Hidden arrows on dashboard

[jose456891]

The best modification I've done to my 850 wagon GLT is the addition of a trip computer from another 850. I easily get 30 miles to the gallon, or 540 miles to the tank. I drive alot for work, I sell life insurance and I've racked 3k miles in my most productive week.

Experimentally I've discovered that if I keep the tachometer shy of 3k I'll get the best economy even with the AC on. One night I was looking for coolant leaks by adding UV pigment to the coolant. I shined the light on the drivers area and noticed this on the dash:

Left

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Right

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Starting on the fuel Gage, the top arrows correspond to the exact full tank reading, and low it marks the reserve.

Temperature gauge has 3 sets of arrows. The top being a overheating condition, operating temp on the middle, and cold on the bottom. My car was right between the set of arrows rotating operating temp. The bottom arrow of that set is obscured by the gage itself.

The speedometer has 4 sets of arrows. When I keep the car within those arrows I always get 35+ MPG with the AC on.

The tachometer has 3 sets. I don't know what they mean, but if I needed to guess I'd say the first is idle target, last is the rev limiter and middle has to correspond with peak torque (this is where I get the best mpg.

I don't know if other models have these elusive UV arrows, or exactly what they mean. I'm here to share them with the community, hopefully you could try to drive within the arrows in the spedo and get high MPGs like I have.

-JG

[jimmy57]

Calibration markers for QC checks at gauge supplier.

[jose456891]

Calibration markers for QC checks at gauge supplier.

Trust Me, I agree. But then why is the max torque stamped on teachometer. And the gear shift points on the spedo?

It's useful info for hypermiling.

[bmdubya1198]

That's really interesting. I'll have to get a UV light at some point and check out my cluster.

[abscate]

Only if you know the history of what hasn't been done in your car

[FlyingVolvo]

Only if you know the history of what hasn't been done in your car

( ͡° ͜ʖ ͡°)

[bmdubya1198]

Only if you know the history of what hasn't been done in your car

My car has had many owners before me. Maybe I'm better off not doing that...

[jose456891]

Only if you know the history of what hasn't been done in your car

I'll be willing to bet my entire yearly income that these arrows are on most volvo 850's independent of the number of owners.

It's highly plausible that v70's have this.

I also bet that the arrows on the speedometer correspond with gear shifts and the ones on tachometer correspond with idle, max torque, and rev limit.

[Clemens]

They are not afraid of the arrows, jose, they are worried about traces of man-juice if you know what I mean. It becomes visible under UV light.

The arrows though are an interesting find. Very cool.

[abscate]

The Oxford dictionary

jimmy57....noun....knows more obscure and useful stuff about Volvos than Volvo themselves.

Simple test. In a given model year P80s came With three engine options of NA LPT and HPT. Is there a different part number DIM for each one to reflect the shift points ?