Stiffer Anti Rollbar

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Re: Stiffer Anti Rollbar

Postby 2fast4u » Mon 31.08.2009, 00:28

Lets not forget that when the Elan went for sale one of the slogans were that was a car to be driven by 90% of the people at 90% of its capabilities on 90% of the time. I believe that now what people that own an Elan M100 are looking for as nothing to do with that.

Nige wrote:

“What I want for my car is to move the superb road use suspension setup a little way towards something that is more suited to occasional track use, but without wholly compromising my enjoyment of driving the car on the road. I am greatly interested in anything that will assist in achieving that objective.”

That’s also what I’m looking for.

I’m not going to enter in technical discussions, I’ve learned more from reading the LEC forum in the last days that in all my live, so be please to correct me if I write something that is not correct (you can also correct my English) .

I have no doubts that fitting a stiffer rear ARB would make an improvement on the driving, I’ve had a Peugeot 106 Rallye with a stiffer rear torsion bar ( + 1mm than the standard) that made a lot of difference in cornering after that I’ve fitted Koni Sport with racing track specifications, and for me its in the top 5 on the best FWD that I’ve driven

One thing that I call to attention is “how much?” . In the Pug 1 mm makes a big difference in the handling that I felt.

When lotus made the car I’m sure that they have tested and tested different set of ARB but don’t forget my first sentence.

I believe that a small increase in the stiffness, with the suspension available on the market would make a difference, but will turn a car that was made to be driven by 90% of the people at 90% of its capabilities on 90% of the time in to a car that can be driven 90% of the people at 75% of its capabilities( = 90% of the old setup) on 90% of the time.

I’m sure that that would made the rear more a little slippery but the front would be able to deal with more power providing better powerful corner exits(I don’t find a better way to say it )

I hope that the work that Bob is making on the suspension with Eibach and Bilstein will make some results, my opinion is that he is in the right and correct way and that the understanding that we has on this issue is the right one.

If that suspension upgrade from Eibach/Bilstein comes I believe the next step will be also Eibach making a stiffer ARB.

Bob instead of 2 in 1(springs/shock upgrade from Eibach/Bilstein) why not 3 in 1 (springs/shock/ARB upgrade from Eibach/Bilstein/Eibach)

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Re: Stiffer Anti Rollbar

Postby superbad » Mon 31.08.2009, 16:29

Kuching wrote:Nor does it have much effect on the load transfer – this is essentially a product of lateral acceleration and CofG height.


I may be misunderstanding what you wrote here, but the ARBs definitely have a big effect on lateral load transfer. You can clearly see this in the extreme case of a very stiff bar leading to the inside wheel lifting- in that case, 100% of the load has been transferred to the outside.

The rest of what you wrote is spot on. There's nothing wrong with roll per se. We generally try to limit it if the suspension geometry has adverse characteristics, or if there are big aero effects. I come from a background philosophy of letting the suspension do its job. We would routinely run Indycars with no bars at all and (relatively) soft springs, and use low speed damping in the shocks to control transient chassis movement.

I haven't had the M100 on a track, so I have no idea what its balance is like at the limit. I'm pretty sure you wouldn't want to stiffen the front bar, as that's bound to lead to inside wheelspin. Stiffening the rear bar will in effect "kill" the rear, which is kind of a last ditch way to fix understeer. That may be appropriate, but it's not where I would start.

Brian's idea of an adjustable length lever arm on the bar end is the way ARBs were adjusted on race cars for years. You would just have a series of holes on the arm, and then you can attach the drop link closer or farther from the bar to increase or decrease the stiffness. I think you are picturing the more modern cockpit adjustable rotating blade end, which I would agree is overkill.

Whoever is designing this needs to also look at how much roll the car is going through, so it can be translated into degrees of twist on the bar, and thus stress. If you get it wrong its not hard to overstress the bar and subject it to plastic deformation. Bending a bar in the middle of a corner is usually bad news.
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Re: Stiffer Anti Rollbar

Postby Peter D » Thu 21.03.2013, 00:01

Any development or outcome which on this topic (stiffer rollbar) ?

I've read the drop-links topic by BB, anyone who has them not in use and for sale ?
Or any alternative source available ?
Maybe someone has them still not mounted, and can make some technical details (relevant measurements) available ?
Most relevant would be the inside diameter of the ball joint...
Which one could it be, if this was the suppliers catalog link :
http://www.midwestcontrol.com/series.php?id=128
Speed has never killed anyone, suddenly becoming stationary… that’s what gets you.
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