Exige - the Diff debate

[GFWilliams]

Just read the article, I still want an LSD though!

[alias23]

I still just want to do donuts 

[NW76]

Donuts??? Me too ... can I order 6 please?? ??

[Dani]

May you clear up my mind please? 

I have read about Tour, Sport and Race mode. But I am more interested about OFF mode.

The more I know this car,  the more I love to drive it (only at track!) in OFF mode.

In OFF mode is the way that the car behave naturally and even smoothy.

This is something I have found out after doing many track sessions and knowing the car and its reactions very well.

My question is: what are actually the helps "on" and "off" with DPM OFF ?

Thanks!

P.D: IMHO electronic differential is not an optimal system for use on track. I think that using brakes to keep traction under control have bad consequences in brake temperatures (and its wear, of course). And I think that driving with a LSD should be more enjoyable than E-Diff. 

P.D. 2: sorry for my english 

 

 

Edited March 8, 2017 by Dani

[Swiss380Cup]

VERY INTERESTING TOPIC.....The 380 Race, as well as the Porsche 991 GT3 Cup both have LSD....so for me it tells everything...... having owned three GT3 RS (different generations...) before the Lotus 360 Cup,  the "potential" of plates LSD, once you know how to master it, is amazing and can provide you with an incredible amount of traction.... with "race spec" plates, you can even hear them working and  feel the directional effect in your back..... this is true on Porsches that I know so far better.... it can also be very tricky on wet or uneven surfaces, and in these circumstances, definitely work against you sending you in directions you didn't intend to go in the first place.......you can compensate with different "plates" or tuning which is a pain in the a... if you're a track enthusiast and not a pro driver with a full staff of mechanics to support the changes and tuning.....So my personal conclusion is that I would however definitely go for an LSD for track use..... I don't like "someone" (the robot under the bonnet..) doing things I don't really understand or are unexpected, like cutting the power, breaking this wheel or the other, etc........generally speaking I don't like electronics having the final word.... it's ok on the road for daily use, but on a track I prefer to have to face the reality that I did f....k it up somewhere and pay the consequence......and learn to do it better the next time..... but I need to get used  to this new brand so far......... Finally and correct me if I'm wrong, but my understanding is that, to get the benefit of the LSD, be it plate or Torsen, you'd have to turn everything off, otherwise, you'll have the ELD and the LSD working alongside, hopefully together and not against each other... The reason why I "dumped" Porsche GT3 is that now it's full of things I don't want, mainly electronic controls..... and all the saloon like atmosphere.... I've followed the evolution of the GT3 since it's start, and I'm a little bit afraid that Lotus will follow the same course in the long run.....I switched to Lotus because it's the closest of a racing car you can get (beside a Radical) to drive on an open road..... but for me it has to remain this way, even though I understand that economically it makes sense to build cars which are understanding, forgiven and nice to everybody with a driving license... Porsche did that very well and sell now GT3s full of electronics and driving assistants which make it possible for sunday drivers with some knowledge of the ideal trajectory to go to Spa, or Dijon or wherever and do great lap times without understanding everything going on under their seat.... People like me who want to fight with their driving abilities are definitely not a target market...... so please Lotus keep doing lighter cars, don't fool with electronics too much, and please, the ideal weight/power ratio for the Exige should be around 400 ps / ton.....the 3.5 Toyota V6 has plenty of resources yet.... The last generation of GT3 Flat 6. 3.6 could extract 415 ps and a little bit more (435) with some little tuning (air filter, etc.), with a normal aspiration.... so at least 400 with the current Exige shouldn't be a big challenge, though it might necessitate to revise things here and there (transmission, etc.)... still work to do....

Edited April 9, 2017 by Swiss360Cup

[GFWilliams]

This photo sums up why I want an LSD.

[pete]

is that good or bad?

[C8RKH]

Bad in my book. I have too much sympathy for my car...

[GFWilliams]

1 hour ago, pete said:

is that good or bad?

You can see the inside wheel is spinning faster.. LSD would make them spin at a more similar rate which would mean a smoother drift

[Maxi_z]

8 minutes ago, chumaxa said:

I guess the throttle response is when all is off ? It is weird because on the normal v6 I feel like there is a compensatro actuatly to increase the throttle on heel and toe .. DO you plan to fit the LSD then ? 

