Any Advice?

[Laird Scooby]

Originally Posted by Chris152

This is another thing we're coming up against - I've realised both 2.0s have catalytic converters (G, 1990 and J, 1991). I see the cat led to about 10% reduction in power, so if it has to be a 2L, it really has to be no cat?
I do hope people don't mind my endless questions, it's way more complex than I'd assumed!

Yes, either that or decat it after you get it. It's legal to decat a pre-1992 car as cats weren't an original requirement, just optional.
There are ways to legally decat post-92 cars as well such as converting to LPG but as yo're looking at cars before that time, not really relevant.

Purely for comparison, the cat version of mine which is the B280F develps 146bhp, mine being the non-cat version (B280E) is 170bhp so more like 15% power loss just by having a cat!

Remember that also impacts on fuel efficiency so arguably decatting will give you 10-15% more economy as well.

[Clifford Pope]

Originally Posted by Laird Scooby

Yes, either that or decat it after you get it. It's legal to decat a pre-1992 car as cats weren't an original requirement, just optional.
.

I believe July 1992 is the crucial month -not sure which actual date.

It's important too for meeting MOT emission standards. Post July 1992 and you get the full works.
Pre-July and the test is the older and much easier to pass standards for a carburettor engine.

[Chris152]

Is it an easy job to do - do you just fit a new exhaust system or are there complications? I did do a search but found little. And would it count as a modification for insurance purposes? We're off to try a 2.0 with cat tomorrow but think it'll be good to wait before we buy anything, til we try a 2.3 (as suggested above) to see how they compare. Unless we fall in love with it... :-)

[Laird Scooby]

Originally Posted by Clifford Pope

I believe July 1992 is the crucial month -not sure which actual date.

It's important too for meeting MOT emission standards. Post July 1992 and you get the full works.
Pre-July and the test is the older and much easier to pass standards for a carburettor engine.

Originally it was 1/1/92, this was later (when i'm not sure) "relaxed" to 1/7/92 but after then you don't get "the full works" as you put it. There are still less stringent standards to be met for the first few years of cat testing and has been shown on this forum many times to my knowledge.
The limits for cat testing from 1992 on are CO <=0.3%, HC <=1200ppm, Lambda value 0.97-1.03.

However, i have a March 1994 registered car that is eligible for the BET - Basic Emissions Test which is 3.5% CO and 1200ppm HC maximum - there are many more like it and somewhere (can't remember where) i posted a link to a governemtn document outlining which cars are elgible for that sort of concession as they wouldn't meet the standards when new or weren't expected to.

That said, my 1994 car has always reached the cat standard, even when i was running a decat pipe!
Then again, i've had many Volvos that never had cats at any point making the tester search for the cat because they run so cleanly.

[john.wigley]

Wasn't it the 31st., Clifford? Didn't cats become mandatory with the introduction of the new 'K' registration cars on August 1st. In that year?
Volvo were early in the field with the introduction of cats; I recall that my 'H' reg 944 even sported a badge to that effect, just so no-one was in any doubt!

Regards, John.

P.S. Like 'L.S.' above, I've also had non-cat cars which were exceptionally 'clean'. I also had an '87 (E) carburettor auto 745GL that was the devil incarnate to set up and never managed more than 22 MPG! J.

[Laird Scooby]

According to this John, it was 1/1/93 :

http://air-quality.org.uk/25.php

However, i remember the Rover 800 Mk2 was launched 1/1/92 to coincide with the catalytic converter regs coming in. Some late Mk1s had cats like the various Volvos had them before they were mandatory.

In the USA they were mandatory since 1965 so Volvo had been using them for some considerable time before we got them.

https://en.wikipedia.org/wiki/Catalytic_converter

That said, i think the definitive answer is to be found in here :

https://assets.publishing.service.go...th-edition.pdf

[Chris152]

Bit technical for me! :-) Is it just replacing the cat and exhaust with a new exhaust without cat, and is that a mod that insurance companies would expect to know about?

[Laird Scooby]

Originally Posted by Chris152

Bit technical for me! :-) Is it just replacing the cat and exhaust with a new exhaust without cat, and is that a mod that insurance companies would expect to know about?

Not necessarily!

That answer goes for both questions by the way! A simple decat pipe is often all that's needed and the insurers have almost certainly gone on the assumption you don't have a cat.

[classicswede]

You can use the downpipe and front pipe from any of the older 240's and add the lambda boss.

To get the most of your exhaust fit something freer flowing. For 2ltr 2.25 inch is best or for a 2.3 go with 2.5 inch

[DW42]

I've had a 2.0 automatic and now have a 2.3 automatic. The only time I can tell there's a difference is when the car is heavily loaded, particularly when going up steep grades. I would imagine that if you plan to tow with a 240 then the 2.3 is a much better choice.

If you plan to replace an exhaust yourself at home, the problems are getting the old one off and attaching the rubber hangers. It's conceptually a very simple job, but a PITA in actuality.