5th gen catalytic converter help MOT....

Feeniks · Post by **Feeniks** » Thu Apr 09, 2020 12:15 pm

Hey Luders,

The cat on my 5th gen Vti ('97 black top) is rattling and the garage tells me that eBay aftermarket cats cause MOT failures, and I need to buy an expensive sports cat. I also worry that the broken cat is choking the poor thing, but still feels lively enough up at 7k!

So, what advice can people give me, please, including vendors, success stories, second hand cats for sale...

Thanks!

Scott560 · Post by **Scott560** » Thu Apr 09, 2020 6:53 pm

I'm pretty sure you only need a 'type approved' cat if your car is newer than a prelude (2002 onwards?). Otherwise, eBay cat is fine for getting through an MOT. A rattling cat may soon clog up and cause trouble, mine took about 2 weeks from the track day before it started causing trouble.

Feeniks · Post by **Feeniks** » Mon Apr 13, 2020 10:16 am

Thanks Scott. The garage said it would fail on emissions, but I'll check the MOT requirements carefully now to see, and check the last MOT certificates.

Scott560 · Post by **Scott560** » Mon Apr 13, 2020 11:11 am

From the internet:

Do I Need a Type Approved Cat?

If your car is X registration or older and therefore first registered before 1st March 2001 you DO NOT need to buy a Type Approved catalytic converter.

If your car is Y registration or newer and therefore first registered on or after 1st March 2001 YOU MUST buy a Type Approved catalytic converter.

Post by **vanzep** » Mon Apr 13, 2020 11:13 am

I replaced a cheap ebay cat on a 2.0 1996 4th gen with the same cheap ebay cat (non approved) to get it thru the mot - emissions were practically zero so these cats do work - the question is for how long? I also had any holes in the exhaust welded up and did an engine flush and added a petrol treatment (forte). Ive also heard a few people say these sports cats (magnaflow) dont last forever either.
best bet is genuine honda cat in good condition if you can find one - you can always find a decat pipe to fit after mot if you want a bit more performance or for track days although very few folk can be bothered swapping them in and out

Feeniks · Post by **Feeniks** » Tue Apr 14, 2020 11:09 am

Thanks for the help!

The issue with buying a genuine Honda cat is that it'll also be quite old and prone to breaking up, and your feedback on using a cheap eBay one and passing is very helpful. Once lock down is lifted I think I'll visit an exhaust specialist and see what they can offer. The car isn't tracked or driven very hard (but VTEC regularly enjoyed

) so hopefully a cheap cat will do. I'll come back and update this thread once progress happens.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Apr 14, 2020 2:36 pm

I think 'type approved' or not, isn't really the issue here - it's just whether eBay cats are actually decent quality or not (not 'fake')

Cats generally aren't as expensive these days as people remember them to be (because they're now so common/large volume) and there are plenty of more 'legit' sources than some of the eBay sellers though, e.g;
https://www.cats2u.co.uk/2301-22

Interestingly... Downpipes on there are coming up amazingly cheap, too!

Post by **Vtecmec** » Tue Apr 14, 2020 9:11 pm

Bloody hell, they are some low prices.

Scott560 · Post by **Scott560** » Tue Apr 14, 2020 9:45 pm

if you look closely though, the downpipes look gash , huge double bends, no where near the quality of the OE part. Yeah it'd probably last a couple of years or a touch more, but i bet it fits like pants aswell. i resisted buying one and instead had my flexi repaired when the gearbox was off. I think the OE one is double skinned aswell.

Could be wrong , but cheap stuff is generally cheap for a reason.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Sat Apr 18, 2020 12:17 pm

Scott560 wrote: ↑
Tue Apr 14, 2020 9:45 pm
I think the OE one is double skinned aswell.

JDM downpipes are double skinned, UKDM aren't. The JDM second skin is just a heat-shield, performs no other purpose.