Is it a good idea to put a vacuum gauge in your console, and how will this help you when driving . What do you look for as you are driving , if it is suppose to help?

Thanks
Dave

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81 Dodge D150
It looked easier in the book .

It is a very good idea. A vacuum guage will tell you all sorts of things. It will tell you if you have low vacum, indicating a vacuum leak or misadjusted valves. It will telll you if your vacuum rapidly fluctuates which can indicate a crack, burned, or misadjusted valve. And it is a great way to maximize fuel economy. Specifically, you drive to achieve maximum vacuum and therefore save gas.

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Casually looking for a Clifford hyperpak intake for cheap.

Thanks Reed
So you drive to keep the highest vacuum possible.
I have one more question . Where would you tap in at ? I think I read here somewhere to tap into the choke pull-off hose, or is it best to hook it to manifold vacuum.

Dave

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81 Dodge D150
It looked easier in the book .

On a slant six you can tap into one of several places, but the key thing to remember is that the vacuum source must not be "ported." Ported means the vacuum signal goes away when the throttle is closed. The easiest is the #6 runner on the intake manifold. however, this makes the guage susceptible to fluttering due to the pulsing of the charge down the #6 intake tube. I had this problem when I installed a vacuum guage on my brother's 83 Dodge van. Another choice is splicing into the choke pulloff hose, like you said. I don't lke this idea personally. Most carbs (especially ones built after the mid 70s) have "extra" vacuum nipples for smog devices. Usually you can find one of these that is a non-ported vacuum source. That is what I did in my brother's van. This way the guage reads the exact vacuum that the carburetor is experience. Much more accurate.

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Casually looking for a Clifford hyperpak intake for cheap.

I use the choke pull off or you could use the line that goes up to the control valve for the snorkel heat. On a 1920 Holley, either fitting on the drivers side that comes out of the base works fine.

The gauge also shows you where the power valve kicks in so you can stay out of that range or change/tune the power valve. It will also help with tuning your vacuum advance. Like Reed said, if you engine is going out of tune, you will see the change in vacuum. If your gauge is not nice and steady at idle or at cruise, you know you got problems.

Example: On mine at 750 idle out of gear it's at 18" and at 600 rpm in gear it's at 16.5" steady, no fluttering. In fact it will idle for hours like that in rush hour traffic and never skip a beat or flutter.
At a 60 mph cruise, 2500 rpm I can run at 16 to 18" and have plenty of wiggle room on the pedal/power and the gauge will not drop down at all unless I really press harder to pass or go up a significant hill.
If you have a lead foot you may stay around 12 to 14", or even less say 8 - 10" where the power valve comes on the economy really goes down.
If you can tune your car to cruise at a higher vacuum, you will get much better fuel mileage.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

00spy,

Lots of good info here already for you, but I want to add a plug for you putting in two! Put one under the hood near your carb, a small one about an inch in diameter and run the line on into your driving compartment. There put in one big enough to read easy, I like a 2 5/8 inch diameter one.
Reason for under the hood is so you can tune your carb mix and idle speed and know what is happening without running around to look inside the vehicle.

But as to just having one, I can't imagine not having it because it is so fundamental a tuning device. Don't limit yourself to a console unit, gages are easy to mount to a steering wheel column too. Or hang from a wire til you figure out where you want it!

And as for putting in one to make sure you drive steadily at the most vacuum, well I didn't build an engine to drive at the most vacuum, so I see 10 inches a lot. A gage is kinda like a breathalizer, you already knew you were drunk, it just confirms the point! In other words if staying off the gas was my objective, I don't need a gage to tell me where I am.

rock
'64d100

I have a big 2 5/8" gauge inside my car, and I have it velcroed to the dash right under the gauges at the top of the cluster. It covers the seat belt warning light, but I dont need that anyways. It has worked well for me, and let me know on my old car that I had a damaged intake valve. It had little color sections, and so long as I stayed in the green on the gauge, I was getting close to 27 mpg on the freeway @ 55 mph. They really do help. I would also follow the suggestion of placing one under the hood. I plan to put vacuum, tach and oil pressure under mine at some point as well.

~THOR~

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1984 D100 Shorty Custom
Certified Auto Appraiser - RevItUp Classic Appraisals
President - Cherry City Bombers CC
Part of Tyrde-Browne Racing

As far as putting ine under the hood, why not installa cluster under the hood? Fuel pressure, tach, oil pressure, vacuum, volts, amps, water temp, and oil temp? That way you can pop the hood and see everything at a glance. You could even wire them to light up when the hood was opened.

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Casually looking for a Clifford hyperpak intake for cheap.

Reed,

Not a bad idea! One doesn't tweak voltage, oil pressure, etc as often as vac though. I do have fuel and oil pressure gages under the hood though because I like data and don't like walking around and around. But a small cluster is a cool idea. It would go right on my firewall.

rock
'64d100

I am absolutely going to get one to put in my truck .
Thanks for all of the info, I will bookmark this , with my thousand others to look at later


Dave

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81 Dodge D150
It looked easier in the book .

Aren't you glad you asked? Now you need two!

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Sure, but what an easy way to see the condition of your motor. You can see it all at a glance. The hard part would be mounting and protecting the guages. Myabe finding them cheap at junkyard would be the way to go. Mount them all on the driver's side fenderwell facing out over the fender so you can tweak the carb and tune at the same time. Of course, if you have a van you will be tuning while you sit in the driver's seat...

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Casually looking for a Clifford hyperpak intake for cheap.

Thats the story of my life .

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81 Dodge D150
It looked easier in the book .

I love this thread, there's some great ideas!

I am building a cluster for under the hood in my '60 Belvedere, I am looking forward to actually getting some good numbers out of her, will make reporting back here to the board easier.

Just wondering what the least intrusive way to put some real instruments in the car would be? My big finned bird has a classic Wurlitzer Juke box interior, with ribbon speedo, oil light and temperature gauge, and that's about it. I'd prefer a little more info whilst I am driving but don't want to upset my interior.

Any ideas?
60Ply

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1960 Plymouth Belvedere 4 door sedan
Stock 60 225
Push button 3 speed Torqueflite
Right Hooker

Oh yeah, she has a fuel gauge too!
60Ply

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1960 Plymouth Belvedere 4 door sedan
Stock 60 225
Push button 3 speed Torqueflite
Right Hooker