Location of lambda sensor

[Catkins]

I have a K R300 with CAT which has the lambda sensor located in the pipe just before the CAT where the four primaries have gone into one main pipe. If I was to get a CAT bypass pipe that does not have the boss for the lambda in the same location would it be a problem moving the lambda sensor to where what I think is an alternative location in the side of primary 4 inside the engine bay where there appears to be a bolt head covering over a boss location? Would it cause any problem with the MBE map or need re-mapping?

Thank you for your advice.

Marcus

[Paul Deslandes]

ideally the lambda sensor should be where all four pipes are 'collected' so its reading the average of all cylinders. In reality it probably doesn't make a great difference if its only in one of the downpipes so long as all the injectors, plugs, cylinders are working properly and are reasonably well balanced. Presumably this is a narrow band sensor and is only functional at idle and moderately low revs and throttle openings, otherwise the MBE will ignore it.

Apart from possibly leading to lumpy idling, the only time you might have a real problem is if one of the above is 'out', and causes a false reading to the MBE, will be during an MoT when the exhaust gas analyser sniffs the average of all four cylinders.

Better if you can get a boss welded into the bypass pipe. A local engineering firm should be able to do it for tea money. Make sure that boss is located such that the sensor is mounted above the horizontal to stop condensate fouling the sensor element.

[peter clarke]

As above. I use a wide band set up and use cat for the equivalent of your mot. Slight difference in location one before cat and my normal set up is just in front of silencer on the 4,2,1. Used the down pipe on 4 at one time but much more consistent result when set up as above. Also easy to swap pipes and don't need to relocate sensor.

[Mankee]

Hi Marcus.

 

If you really wanted the lambda sensor situated in your CAT bypass pipe, you can get a boss welded into it fairly easily and cheaply. Plenty of places around our way who can fit one for you.

[Catkins]

Thats great thank you very much for the replies and very helpful.

Hello Mankee great to chat again. if you got a chance it would be great to have your recommendation of places that could do the modification to the pipe. I hope to catch up with you soon.

Marcus

[Mankee]

I've not had the need to have a lambda boss welded in before, but two places/people I wouldn't hesitate to use would be Rindy (who now operates at Scholar in Mendlesham) and Dave Walker at Emerald. Might be worth a chat to some of your local 7ers who might be able to recommend someone closer to you? There are at least 2 or 3 tyre/exhaust places at the bottom of my road which you are welcome to come over for a cuppa and we can go ask them in person if you like.

[Catkins]

Thanks very much Mankee 😬. I have dropped you a quick mail.

[Stationary M25 Traveller]

Moved my sensor from primary no. 4 to the single pipe into the silencer after the 4-2-1 collector. Seems to perform better there