AFR measurement
Thread Starter
Member
Joined: May 2019
Posts: 111
Likes: 19
From: PL
'04 E55 Wagon
AFR measurement
Hi.
I'd like to measure AFR in my car. What's the easiest way?
- AFAIK there's no way to do it without an extra wideband O2 sensor with an extra controller and some tool which will monitor/show it's measurements isn't it?
- Where to put the extra O2 sensor? (does it have to be as near to cyinder head as possible or not really?)
- Does AFR monitoring AFTER the cats make any sense?
- I still have a stock exhaust system but my secondary O2 sensor monitoring is switched off. Can I somehow use the stock secondary O2 sensors for this purpose?
- If not, do I have to buy two separate O2 sensors and controllers for each side or maybe I could buy just one and weld "sensor bunghole" where both sides of exhaust mix with each other (near secondary cats)?
- Is the place where both sides of the exhaust connect (nearby the secondary cats) enough for such thing, or would it be better to weld some X-pipe in there?
I'd like to measure AFR in my car. What's the easiest way?
- AFAIK there's no way to do it without an extra wideband O2 sensor with an extra controller and some tool which will monitor/show it's measurements isn't it?
- Where to put the extra O2 sensor? (does it have to be as near to cyinder head as possible or not really?)
- Does AFR monitoring AFTER the cats make any sense?
- I still have a stock exhaust system but my secondary O2 sensor monitoring is switched off. Can I somehow use the stock secondary O2 sensors for this purpose?
- If not, do I have to buy two separate O2 sensors and controllers for each side or maybe I could buy just one and weld "sensor bunghole" where both sides of exhaust mix with each other (near secondary cats)?
- Is the place where both sides of the exhaust connect (nearby the secondary cats) enough for such thing, or would it be better to weld some X-pipe in there?
Junior Member
Joined: Feb 2016
Posts: 58
Likes: 9
From: Canada
'06 E55 / '10 GLK 350
Hi.
I'd like to measure AFR in my car. What's the easiest way?
- AFAIK there's no way to do it without an extra wideband O2 sensor with an extra controller and some tool which will monitor/show it's measurements isn't it?
- Where to put the extra O2 sensor? (does it have to be as near to cyinder head as possible or not really?)
- Does AFR monitoring AFTER the cats make any sense?
- I still have a stock exhaust system but my secondary O2 sensor monitoring is switched off. Can I somehow use the stock secondary O2 sensors for this purpose?
- If not, do I have to buy two separate O2 sensors and controllers for each side or maybe I could buy just one and weld "sensor bunghole" where both sides of exhaust mix with each other (near secondary cats)?
- Is the place where both sides of the exhaust connect (nearby the secondary cats) enough for such thing, or would it be better to weld some X-pipe in there?
I'd like to measure AFR in my car. What's the easiest way?
- AFAIK there's no way to do it without an extra wideband O2 sensor with an extra controller and some tool which will monitor/show it's measurements isn't it?
- Where to put the extra O2 sensor? (does it have to be as near to cyinder head as possible or not really?)
- Does AFR monitoring AFTER the cats make any sense?
- I still have a stock exhaust system but my secondary O2 sensor monitoring is switched off. Can I somehow use the stock secondary O2 sensors for this purpose?
- If not, do I have to buy two separate O2 sensors and controllers for each side or maybe I could buy just one and weld "sensor bunghole" where both sides of exhaust mix with each other (near secondary cats)?
- Is the place where both sides of the exhaust connect (nearby the secondary cats) enough for such thing, or would it be better to weld some X-pipe in there?
I’ve installed my wideband where my secondary O2 was for the right bank of the engine so I’m only monitoring one cylinder bank. Ideally you’d want to monitor both, but as cylinder 8 is known to be “leaner” I was OK with that.
Junior Member
Joined: Nov 2018
Posts: 26
Likes: 4
E55 - Audi
- AFAIK there's no way to do it without an extra wideband O2 sensor with an extra controller and some tool which will monitor/show it's measurements isn't it?
I don't think there is another way that I'm aware of.
- Where to put the extra O2 sensor? (does it have to be as near to cyinder head as possible or not really?)
About 2 feet or so from where the gases exit the cylinder heads or Turbo, in an orientation of "Ten and Two O'clock" from the top of the pipe.
- Does AFR monitoring AFTER the cats make any sense?
Before the cats only.
- I still have a stock exhaust system but my secondary O2 sensor monitoring is switched off. Can I somehow use the stock secondary O2 sensors for this purpose?
No they are narrow band and won't do the job.
- If not, do I have to buy two separate O2 sensors and controllers for each side or maybe I could buy just one and weld "sensor bunghole" where both sides of exhaust mix with each other (near secondary cats)?
One sensor could possibly work in the right position to get an equal sample from each bank but a sensor for each bank would be more accurate.
- Is the place where both sides of the exhaust connect (nearby the secondary cats) enough for such thing, or would it be better to weld some X-pipe in there?
An X or cross pipe would possibly be better..
I don't think there is another way that I'm aware of.
- Where to put the extra O2 sensor? (does it have to be as near to cyinder head as possible or not really?)
About 2 feet or so from where the gases exit the cylinder heads or Turbo, in an orientation of "Ten and Two O'clock" from the top of the pipe.
- Does AFR monitoring AFTER the cats make any sense?
Before the cats only.
- I still have a stock exhaust system but my secondary O2 sensor monitoring is switched off. Can I somehow use the stock secondary O2 sensors for this purpose?
No they are narrow band and won't do the job.
- If not, do I have to buy two separate O2 sensors and controllers for each side or maybe I could buy just one and weld "sensor bunghole" where both sides of exhaust mix with each other (near secondary cats)?
One sensor could possibly work in the right position to get an equal sample from each bank but a sensor for each bank would be more accurate.
- Is the place where both sides of the exhaust connect (nearby the secondary cats) enough for such thing, or would it be better to weld some X-pipe in there?
An X or cross pipe would possibly be better..
Last edited by L*M*S; Oct 28, 2019 at 04:47 PM.
Thread Starter
Member
Joined: May 2019
Posts: 111
Likes: 19
From: PL
'04 E55 Wagon
Guys, thanks for clearing the things out a lot.
So... most probably I'll go with just one wideband. The question now is... Should I put it in the stock 2nd bank secondary 02 sensor place, or should I weld an X-pipe in place of stock exhaust cross section (just before secondary cats) and place the sensor there? What's lesser evil? Having the sensor right after the primary cat but on one bank only or having it further down the exhaust but in a a place which gathers both side gases evenly?
So... most probably I'll go with just one wideband. The question now is... Should I put it in the stock 2nd bank secondary 02 sensor place, or should I weld an X-pipe in place of stock exhaust cross section (just before secondary cats) and place the sensor there? What's lesser evil? Having the sensor right after the primary cat but on one bank only or having it further down the exhaust but in a a place which gathers both side gases evenly?
