So I have decided I will build a custom system, on the design of the Miltek System.

I't can't be that difficult to do, especially when basing it off a system just paying a quarter of the price.

Stainless steel is cheap to buy and I have a stainless stell fabricator buddy who for a bottle of booze will weld it all up.

Problem is, I know Milltek run a 2.36" pipe, which is ahn odd size to buy off the shelf, so thought I would go for a 2.25" system, only to find that stainless is not available in NZ in this size... weird.

I now have to decide whether to take a step up to 2.5" or step down, to standard 2" piping.

Has anyone ever known a 2.5" system on the Fiestas? I'm worried I will loose too much back pressure, though running a 2" I'm worried there will be very little advantage.

Advice would be good. I know it would probably be much more straight forward to just buy a Milltek, though, given my past project cars, am trying to be a little sensible with what I am planning to spend on this.

Appreciate the help in advance,

T

Id use smaller tubing tbh.

I agree go smaller mate

The milltek is 60mm, surely that would be available in NZ?

Milltek is 63mm which is 2.5"

Here it says 60mm
http://www.millteksport.com/exhaust.products.cfm?variantid=171

I measured the milltek cat-back I've not fitted yet and it's 60mm outer diameter. (The bore itself is 57mm)

Ahh ok, so that's outter diameter...

You would think so aye, but one of the pipe suppliers reckons id have to ship it in from the US and noone has the tools to bend it in NZ...

I should think 2.5 will be fine, I'm sure that's what the Milltek is. It's slightly bigger than standard but the biggest restriction in the exhaust system is the flexi pipe. I was shocked when I swapped over that puppy and saw the difference in internal diameter!