think of a single race class that allows LSD's where they aren't used by the front runners.

So while I'd be the first to agree that the Lotus folks know more than I do, I disagree that they know more than the entire racing community.

Steve

[Robert Puertas]

Having sat in the pax seat of a 2-eleven for more laps around Hethel than I can count, I see no reason to put an LSD in it. You're only likely to need a LSD on the tightest corner of whatever track you're driving. The driver adjustable traction control allows a pretty big range of intervention, and even on the fairly tight skid pad turn at the south end of the track, you could dial in a % of slip that worked perfectly, regardless of whether you were pitching the car in and drifting it out, or taking a more deliberate line.

I think for the track day customer likely to buy a 2-eleven the adjustable traction control really is the perfect solution.

It's not like anyone's going to race their 2-eleven against real race cars like Radicals, Stohrs, Junos, etc. That's not what the 2-eleven is all about. It's not meant to be a race car in the way that purpose built formula cars and sports racers are. Instead, it's the distillation of the Elise concept into the ultimate track toy.

OTOH, as a spec race series, it could be very entertaining!

[Bgwilly31]

Originally Posted by Patricko

What does Lotus know about cars anyway

Lotus are the best suspension and chassis engineers in the world. We should give them a bit of credit, they might just know more than we do

Understood But still...why no option? If a customer wants to be stupid, then let them be stupid.

Originally Posted by SteveLevin

While I give Lotus plenty of credit, the truth is that there's not a single authoritative racing source in the world that doesn't say "limited slip is better." This comes from not only well-accomplished drivers such as Mario Andretti (who, no disrepect to the Lotus testers, but let's face it...he's Mario Andretti), engineers such as Carroll Smith, and the fact that, well, I can't think of a single race class that allows LSD's where they aren't used by the front runners.

So while I'd be the first to agree that the Lotus folks know more than I do, I disagree that they know more than the entire racing community.

Steve

Great point.

[SteveLevin]

I won't argue that there's a valid point that the 2-eleven is very quick, and not likely to be raced much -- at least, not in a series against other cars.

I guess I just feel like I'd buy one for speed, and, well, not having an LSD is leaving speed on the table -- and fairly "cheap" speed.

That said I fully admit to being a nerd-racer

Steve

[Patricko]

Originally Posted by Robert Puertas

Having sat in the pax seat of a 2-eleven for more laps around Hethel than I can count, I see no reason to put an LSD in it. You're only likely to need a LSD on the tightest corner of whatever track you're driving. The driver adjustable traction control allows a pretty big range of intervention, and even on the fairly tight skid pad turn at the south end of the track, you could dial in a % of slip that worked perfectly, regardless of whether you were pitching the car in and drifting it out, or taking a more deliberate line.

I think for the track day customer likely to buy a 2-eleven the adjustable traction control really is the perfect solution.

It's not like anyone's going to race their 2-eleven against real race cars like Radicals, Stohrs, Junos, etc. That's not what the 2-eleven is all about. It's not meant to be a race car in the way that purpose built formula cars and sports racers are. Instead, it's the distillation of the Elise concept into the ultimate track toy.

OTOH, as a spec race series, it could be very entertaining!

Great explanation Robert

[SteveLevin]

I would geekily point out that the LSD would be useful in a lot more than the slowest corners. If my 100hp SRF can almost spin the rear tires exiting Turn 2 at Thunderhill at 80+mph, I am sure that the 250hp 2-eleven can get well and truly into the traction control there.

Steve

[sandsmuseum]

I do not argue that a limited slip differential will benefit a car on corner exit. It helps deliver torque to both rear wheels, not just the one with the least amount of traction.

However you do not talk about corner entry. What if you understeer into the corner so badly that you scrub off speed and do not maintain it through out the corner?

As I have said (and get tired of saying, hence the search-is-your-friend comment), but limited slip differentials have advantages and disadvantages, even amongst the different kinds. How about talking about what some of the disadvantages are so people can make an informed decision?

All racers do not recommend a limited slip for all situations. And while Lotus believes limited slip is not needed for most track situations, they recognize the need for our American autocross racing.

I encourage the reading of Carroll Smith's "Engineer to Win, pages 227-229, about the limited slip differential.

(sorry, got up on the wrong side of the bed...)

Michael

[fpitas]

Carroll Smith's books are well worth reading, but I think Engineer to Win was written before the Torsen differential was used in road racing.

[SteveLevin]

I was just re-reading 'Engineer to Win" the other night, but I honestly don't recall him saying he would prefer to run an open diff. In fact, he specifically points out that while some folks thought the massive download of wings and tunnels would make LSD's irrelevant, that they were still crucial.

He does talk about negative Torsen experiences, but that was long ago (you have to remember those books were written quite a while ago). In the intervening times the Torsen has overcome the primary issue that he experience with metallurgy and design improvements.

As far as entry understeer, as Smith points out, you can tune that out of the car, and/or compensate your driving style to minimize it. The biggest thing is changing your driving style slightly to rotate the car ever so slightly on entry. You may sacrifice a little on entry, but you will more than make up for it on corner exit. Anyone who is slower racing a car with an LSD is simply trying to force their own style of driving onto the car rather than letting the car do what it does best.

I simply don't believe that any track focused car is better without LSD under any circumstances, and I believe I'm safe in saying I am in the vast majority there.

Steve

[Randy Chase]

My 2 cents. I can tune my car and my driving to work around minor understeer. I can't drive around the loss of acceleration when the inside rear wheel is spinning. Note, I can tune a bit to help mitigate that (more front bar) but then I increased understeer doing that.

Just my perspective also... but I think often that Lotus engineers with a focus on feel and response and fun. In my opinion, the Non-LSS car, with no LSD is the funnest car to drive. But not the fastest.

[charliex]

Understood But still...why no option? If a customer wants to be stupid, then let them be stupid.

A guess, but it might be that if they feel it negatively impacts the car, that people might complain about its handling and give it bad press, i believe that lotus are very sensitive to this sort of thing, like putting 18" on the front of an exige

Just a thought.

[fpitas]

When Smith wrote that book the Torsen was too unreliable for racing, he talks about it here: http://books.google.com/books?id=5a8...9ZNM#PPA229,M1

As we know, Gleason did solve most of the problems.

[ericwgexige]

Originally Posted by sandsmuseum

And while Lotus believes limited slip is not needed for most track situations, they recognize the need for our American autocross racing.

...and our American stoplight drag racing. (not that I am condoning such behavior)

[Kiwi 2-11]

Here is a quote from Nick Adams of Lotus Cars UK
"An LSD is only really of benefit if driving on very bumpy/loose surfaces or on a track with very slow, tight corners taken in first or second gear. In these cases the LSD will give superior traction. Against this the LSD will reduce steering sensitivity and also will induce high speed understeer on fast corners so in most cases the car is faster without an LSD. We don't like them and therefore tend to try and put people off them, but if you feel you want one we can oblige"

To a high degree the T/C negates 99% of why you would require LSD..and of coarse there is the additional weight to be factored in here.

[Vampyre]

Originally Posted by SteveLevin

While I give Lotus plenty of credit, the truth is that there's not a single authoritative racing source in the world that doesn't say "limited slip is better." This comes from not only well-accomplished drivers such as Mario Andretti (who, no disrepect to the Lotus testers, but let's face it...he's Mario Andretti), engineers such as Carroll Smith, and the fact that, well, I can't think of a single race class that allows LSD's where they aren't used by the front runners.

So while I'd be the first to agree that the Lotus folks know more than I do, I disagree that they know more than the entire racing community.

Steve

+1