Wideband in tailpipe

[lolsteve]

So wanting to do some testing in the new year in regards to ensuring my mapping isn't running too lean or rich, already getting Dad to make me up a set of det cans for Christmas.
However don't really want to go through the effort of having another lambda hole put into the exhaust pipe as would like to be able to test on a variety of cars and not have to modify all their exhausts.
Is it feasible to have the lambda sensor sat in the tail pipe of the backbox? Recall a sensor being put there on one of my rr sessions once but don't know if its the same sort of device

[bashbarnard]

Widebands work best the closer to the mani you can get them. Its not a true reading by the time it hits tailpipe. Specially if yoy have a small blow. The rr stuff is slightly diffrent from memory though.

[Stef205]

it needs to be at the top of the downpipe.

[Niall]

As above, needs to be by the manifold to be effective. If it's just for your car, just buy a wideband kit. The controller will have a narrowband output which you can use to replace your stock lambda plus you get the wideband gauge for monitoring.

[Eeyore]

yeh its on the downpipe for a reason. It wont be very responsive at the end of the exhaust either.

[nominous]

I've got an innovate LM1. I got it with the exhaust pipe clamp. It works fine.
Same as the MOT station is able to sense the oxygen content of your exhaust gases from the exhaust pipe sampler.

The only complaint I would have on it is that it can be a pig to bolt up to some exhausts depending on back box design. And I added bits to it in case the screw came loose... (which it did).
Never run a parallel test with a boss fitments, but it's happily tuned things to the correct AFR's.

The boss wants to be at the collector too, or you're going to get odd reads with only one or two cylinders. Else you're fitting 4 WB's.

However for the cost of a boss off ebay with a blanking plug, weld a spare in situ if it's a car you intended to frequently mess with.
The narrow band output in helpful yeah, but it's far easier to run it without dicking around with the stock items.
For example in a Honda with a 4 wire O2 you have to either leave it connected and hack it's sample wire, else trick the ECU to disable the heater circuit or it'll flag as a failure and adjust the map dynamically itself. So it's best IMHO to go separate.

[Niall]

Lambda sensors are designed to work optimally at a few hundred degrees. The one in mot stations aren't so aren't comparable.

[nominous]

To be fair I wouldn't know what's inside the MOT station testing box.
It could be a standard WB sensor for all I know or they could use a different detection method.
But If I recall the other day getting my MOT it fannied about for a bit (warming up??) then did a free air sample, before being stuck in the exhaust pipe.
Similar to my LM-1 doing a free air at inital startup for getting a reference.

Since WBO2's have a heater built in to get the sensor up to working temp the distance doesn't matter in so far as the exhaust loosing temperature as it's the element that will regulate it at the operational temperature. So distance from the exhaust ports in terms of temperature of the gas isn't really a problem.

[welshpug]

mot test probe isnt a lambda as such.

[nominous]

yeah good point. It's testing for something else isn't it:
carbon monoxide (CO) and hydrocarbons (HC)

Sorry. my bad.

[lolsteve]

To be fair I wouldn't know what's inside the MOT station testing box.
It could be a standard WB sensor for all I know or they could use a different detection method.
But If I recall the other day getting my MOT it fannied about for a bit (warming up??) then did a free air sample, before being stuck in the exhaust pipe.
Similar to my LM-1 doing a free air at inital startup for getting a reference.

Since WBO2's have a heater built in to get the sensor up to working temp the distance doesn't matter in so far as the exhaust loosing temperature as it's the element that will regulate it at the operational temperature. So distance from the exhaust ports in terms of temperature of the gas isn't really a problem.

Is it just a case of it being laggy then? How do you find your lm1? 

Thanks for responses, really would like it to be transferable easily/ non permanent 

[Ruan]

They work fine in the tailpipe as they usually have their own heater element - however that's in terms of actually giving a measurement - however they're really only any good for steady state testing (i.e. holding back on an eddy current or water brake dyno) as there is a significant delay from the exhaust gasses getting from the exhaust valves, through the manifold, down the exhaust and to the actual sensor - they naturally work better at higher RPMs where the gas is moving faster and you get a representative reading in less time...

