s2000Junky

Interesting. Yeah its quite a bit more strait forward/predictable tuning 00-05 throttle cable with e-manage. All the work is in the fine tuning area between closed and open loop transition at about 30% throttle and after 50% throttle its all WOT/same afr. The factory tune on those years are quite good. Still retaining some mechanical means of controlling air flow isnt a bad thing.

imstimpy

On a comprehensive engine management solution, there would be a barometric pressure compensation for the fueling or the throttle angle. We lack that sensor on our cars. As Gernby stated, Honda had to approximate the tune by tuning against a manifold pressure regardless of throttle angle (optimizing a greater closure of throttle for fuel efficiency rather than a greater opening of throttle for power). I've been brainstorming on how we can minimize the throttle plate as an airflow diversion when it has no measurable impact on the manifold pressure. What Gernby has done here is great if the altitude remains constant. I, for one, race the car throughout the country so I'm left scratching my head on how I can compensate for altitude. I'd hate to set my car in a way where it requires a retune at each venue.

[EDIT] After doing a little digging, it is not unprecedented for some engine management solutions without a baro sensor to sample the map sensor before the engine starts. There may be hope afterall!

I have a number of logs from this weekend's on-track autocross. I'm going to be writing some macros or scripts that will collate information such as RPM vs TPS vs MAP. In Austin, my max MAP was 987mbar at 75*F over the weekend. At 6000 RPM, as an example, I can see that ~55% TPS gets me within 20mbar of my max MAP. Hopefully I can build a graph describing when the throttle angle may as well go to 100%.

Does anybody else have data to share from different altitudes?

Gernby

I believe the OEM ECU does have a baro sensor located within the ECU.

The only issue that altitude has on my tunes is that it changes where I split the load lines from high load / part throttle over to true WOT. The 2 maps below illustrate this.



Honestly, for a autocross / race / track car, there's no need to worry about this issue. There is not a performance issue as much as it is a fuel economy issue. In that case, just tune the high load map for WOT only, and tune all the light / mid load stuff for part throttle.

imstimpy

I think I've managed to visualize the data properly. Here is an image plotting the average MAP values against RPM and TPlate. This particular image doesn't entirely express the crappy zone, however, since this is a log from the track. Fortunately, it does show subtle details of where the TPlate is a restriction and where it isn't.

phantom_

@imstimpy, what program are you using to display CSV log?
very nice output.

imstimpy

epifanSoftware logViewer