Scottish Elises

Did anyone else see last night's wheeler dealers? - the Noble. I know there are plenty who don't like the show, but I don't take it too seriously and quite enjoy it, and quite like some of the wee tips and things I learn too.

In last night's show, Ed decided to fit a baffled sump to the Noble they were doing. In order to access it, he cut out a chassis cross member. In his words "converting it to a removable section". He modified it so that he could refit it with a single bolt at each end. I am no engineering expert, but surely that mod would have no where near the structural rigidity of the original. To me that seemed like a crazy way to go about the mod. Thoughts?

At 27 mins;

Watch on YouTube

Totally agree Dominic; I'm a millions miles away from being an expert, but it looks like a total bodge to me........ Cutting away a section of the chassis because he couldn't be bothered removing the engine? Begs the question, what other corners did they cut?
I noticed there was a disclaimer at the end stating that all modifications were legal when the show was produced.

I wonder if they are the first to do it, or if it's a common "mod" with owners for servicing/sump access? Might even be factory sanctioned? Seems drastic for an unnecessary upgrade, but I wonder if the mod was invented by somebody who had some essential work to do but wanted to avoid engine-out?

I'm with Graeme - they tend to be very internet savvy and are pretty switched on about how to go about stuff before they plan a show - I'd be massively surprised if that wasn't an accepted mod and he'd just hacked away at a chassis with no investigation.

And Edd China does have an engineering degree, supposedly.

I used to hang around the odd Noble forum when I was contemplating getting one, I seem to remember this was a fairly common mod back then.

Okay so common mod, maybe I was harsh in being critical. Do still wonder, common mod or not, is it ill-advised. S'pose not if "common".

Having messed around with the space frame chassis on the caterham, I think there are two engineering aspects to it. Firstly is the strength, and on that I suspect this mod is similar to the original - at least up to the point of failure. Secondly is the stiffness, and this probably where it suffers most, but whether that's important, or even noticable, is a matter of opinion.

Caterham switched from brazing to welding their chassis and that reportedly increased stiffness by 12%.

It does seem like a bit of a cowboy approach but it's not a load bearing part of the chassis as such. By that I mean it's won't really effect the structural safety of the car/chassis as that section is just a cross brace to provide a bit more rigidity under hard cornering. Think of it in the same way as the cross bracing above the engines in lambo's. They bolt in and out for access as well only difference being that it was designed that way from the outset. Provided the bolts are suitably rated and holes are correct for the bolt and not massively bigger then shouldn't really have any effect on the car.

That said just because it's possible on that particular car doesn't mean you can go taking your angle grinder to any car/ chassis willy-nilly

Yes, would need to see the whole chassis arrangement and if it's ever possible to overload this particular crossmember or indeed how loaded it actually is. You might find it's not fully utilised and it's cross section is a convenient size for manufacture rather than on the limits of structural integrity.

Carefully looking at the bolting arrangement any loads would be transferred via friction between the original box section and the welded tabs on the new removable part (not via bolts/holes Si). This frictional connection is preloaded by the pretty chunky bolts. The tabs are obviously much less stiff than the original box section but over a very short length so I doubt it would have that much impact on the overall member tensile/compressive stiffness.

Maybe a 'shear panel' would add rigidity/move failure point elsewhere...

Just had a search and it seems to be suggested that Noble themselves introduced a removable chassis section from about the time the M400 started production, so hopefully they did all the homework to ensure its a suitable.

Discovery now, Noble show