Lambda sensor question.

[FLYGTR]

I realise this question is generic , but how many of you guys tune your cars with a lambda sensor fitter to the tail pipe . I had one recently fitted on a track day and noticed the the more laps i did the leaner the car got , once the car cooled down mixtures were back at their targets . Upon further questions to people i found that the cheaper units arent very accurate especially when they get hot and usually read leaner than the mixture . I thought that this way of measuring mixtures would be the best however am i wrong? or are the good lambda meters ie motec , worth their weight in gold?

adam

[bean_8044]

Im not sure if its the meter so much as the sensor. The meter is just a graphic representation of the voltage produced by the sensor. There is an ideal operating temperature for the sensors as most wont operate until 300deg. The new four and five wire sensors have the ability to heat themselves, but there is still a max operating temperature. I know some people with the LM-1 use something like a heatsink to keep the temps from going too high. Its just a piece of copper plating drilled in the center for the sensor to go through.

[Sydneykid]

Mr Bean is spot on, that is why there are $100 lambda sensors, $400 lambda sensors and $1K+ lambda sensors. We have $1K+ lambda sensors fitted as close to the turbo as we can get, that way we get fast response to changes. The long travel though the exhaust pipe slows down the results and you have to wait a few seconds after every change to see the result of the tuning change. Those few seconds can be dangerous if you are pushing the envelope. Plus if the lambda sensor is too close to the exhaust outlet you can get distorted readings as some atmosphere sneaks in.

Unfortunately this is one case where you definitely get what you pay for.

[FLYGTR]

I agree with you SK regarding the distorted reading especially on idle as the car fluctuates between 14.7 and 16 depending on how much wind their is . The lambda sensor i use is valued at a little over 1k but is a few years old now and i fear is just not accurate enough .

ac