Lambda meter

[Kevin Bacon 5]

Can anyone recommend a good lambda meter? I can't think of their proper name but it's basically a little LED display that mounts on the dash and monitors fuel/air ratio in real-time using the lambda probe. I used to have one on my 16V Turbo but can't remember who made it or where it came from (was in the car already). I found it useful because on a few occasions it sank into the red (too rich) instantly highlighting a problem. That way you can look into it before wrecking the cat and wasting fuel. Likewise if it goes into the green (too weak) you can avoid detonation if the Knock sensor can't pull the timing back far enough.

 

Any ideas?

 

Cheers

Kev

[Banana Man 0]

Try http://www.Demon-tweeks.co.uk I know they used to do them!!!

[iceman 0]

i used to have a APEXi super air flow controller. thing was pretty cool till someone looted my car. :mad:

[steveo29 0]

its called an a/f gauge..http://www.summitracing.com about $30 or so...that what most guys in the states use

[bazgreener 0]

Kev,

get in touch with dubcharged on this forum, he has some of the summit ones for sale.

[Kevin Bacon 5]

OK thanks chaps

 

Kev

94 VR6

[G60 0]

i've seen people make their own since its just a set of LEDs hooked up to a range of electrical pulses. don't know exactly how to do it though..

 

i think i saw someone post an in progress project with a line of LEDs mounted right in the cluster below the tach. who was that?

 

i've been told that hooking the meter up to your current O2 sensor will weaken the signal and possibly effect performance, so some people fit a second sensor. dunno if this is necessary but worth considering..

 

can anyone offer some advice? anyone made their own LED display?

[Dubcharged 0]

Performance won't be affected since under Wide Open Throttle the ECU goes into Open Loop mode where the Lambda is not used. There are a few sites on the web which show how you can make your own, do a search with google.

[bazgreener 0]

You can make your own using an LM3914 bar graph module and a few other components but at £30 for a `proper` one it`s hardly worth the aggro.

[G60 0]

i've read that unless you go with the top of the line meter, air/fuel gauges are laggy and don't give you a readout in real-time. it is my understanding a way to get a read in real-time is to wire up some LEDs yourself, with a greater range than a typical a/f guage. maybe 20 LEDs instead of 6 or 8.

 

you're right, for the money its not worth the aggravation.. but is it just as accurate?

 

i really don't know, these are just concerns that i've come across while trying to find the best solution for an a/f readout.

 

Dubcharged: how about performance when not under WOT.. since that's when its in closed loop? i'm not talking head-snap performance.. i mean running an ideal mixture in regular driving performance.

 

thanks.

[Kevin Bacon 5]

Ah the good old LM3914/5 & 6 logarithmic chips! Used those years ago to make a really accurate 50 led per channel audio db meter. They're scalable and you can do pretty much measure anything with them!

 

If you run the 'take off' leads in parallel with the ECU leads, it shouldn't drain the current to the extent of confusing the ECU.

 

Kev

[stormseeker 0]

i've been told that hooking the meter up to your current O2 sensor will weaken the signal and possibly effect performance, so some people fit a second sensor. dunno if this is necessary but worth considering..

 

Not if you have a high imepedance input to your home-made meter - something like a good old FET input stage ought to do it.

 

 

Chris.