Advice on exhaust fitment required


ibiris

Armourer
Joined
Feb 26, 2012
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37
For anyone interested, and for future reference I've gone for the following. Original, rather lengthy, message is below.

UNIVERSAL-FIT CATALYTIC CONVERTER Part #59956

I found a number for Nemesis UK, which are a official distributor of Magnaflow products. Spoke to a helpful chap who recommended this cat, as it has a metallic core (the one I was looking at was ceramic core). It's only 8" overall length, but we came to the conclusion that coming up short was better than being too long, as the exhaust fitter could fabricate a pipe to fit. Just got to order the O2 sensor and hopefully can get it all fitted in the next couple of weeks.



Original message:

I've currently got the standard OEM exhaust system fitted to my EK4. The manifold and cat are pretty much knackered. I've managed to get hold of a second hand DC Sports 4-1 manifold for a decent price, whereas I was going to spent £400ish on a Tegiwa one. I realise it might not be as good for this application, but I've saved some pennies.

The DC manifold has a 2.5" collector. I intend on keeping the standard B-pipe and back-box fitted for now because I don't want to spend the money on a custom cat-back - but will be doing so in the future. My intentions would eventually be for a 2.5" diameter exhaust throughout.

Since the cat is knackered, I will be taking the opportunity to replace that when replacing the manifold, with a high flow cat.

Having searched the web for high flow cats, I've come to the conclusion that the following Magnaflow one would do the trick:
Magnaflow UK Performance Exhausts - Performance Cats
Please scroll to item Part No 54306.

The plan I've come up with now is; to fit this cat along with the DC manifold, and keep the standard b-pipe and back-box. There are just a couple of things I'm unsure about, and have doubt about the compatibility of it all.

The manifold came off an EK9, hence my choice for a cat of 13" overall length. If the cat is cut to fit (12" overall length required I think) and fitted with a 2.5" flange at either end, will the rear end mate to the OEM b-pipe (which I believe is 2.25" diameter) okay? Or will I need to fit a 2.25" flange to the cat and then replace that in the event that I fit a 2.5" diameter custom cat-back?

I'm hoping that I can get away with the 2.5" in-out cat, and with clever use of a gasket, fit it to the 2.25" b-pipe and still keep it future proof.

Also, is my choice of cat fit for purpose? Not knowing too much about them, I've picked this one following reading a few other threads. I've considered a decat, but would prefer this to save changing come MOT time.

If the Magnaflow cat is the one to go for, where on earth do I buy them?
I can't seem to find the Part Number I want on the Nemesis eBay store, and the only other option is Tokyo Express (anyone have experience with them?).

Any help/advice would be much appreciated.
Thanks.
 
Last edited:
can you ask the question in a shorter way? cliffs? sorry i try to answer as many threads as possible so i cant read the really long questions.
 
I'll try:

Is it physically possible to fit a cat of 2.5" diameter to a 2.25" diameter B-pipe and still maintain a gas tight seal? Or will I need to fit some sort of reducer in between to make them compatible?
 
If the 2.25" B-pipe has a 2.5" flange then its a perfect fit. If its not a 2.5" flange then you will need to modify the flanges on the cat and b-pipe to make it fit, then put a reducer from the flange onwards to fit onto your 2.25" b-pipe.

Just some standard cutting and welding which is your standard everyday job in an exhaust shop.

Just bring your car in and they'll know what to do.
 
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