How is the vacuum guage used - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Yukon Jack** · 10-25-2005, 10:21 AM

A buddy just got a tach dash for $75 and it has a vacuum gauge. Where does it read vacuum from and how does one actually use that guage? What is the benefit of knowing the amount of vacuum?

71-longbed · 10-25-2005, 10:32 AM

im not sure where those dash gauges hook exactly to ... all you need is any port with full time manifold vacuum

vacuum gauge in the cab can help the driver maintain the most efficient throttle .... more vacuum = more mpg

cdowns · 10-25-2005, 10:37 AM

in all honesty the vaccume gauge is mostly used to say"hey i've got a vaccume gauge" so you can WOW people//if you're getting 10mpg without one you'll get 10mpg with one

**Yukon Jack** · 10-25-2005, 10:39 AM

Just noticed I need to remember how to spell gauge - thanks for the info. He wants to have it work even if it is actually not something that he would use.

jhow66 · 10-25-2005, 10:41 AM

Hooks to a full time vacumn port. Was used on C30 and up that had vacumn assisted brakes. Can be used to show state of tune on your engine. Higher the reading better the state of tune (except with wild cams). Use to adjust fuel mixture on carb--higher the better. Can be used to find engine problems-
check here:
http://www.gmcpauls.com/Tech%20Tips1.htm
scroll down.

**Yukon Jack** · 10-25-2005, 10:44 AM

Great link. Thanks.

**Yukon Jack** · 10-25-2005, 11:16 AM

Just gave this info to my friend and turns out the bezel is actually missing the guage, it just has the markings on the lens. So, I'm off to post a wtb in the classified section.

I'm assuming he will need just the guage and then some rubber line for the vacuum gauge.

*wolfthing2000* · 10-25-2005, 12:08 PM

I would buy a new one after market repop.

70c10 · 10-25-2005, 01:12 PM

I always thought the vac gauge for our trucks was for rear brakes or something on heavy duty trucks.

aitch · 10-25-2005, 02:13 PM

I have an after market vacuum gauge that the PO mounted on the stearing column.
It reads Economy (green zone) and Power (red zone). Depends on how deep I've got my foot.

I can't help but look at it because of where it's mounted. Frankly it does not do anything for me and once I get going on this project, it will come off.

blazerparts · 10-25-2005, 06:22 PM

fills a hold in the instrument panel. Mine is hooked to a port on the 1406

llegos · 10-25-2005, 06:48 PM

yea, i think its just to hold a space on the bezel, unless on a med.+ duty truck. Hopefully if all goes right, that place on my dash will be filled with a boost gauge....

Solver · 10-25-2005, 10:23 PM

Blazerparts did you use a rubber or a metal line for the vacuum guage?

10-25-2005, 10:21 AM	#1
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,684	How is the vacuum guage used A buddy just got a tach dash for $75 and it has a vacuum gauge. Where does it read vacuum from and how does one actually use that guage? What is the benefit of knowing the amount of vacuum? __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

10-25-2005, 10:32 AM	#2
71-longbed Its Magically Delicious Join Date: Jan 2003 Location: oregon Posts: 2,398	Re: How is the vacuum guage used im not sure where those dash gauges hook exactly to ... all you need is any port with full time manifold vacuum vacuum gauge in the cab can help the driver maintain the most efficient throttle .... more vacuum = more mpg __________________ 71 C10 LWB 350sbc -TH350 12 bolt 3.42 Posi Of all my favorite things to do, The utmost is to have a brew. My love grows for my foamy friend, with each thirst-quenching elbow bend. Beer so frosty, smooth, and cold it's paradise pure liquid gold. Yes beer means many things to me that's all for now cus I gotta pee.

10-25-2005, 10:37 AM	#3
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: How is the vacuum guage used in all honesty the vaccume gauge is mostly used to say"hey i've got a vaccume gauge" so you can WOW people//if you're getting 10mpg without one you'll get 10mpg with one __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

10-25-2005, 10:39 AM	#4
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,684	Re: How is the vacuum guage used Just noticed I need to remember how to spell gauge - thanks for the info. He wants to have it work even if it is actually not something that he would use. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

10-25-2005, 10:41 AM	#5
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Re: How is the vacuum guage used Hooks to a full time vacumn port. Was used on C30 and up that had vacumn assisted brakes. Can be used to show state of tune on your engine. Higher the reading better the state of tune (except with wild cams). Use to adjust fuel mixture on carb--higher the better. Can be used to find engine problems- check here: http://www.gmcpauls.com/Tech%20Tips1.htm scroll down. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

10-25-2005, 10:44 AM	#6
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,684	Re: How is the vacuum guage used Great link. Thanks. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

10-25-2005, 11:16 AM	#7
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,684	Re: How is the vacuum guage used Just gave this info to my friend and turns out the bezel is actually missing the guage, it just has the markings on the lens. So, I'm off to post a wtb in the classified section. I'm assuming he will need just the guage and then some rubber line for the vacuum gauge. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

10-25-2005, 12:08 PM	#8
wolfthing2000 Account Suspended Join Date: Oct 2004 Posts: 1,276	Re: How is the vacuum guage used I would buy a new one after market repop.

10-25-2005, 01:12 PM	#9
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,857	Re: How is the vacuum guage used I always thought the vac gauge for our trucks was for rear brakes or something on heavy duty trucks. __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

10-25-2005, 02:13 PM	#10
aitch Senior Member Join Date: Sep 2004 Location: N.W. Arkansas Posts: 456	Re: How is the vacuum guage used I have an after market vacuum gauge that the PO mounted on the stearing column. It reads Economy (green zone) and Power (red zone). Depends on how deep I've got my foot. I can't help but look at it because of where it's mounted. Frankly it does not do anything for me and once I get going on this project, it will come off. __________________ 69 GMC 3/4 ton LWB 383 TH400 Dana 60 '84 300ZX '79 Nova (for sale)

10-25-2005, 06:22 PM	#11
blazerparts No,I DON'T have Tourett's Join Date: Mar 2005 Location: Reno, NV Posts: 556	Re: How is the vacuum guage used fills a hold in the instrument panel. Mine is hooked to a port on the 1406 __________________ '72 K5 CST 350/350 Daily Driver '69 GMC3500 Camper Special CST Flatbed 396/400 Upgraded to show truck '69 GMC 2500 L6292, 3spd beater

10-25-2005, 06:48 PM	#12
llegos Registered User Join Date: Aug 2005 Location: pleasanton, CA Posts: 570	Re: How is the vacuum guage used yea, i think its just to hold a space on the bezel, unless on a med.+ duty truck. Hopefully if all goes right, that place on my dash will be filled with a boost gauge.... __________________ -Steve

10-25-2005, 10:23 PM	#13
Solver Registered User Join Date: May 2000 Location: Storm Lake, Ia Posts: 1,449	Re: How is the vacuum guage used Blazerparts did you use a rubber or a metal line for the vacuum guage? __________________ 1972 Cheyenne Super 20 LWB-Blue 1972 Cheyenne Super 10 LWB-Black 1972 Cheyenne Super 10 LWB-Red 1972 Cheyenne Super 10 LWB-green 1972 GMC 4x4 LWB-White 1971 Cheyenne 10 LWB-Ochre 1971 Cheyenne 20 Longhorn-Copper 1971 Cheyenne 20 Longhorn-Black 1969 Custom 10 LWB-lt blue 1968 GMC 3/4 ton-green 1968 1/2 ton swb stepside-silver 1967 Chevrolet CST 10 LWB-green 1967 Chevrolet custom 20 LWB-Maroon



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