Legalities of removing a catalyst

You're OK to remove this as due to the age of the car the emmissions test is at a higher level than later vehicles - and a CAT shouldn't be needed to pass.

D. Brown ( snipped-for-privacy@nottingham.ac.uk) gurgled happily, sounding much like they were saying :

No. A cat's only required on post 8/92 cars.

As I understand it '91 cars had to be fitted with cats by british law (Volvo and Saab fitted them before then though) but MoT's don't take them into account until '92 for some reason. Thats why Saab 900 buyers who are performance oriented tend to buy '91s and replace the cat with straight pipe for a few more bhp

Ken ( snipped-for-privacy@lboro.ac.uk) gurgled happily, sounding much like they were saying :

That's because they didn't have to be fitted until 1/8/92. So that's the MOT date.

Thanks for all your replies, they've been very helpful.

I'd be interested to hear if anybody has actually done this as to how it affects the car in general. Obviously it'll shorten the left of the world because of the emissions, but will fuel economy suffer?

The fuel injection and other electronic wizardry in there was all designed as one system after all.

When I've done it (cos I probably will) I'll report back and let you know.

Dave

D. Brown ( snipped-for-privacy@nottingham.ac.uk) gurgled happily, sounding much like they were saying :

It'll probably improve without a bloody great big block of stuff in the middle of the exhaust.

It *may* affect the mixture because of the freer breathing, but - given that a cat'd be paired with a lambda, it should sort that out automagically.

A cat as such isn't required. The car must just pass the emission regs. Which in practice means a cat. ;-)

As Adrian said, you will notice an improvement. I did the same on my 740

-- Stuart

used to rip the cat out of my Xedos 6 and replace it with a bit of pipe, and bolt the cat back in for MOT tests. ECU cottoned on after a few miles and all was sweetness and (ever-so-slightly elevated BHP) light. YMMV.

Postscriptum: Aw, hell with it, just do it, the damage has been done to the environment, let's have scorching December beach parties.

....and it applies to the date of manufacture of the engine, not the car. If you install a replacement engine which dates from before 8/92

- and can prove that fact - then you should be MoTd on the earlier emissions standards.

David Betts ( snipped-for-privacy@motorsport.org.uk) The Classic Car Gallery:

Question -

Do cars in Britain have a compliance plate? Here we have a compliance plate which has the design rules (number) stamped on it which are applicable at the time the car was manufactured.

Example - So if a car was manufactured in say 1977 at say ADR27 then it did not have to have a Cat exhaust even though the manufacturer may have fitted one to comply within another country and then its quite legal for it to be removed. (the US was the most stringent)

This is our compliance situation.

Rob ( snipped-for-privacy@mine.com) gurgled happily, sounding much like they were saying :

No.

The default rules that apply are those that apply to the date of first registration of the car. If your car gets some kind of exemption or exception, then it's down to you to prove it.

Yes, it certainly looks easier to just cut the cat out and replace it with a straight pipe rather than the old fashioned front silencer arrangement. I was thinking it may be a bit on the loud side if I tried this though? What was your 740 like noise-wise when you did this?

I had a 240 with the 2.3 in, they're good engines. It easily out-lasted the body.

Thanks again for your help.

Dave