Greddy RPM gauge

Very nice, does it use OBDII signals, or is it getting ignition signals?

I use RPM as one of the four gauges in my OBDII ScanGauge II, which looks less cool. (stock photo)


I track RPM, instant MPG, Intake Air Temp F, and Coolant temp F.

 

Also available on many of the smartphone app OBDII-port products, newer than Scangauge.

 

I'm both amused by this and a little nostalgic for my old import-street-racer days (I really regret not buying an Integra Type R).

Any reason you didn't mount it on the A-pillar like all the cool people used to (along with a boost gauge )?

 

It's a cute thing to have on the dash, but are either of these parameters important for daily driving? The Prime is either on EV (with RPM = 0) or on ICE and you have no control over the RPM except with your right foot. The equivalent RPM meter exists in the multi-informatiom display - the farther to the right the power level, the higher the RPM.

 

As a Gen 2 and v driver, yes. If i know my RPM at a given speed that is my MPG, right there.
Now the factors that make a given RPM at a given speed are often out of my control (Temp, wind, precipitation, etc.) but if I am at 1800 RPM at 72 MPH I am getting 44 MPG.

So I am trying tricks to get my RPMs down so my MPG goes up. (Oddly, using cruise control in town greatly improves my chance of being in EV)

Various temp gauges give me clues why I am getting the MPG I am, so I am watching instant MPG as well.

I have not had my Scangauge when driving my relatives Primes, although I did take it to move the backup beep to a single beep.

 

I tried using my Scan Gauge II on my 2019 Prime, but the OBDII port is powered on all the time, even when the car is supposedly "off", so the Scan Gauge stays on, and it twice killed the car's12 volt battery when I didn't drive it for a couple of days. Had to disconnect the scan gauge. The Prius Prime has many more components that get very hot besides just the ICE: the traction battery, the DC converter, the stator coils in the transaxle, etc., that it really bothers me that the MID has nothing to warn you of an overheating problem except an idiot light. I live in a city where daytime high temps in the summer months are often in triple digits (105~110°F), and I almost always get that message "can the car use the air conditioning to cool the traction battery while charging?" This message means that the battery is too hot to safely charge it, and the message pops up almost every day in July and August. The Corolla Hybrid has a tach and a temp gauge, and the Prius Prime should, also. They have the same powertrain except the Prime has the big 25 mile EV range battery and the Corolla's is much smaller.

 

That's not quite what it means. it will charge without the A/C, but at a reduced rate unless the temperature is really excessive (which it probably won't be in a garage or shade). None of us who own Primes have figured out why they don't just let us set that parameter once and be done with it, and not be asked every time we shut the car off (and then for only a few seconds).

Pick up a Bluetooth OBD adapter and run Hybrid Assistant - it will show you the temperatures of the ICE, motor generators, inverters, etc. I have drivien my Prime in all kinds of hot weather, and the temperatures have never caused alarm and never a warning light.

Since these components are well cooled, you don't really need more than an idiot light. I watched the temps for a while and then stopped watching them.

Hybrid Assistant also provides a tach - I looked at that for a while and then stopped looking at it also. You can pretty much hear the engine and the MID on the dash power level pretty much corresponds to engine RPM.

 

I thought that (nearly) all OBDII ports had power all the time. My Gen3 Prius and my Subaru do. This sounds like a possible ScanGauge configuration problem.

 

The other advantage to Hybrid Assistant over a Scan Gauge (I have both) is that it can record data and then produce graphs, charts, spreadsheets, etc. Very handy if you want to review a drive and study the data at your leisure. Here is an example of the output:

 

I confess I have used it on a Gen 2 and a V myself. I took it to WA to set my brother and daughter's Primes reverse beep to one beep, but did not leave it attached to either car.