I was doing a search on EGT guages and found this place. They have air/fuel guages that are mechancial sweeping guages and not the LED style.

Not sure if these might be more accurate than the standard dithering lights guages for a/f.

http://www.frostalarm.com/cat/dp2.html

 

It's not the gauge that's the problem its the sensor. Those use a stock O2 sensor which has a voltage range of 0-1V as I understand it. The wideband sensors are 0-5V IIRC(might be higher...not 100% sure on that). Basically by having a wider range you have better resolution. That's why the cheap ones dither so much....they're measure 0-1V

 

ok, gotcha.

 

As far as bar type A/F meters go, I like the Rennbay one I got from Travis. It mounts in place of the clock in the dash, and seems to work pretty well.

Regards,

 

Is Travis still around????

 

He must be, as I bought traded a couple of PMs with him earlier this week. He's been very responsive for me.

Regards,

 

Wideband setups are so expensive!

I was looking at them the other day, and OMG I couldn't believe the price they were selling at. The ironic thing is people are still going to buy them.

 

Actually it's not the voltage range or any resolution issues that cause the large dithering you see with the inexpensive LED gauges. It's the highly nonlinear voltage output of the narrowband O2 sensor. By design, the sensor produces very large swings in voltage for very small changes in A/F in the range of about 14.5:1 to 15:1, which is centered around 14.7:1 (stoichiometeric). It produces very small changes in voltage for large changes in A/F leaner than about 15:1 or richer than about 14.5:1. This type of output is highly effective at driving the DME to maintain an A/F ratio at 14.7:1 for low emissions. The narrowband sensor is not designed to accurately measure A/F ratios much outside of stoichiometric because as long as the DME does its job in tightly confining the A/F ratio around 14.7:1, there is no need to do so. When you see the inexpensive gauge dithering over most of its scale, it really only represents a small change in A/F ratio around stoichiometric and most of the useful information is highly compressed in the region near the end of the scale. If you tried to use the output of a wideband sensor to drive the DME in place of the stock narrowband sensor, you would actually get poorer control of the A/F ratio.