CAT removal
 

Hi again,

I looked into this a few years ago but want to check again.

My exhaust is ropey and blowing worse each week from several places. Ideally I'd like to replace it with something a bit better flowing, see if we can realease a few extra bhp.
Simons and Jetex both seem popular 'Sports' systems.

However, my car being 1991 has a CAT. B230f. Many of these sports systems are for non cat earlier cars. A few years ago when i investigated it sounded like legislstion dictated that if a car was built before X month in 92 (or something or other) then the cat could be removed. Obviously i'd then get a boss welded onto the new exhaust for the 02 sensor.

Anybody know what the current regs say?

Thanks

From Aug 1st 1992 registration date is the date for catalytic converter MOT tests ..

If you get the right downpipe there's a socket for the sensor anyway.
The genuine Volvo one I fitted a few years ago had a blanking plug screwed in, as I was keeping the cat.

Thanks guys.
I need to check with my local friendly garage really. Partsforvolvos do a Jetex and apparently Brookhouse can get a Simon's. Not sure which is best.

Reviving this useful old thread please.

Thank you for the reminder Clan. So I can just have a pipe and sensor.

Thank you. We shall have to see whether my existing down pipe has to be replaced or not. I'll have a further look at the situation after a night of hopefully restorative sleep.

Can one buy a pipe with a boss fitted? A straight pipe with a boss, to fit instead of the cat. I seem to remember that one could do that.

If I have to get a boss welded on, is it a standard boss for sensors on any car, or?

And as I probably need a sensor. Where can I get a good one, obviously I will check with a dealer first.

I must look to see if I need any wiring.

Someone has stolen my catalytic convertor. Cut off each side of the cat.

Stephen

.

I've had a look and it is, promising. A little bit promising.

There is a hexagonal head about four to six inches forward of the forward CUT. Time to start applying Plus Gas I think.

It looks online as if the sensor, Oxygen Sensor?, comes with a connector and a length of wiring.

I think I need the three wire version for my January 1992 car?

Is there any experience in the forum between Volvo Branded sensors and reputable other brands please?



EDIT
Feeling just a little calmer
BUT.
I hear there have been social media warnings of convertor thefts in the area,
AND a neighbour couple actually saw it happen to my car!
They did NOTHING!!!
Nuf said ...

Stephen

.

okies

my garage, not 240 experts but they have their virtues.

Say without the catalytic convertor I don't need a sensor.

They might be, mistaken?

So if they fit a length of pipe and discover it needs a sensor, I guess that can be fitted and while a sensor is obtained perhaps the car will be back on the road?

Stephen

.

I'd have thought you'd need a sensor in order to ensure that the computer got the right input? With no sensor but with a system designed to run optimally with a sensor, it would be like permanently being in limp-home mode?

The catalyst has no actual connection with the sensor - it's just a convenient bit of pipe to hold the boss. Some models have the sensor in the downpipe just upstream, some I think have the sensor near or even in the exhaust manifold.
Whatever the catalyst does to the exhaust the sensor is always up stream so it can't know about that, so the decisions on whether to remove either the catalyst or the sensor are surely entirely separate. Removing the cat is a purely mechanical one - how do you connect up pipes to bridge the gap - but removing the sensor would need more fundamental tweaking of the control system, seemingly pointless anyway.

Just my thoughts - I've no real knowledge. :)

The trouble with garages these days is they are really just fitters and have little idea about how the cars control systems works. Without the lambda sensor the engine will run on its base map and make no mixture corrections. The improved consumption from LH2.4 over K jet or carb comes from the lambda correction.

To get the best out of what you have you will need a lambda sensor. I prefer to keep to Bosch but some of the cheaper ones work. Do not waste your effort with a universal sensor.
The correct Bosch https://www.classicswede.co.uk/Lambd..._14206088.aspx

or if you want cheap and cheerful https://www.classicswede.co.uk/Lambd..._20715522.aspx

Hello.

I suspect I will end up getting the pipework done, and then fitting a sensor to the down pipe myself. I am applying PlusGas to the blanking plug daily.

There appear to be two Bosch items available and no indication as to engine type or year &c variations. One type has vehicle specific plugs to fit so that looks favourite. Can anyone advise, including part number(s) please?

Where is the sensor connected, where will I find the connections please?

If the car is driven with a pipe instead of a catalytic convertor EDIT: but without a sensor temporarily, will the car be simply less efficient, or worse, please? Any specific advice or experience please?

Thank you all
Stephen

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