Re: [doc] Cat replacement / Lambda-sensor

["Stian Birkeland" <delorean@xxxx>]

Thanks Martin - 

So what you're saying is that I can simply swap the cat with a cross-
over pipe and leave the Lambda-sensor/Lambda-system on the car as it 
is without adjusting anything???

I've have always thought (obviously incorrect)that the Lambda-
sensor/Lambda-system/Catalytic converter interacted with each other, 
so for instance, if the cat was removed, an adjustment would be 
needed on the other Lambda-components.

To sum it all up - the Lambda-system will work as before regardless 
whether the motor is fitted with a catalytic converter or a cross-
over pipe, right?

Best wishes
Stian Birkeland
Norway

VIN # 06759


--- In doc-uk@xxxxxxxxxxxxxxx, Martin Gutkowski <webmaster@xxxx> 
wrote:
> The lambda system reads the emissions* through the lambda sensor 
> upstream of the cat, so getting rid of the cat will not affect the 
> lambda system.
> 
> Getting rid of the lambda sensor will put the lambda computer 
into "limp 
> home" mode and set the mixture a bit rich. You could dial this 
back 
> down to anywhere between 1% and 2% and still pass a UK MOT and not 
> damage the engine (1.5% is the setting for non-lambda european 
Volvo and 
> Renault PRVs) but you'll still be relying on the lambda computer 
and 
> frequency valve. The correct way to remove the lambda system is to 
fit a 
> metering head that doesn't have a frequency valve port. However, 
once 
> this is done, you've still got ignition timing appropriate for a 
leaner 
> mixture. So unless you plan on changing Metering head, ignition 
> distributor and control pressure regulator, there's not a lot of 
point 
> in getting rid of the lambda sensor.
> 
> The cat bypass reduces load on the engine so it does make a 
noticable 
> improvement.
> 
> Martin
> 
> * it actually reads the oxygen in the exhaust but this is used as 
an 
> indicator of how complete the burn is in the engine and therefore 
what 
> the emissions are
> 
> Stian Birkeland wrote:
> 
> >Hi,
> >
> >If you swap the cat with a crossover pipe, would this effect the 
Lambda-system?
> >
> >Would the Lambda sensor not be necessary any more?
> >
> >Would this also effect the actual CO2 emissions testing / passing 
on the MoT?
> >
> >Best wishes
> >Stian Birkeland
> >Norway
> >
> >VIN # 06759
> > 
> >