by Freon » Mon Nov 27, 2006 4:18 pm
It depends completely on what you are tuning.
You can't adjust the fuel and timing for part throttle if you are always logging full throttle, and vice versa. You should decide what you want to tune and figure out the best way to log for it. There is no one technique that covers it all. Target a few things you want to tune and decide the best way to log for it.
For instance, on fuel and timing I am most concerned with getting best power under WOT. So I will log full runs from 3000-7500rpm under WOT. I'll do this in every gear I can (usually only through 4th, as 5th is going *really* fast, faster than I'll usually drive) because I want it to work well in every gear. If you only tested in 3rd gear, you may be sacrificing in another gear. But the best way to get a lot of data points is in the gear that takes the longest to run, or the highest gear.
Keep in mind that the logger is only so fast. It doesn't record very fast events well. You can't really tell what happens in between log points if things are changing to fast. At the same time, there are certain things like throttle tip-in that don't do anything under a steady state. These sort of things require some subjective feedback from the driver (i.e. how it "feels"). Most things do require a more steady state, and then you have to understand and trust that the ECU is correctly doing what you told it to when under more transient conditions. For instance, when you peg the throttle at 4500rpm, you're going to go up the load columns very quickly. You have to trust all the loads are being hit and correct values being used inbetween the relatively slow logger speed. Luckily, this is a positive trait of MAF based systems.