35 replies to this topic

[piwo]

porsche boxster has it. toyota mr-2 has it. speedster,lotus haven't. why? is anybody equip it? from which cars will be fit it?

[The Batman]

there is a company that do it for the vx220 i cant remember there name though all i know is they are soft poofs when it comes to spring rates

[techieboy]

The new Exige V6 has them, as does the Evora. Cornering Force are the people you need to speak to.

[cnrandall]

I've tried them but they tend to make the car snappy. Best without IMHO.

[JG]

no snapping in my experience.

[JG]

http://www.mangomoto...p?id_product=23 or direct from CF

[SteveA]

no snapping in my experience.

Ditto, I find it very progressive but then I don't drive with quite as much gusto as Chris

[JimmyJamJerusalem]

Think Chris was referring to proper rear arb's not the bendy wendy stretch armstrong units you guys fit to your duck feathered cloud gliders

[Aerodynamic]

Please explaine snapping behaviour for a stupid sweed. As I understood it roll bars are less needed if the body/chassie is very rigid. Also a roll bar is much a comfort detail. I also belive adding a roll bar to our cars in the rear would give less traction out of a corner. But then there are different strong roll bars. BR, Per

[Mike (Cliffie)]

The CF bar works as the cars are softly sprung, if I fitted one on my car it would be more of a hindrance than help due to my chosen set up. As I am in effect building a no (OK some) compromise race car, I will take Randy's opinion as good advice. Per, snapping is where the back end of the car will let loose into a potential spin with little or no notice. In effect taking away the progressive nature of the rear end in a corner.

[TheRealVXed]

I wouldn't think that it is necessary to fit a rear anti-roll bar. reducing the compliance in the rear end will result is faster breakaway than the front if you don't do anything there, hence the "snap". Some complaince is required in the car to create progressiveness at the limit. In essence in relation to front vs rear end balance. Understeer = too hard at the front end, oversteer = too hard at the rear end PLUS adding an anti-roll bar will make the ride harsher.

[techieboy]

If you say so.

[Baron Von Scubadaddy]

Did Lotus get it that wrong ???? These people must have some idea as to what they were doing otherwise we wouldn't have odd sizes wheels front to back would we ????

[VIX]

I seem to remember similar discussions regarding the merits/demerits of the Spitfire brace bar overcoming some of the rear-end flex which Lotus clearly thought was ok.

[FLD]

I seem to remember similar discussions regarding the merits/demerits of the Spitfire brace bar overcoming some of the rear-end flex which Lotus clearly thought was ok.

Have you looked at the other lotus subframes? I cant remember if its late elise or europa but one of the lotus subframes looks just like the VX one but with a 'brace bar' welded in at the bottom of the two strut tower bits.

[cnrandall]

OK, to take it from the top! Our cars have the engine/gearbox sitting over the rear axle, placed nice and high with a narrow track meaning a nice big moment over the contact patch. This means there is plenty of load transfer through the twisties and to keep your load sensitive tyres in intimate contact with the tarmac you need to make the transient movements of the car as progressive as possible. In my reasonably extensive experience of these cars the best way to do this is really fine control of the slow speed damper movements to nurse the tyres into generating more grip. Anything that upsets the rear tyre and loads it too much too fast will reduce the grip limit and the rear ARB is one of these things. I had a good play with rear bars when I was racing the GT3 with Lotus and couldn't find a setup I was happy with so left them off. I have since tried several other cars with rear ARB's, including CF ones and always found they effect the car in pretty much the same way. The VX is longer wheelbase than the Lotus so they are more progressive at the grip limit anyway but I still don't think they are effected in a positive way by a rear bar. I will caveat the above with the fact that all drivers are different and what helps one driver might hinder another. Going fast around the track is as much about getting the driver comfortable and confident than anything else.

[cnrandall]

I seem to remember similar discussions regarding the merits/demerits of the Spitfire brace bar overcoming some of the rear-end flex which Lotus clearly thought was ok.

Have you looked at the other lotus subframes? I cant remember if its late elise or europa but one of the lotus subframes looks just like the VX one but with a 'brace bar' welded in at the bottom of the two strut tower bits.

Lotus didn't think it was OK, they just needed a hole in the subframe to route the exhaust! IIRC the original designs had a bonded ally rear end but they didn't work with the heat so they went for the pressed steel design. For most road applications the rear subframe is just fine, it only becomes an issue when you load it up on track with sticky tyres and also restricts the amount of spring rate you can run (not that you want high spring rates on road cars). The worst subframes are the S1 Elise, if you generate lots of grip you will feel the thing unload under you when you breach the grip limit... It can be quite abrupt on cars with lots of grip!

[2-20]

I wouldn't think that it is necessary to fit a rear anti-roll bar. reducing the compliance in the rear end will result is faster breakaway than the front if you don't do anything there, hence the "snap". Some complaince is required in the car to create progressiveness at the limit. In essence in relation to front vs rear end balance. Understeer = too hard at the front end, oversteer = too hard at the rear end PLUS adding an anti-roll bar will make the ride harsher.

The Cornering Force kit is not only a rear ARB but also a new Front ARB + dedicated spring rates and valvings on the shocks. So you keep a balanced car. An ARB has minimal effect on the ride quality.

[JG]

bendy wendy stretch armstrong units you guys fit to your duck feathered cloud gliders

[TheRealVXed]

I wouldn't think that it is necessary to fit a rear anti-roll bar. reducing the compliance in the rear end will result is faster breakaway than the front if you don't do anything there, hence the "snap". Some complaince is required in the car to create progressiveness at the limit. In essence in relation to front vs rear end balance. Understeer = too hard at the front end, oversteer = too hard at the rear end PLUS adding an anti-roll bar will make the ride harsher.

The Cornering Force kit is not only a rear ARB but also a new Front ARB + dedicated spring rates and valvings on the shocks. So you keep a balanced car. An ARB has minimal effect on the ride quality.

Tell that to McLaren....

But agreed it would work better if the front was uprated too.