Lexan Firewall for Mid-Engine project?

[nedge2k]

Hi,

Slowly converting a front-engine coupe to mid-engine. Anyone know if Lexan can be used for the entire firewall? Or would it have to be half steel/ally (up to the height of the engine) and then Lexan thereafter?

TIA

[NoCorseChris]

Lexan isn't fireproof as I'm sure you know...so using it as part of a firewall isn't going to pass any kind of official scrutiny I suspect. If there is any way the layout will allow you to box in the engine with fireproof materials, removable if need be, but sealed, and leave you some space for a rear view, that would be preferable.

[PaulKemp]

Colin Chapman famously painted some cardboard with aluminium paint and tried to convince scrutineers it was a firewall.
I suspect lean would provide a similar level of protection

[CrutyRammers]

You'll have to read the manual:
https://www.gov.uk/government/publications/iva-man...

IIRC there's nothing which specifies materials like this, it's more general guidelines about preventing fuel getting into the passenger compartment etc. Various cars are made of GRP and other composites so they won't have a fire proof "firewall" either.

If you can't find anything, check with VOSA, or whoever they are now (DSVA is it?) Their policy department has been very helpfull when I've emailed them specific queries like this in the past.

[dom9]

nedge2k said:

Hi,

Slowly converting a front-engine coupe to mid-engine. Anyone know if Lexan can be used for the entire firewall? Or would it have to be half steel/ally (up to the height of the engine) and then Lexan thereafter?

TIA

Would love more details of this project!

[Steve_D]

Would help if we knew what legislation you are working towards.

If a race car then the term 'firewall' is likely correct and would need to be metal.

If you are heading for IVA then just call it a 'Bulkhead' and make sure it is sealed to the passenger compartment. As has been said, plenty of kitcars have GF bulkheads so your Lexan would not be an issue.

Steve

[nedge2k]

Cheers guys, bulkhead not firewall, gotcha

Initially it'll be a road car. If I can find a category of motorsport to be legal in without having to chuck 20-30k at it to make it competitive, i'll look at that once the novelty wears off :P

Bought the car as an unfinished project a couple years back, not had time to spend on her but i'm starting to pull all the bits together now. The engine has been the major thing...

http://nedge2k.com/projects/fiat-2.0-20v-na-race-e...

http://nedge2k.com/projects/mid-engine-fiat-coupe

[dom9]

That looks a fun project - would be great to see a build thread in Reader's Rides!

[Steve_D]

You had best be getting the IVA manual down loaded as you are going to need it bigtime.
This will also be a Q plate which I doubt will be an issue for you.

As has been said get a build thread going as there are plenty who will be interested and again plenty who can offer advise.

Steve