Why is this gauge in my dash instead of the clock???

[disfrutalaruta]

Hey folks,
Bought this 77 911S (w/ 3.0) a few months ago and have been sorting out issues for a while now but I can't find anything on this:
Anyone know why this Vacuum Inches Gauge is in my car instead of the clock? Would this be a turbo gauge? It does not move under normal driving conditions. Might not even be hooked up - haven't checked. I can't even find a pic of one like it on the inter webs. What gives?
Lastly, anyone want to trade it for a clock?
Thanks,
Shane

[disfrutalaruta]

[ReconTrojan]

Your car does not have a turbocharger? That is a badass gauge, I bet 930 owners would prefer it over a clock and the factory boost gauge...like the one in my 951.

[disfrutalaruta]

No turbo... I am not much of a mechanic but I would notice that! Its a cool gauge but seems useless for my car. Maybe PO had a plan for a turbo and this is as far as they got?

[ganun]

Useful only if it's a turbo so you can monitor boost pressure and not break something in the engine. Without a turbo it will show around 15 inches vac at idle, 10 or so cruising and close to 0 at full throttle. Boring, but if an intake valve starts leaking the needle will vibrate at idle, and if the engine is worn it won't reach hi vacuum at idle...... btw it was popular many years ago as a fuel saver indicator, the closer to 0 the worse the milage.
Swap it for a clock, someone with a turbo will surely want it.
I have a similar gauge in the 505

[disfrutalaruta]

George! Haha - like the little gas mileage needle in my old BMW 530. Thanks for the info... Seems I need to post on the buy/sell thread for a swap.

[fanaudical]

Nice gauge!

I'd look for a disconnected vac line somewhere. Maybe pull the coupler cover and see if you can find an extra vac line running through the tunnel. I'm guessing the previous owner had this hooked up at some point. He probably chose this gauge (combo vac/boost) because VDO probably doesn't make a vacuum-only gauge that size.

[vintagecarlover]

I'll trade ya. Not high end but fills the hole. The good one has reset not this one.

[RarlyL8]

I have a factory clock, if you would like to trade shoot me an email.

[Pstallo]

Is there such as thing a factory-looking voltmeter that could replace the clock? I usually disconnect the battery on my car when I'm not using it, so the clock has no useful function for me.

[Driven97]

Bummer the font isn't a perfect match, but that's a super cool gauge for a turbo guy. Never seen that before.

[group911@aol.co]

Lots of cars used them a a fuel economy gauge.