McPikie

Right, as most of you know I have got a MK4 MFi XR3i.

It currently has a full stainless system which I am assuming is 2" bore. But, and this is a big but.................. it has a DTM tailpipe Now dont get me wrong, it sounds really nice and pops/burbles like a good one, but they just look soooooooo shit.

I was thinking about cutting the upswept bit from the tailpipes so it looks like a jap-style slash cut or fitting another backbox.

I already have a 4" scorpion (awaits the sniggers) off my mates old ERSturbo, but obviously this is gonna ba a bigger bore. If I get the correct pipe down sizer so it fits right, will it be detrimental to the engine? How much back pressure is actually needed?

I was told scorpions were restrictive for RST's so surely this will be fine on a 3i???

Please help before I am ridiculed for this disgrace for an exhaust

CabrioTurbo

ive got an Magnex RST back box if you want to bodge that in?
Before my cab got turbo'd it had the downpipe off a 3i then it was propper bodge welded from where the 2 go into one onto an RST system with a maxgex backbox sounded fuckin mint!

CabrioTurbo

or you could just buy an ashley back box for 60 odd quid. sound good ive had one of them before too lol

McPikie

With the amount of things going wroing for me at the moment I am not liking the sound of that

This 4" I have is just the backbox and the S pipe up to where it bolts to another system. I like the 4" sounds and looks on RST, just not sure whether I will loose power with it?

CabrioTurbo

no idea! the magnex i had was a propper pea shooter and there was no chance of loosing any back pressure with that on

Sticky.

iTrader: (4)

There's a bloke in Wigan that will weld you a new tail pipe on your back box.

Any size etc, he's got the tailpipes on the shell from 2" to 5" rolled out.

He charges about £30/£40 depending on tailpipe all in

Ive got his number if you want it

McPikie

I really wanna put this 4" on tho.................... but will it run ok/do any damage?

mattysxguy

just do it and see what happens

McPikie

That's some real shit hot tuning advice that mate.

Stu, can we put that in the technical section as a general rule of thumb for problem solving?

mattysxguy

well surely the internals of the exhaust are the same what ever tail pipe sticks out the back of it

McPikie

Different bore size you fool. I need to know if its gonna be a hinderence

McPikie

BUMP for the clever peeps

Escy

bore size of a back box shouldn't really matter anyway. an exhaust is only as free flowing as its most restrictive part which in your case would be the rest of the exhaust.

kay2

get someone to cut the box open and weld in the correct size pipe??

McPikie

Awesome, I will throw it on.

Where can i get a pipe downsizer, dont really wanna just "clamp it on tight"

CabrioTurbo

halfrauds sell them i think! i also think 'sossymad' does them as well

McPikie

yeah, but his will have a fucking neon ring round them

Escy

go to any exhuast place (the ones that sell shite standard replacements) and they should be able to get a reducer for you.

Big G

Get the luxury edition Cherry Bomb, set it to 'Rasp' and job's a good un

McPikie

Afraid I am no longer welcome at Stanley Green so it would be wasted on just my neighbours

It's Czech Mate

IIRC the best bore for a n/a 1.6 cvh exhaust is between 2.5 - 3 inches, anything bigger was detrimental due to the loss of backpressure, I have an idea it's quite important to have the correct bore exhaust on an n/a cvh due to needing the right backpressure, something to do with the way the combustion chambers are on a CVH??? I read an article on it somewhere and cant think where.