This would be an easier route. The most basic way to look at it would obviously mean hotter=leaner. To get a better idea of what the numbers are, you would look at what afr you see on your wideband, and then take an average of egt. Then do the same at a richer condition, and a leaner condition, and basically build a table comparing afr to egt. Egt probes also create less drag in the exhaust stream, and can handle extremely high temperatures, making it possible to place them inches from the cylinder head exhaust port. A good egt probe also can have similar response times to most 02 sensors used with widebands.

 

I know that you know this, but you should still be careful about how you say this. You are risking making the "affirming the consequent" error (which humans are very prone to do; that's my day job). To be clear, while leaner will always cause hotter, hotter does not always imply leaner. Retarded timing, for example, can also cause an increase in exhaust temp. Thus, while an EGT can act as a warning that something is wrong and you should lift before you cause damage, it isn't always the AFR that is causing the problem. This is why many people argue that it's nuts to tune with an EGT. It's a warning device; not a tuning device.

 

except in this case.. Timing is a constant between cyls..

the only difference in this case is Air/Fuell per cyl.. which will cause the fluctuations in EGT

so WB for tuning overall and EGT for tuning per cyl.

 

Excellent point. That is exactly what people do with multiple EGTs and ECMLink in the DSM world.

 

aem makes a kit. total price including pressure compensation system is about $1000-$1100. all four signals can be read by evoscan using the standalone adc usb adapter hamish now sells.

 

The EFI University makes the case that the big bang for the buck is in timing. AFR can vary a point before power is noticeable. (give or take from the optimal.)
If you could control individual cylinder timing you would have a powerful tuning edge.

 

yea, using pressure transducers in each cylinder and graphing pressure during ignition along with injection DC, spark charge, and both intake and exhaust valve lift makes sense when you graph it against crank position. You can get some really nice results that way. I dont think many people do this with the engine out of the car. Usually reserved for OEM and high-end lab type work. Check out AVL IndiCom

as for per-bank AFR measurements... unless your controlling the intake air source, there's enough variation that i don't see how that buys you anything.

 

Haha nice, that's exactly what I meant in my post above, just didn't give the extra detail. My apologies about that, Iowa999.

Good point. I figure it would work well as a warning system, telling you about impending cylinder doom before it happens. I don't think it would make much difference to tune per cylinder. You could, however, tune for the differences in the flow per cylinder, since the intake and exhaust manifolds don't allow for identical flow volumes across cylinders. This would make a huge difference when tuning for big power.