fiestaturbo.com

[matt_h76]

Hi

I want to fit a backbox to my XR2i... however I see quite a few backboxes for sale that are "universal" and have an inlet diameter of 2.5"...is this too big? Ideally what inlet diameter should I need on the backbox to fit my XR2i pipes... I was thinking closer to 2" would be a better fit??

Thanks for any info.

Matt

[heeman10]

I THINK the 2i backbox is 52mm, but I could be wrong

[dave_si]

If im right the 2i 16v uses the same system as the 1.6si. This has a bend in so most "universal" backboxes will not go on without some sort of fabrication.

And the bore size, if the same as the si, it is 48mm.

[baz1986]

no the 1.6 si is a different bore to the 16v2i cos i had probs wen getting my backbox for my 1.6 si! i think the 16v2i bore is 52mm, and with the si you need 52mm internal as they gave me a 2i backbox to try and the bore was exactly the same so it didnt fit. in the end sportex made me one to fit my car.

[Ollybee]

That's strange cause when I got a new one on my Si it was the same as the RS1800 exhaust

[javablu]

thats because the RS1800 is the same as the si just a different size engine

[baz1986]

thats because the RS1800 is the same as the si just a different size engine

well it aint the same then!, was jus saying what happened to me when i changed my backbox, when every one else changed theirs on an si did they need a 52mm internal?

an exhaust for a 1.6s is even harder to get no one makes one my mate is try to get one at the momment!

[matt_h76]

What inlet diameter on the backbox should I go for? The backboxes I've seen either have 2" inlet diameter, 2.25", or 2.5" inlet diameter. Which backbox would fit my XR2i? By the way my XR2i is an H-reg 8v (not sure if that makes a difference)

Cheers

[dave_si]

the red bit circled is 48mm on an si

[Ollybee]

thats because the RS1800 is the same as the si just a different size engine

That's what I thought.

[baz1986]

well i have a ford fiesta si 1.6 16v n reg and the diameter of my bore is 52mm and thats been measured several times! before any one asks its the standard ford bore and had never been changed!

[Ollybee]

well i have a ford fiesta si 1.6 16v n reg and the diameter of my bore is 52mm and thats been measured several times! before any one asks its the standard ford bore and had never been changed!

That's right, and it's the same as the RS1800 and 2i 16v

[matt_h76]

the red bit circled is 48mm on an si

So assuming the bore size on my XR2i is 52mm what size inlet diameter (in inches) do I need on the backbox (or bore adapter)? Does it have to be slightly bigger than 52mm?
(Just looked at ruler and 52mm seems to be equal to just over 2".)

Thanks for any help

[baz1986]

it needs to be 52mm internal so it slips straight over standard bore. thats exactly the same as mine.

[matt_h76]

it needs to be 52mm internal so it slips straight over standard bore. thats exactly the same as mine.

Is your car an XR2i too? If it is then I'll look for a backbox with inlet diam of 52mm then. I'm pretty sure my standard bore size is 52mm ...just as some else said further up. Basically I assume if my bore size is 52mm then I look for a backbox with same size inlet diameter? Is this correct...or does the inlet diameter have to be slightly bigger??

[baz1986]

no i have a 1.6 si, to be honest mate i would measure it if i were you, just to be safe as i got information about the size of the bore and it was wrong so i had to send it back to sportex for them to change it, just get under your car and measure or just take it to ATS or someone like that to measure it to be save, but yes you should need 52mm internal but as i said nothing beats measuring it!