MFI AFR reference measurements?
 

Hello all,

I'm about to install an AFR gauge/O2 sensor etc on my rebuilt engine so I can monitor the engine's performance. I noticed that compared to a few yrs ago, there seems to be more experience with this on this BBS now.

So my question is: is there some consensus about which DIY measurements I need to take? For example: one test could be 'drive on a level road, 3000 rpm, coasting, AFR should read between so and so'. Maybe this is a rubbish example, but I hope you understand what I'm looking for.

Any thoughts on this, as it's fine to have the tools, but they're a lot more useful if the measurements can be compared to a 'baseline'

Cheers!

Well, I would first focus on making sure you have the correct mixture at WOT under load. I did this on the racetrack a few years ago:

http://forums.pelicanparts.com/911-engine-rebuilding-forum/410655-one-lap-lime-rock-through-eyes-oxygen-sensor.html

Once you have that under control, then go for a part-throttle test like that described in Check Measure Adjust- although that's really more for emissions than power.

Remember that you set the part-load adjustment first and then the idle.

norm op temp, level road etc...

part throttle/steady state at 1,000, 2,000 rpm etc

WOT at 1,000, 2,000 etc....

part throttle is easy, WOT is harder. I have a data logger so I can download the results and analyze at home. I don't know if you can get valid data with an assistant and a note pad.

Thanks.
I've indeed read the Track thread with much interest. But as I'm lacking a logger, I was hoping that there might be some pointers of general reference points that would give me some impressions to start with. I recall some threads discussing this, but can't find them.

Will keep (attractive) assistant + notepad in mind

Any other ideas on this?

Maybe a video of the AFR and tach, then you can analyze frame by frame.