I logged a few pulls today. 3rd gear wot from 2K up to redline. SF is not the best urban environment for this type of exercise, therefore no 4th gear data yet. I used Jon's advice on what to log and a fascinating story is unfolding. Max boost is at 34 to 3600 rpm or so, with a high of 1.1bar. Injector duty cycle is at 57% and 63%. AR 13.23 and 12.34. The boost drops down to a low of .85 around 4800rpms with an injector duty cycle of 88 and 85% AR 11.61 and 11.90. Then as the rpms rise to red line the boost starts climbing again up to 1 BAR with AR at 12.49 and 12.78 Duty cycle are respectively 88.64 and 91.31. I am going to take a stab at this and it appears as if boost drops as AR lowers and duty cycle increases. As if the ecu is running too rich in that rpm range, say from 46 to 5500 rpms. Does any of this makes sense? Thanks.

 

Amazing what a little bit of data can do to help you understand better what's going on. I think that you can see already though, that boost is not the entire story by any means.

One thing I have learned is that different tuners go about making power in different ways. They don't tell you exactly what they do. That's as it should be - it is after all what they actually have to sell. But they all have to do basically the same thing, which is to produce power by burning fuel with air. I think the thing that what really matters most then is the mass air flow - that is what ultimately determines how much fuel you can burn. Boost is one way to increase mass air flow through the engine. Fueling has to be able to keep up.

We're starting to get to the edge of my level of understanding, so maybe I should stop talking. An expert in this could probably figure out Ruf's control strategy from looking at detailed plots of your results. So you probably shouldn't post them.

A couple of things...

If you're getting enough data points in 3rd gear, no reason to go to 4th. I live in a rural area so I have a place to do them. No reason to get busted or injured just to collect some data.

If you log torque as well, then you have your very own dyno curve! Just plot torque vs rpm. You can also plot hp = torque*rpm*pi/16,500.

I found the data much easier to understand as a series of x-y plots of various values vs rpm.

Jon