fine tuning carb with O2 sensor
 

Has anyone ever installed an O2 sensor on their exhaust header/manifold for the purpose of tuning the carburator? What about an EGT sensor? I've been reading Paul Yaw's page on tuning carbs and I'm wondering what the best setup would be for this. TIA

I'm using my DIY wideband oxygen sensor to tune my holley. It has been very helpfull. It was also instrumental in the tuning of my FD. I've never used a EGT sensor, though I hear that they can be very helpfull as well. Several of the guys I know at Mazdatrix were impressed with the DIY unit.

heres a link:
http://www.techedge.com.au/vehicle/wbo2/default.htm

Excellent, thanks! That's exactly the kind of info I was looking for.

Anyone else have experience in this area?

This is a great way to tune any car, fi or carb. Very fast and accurate.

But it must be a Wide Band High Speed O2, using a conventional O2 will not work, and the gauges offered at Summit and the like use a std O2 which is not worth while.

Now if you did have a FI car you could go off of the stock O2, at WOT under full load you want to see .860mV, but this is just going to get you in the ball park, not spot on like the WB setup.

The EGT work good to, but you need to know what temp for your combo is ideal. If you went to a dyno shop with a WB A/F meter you could tune it, and see where your ideal temp is at that time, and use this info accordingly.

Here is a neato little mixture meter:
http://www.sdsefi.com/mmm.jpg
Simple Digital Systems also explicitly mentions rotaries.

As neato as it might be, it relies on a narrow band oxygen sensor. Narrow band oxygen sensors (what most cars come with stock) are only accurate within a very narrow range, hence the name. They are pretty much worthless for WOT tuning, as mixtures desired for those loads fall way out of there "narrow" range of accuracy. The effective range of the narrow bands are way up in the lean area, and are only good for getting the most fuel economy out of an engine.

a narrow band O2 sensor uses only a 0-1 volt output for it's entire range, full lean to full rich.

a wideband uses anywhere from 0-4v or 0-5v for its entire range.

Here is a excel chart I made a while ago of the logging of a run of my FD with the DIY wide band:


https://www.rx7club.com/forum/attach...&postid=990679