Yes on race mode with all off and the lotus traction control off

Even if you try on the road to push the clutch and blip the throttle is not that reactive at all sometimes almost no response and sometimes too much maybe if you push the pedal a little more

I think it s the throttle mapping that is not responsive but it could also be too much fuel at very low rpm on the ecu map I don t know

I think I will fit the quaife lsd as it should "push" less the car cheaper and no mainteinance

It s supposed to not work if one wheel leave the ground but I tried it even on a rental lotus elise cup with slick tyres on kurbs etc and it works

 

[Maxi_z]

11 minutes ago, Cristiano said:

Cool, it looks similar to mine, I think I saw a few Instagram pictures of this beast! I will take mine to Hockenheim next weekend, I am so excited about trying it!

Where do you feel the lack of slip differential? Slow sharp turns? Does it unsettle the car or what is the effect you get.. I lack experience on this side.

Did you changed regulations for the Nitron for track? Looks like standard compression is quite soft while rebound is very aggressive, with 6 behind. Any feedback?

Hope we see around some time.

Ciao!

I feel the lack of differential especially when exiting second gear turns and the car load is on the outside a lot then you accelerate and the car do not go a lot forward and the interior wheel spin and smokes and the rpm go up a bit like a clutch slipping

The exige 380 cup have wide rear tyres so you can adjust the throttle and get used to it a little but then you are slower and the car do not feel as a cup should

On slightly faster turns near the limit it also feels less natural and predictable but then tend to get back straight instead of drifting if you do not turn too much so maye in that case its a little easier but do not feel too right

It should be really better with a limited slip differential

I did not change the nitron settings when on track but yesterday I noticed that also my nitron were not setted as the manual say but similar to yours at around 6 from full closed in compression

I still got to drive it with the manual suggested settings

I am  not too surprised that the suggested settings are softer in compression than rebound for the track to be efficient with street semi slick tyres but I will tell you more next time

I would also like to see how it is with even more track specific semi slick tyres as kumho or a048r that should exist in the right exige cup 380 sizes and more camber

 

 

[Arun_D]

17 minutes ago, Maxi_z said:

I feel the lack of differential especially when exiting second gear turns and the car load is on the outside a lot then you accelerate and the car do not go a lot forward and the interior wheel spin and smokes and the rpm go up a bit like a clutch slipping

 

This is frustrating, it's certainly something I've experienced myself a number of times, as I drive mostly with DPM off on circuit. I am worried about the negatives people have described when adding a LSD to an Elise platform car (additional understeer?), but I'm sure this can be dialled out to an extent. 

The Cup260 had a Quaife (or similar Torsen type) fitted as standard, right?

[Maxi_z]

1 hour ago, Arun_D said:

This is frustrating, it's certainly something I've experienced myself a number of times, as I drive mostly with DPM off on circuit. I am worried about the negatives people have described when adding a LSD to an Elise platform car (additional understeer?), but I'm sure this can be dialled out to an extent. 

The Cup260 had a Quaife (or similar Torsen type) fitted as standard, right?

I think that with the quaife there should not be a real understeer problem while with a plate type differential it could do that depending on how it s setted

If you look at most of the race versions of the lotus they would fit a differential even if they are built by lotus (2 11 gt4 or v6 cup r or 3 eleven race)

The 260 cup had some differential fitted but I do not know what type and no particular problem at all on the same track

 

Edited October 30, 2017 by Maxi_z

[Jack]

1 hour ago, Arun_D said:

This is frustrating, it's certainly something I've experienced myself a number of times, as I drive mostly with DPM off on circuit. I am worried about the negatives people have described when adding a LSD to an Elise platform car (additional understeer?), but I'm sure this can be dialled out to an extent. 

The Cup260 had a Quaife (or similar Torsen type) fitted as standard, right?

@Arun_D …. plate-type LSD vs  Torsen is the way to go.

[alias23]

@Jack so are you saying Torsen diff is all good aka Evora 400 diff as a suitable option? 

Out of interest care to share your geo? Would be interesting to see you front camber settings as a starter

[Jack]

1 hour ago, alias23 said:

@Jack so are you saying Torsen diff is all good aka Evora 400 diff as a suitable option?

@Jack so are you saying Torsen diff is all good aka Evora 400 diff as a suitable option? 

Out of interest care to share your geo? Would be interesting to see you front camber settings as a starter

No, I'm saying the opposite.   From my firsthand experience with Lotus S2 variants and my 2-11 and V6 CupR, a Torsen-style (aka torque sensing) LSD does add some understeer in certain situations.    Plate-type LSDs are superior IMHO.