[Niall]

To be fair I wouldn't know what's inside the MOT station testing box.
It could be a standard WB sensor for all I know or they could use a different detection method.
But If I recall the other day getting my MOT it fannied about for a bit (warming up??) then did a free air sample, before being stuck in the exhaust pipe.
Similar to my LM-1 doing a free air at inital startup for getting a reference.

Since WBO2's have a heater built in to get the sensor up to working temp the distance doesn't matter in so far as the exhaust loosing temperature as it's the element that will regulate it at the operational temperature. So distance from the exhaust ports in terms of temperature of the gas isn't really a problem.

Wrong wrong wrong

Lambda heaters do not get them to their optimum working temperature. They aid in getting them close quicker than the exhaust gases can. Quicker the sensor is up to working temp, quicker it can be active and helping with emissions.

A Lambda sensor WILL NOT work correctly in the tail pipe. It will give a reading but the accuracy will drop big time. A lambda sensor is nothing like a gas analyser in a garage.
The sensor needs to be as close to the collector as possible to get an accurate reading. Anything else and i wouldn't rely on it. Also, its going to be after the cat then as well. You want the reading before the cat.

[nominous]

Wrong wrong wrong

We will have to disagree then on how lambda sensors work.
I wonder why my LM1 has a warm up stage before sampling then and why it came with an exhaust fitment part and why innovate are still selling that part 10 years later.
http://www.innovatemotorsports.com/xcart...271&page=1


Yeah, pre CAT. I forget about cats since nothing I've had has either had one from factory or had one fitted for very long.


lolsteve:

It's been great. I've got a couple and both have had to be repaired over the years. Similar fault. Very early batch. Can't remember what it was but long ago rectified by them.
One is a white one and one is a black one IIRC black was real early.
They've been used very well and back when I was tuning more often they were great. But they suck for a permanent install and if that's the use then a gauge type like the AEM Uego or possibly a LC1 and gauge from innovate is definitely the way to go.

[lolsteve]

Bit of a thread revival.
If the tuning wasn't major as in a complete rewrite of the engines fuelling just a minor tickling could the narrowband voltage be used to see if it's moving more towards rich or lean?  By comparing with a graph like this?
Obviously not as accurate/easy to read as a narrow band but if the speed could be held at a constant rate and do a before/after on the voltage?

[Ruan]

You're assuming you're tuning to 14.7:1 - which at WOT you aren't unless you're planning to toast valves and pistons... Hence you need a wideband.

Lambda in the OEM application is simply for mixture trim whilst cruising for emissions - most of the time soon as you go WOT it'll totally ignore the lambda.

If you're steady state tuning on a dyno, you're absolutely fine to put a wideband up the poo pipe. You should have a reasonable idea of what's going on with the engine anyway in terms of the change in VE... So the stock narrowband is useless anyway, just do it properly IMHO if you're tuning it, otherwise it's not tuning it, it's guessing some figures.

[lolsteve]

Fair enough. Just trying to debate either getting a wideband and a tail pipe attachment or one of these http://pscan.eu/ and using the difference in money to go on dyno. Can't afford both right now

[welshpug]

http://www.ebay.co.uk/itm/Exhaust-Lambda...1115094630

jobbered.

[Niall]

If you want to map it, buy a wideband kit and put it in the location of the stock lambda. Nearly all wideband controllers have a narrowband output so you can wire this into the original lambda cabling and issue solved. ECU stays happy yet you have a proper sensor so you can map safely.
A narrowband just changes voltage when its above 14.7 and changes again when below. Like Ruan says, you could work this out if you were mapping to 14.7 but you're not. You'll be going down into the 12s at points and theres no reason on very light throttle why you can't save some fuel and go into the 15s.