Thread: Math Wizzards - BEN Factor IAT correction

1. Math Wizzards - BEN Factor IAT correction

I performed an experiment today with the BEN factor. My car had been baking out side for the better part of 9 hours when I left work. I flashed the changes from this mornings log, fired her up, let her come to full operating temp, then started logging. I noticed the BEN factor at idle was 1.02. No biggie, I'll just fix it when I get home. When I got home, I started a new log while I was idling in the driveway. BEN factor 1.00.

I went back to the data tab of both logs and noticed: The first log had an average temp of 104*F and the second 97*F. Even better, this mornings log had an average IAT of 84*F.

So now I'm wondering, is there a mathmatical formulation that can be done to correct the BEN factor to a given/fixed IAT?

My VE Table is close, but I feel like I'm chasing my tail now...

2. The BEN factor shouldn't need to be changed to compensate for changes in charge temp. (charge temp being the temperature of the air that enters the cylinder).

What needs to be done, is the PCM needs to adjust the VE table values (on the fly) based on changes in the charge temp.
The PCM does this by estimating the charge temp using the IAT and the ECT and the estimated airflow. The estimated airflow is calculated based on RPM, TPS, MAP etc.

More discussion here:
http://efilive.com/forum/viewtopic.php?t=1829&start=14

I'm not sure if you have access to the charge temperature calibrations.
If they are in the version you have, you can find them in:
Engine calibration->Fuel->Airflow
They have only been added recently to one of the internal pre-release versions. That version should be publicly available very soon.

Regards
Paul

3. If your BEN is running 1.00 to 1.02 - calibrate your MAF and be done with it man! As you said, stop chasing your tail.

Disclaimer: The opinions expressed here are just that and are not a reflection of EFILive, its management or subsidiaries.

If your BEN is running 1.00 to 1.02 - calibrate your MAF and be done with it man! As you said, stop chasing your tail.
Yeah you right... but the anal side of me is not gonna let this go

Besides, the car runs so awesome in SD, why fix what ain't broke?

Originally Posted by Blacky
The BEN factor shouldn't need to be changed to compensate for changes in charge temp. (charge temp being the temperature of the air that enters the cylinder)...
Regards
Paul

I agree the PCM should do that, but...

My wife and I just got done with some figuring... Using the formula to calculate density, we came up with a factor. We applied this factor to my logged average data and the numbers add up.

I will put together a calculated PID in the next few hours. Anyone care to help me test this (knowing good and well this might be a wild goose chase)?

5. Paul - I just finished reading the link in your post. Very good stuff. Now I'm on the edge of my seat to see the new tables. When do you anticipate the release of 7.2.3?

6. Originally Posted by TAQuickness
Paul - I just finished reading the link in your post. Very good stuff. Now I'm on the edge of my seat to see the new tables. When do you anticipate the release of 7.2.3?
It was supposed to be ready about 3 weeks ago. But testing has shown up some issues that are still being fixed. I new beta version should go out today - **if** that proves successful then we will make a public pre-release available in a few days.

Paul

7. Paul - After talking my self into a giant loop - you're right. Eventually all the data collected by the SD tuning will set the values in the VE table relative to absolute density...

8. Originally Posted by TAQuickness
Paul - After talking my self into a giant loop - you're right. Eventually all the data collected by the SD tuning will set the values in the VE table relative to absolute density...
I know sleep on my feet (wth eyes open) all the time, but did I miss part of this...?

9. Originally Posted by joecar
Originally Posted by TAQuickness
Paul - After talking my self into a giant loop - you're right. Eventually all the data collected by the SD tuning will set the values in the VE table relative to absolute density...
I know sleep on my feet (wth eyes open) all the time, but did I miss part of this...?
It's in the link Paul posted up there ^^^

Even though I almost convinced myself that everything would work out, I had to run a test. My laptop has a dead battery right now, but I'll post the pics of my experiment when I get it charged.

Things aren't working like I think they should

10. Re: Math Wizzards - BEN Factor IAT correction

Originally Posted by TAQuickness
I performed an experiment today with the BEN factor. My car had been baking out side for the better part of 9 hours when I left work. I flashed the changes from this mornings log, fired her up, let her come to full operating temp, then started logging. I noticed the BEN factor at idle was 1.02. No biggie, I'll just fix it when I get home. When I got home, I started a new log while I was idling in the driveway. BEN factor 1.00.

I went back to the data tab of both logs and noticed: The first log had an average temp of 104*F and the second 97*F. Even better, this mornings log had an average IAT of 84*F.

So now I'm wondering, is there a mathmatical formulation that can be done to correct the BEN factor to a given/fixed IAT?

My VE Table is close, but I feel like I'm chasing my tail now...
I am also seeing a difference in the Ben factor with different IAT. Do you think we should only log values that are below a certain temp? What do you think that number should be? We could apply a filter to weed out the higher IAT counts..

Bill

Page 1 of 4 123 ... Last

Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•