Alignment specs set forth below ….. bear in mind that I'm running slicks.

 

[Maxi_z]

Hi Jack

If you remember I sent you some message about the v6 cup r xtrac (not on this forum) as I wanted to get a v6 cup r but the owner of the one I was interested in wasn t decided to sell it yet so I got the exige cup 380

I don t know what type of differential is fitted to the 260 cup but I tried the elise cup italy cars fitted with quaife sequential and slicks with the quaife differential and they do not understeer and my friend use the plate diff on a 2 11 gt4 and say he feels some more pushing with it than on the elise cup race car

I would think that the plate type differential is superior if fitted to a race car with everything correctly set up but that the quaife would be better all around with semi slick tyres but of course I did not drive one or the other on a v6

What type of diff is fitted to the evora 400 and what brands of plate diff are available for the exige v6?

I just saw that quiafe and drexler are for sale from komotec

Do you use the oem engine and transmission mounts and do you know how they compare to the innovative motorsport ones?

 

 

[Maxi_z]

5 hours ago, Cristiano said:

Oh, that sounds interesting.. I asked to the garage where I got the car and they say the settings were made by Lotus.. I wrote to Lotus asking about a potential mistake in the  manual and they say I should use the one on the manual.. what the hell!!

The settings were quite different: 6 compresion all around and 11-12 rebound front and rear. Could you check what you have for rebound also?

After the garage put normal setting I feel the car more comfortable and handling looks good although no experience yet on track.

I suppose on track, from standard settings, I can harder a bit compression, (maybe to 10)  but not sure what to do with rebound..

 

I already put the manual settings but I think it was set similar to yours with the compression around 6 or 7 all around and 11 or 12 rebound front and maybe even more rebound clicks on the rear

I think that it was ok but not perfectly setted on track

I would think that the manual setting would be better to start with

 

[Jack]

5 hours ago, Maxi_z said:

Hi Jack

If you remember I sent you some message about the v6 cup r xtrac (not on this forum) as I wanted to get a v6 cup r but the owner of the one I was interested in wasn t decided to sell it yet so I got the exige cup 380

I don t know what type of differential is fitted to the 260 cup but I tried the elise cup italy cars fitted with quaife sequential and slicks with the quaife differential and they do not understeer and my friend use the plate diff on a 2 11 gt4 and say he feels some more pushing with it than on the elise cup race car

I would think that the plate type differential is superior if fitted to a race car with everything correctly set up but that the quaife would be better all around with semi slick tyres but of course I did not drive one or the other on a v6

What type of diff is fitted to the evora 400 and what brands of plate diff are available for the exige v6?

I just saw that quiafe and drexler are for sale from komotec

Do you use the oem engine and transmission mounts and do you know how they compare to the innovative motorsport ones?

 

 

Maxi,  

Yes, I do recall our conversations regarding the CupR and X-trac.  Your 380 is a beauty and I'm sure that you will enjoy it.

Stefano does a great job setting up his PB race cars and he's also one very talented driver.

I've been running  an OS Giken LSD in my 2-11 for several years and it has worked great.  My experience with a Torsen LSD was in an Exige (Lotus factory option), and it suffered from LSD-induced mid-corner understeer, especially in higher speed sweepers.  I have no knowledge of what Lotus is using in the 400 nor what's available for the Exige V6.  The CupR with X-trac came with a plate-type LSD from Lotus, as well as "beefier" motor mounts than those which come standard on the V6 Cup.

As for Innovative, I've been using their mounts on my 2-11 for years.  I also had them installed on my Cup255 --- they did help tame some of the excessive motor/transmission movement, which in turn did improve shifting.  Of course, you will experience much more in-car vibration during normal street driving, especially at idle/low speed.  I don't know of anyone who has installed them on the Exige V6.  As you know, we have very few of those cars here in the States.

Good luck!

 

[Arun_D]

14 hours ago, Jack said:

No, I'm saying the opposite.   From my firsthand experience with Lotus S2 variants and my 2-11 and V6 CupR, a Torsen-style (aka torque sensing) LSD does add some understeer in certain situations.    Plate-type LSDs are superior IMHO.

Alignment specs set forth below ….. bear in mind that I'm running slicks.

 

Thanks for sharing. Oh wow, interested settings on the TTX. Front rebound especially. Lotus recommended setting is 11 for this!! Mine are going on the car tomorrow, so it will be interesting how their recommended settings feel. 

