I didn't like that either but like you said....oh, well. It's nice to have the gauge.

 

Does anyone know why the VSS on the brockway reads over 5mph different than the actual speedometer even though the VSS setting on the brockway is at the stock 100% drivetrain calculation?

Shouldn't they read the same info and be the same, even if its up or down, it should be the same.

 

Been trying to figure that one out as well, and have a theory. First, there will always be a difference between the VSS and the speedo due to the fact that all speedos have a built in fudge factor. They all read high. But, the brockway reads ~2MPH lower than my GPS. So I have three speed readings (from highest to lowest) 1. Speedo 2. GPS 3. Brockway. The low VSS reading, and thus low Brockway reading since it relies on the VSS output, can possibly be explained by the fact that I have nearly new stock size tires. Since the VSS does not measure vehicle speed by GPS, it is only as accurate as the gearing combined with diameter of the tires. Since my tires are new, they're at their tallest and travel further with each revolution. Thus the car goes faster for a given engine RPM. As they wear the car will go slower for a given RPM and the VSS will read higher for a given vehicle speed. So, the VSS may logically be calibrated for the mid-point; a half worn tire. Being a 'mechanical' reading, it's not possible for the VSS to be accurate for more than a very specific tire diameter. Clear as mud? Do you have either new or taller than stock tires?

I'm assuming the GPS is closest to correct, but I'm going to grab another one to verify.

 

One more question - When I first drive the car in the morning, the Brockway turns on and works normally. When I get in the car to drive to lunch, the Brockway does not turn on unless I unplug it first. I'm pretty sure it's not a plug seating issue since it does not turn on if I simply press on the OBD plug. I have to unplug it. Is this normal?

BTW, despite the little issues, I'm really liking this thing!

 

I don't have the issue with it not coming on. In regards to the VSS I agree I would think its off since the tires I have are taller than stock but I don't understand how the speedo can read so far off from the actual numbers its getting from the VSS. Maybe the brockway is always off a little and we need to know how much to adjust it in the setting screen.

 

I am not certain about the answers to these questions, but I believe I asked Eric about the speed variance and he commented that the brockway takes its info from the ECU and the speedometer is off.

Jeremy, it should start up every time you start the car. I will mention it to eric and see what he says.