As I stated in my other thread I have found more issues with the way the ECU is deteriming the load.

I found when I am under boost and everything is increasing (boost, RPM, airflow, etc.) & I am already at 100% load (cell #18) it will drop down to as low as cell #14 with the same variables or everything increasing!?

 

Can you give me a time point that this is happening in the log?

 

Take a look at the log & set one of the graphs to display boost and load on top of each other. If you look at the second gear pull you can see boost increasing from 8.7 (Load 18 Timing 15 deg.) to 9.6PSI and the load drops to 17 then Load 16 (Timing 23 deg) all while airflow and rpm is increasing. So it advances my timing while boost is increasing & my timing map is not set up that way.

Why?

You can see a similar thing in the 3rd gear pull as well.

ed

 

I was typing that before I saw your post.

 

If you assume the 1st boost ramp is 1st gear it should make sense.

The time is at about 7.42-8.27.

 

Hmm.

I see what you are saying in the second gear pull. I dont see it in the third gear pull.

I exported to CSV so it makes it a little easier to compare and removed non relavant parameters.

What I think you are seeing is a delay in the data at the gear change transition. You logged a lot of parameters. I would like to see a log with just the basic parameters logged and I bet you won't see this.

I drew lines after the highest RPM was reached to indicate a gear change.

At 6:36 (last sample in first gear) RPM, airflow and boost went up, TPS and IPW went down as well as the load index as compared to the sample before that. If you look at the time stamps, there was nearly half a second between the two samples.

At 9:46 (last sample of second gear) RPM is the only thing that increased. Airflow and TPS stayed the same, boost and IPW dropped as well as the load index.

Same deal with last 3rd gear sample. RPM went up , but Boost, Airflow, IPW, and TPS all dropped, theres no reason you wouldnt see the load drop like it did.

If this was happening in the middle of a pull and away from a gear change transition, I'd say you have something but I think it's simply a data timing issue due to the number of parameterss you logged.

I will forward your log to Henrik for a second opinion.

 

You may be on to something but I dont know if that is the case because it is happening in the middle of a pull. In second gear the load drops at 7.42 through 8.27 in the middle of the pull. Then it does it again at the end off the pull at 8.79 6400RPM 8.7PSI at 9.10 6600RPM it drops to 17 Load with boost rising to 9.6 then at 9.46 7000 RPM 9.4PSI it drops to 16 Load.

In third gear it drops at 13.17 through 13.46 and then goes back up to 18 Load at 13.79. If it was simply a gear change why does it go back up to 18 Load before the shift after dropping.

ed

 

Hi Edomund,

I had a quick look at your logs (the ones Mike converted to Excel) and to me it would appear that your maxing the airflow reading ability of the AFM. Take 09:10-09:46 as an example. Measures airflow is constant at 880kg/hr yet there's a different of 400rpm and boost is more or less the same which would suggest airflow is still increasing. Since the ECU doesn't see this additional airflow but it sees the increase in rpm's, it thinks the load is going down which is what you see in the indicies. Same sort of thing between 12.06 and 13.79. I would discount the 16 as its right at the gear change.

Now this also would suggest that for your setup, you wont reliably hit load cell 18 at max rpm so you'de tune load cell 17 as your max load. Note also that the ECU interpolates between points, so you'de want to tune the higher cell to the same as your max load cell.

Hope this helps,

-Henrik

 

That makes sense. Thank you.

Once we get the update (boost vs. rpm timing map) this will all be a mute point anyway, correct? Once the ECU is reading boost to determine the timing degrees will it eliminate this issue?

Will the ECU determine timing solely based on boost independent from load or is it just going to be load converted somehow to the corresponding boost pressure? (don't know if that last part made sense or not )

If it is independent does the AFM serve any function any longer?

thanks
ed

 

if the AFM is maxing out, since corrections can be made but depending on the flexibility of the amount that it can be adjusted can't a different spring be placed in the AFM? that would raise the peak for the amount of HP it would be currently limited to but even more correction would be required.