Board logo

Catalytic Converter Selection
SteveWallace - 17/2/14 at 05:02 PM

The exhaust maker/fitter is booked for next month and after that the Viento will be off to IVA. Hopefully I will get through IVA and DVLA registration in time for Stoneleigh.

I'm running a 1997 2.8 BMW engine so it will need a cat. I did a bit of e-bay and internet research and my choices seem to be 100, 200 or 400 cells per square inch, which Demon Tweeks describe as motorsport, performance and standard respectively. At around £140 from D-T, they all seem to be cheaper than what I was expecting given what they are made of.

The question is, how big a cat do I need to make sure that my big straight 6 gets through the emissions test. I'm thinking of going for 400 CPSI to be on the safe side, but obviously they have more restricted gas flow than the other units.

Any thoughts, advice or suggestions for alternative suppliers would be appreciated. Also, ideally I would like a mirrored steel one, but D-T only seem to do brushed stainless

mark chandler - 17/2/14 at 07:48 PM

You only need to achieve 3.5% so 200 will be fine.

£140's a lot, I got a spun stainless one from Profusion on eBay £90, you need to add a bung and plug on top.

Regards Mark

adithorp - 17/2/14 at 09:21 PM

quote:
Originally posted by mark chandler
You only need to achieve 3.5% so 200 will be fine.

£140's a lot, I got a spun stainless one from Profusion on eBay £90, you need to add a bung and plug on top.

Regards Mark


Post '95 engines have to meet 0.3% CO, 200ppm HC, and 0.97-1.03 lambda

400cpi will get the CO down easily. 200cpi will do as long as it's well warmed up (thats what I used). 100cpi will be very iffy/borderline.

SteveWallace - 18/2/14 at 09:59 PM

So by the sound of it, I need either one of these...

2.5"' SPORTS EXHAUST CATALYTIC 200 CELL CONVERTOR CAT UNIVERSAL STAINLESS STEEL

Or one of these...

Magnaflow cat

Even though the Magnaflow one looks better made, I'm probably going to go for a mirrored finish on the exhaust system to match the mirrored sides of the car. Does anyone have any experience of the Turborevs ones before I buy?

SteveWallace - 5/4/14 at 07:03 AM

Just an update on this thread following my IVA test yesterday, which I failed on a couple of things, but not the emissions.

I ended up going with a Magnaflow 200 cell sports cat

Magnaflow Exhaust 200 Cell High Flow Sports Metallic Catalytic Converter Cat

With this my results were as follows, so well within requirements:

Fast Idle CO = 0.04% (needed to be <0.2%); HC 25ppm (200ppm); Lambda 1.013 (target 0.97 to 1.03)

Idle CO = 0.1% (target <0.3%);

Just thought that I would log the result in case others needed to go down this route.