Hidden arrows on dashboard

[erikv11]

Along those lines, the shift points within each car are different depending on whether you push the sport/economy button. And the lower arrowhead on the tach appears much too high to mark idle.

It's cool that we've (or at least I've) never seen them before, but 99:1 they aren't shift points or anything else directly related to driving the vehicle.

[bmdubya1198]

That's what I was thinking, the mark that would be idle speed is too high. And shift points can definitely vary, between how you drive and whether the transmission is in sport or economy mode. My typical shift points are near redline, which would explain why my car makes a Fuelly estimated 20 MPG.

[jose456891]

They are not afraid of the arrows, jose, they are worried about traces of man-juice if you know what I mean.

( ͡° ͜ʖ ͡°)

Along those lines, the shift points within each car are different depending on whether you push the sport/economy button.

The sports mode will use the same shift points as economy mode unless rate of change of TPS is aggressive enough to warrant agressive/late shift. I'm on my phone right now, but I remember reading about it on Volvo's own transmission troubleshooting guide for the 850.

And the lower arrowhead on the tach appears much too high to mark idle.

My car idles at 850 RPMs, as told by my scanner, and that aligns perfectly within the lower tachometer arrows. Same magic number appears in Volvo's own engine troubleshooting guide as normal idle speed.

It's cool that we've (or at least I've) never seen them before, but 99:1 they aren't shift points or anything else directly related to driving the vehicle.

Agreed, but they could still be or not. I say they correspond atleast to best economy. I get higher than normal MPGs when I keep my speed within the arrows.that's how I arrived at the conclusion that the arrows meant shift points.

[erikv11]

Yes, behold the power of Occam's razor, LOL.

...

Along those lines, the shift points within each car are different depending on whether you push the sport/economy button.

The sports mode will use the same shift points as economy mode unless rate of change of TPS is aggressive enough to warrant agressive/late shift. I'm on my phone right now, but I remember reading about it on Volvo's own transmission troubleshooting guide for the 850.

Yes that''s right, the vehicle uses different shift points in sport mode. In fact it's the only thing that sport mode button does, it's the whole point of the button. For sure this is documented in Volvo publications, but more obviously anyone who has driven a P80 a few miles knows it very well. In practice it doesn't take much "aggression" at all to change the shift point.

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And the lower arrowhead on the tach appears much too high to mark idle.

My car idles at 850 RPMs, as told by my scanner, and that aligns perfectly within the lower tachometer arrows. Same magic number appears in Volvo's own engine troubleshooting guide as normal idle speed.

...

That's right, the marks are only barely relevant to the magic idle number (your car ideas where it should!), that's also one of my points. If they were meant to mark idle RPM, surely they would be centered around it, or at least close to centered.

We're arguing on the internet about something we can't prove, and I don't pretend to know the answer, these are just points to consider if you want to guess about it.

[bmdubya1198]

Someone contact Volvo and settle this!

[jimmy57]

The gauge clusters are programmable. The diesel uses the same hardware but they change the program to reflect the diesel tach having a smaller RPM range. A person sitting at a bench checking gauges can use a blacklight to see those marks and punch a button on a tester and it will go through a calibration verification sequence. The needles in most cases do not go onto D shaped shafts. The number plate applique gets applied and the gauge plate is energized to assure zero position or whichever position the needles are affixed in on the plastic piece that holds the needles so they are pushed on in one motion. The action is likely robotic today.
I couldn't find gauge manufacture videos but I did find this by chance:

[bmdubya1198]

Pretty cool, that would make sense as to why they're marked.