Rollbar specs of Elise S2

[nobbles]

I'm interested in a track day but the technical requirements from the track stipulate that if the vehicle is a convertible then it must have a four point rollbar with substantial rearward bracing that passes through the decking and bolts directly to the uni-body?

Does it?

[Bonce]

Rollover protection in the elise is pretty damn good, with a rollbar built into the windscreen surround and another one behind the seats.
If it is not substantial enough, you can fit a cross-brace that runs diagonally across the car into the passenger footwell. Should be enough for the most adventurous of crashers!

[Elise4me]

For track purposes, the Elise's integral rollbar is fine, as it is built into the chassis. The "substantial rearward bracing" requirement is for true convertibles which only have a simple (mainly cosmetic) rollbar "hoop" bolted in behind the seats. The cosmetic "hoop" provides little or no protection.

[Elise4me]

go here for a picture of the chassis with integral rollbar and rearward bracing:
http://lotus.roadfly.org/lotus/forums/elise/forum.php?postid=2227&page=1

[fergusd]

Bonce said: Rollover protection in the elise is pretty damn good, with a rollbar built into the windscreen surround and another one behind the seats.

The Elise windscreen is not a roll protection structure, it's a foam filled plastic structure. It'll fold if you roll the car.

However because of the rake that it's already at, and the design of the car it probably won't intrude into the cabin too much, if you roll it on a flat surface.

The built in roll bar is a 4 mount unit, the main bar is braced (to the rear) and is bolted directly onto the chassis.

Having seen what can happen to the built in rollbar, and if I were racing the car, I think I'd put in a rienforcement package.

Fd

[joust]

Fergus,

I've heard a few people say that about the windscreen surround - however, when I had the accompanied factory tour at the last but one Lotus open days, the person who showed us around said that the windscreen *was* a roll over protection. The "foam" is, according to him, an integral part of providing protection (however we were standing around a MK1 at the time he was explaining this).

However, I've seen a few rolled Elise's and it seems that some of them they "bend" and some others they don't - so I'm not really sure what the truth is.

However, the angle between the roll over bar and the front of the nose of the car means there is a good amount of space if you do roll it!

J

[Bonce]

Strange, I don't know where I heard that it was part of rollover protection (I probably read it on the Internet ) but I'll be a bit more careful about passing that 'fact' on in future, thanks Fergus!
Strange that Joust has also heard conflicting information.

[joust]

Even stranger Bonce that it was a Lotus employee (presumably picked for the tours given his technical knowledge - he certainly knew everthing there was to know about how the things were made and bolted together) should say it was an integral part....

J

[fergusd]

Well, I don't know where this info is coming from, but I've seen 2 rolled elises at close quarters and the windscreen was flattened on each one.

In both cases the roll bar was intact.

I honestly cannot believe that a foam filled plastic tube can be considered a roll structure by anybody.

Unless of course the S2 has something strong inside the windscreen surround, like a substantial metal tube . . . perhaps that's why the S2 is heavier than the S1 . . .

Fd

>> Edited by fergusd on Sunday 2nd February 18:58

[DanH]

Don't remember the windscreen being squashed on that rolled S2 190... Hmm dunno. Given its construction I doubt it can take much impact though. The rear bar is good enough though imho, although without 4 points you are still going to cut the top off your head if you roll it.

[fergusd]

Depends on how tall you are.

The 3 point belt seems to work very well . . . knowing a guy that has rolled his S1 elise with only 3 point belts in use . . .

Fd

[DanH]

Also probably depends on how you roll. I suspect it would be very nasty if you slid along on the roof of the car given that its a soft top. If you are rolling quickly depending on the centre of roll I guess it may push you down into the seat (or up out of it...)

[fergusd]

. . . he slid aling the road on the roof . . . after ploughing into and out of a forest (by all accounts) . . . and stopped when he hit another car . . .

walked out with a couple of minor scratches . . .

Fd

[DanH]

Interesting to know that Fergus. I wasn't really going by any real evidence, just thining about the physics. Might save me 350 quid on harnesses though.

Tim Skipper who rolled his S2 190 did seem pleased to have been in the harnesses though, so hard to tell. I'd be bloody scared sliding on the roof in an inertia belt, although I guess if its worked properly you will be securely held.