Clips the undertray bolts screw into?

C clips.
Any harware store should have them

Technically, they are called "Spire Nuts". M5 size/thread.

These are special because they are self-retaining fasteners that bring extra strength and reliability wherever vibration, impact or migration prevails.

Make sure you get stainless steel ones.

Regards,
Wayne

waydui said:

Make sure you get stainless steel ones.

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Why SS? Wouldn't that react with, and corrode, the aluminum? If you use zinc plated steel, it might corrode eventually, but would protect the aluminum parts and could just be replaced as needed.

MattG said:

Why SS? Wouldn't that react with, and corrode, the aluminum? If you use zinc plated steel, it might corrode eventually, but would protect the aluminum parts and could just be replaced as needed.

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I said SS as it is the best compromise for minimizing possible corrosion.

I'm in the aluminum business and we deal daily with fastening issues for this metal.

That said, a brief explanation:
1. Aluminum and Stainless Steel both have a thin oxide layer. These two oxide layers, when in contact with each other, tend to "insulate" the two metals from galvanic reactions, which lead to corrosion.
2. Ferrous fasteners on aluminum are the worst combination as they will definitely lead to corrosion.
3. Zinc isn't much better as both zinc and aluminum are very "active" metals. The aluminum will actually sacrifice itself (corrode) to protect the zinc it is in contact with. Aluminum is a very sacrificial metal.
4. A better solution is to use plastic washers on the assembly between dis-similar metals (which I do), to minimize corrosive reactions.

Regards,
Wayne

order them from FVMC, they are relatively cheap.
the screws are available from fastenal and they're cheaper yet.
buy a hundred screws and pass them out to your friends.
also, the washers are available in SS.
sam

Always nice to know our chassis is made out of "sacrificial metal."rotfl

dasmoofler said:

Always nice to know our chassis is made out of "sacrificial metal."rotfl

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Don't worry, our cars won't self-destruct becuase they are made of aluminum!! anic:

I was making a general comment about aluminum. I'm sure the specific aluminum alloy used in the tub and other parts are chemically optimized to minimize corrosion potential.

Atmospheric corrosion of aluminum is very rare. The metal is very good in these applications, such as cars. It is when moisture or water is introduced that you can get cathodic reactions depending on water, ph, presence of heavy metals, etc.

Probably too much information, but thought I'd pass it on.

Regards,
Wayne

Gonna replace my frame with Alka-Seltzer.

madden said:

When you bolt the undertray back onto the car the 8mm bolts screw into those metal threaded clips. does anyone know what those clips are called and were I can order some? I lost a couple and need to get more but dont no what they are called.:thwack:

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Bought mine from lotusgarage.com

waydui said:

Don't worry, our cars won't self-destruct becuase they are made of aluminum!! anic:

I was making a general comment about aluminum. I'm sure the specific aluminum alloy used in the tub and other parts are chemically optimized to minimize corrosion potential.

Atmospheric corrosion of aluminum is very rare. The metal is very good in these applications, such as cars. It is when moisture or water is introduced that you can get cathodic reactions depending on water, ph, presence of heavy metals, etc.

Probably too much information, but thought I'd pass it on.

Regards,
Wayne

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Yeah, I was just joking around
My van has aluminum running boards and after 9 years they're doing much better than the body.

i got a box of those clip nuts from mcmaster carr.its hard to find the exact same type used on the lotus.the ones i got have a ring that drops down into the hole.so you have to drill the hole larger.or bend the ring up.i found them on lotus garage.but i have a problem paying 2 bucks a piece for them.a box of 25 at mcmaster was 8 bucks.

dasmoofler said:

Always nice to know our chassis is made out of "sacrificial metal."rotfl

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But the aluminum is much less "sacrificial" than the steel that most cars are made of.

Seriously, the Aluminum chassis of the Elise should outlast a typical steel chassis by a factor of at least 5 (unless it gets bent).