Catalytic Converters - are the cheap ones any good ?

[Rufus Roughcut]

Anyone got any experience of using cheap after market cats come MOT time ?


I'm sure the bargain hunters out there will have stumbled across these, or similar...

http://cgi.ebay.co.uk/TVR-Cerbera-4-5-01-97-02-01-...

at £186 a pair delivered they appear to be a bargain, well, compared to just shy of a grand for OEM

On the face of it they do sound too good to be true

I've done a little bit of homework

http://www.catalyticconverter.org/about/index.htm

and understand the catalytic coatings will be thinner, generally the cheap stuff is designed to last 25k miles whereas OEM are designed to last 80K.

At that rate they should last me 10 years...

anyone got any experience of using cheap stuff on a Cerb


Mark

Edited by Rufus Roughcut on Monday 2nd August 19:47

[ridds]

I can guarantee that the pattern parts will not be hi-flow metalic foil cats like the OEM ones are, I think ours are 100 or 200 cell times where-as they will be 300-400 cell matrix style.

If you just need them for an MoT they'll be fine. I wouldn't run them permanently though as the back pressure will be pretty high.

[Ireland]

Are these any good ?

http://www.bmcatalysts.co.uk/details.php?id=4377

[Ireland]

Right so ..... update on the BM Catalyst ones

Their part no. BM-90558 is a 400-cell.

They can also manufacture a sports version, part no. BM-40558, which is a 200-cell (there would be a lead time of a few days on this as they are made to order).



ETA they are not cheap ones, about £300 each plus VAT for the sports ones.

The standard ones are about £40 cheaper.

Edited by Ireland on Tuesday 3rd August 10:06

[Rufus Roughcut]

Thanks for the info gents, very much appreciated

I'm currently running without cats, my initial thoughts were to buy and fit the cheap ones come MOT time.
I'd also like to do a track day, however there's no way I'd get past scrutineering without fitting track day silencers or the cats.

It would appear the cheap cats wouldn't be of any use for this...so sports cats it is

[Ireland]

I'm thinking of getting a set of the cheap ones with the "restrictive" cores for getting my car through the NCT (Irish equivalent of the MOT ..... only stricter on emissions ) and then going back to being de-catted for the resto of the tme.



FWIW would sports pipes behind cheap cats help reduce the back pressure ????

Just a thought .....

[ridds]

Nope, those cats would be the defining feature in the system.

[Rufus Roughcut]

Sorry to be a pain, would these 'universal' cats be suitable ?

http://cgi.ebay.co.uk/Universal-200-cpi-Sports-Cat...

I'm not sure of the dimensions of the originals (Car came without them).

The dimensions according to the seller are:

Overall Length 200mm
Maximum Diameter 100mm
Bore size: Choice of 51mm, 57mm or 64mm (I'm assuming 2.5" for the Cerb)

Obviously I'd need the appropriate length of pipe/flange (lovely word) welded to either end, if that cost me £400 I've lost nothing.

I've read the blurb, it says the substrate is made of a stainless steel monolith ? .....sound good to me

[ridds]

SHould be fine providing you get your dimensions right. The tricky but will be getting the flange right.

[Ireland]

I'll see if I can get at one of my old ones later to measure it.

[JensenA]

Ideally you should spend a bit more and go for 100 cell cats. 100 cell CATS will have a negligible effect on power and will be almost as good as having a de-cat system.

[Ireland]

Dimension time .....

The following are the details of one of the cats off my 4.2


Flange pipe OD - 53mm

Cat body OD - approx 105mm

Overall length (incl flanges) - 448mm

Overall length (to where the flanges are welded in) - 360mm

Length of the honeycomb - approx 200mm


There is a number stamped on the cat E 5516116 08

[SL500]

I normally run with no cats and put the only good one I have for the MOT in.

The cats are actually too far from the engine to get hot enough anyway to work as well as they should. Mine always struggles.

Just get a good second hand one.

[Ireland]

JensenA said:

Ideally you should spend a bit more and go for 100 cell cats. 100 cell CATS will have a negligible effect on power and will be almost as good as having a de-cat system.

Would they pass MOT / NCT though?

[mybrainhurts]

Don't know if this is relevant to you lot, but I spotted a notice in a Quick Fart outlet yesterday...

Vehicles manufactured after 1 March 2001 must have a "Type Approved" cat...

Penalty, if not, up to £5000 fine.

That'll be a bit of EU arsery, I would imagine.

[ridds]

It 's also "technically" not allowed to interfere with the emission control system of a vehicle in any way. Which means the exhaust system and catalysts......

Still, 'tis only rules.

[JensenA]

Ireland said:

JensenA said:

Ideally you should spend a bit more and go for 100 cell cats. 100 cell CATS will have a negligible effect on power and will be almost as good as having a de-cat system.

Would they pass MOT / NCT though?

Yes - My Saab failed the MOT on Emissions, no CAT was fitted. I fitted a 100 Cell sports CAT and it sailed through, emissions were almost Zero, and performance of the Car, it's a 300hp Saab 9000, hasn't suffered bit - well not that I can tell anyway.

[jammy_basturd]

When someone on PH asked to borrow some cats on here about 3 weeks ago there was no end of offers. What about just buying some de-cat pipes and borrowing some cats come MOT time.

[Rufus Roughcut]

Ireland said:

Dimension time .....

The following are the details of one of the cats off my 4.2


Flange pipe OD - 53mm

Cat body OD - approx 105mm

Overall length (incl flanges) - 448mm

Overall length (to where the flanges are welded in) - 360mm

Length of the honeycomb - approx 200mm


There is a number stamped on the cat E 5516116 08

[Rufus Roughcut]

jammy_basturd said:

When someone on PH asked to borrow some cats on here about 3 weeks ago there was no end of offers. What about just buying some de-cat pipes and borrowing some cats come MOT time.

I've got the ACT six silencer jobbie with decat pipes fitted already

There is another reason I'd like to fit a cat, I don't like the fume smell of decatted cars.