I'm sat on the fence regarding diff type at the moment, I'm almost certain here should be a benefit from either over the standard open type, but Torsen or plate, really not sure!

 

 

[Maxi_z]

4 hours ago, Arun_D said:

Thanks for sharing. Oh wow, interested settings on the TTX. Front rebound especially. Lotus recommended setting is 11 for this!! Mine are going on the car tomorrow, so it will be interesting how their recommended settings feel. 

I'm sat on the fence regarding diff type at the moment, I'm almost certain here should be a benefit from either over the standard open type, but Torsen or plate, really not sure!

 

 

I would also like to have even more feedback regarding the different options but both are for sure much better than nothing

Stefano from PB racing would recommend the quaife over the plate lsd for a trackday car as it should work well all around even if used aggressively as that s also what they use in their elise cup italy race cars but say that a plate type lsd could be better on a race car where everything is set up and modified to work together or at least that s what I understood.

Would like to have the opinion of other tuners or racers that used both types on the same cars anyone know the opinion of komotec for example?

 

7 hours ago, Jack said:

As for Innovative, I've been using their mounts on my 2-11 for years.  I also had them installed on my Cup255 --- they did help tame some of the excessive motor/transmission movement, which in turn did improve shifting.  Of course, you will experience much more in-car vibration during normal street driving, especially at idle/low speed.  I don't know of anyone who has installed them on the Exige V6.  As you know, we have very few of those cars here in the States.

Jack

I also used the innovative motorsport mounts on the exige cup 260 I think they were the 75A and thei improved a lot the shifting but off course the oem ones were really too soft to start with.

Do you have a rough idea of how the stiffness of the oem ones would compare?

I don t know if I should get the 75A or 85A

Thanks

 

[chumaxa]

Would be good to knw also if they are different between the 350/380/cup, Silvertsone reckon they were different with the cup, as the engine moves more with the stiffer suspension, if that improves the gear change on the v6, would also go that way ! Sorry not an answer, just additionel question  

[Jack]

5 hours ago, Arun_D said:

Thanks for sharing. Oh wow, interested settings on the TTX. Front rebound especially. Lotus recommended setting is 11 for this!! Mine are going on the car tomorrow, so it will be interesting how their recommended settings feel. 

I'm sat on the fence regarding diff type at the moment, I'm almost certain here should be a benefit from either over the standard open type, but Torsen or plate, really not sure!

 

 

Arun, you are more than welcome.

I run different rebound and compression settings than those listed in that setup sheet …. depends on track layout and other factors.  Also, we've gone to softer springs up front than those which came from Lotus.  

As for the factory recommended shock settings for the CupR with R-comp tires, 2 (from full stiff) is what Lotus recommended for rebound (I'm running softer rebound) ...see below for the factory alignment specs…...

 

[Jack]

1 hour ago, Maxi_z said:

I would also like to have even more feedback regarding the different options but both are for sure much better than nothing

Stefano from PB racing would recommend the quaife over the plate lsd for a trackday car as it should work well all around even if used aggressively as that s also what they use in their elise cup italy race cars but say that a plate type lsd could be better on a race car where everything is set up and modified to work together or at least that s what I understood.

Would like to have the opinion of other tuners or racers that used both types on the same cars anyone know the opinion of komotec for example?

 

Jack

I also used the innovative motorsport mounts on the exige cup 260 I think they were the 75A and thei improved a lot the shifting but off course the oem ones were really too soft to start with.

Do you have a rough idea of how the stiffness of the oem ones would compare?

I don t know if I should get the 75A or 85A

Thanks

 

Maxi, no firsthand knowledge on stiffness of the OEM mounts on the V6 Exige Cup cars.  

My guess, softer than one would want for serious track usage but probably ideal for a street car.

Whenever you make these types of changes on a street car …. stiffer motor mounts, suspension mono-balls/spherical bushings, etc …. ride quality for street use deteriorates significantly.  

Lotus would get too many customer complaints about interior noise, harness and vibration, if they installed these items as standard. 

[Arun_D]

Thanks @Jack once more. Of course the Lotus spec I refer to is the supplementary notice that Motorsport issued for those running ZZR tyres, which differs from the one you have shared.

As you may remember, I will also be on 900lb/inch springs at the front. I think I will need to have a good play around based on your experience (and Gary, Mark etc), as of course I have some road miles to and from circuit to factor in as well.