I don't agree with/follow your logic on this, Dave. Running more airflow can make you run leaner or richer, all depening on how you have your open-loop fuel maps setup. By default, higher airflow and load cells are richer than lower airflow and load cells at the same RPM. Once the car is flashed, it all depends on how the tuner sets up the fuel tables.

If you had to change intakes or filters, I can see that changing the MAF calibration slightly, which could cause a leaner or richer condition, too.


Kevin, I am intersted to see the DSMLink data. The turbo definitely sounds good and looks like it is flowing more air. I'm curious as to where you will see it max out and how much boost it will hold to redline.


Eric

 

jesus christ your dyno is a heartbreaker

 

Luckily my feelings aren't hurt as you all know I don't care if anyone agrees with me or not! haha

If the entire range was tuned properly most people will tune a car at the same boost level under load. So you'd have an AFR of say 11.5:1. If that entire range then goes to 12.5:1 I'd venture to say the car is flowing more air. Since I primarily think AEM and speed density sometimes I talk (type) with only that on my mind. In the case of using the AEM and speed density, you can bank on the AFR's going leaner meaning more airflow.

If every load cell was tuned properly and at the same AFR's on a MAF equipped car a leaner AFR should also translate to more air flow, you don't agree with that?

 

I think AEM and speed density were the missing pieces of information.

EDIT: I just re-read this quote. I thought your said a leaner AFR would be more power, not airflow. So, actually, no I don't agree with that. If all of the load cells were tuned to a certain AFR on a MAF equipped car, and then suddenly you had a leaner AFR after a modification, then I would say that your MAF calibration/air metering was slightly altered.

The MAF is just translating a Hz value into a mass airflow value with other data such as barometric pressure and temperature. If you got more airflow from a bigger turbo, your would simply be in a higher load cell...if that load cell was tuned to the same AFR, you should still have the same AFR, even with the higher airflow.

I'm not saying anything bad about the turbo. I think it will be good...I'm interested in Kevin's data.


Eric

 

I apologize if I misinterpreted what you wrote but that doesn't make sense to me. A properly working MAF should be able to sense any increase or decrease in airflow and then relay that info to the ecu to make the needed changes to maintain the AFR. The AFR should not change provided all of the load cells are tuned properly for any given amount of airflow correct?

On another note, Kevin I look forward to viewing those logs when you're done. Feel free to send them my way.

EDIT: I see Eric beat me to it and got the point across a lot better than I.

 

I see what Dave is saying, and he is correct, but you have to pay attention to the details of what he is saying. . We were both refering to AEM running on a MAP sensor with no change in boost.

It's all a matter of perspective, how you tune, and how the system is set up. For example, in the AEM I stayed on the same load level and got leaner. That means more airflow at a given boost, which is a goot thing. I then turned up the boost. If I had tuned for the same AFR on the next load level, AFR should not have changed. If it's tuned for another AFR, or for an unknown AFR, it will change. Same thing with a MAF based setup. In the case of DSMlink, I am always on the highest load level at WOT, which provides the advantage of giving me the same AFR and timing no matter what boost/airflow is. Any change in airflow is measured and compensated for, and AFR remains where I set it. So you can see that the result of the change in boost/airflow can vary widely based on how the system is set up.

Airflow information posted here.