Lambda sensor query

Road-race engines and ancillaries - general discussion
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Piero

Lambda sensor query

Post by Piero »

Hi, I am in the process of having a 4-2-1 manifold made, for my Fiat Twin cam.
I have been asked, whether or not I want a Lambda sensor incorporated into the system.

If so, do I have one fitted to the last collector, or (as on the Abarth) have one on each primary.

What are the benifits of one or the other :?:
Piero
Guy Croft
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Post by Guy Croft »

Piero,

just to set you right on that, the 130TC probe bosses are for individual cylinder gas checks during test (never known anyone use them in fact) you don't use 4 Lambdas running simultaneously. You only use one and hope the carbs are identically or at least correctly calibrated, a Lambda sensor then picks up an overall reading at one point.

Usually they are located downstream of the last pipe junction on the tailpipe but you need to buy one and read the instructions first really, unless someone here can tell you which model is good and where to put it.

GC
Rich Ellingham
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Post by Rich Ellingham »

1. Yes you should put a boss in, even if your car does not need it then it allows the rolling road to fit one in for tuning. It can be replaced with a lambda bung the rest of the time, this is what I have.

2. Put it whare all the pipes have merged, and consider the probe may protrude by about 3 inches, thus is may foul body work etc it some positions.

3. Use bosch sensors, cheap auto factor ones are not reliable. If your system will not use a sensor at all do not worry, any decent rolling road will have a wide band sensor fortheir work.

Note: Narrow band sensors have a very small ability to measure lean or rich conditions on a narrow band 15:1 lean on a narrow will be no different to a 14:1 as the voltage produced by the lambda reaches its peak over a very small range. A wide band has the abilty to quantify a lean or rich condition, a narrow merely tells you its occuring but not the value. For turbo cars this is more important.

rich
book 38
SteveNZ

Post by SteveNZ »

Make sure the boss is welded in so the sensor sits 90 degrees to the exhaust flow.
Piero

Post by Piero »

Am I right in saying the Lambda probe is only to help with the dyno?

It is not for use when the car is working, as I don't run fuel injection.

Thanks,

Piero.
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