All about BMW: BMW DIY, BMW series, BMW photos, BMW reviews...

Street Dyno


This article is the one in a series that will be released in conjunction with Wayne's upcoming book, 101 Projects for Your BMW 3-Series. The book will be 256 pages of full color projects detailing everything from performance mods to timing the camshafts. With more than 350+ full-color glossy photos accompanying extensive step-by-step procedures, this book should be a staple in any 3-Series owner's collection. See The Official Book Website for more details. The book is due out in October 2005.
Ever wish you had free unlimited use of a dynamometer? Well, with Street Dyno, that is just what you have. I probably would have never thought of this on my own, but I found an interesting link to a page in Finland.

That is how I met Jari "Eppu" Porhio, and he has been very helpful in getting this "completed". You should check out his page and if you use Linux at all, give his revkit a try. You may also want to look at Mike Chaney's "Home Dyno".

Below is a screen capture of the current [but ever changing] user interface. I have "big" plans for the interface and it will generally look the same, but far more features. Right now I consider it a "useable" [barely] piece of shi.. umm I mean software. After the screen capture there is more info on getting data and processing it.


Click to Enlarge

Here is the Voltage Divider schematic that I use to record my dyno runs.

If you have a laptop with a soundcard in it, you can record the WAVE [.WAV] file directly into your PC and eventually directly into the program. If you do not have a laptop, then you will need some type of tape recorder, like a mini recorder, to record your "dyno runs". I made a voltage divider using a few resistors, caps and a potentiometer to vary the voltage down to a small mV scale suitable for recording. Below is an example of what the recorded wave file should look like.


Click to Enlarge

Each pulse that you see is a cylinder firing, and the amount of time between each is where we get acceleration. This along with specific info about your car, like weight, gearing, tire size and others, allows us to get in the ballpark as far as how much uumph you are putting to the ground.

StreetDyno.Zip -- Updated 10/20/98 (700kb)

If you would like to be notified when I upload an update to the program, please drop me an email and I will add you to a distribution list I am building. Also, if you just want to give some comments [good or bad] please do. I am in need of some "dyno runs" & config files from cars with automatics in them and cars with MSD ignitions. email me at glover@blkbox.com, Thanks Mucho!!

Included in the zip should be:

StrtDyno.exe - Win95 EXE [32bit Only]

09299802.Wav - Sample wave from my 93Notch

092998.Cfg - Sample config file for the above "Dyno" run

ReadMe.Txt - Detailed instructions for making runs and installing the program.