Jeff -it figures torque/hp only by measuring RPM over time and integrating that with the gear ratios and vehicle weight. Therefore it cannot compensate for tire diameter, wheel spin and tire slip (which happens under load no matter what) - probably making it more inaccurate in torquey 2wd cars like the M5.
Still - it looks like a good product for other reasons.
Daniel - there are a few other brands. At the racing level there are data logging boxes that will do this and a lot more such as from Pi Research.
At the consumer level, the Escort radar detector folks make the G-Timer (
http://www.escortradar.com/gtimer.htm), and a company called Pocketdyno makes the PocketDyno, which uses a Palm OS handheld for its UI (
http://www.pdyno.com/)
The Gtech with the latest sw is a beautiful piece of work - the best by far. It DOES suck for the following reasons:
1) RPM sensing doesn't work in the M5 - BMW's ignition noise and alternator noise suppression is evidently better than anybody elses. However it will still log acceleration runs, and record x and Y g's. It has a 3-axis accelerometer which can correct for some things that throw a 2-axis one (like the P-dyno and
i think the escort unit.
2) Its display is completely useless if you wear polarized lenses - as I do ALWAYS during the day.
3) It is 100% aimed at drag racers - with a little sw it could do really nice stuff for autocrossers and road racers, such as a friction circle plot, a skidpad mode, and a data logging mode oriented at lapping race course.
I have begged and pleaded with them for 2 years, and have received absolutely no satisfaction. Their customer support is the worst I've ever encountered. (The guy who answers the phone clearly has no real power, so he is at management's mercy. They tell him lies, he repeats them.)
It is a low down dirty shame, because the capability is there, and the unit is elegant in many respects. They just need to write the software.
I have a sample of the p-dyno. Interesting, fairly low quality, doesn't do what I want, looks cheap, hard to use a pilot as a control station. 2-axis accelerometer only, same drag-race-only orientation. It does not sense RPM, nor does the Escort.
Linear Mode
