Fitting A Wideband Lambda

[Mark]

The location in the exhaust is critical to the reading and the live of the sensor, its also a totally different ballgame so fitting one in the same place as a narrow band is really bad.

Main page
http://wbo2.com/lsu/position.htm

PDF on lambda sensor placement
http://wbo2.com/lsu/lsuinstal.pdf


Thanks to Ryanmt for finding the info :thumbs:

[cliffb75]

The location in the exhaust is critical to the reading and the live of the sensor, its also a totally different ballgame so fitting one in the same place as a narrow band is really bad.


Yes, and no.

I don't want to appear argumentative, but since this is a technical reference section, I think I need to correct you on that statement.:)

link from the same site: click (http://wbo2.com/lsu/lsu4.htm)

Scroll down to more LSU information and click the link Y 258 K01 005 000e (it won't allow me to link it directly)

The LSU4.2 is the 'standard' wideband sensor, used for many aftermarket but more importantly nearly all Bosch controlled OEM applications, including turbo engines ( LSU 4.7 and 4.9 are also used, but are basically the same as the 4.2).

You'll see (pg 5, section 2.2) that the exhaust gas operating temperature at the sensor is 930C, with max intermittant of 1030C. In most cases, if you are regularly running to 1030C post turbo (which means more like 1150 - 1200C pre turbo), then you will probably suffer a failure of something else long before the lambda sensor gives up.

Just to contradict some other points in the 'installation guide', on pg19, section 9.3 of the Bosch TKU, it also explains the requirement to NOT turn the power on until after a time based (roughly) on engine speed and ambient temp - this is in fact in respect of the dew point, the time at which all the water vapour that has condensed inside the exhaust system has evaporated. Until all the water is gone, the sensor ceramic element is at high risk of thermal shock, so actually heating the sensor before this time increases the chances of sensor failure. In reality, this isn't something you are going to be able to do much about for an aftermarket wideband installation, but its worth bearing in mind that turning on the sensor heater significantly before the engine is started, especially when cold (i.e. after being left overnight) does increase the risk of damaging the sensor.

So basically, unless you have some really good reason not to, actually fitting the wideband sensor in the same place as the original narrow band is probably the best idea, as that location will have been chosen with gas visibility, sensor lightoff, droplet impingment and possible fluid contamination effects all taken into account since all these things affect 2 point sensor too.:nod:

[Damo]

Just to point out that this is down to make and model of the wide band sensor it self.

As the Bosch LSU4 data sheet stats that its ok with temps upto 930 deg c so will be ok with most applications in the stock place. The data sheet also stats that it should be fitted where the gas is as hot as possable

http://www.bosch-motorsport.com/pdf/sensors/lambda/LSU49.pdf

This post by the bob may also be usefull


I wondered how long it would be before the stuff posted on the technical section yesterday would raise this question:thumbs:

When I looked at it I found that the post turbo temps (which were 180 to 200degC lower that the pre-turbine temps) they were within the temps specified in the Bosch LSU4 datasheet.

Quite often the thing that kills sesnsors is soot from exessive oil burning (turbo seals/rings failing) or excessively rich fuel, vibration, and on some of the other systems they had problems with their Heater driver controllers.

Yak and SM have been running their LSU4s in the standard location for a good while now on the track and road, as have Maff and BenTaylor - but if you are concerned then its very simple to get a suitable bung off ebay, and position the sensor 1m away from the turbine outlet.

I've put a 10metere extension on the VEMS gauge that Mass Race Engines use in their dyno cell, so if you need to lengthen the wires you can easily extend the wires by a fair amount without too many problems. The gauge uses the Rcal resistor so it will adjust its nerst readings accordingly.

As for the readings, Gary@APT was happy enough with the tests he's done on them both up the exhaust pipe and in the standard location.

[DREAD13]

thank you :thumbs:

[Ninja]

links not working for me??

[itrhondaboy]

what is a wide band lambda sensor? why is it different to a regular lambda

[itrhondaboy]

why do you fit a wide band lambda sensor what does it do that a lamba sensor doesnt? sorry for my ignorance

[bobbitt]

how are people mounting the wideband lambda s under they re cars? are you cutting into wires and extending them? how are you keeping the lambda in the exhaust ? thanks

[overdrive]

Very interesting info there, even for basic understanding theory of how they work! Nice!

[rbs13]

i have mine in the same place as my narrow band was and it seems to works spot on :)

[leosr]

its good that i see this!! i have just fitted my lambda afr guage about 3" away from the turbo.and its not reading right.so know i have to weld the hole shut and move the bung at least 20"s down.

[Phantom]

Links are down