Brake & Fuel Lines
 

Hello,

What size brake line is best to use for the roadster? Also how far apart do the need to be fixed to the chassis?

Thanks

David

Hi David

3/16" is the standard size for brake pipes, I prefer to use Kunifer pipe as it is not quite so soft as Copper but that is just a personal choice.

6mm or 8mm should be fine for the fuel pipes, again I prefer Kunifer pipe but copper will be fine.

Not sure what engine you are using but I would probably opt for 8mm fuel pipes.

Both Kunifer & copper pipe is very easy to source from the likes of Ebay or at you local motor factors.
The same can be said of the brake pipe fittings ( M10 X 1 for Ford fitment )

Not sure about the IVA requirements for the support of tubes as I have not done that particular job yet :o

I am sure that one of the builders will be here with the answer to that one shortly.

Hope that is of some help :)

Hi David,

As far as I know the MX5 brake lines are 3/16" with M10x1mm fittings (same as Ford),
and the MX5 fuel lines are 8mm, so best go for that.
For the fuel line I think most people use microbore copper pipe from the likes of B&Q:

http://www.diy.com/diy/jsp/bq/nav.jsp?action=detail&fh_secondid=9264633&fh_locat ion=//catalog01/en_GB/categories%3C{9372015}/categories%3C{9372046}/categories%3C{9372180}/specificationsProductType=copper_pipes/specificationsSpecificProductType=soft_coil_tubing

Hi David,

The manual says that all cables / pipes must be securely fitted at a max 300mm intervals and free from chafing. This reduces in the tranny tunnel though and needs to be every 150mm, preferably laid on a channel.

AndyH

Should that not be at most 300mm ;)

Yes thanks TT.....:p It's been a long week

min 8mm for fuel feed pipe if you use fuel injection return would be at least 6mm but its just as easy to plumb it all in 8mm

Is there any reason people dont use rubber fuel hose for the lot ?

I think the general consensus of opinion is that it is not desirable to have rubber hose hidden away in the transmission tunnel.

Rubber can & will perish at some point, could probably go undetected when hidden from view until it's too late, fuel leaking everywhere.

Solid pipe would be so much easier to fix & vastly remove the risk of chaffing trough ;)

If you mean regular rubber, it is definitely not suitable for fuel. But what you might call "rubber fuel hose", these flexible black "rubber-like" hoses, are actually made of Nitrile, a fuel resistant kind of rubber. Nitrile does not get damaged in time by fuel : that is its purpose. It is use in all aviation-type stainless steel braided hose for fuel and oil, commonly used on racing cars (Goodridge, Aeroquip, Speedflow, and so on). This is suitable for injection (needs to be braided because of the pressure). There is of course a non braided version for low pressure (carb), and I don't see why it could not be used on the roadster except if SVA does not accept it.
The only down side of Nitrile hoses is that it is porous to smells, and if the hose is crossing the cockpit, you might have fuel smell. More of a problem in a closed car than in the Roadster. To avoid that, and to stay in the flexible hose type, you need Teflon hose (but the price is even higher)
Hope these details help.
Bye.
Sylvain