Mk2 catalytic converter replacement

 Hi guys

Our Catalytic converter on our car has seen better days. it scraped through the mot but was told it really needs replacing.

The car is a 1999 Mk2 Rs 1.8 roadster. I have checked under the car and the replacement part on mx5 parts looks like it matches the one fitted to the car.

Now, the Mx5 parts type comes as a catalytic converter and middle box as one unit at a staggering £500 plus pounds!!!

I’ve seen lots of places doing just the cat but my question is can I replace just the catalytic converter without the rest of the middle box and pipe. So just keeping the original middle box as it is?

I’m guessing the pipe would need to be cut but has anybody done this before. I cant afford the £500 for the replacemtn complete unit especially when all i need is the catalytic converter on its own.

Any advice is appreciated.



 Hello Tony, 

When I had my Larini exhaust fitted about 18 months ago I also changed the cat / mid pipe. 

I bought the FM High Flow Sports Cat from Phil at Performance5 for around £250.  Obviously exchange rates have changed since then but it might be worth a try - it’s still advertised at £259.


 Great, thanks for the information.

I checked and they are now at £260.

Does anybody know what the ones on ebay are like? They are available on there for approximately £100 and seem to be from reputable companies not some dodgy bloke selling catalytic converters.

My only concern is that they look as though they come without the mid section pipe and silencer so am wondering how they would fit. is it a job i could tackle or a case of take the car to the local exhaust centre to fit?





When mine was replaced I was suprised at how good the original looked.  Considering the age I was expecting it to simply fall to bits.  But the midpipe looked in good shape with plenty of metal left.  This was apparent when the garage sliced it through as a simple way of getting it off. I wish i’d kept it now!

I suppose if your prepared to persevere it may be possible to slice out the old cat and weld in a new one.  My daughters Ford Focus exhaust was recently upgraded and the local garage had various adapter sleeves and connectors for joining onto the existing cat / midpipe.  But I bet most garages will say its not economically worth it.

Good luck 

 I think the idea with the Ebay ones is you cut out the old one and the new one clamps to the remaining bit of mid pipe by way of a slip joint. The FM job come in 2 parts as well, but a nice, well priced bit of kit.