Evaluating Mods using Data Logging
 

Have you ever wondered if that new widget really helped your car? Sure, you could go spend a hundred bucks on a dyno to find out but I think there is another way that can give you some insight. It will not tell you how much horsepower you have gained but it should allow you to test a lot of mods on your own to see what does and does not improve performance.

Most of the mods out there try to increase air into the engine. For the most part, tuners will tell you that air (plus the right amount of fuel) makes horsepower. The more air, the more power you should get.

The RX-8 uses a mass airflow meter and thus can account for and fuel extra air. If you reduce restriction on air inlet or exit or reduce the temperature of the incoming air, more air should get in. The nice thing about modern PCMs or fuel controls is that you can record the sensors the PCM sees. If you put on a different air inlet system and your maximum mass airflow (MAF) value increases as you rip down the street, you can be reasonably sure you are making more power.

If the above is accurate, would it not be smart to get a data logger and evaluate the positive (or negative) affects of each mod as you do them? Not only can you check for increased (or decreased) airflow but you can also verify that the Air/Fuel ratio is acceptable as well. This theory applies to naturally aspirated as well as forced induction and even works when using a piggy back fuel controller like the Interceptor. It also saves you the money, time and effort of installing things like aftermarket wide band sensors.

It has been done; by me.

Kane,
Please point me to your logger. I've only worked with the EFIDude's ProLogger and would like to see what else is out there.

http://blog.ppo2performance.com

https://www.rx8club.com/showthread.php?t=133797

I am beta testing the software now; you have to be on the "cool" list to get a copy.:rofl:

Wow, someone has spent some time with IC theory.

I was heading down a somewhat simpler path for the average guy. Buy small inexpensive dongle, plug dongle in, record baseline, add mod, record after mod then look for increased mass airflow.

Nice looking software!

The software wasn't designed for that purpose; but since I have to collect all the data anyway.... tertiary uses spring up daily; my new favorite is injector scaling.

Since I am my own very low paid employee (think forced labor rates)...my price point should be low enough that you can use it for a tuning aid and/or a logging VE% aid - the hard part is organizing the data into usable segments; and that is done.

Thanks for the compliment-BTW.

A data logger of some sort is definitely on my shopping list. I also have a scangauge 2 with which you can see the load point the ECU is on at the moment. Of course, when testing something at full throttle, your eyes should be on the road, not on a gauge :lol:

So yes, a datalogger is a great way to evaluate performance and I wish people would post up some hard numbers. I believe air flow data is a much better indicator of the performance benefit of NA mods vs dyno plots which could be affected by so many other things..

I am slacking but NaarLeven gave us some data to post when his car was put through a single pass tune on the dyno. I got the following data using the EFIDude DataLogger and should have it posted soon-

Before dyno on the street rip
On dyno as it arrived pull
On dyno after reflash pulling some fuel out over 5500 rpm
After dyno on the street rip

NaarLeven has already posted the dyno plots. https://www.rx8club.com/series-i-engine-tuning-forum-63/reflashed-today-using-efidudes-138881/

I will also post screen shots of the before and after fuel maps so you can see exactly what was changed and by how much.