Vacuum Guage Readings

B

brent covey

New member
Jul 2, 1999
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Hi Everyone-

Yet another informal survey ;-)

I was talking with a local GMC owner who says he's seeing about 12" Hg
vauum at highway speed, and this sounds darn low to me-

If you have a vacuum guage in your GMC, I'd be interested in knowing what
is a typical range-

Here's what I need to know-

- -Vacuum reading in inches Hg
- -name of the city/state you usually are driving in at this reading, if
relevant
- -axle ratio (factory 3.07 or not)
- -toad or no toad

If you dont have all this info thats OK, just a normal highway speed
reading will suffice- Just trying to get a feel for a basic range, as I am
going to be rebuilding this dudes carb in the next week or two and want to
get it right for him. I'll report what results I get to the GMC net;-)

Please reply either on-list or privately to

deville

Thanks!

Brent Covey
Vancouver

PS apparently theres a GM 3.36 ring and pinion for the GMC, I'm digging for
more info.
 
Hi Brent,

Now I not real sure, But I believe mine ran between 9-15 flat road,
60-75mph, Idle=21 steady, 3.07 no toad, AZ-CA

Ron&Gina
73 Pumpkin-Rose
Ft. Mohave,AZ.

- ----- Original Message -----
From: "Brent Covey"
To:
Sent: Monday, March 06, 2000 10:47 PM
Subject: GMC: Vacuum Guage Readings

> Hi Everyone-
>
> Yet another informal survey ;-)
>
> I was talking with a local GMC owner who says he's seeing about 12" Hg
> vauum at highway speed, and this sounds darn low to me-
>
> If you have a vacuum guage in your GMC, I'd be interested in knowing what
> is a typical range-
>
> Here's what I need to know-
>
> -Vacuum reading in inches Hg
> -name of the city/state you usually are driving in at this reading, if
> relevant
> -axle ratio (factory 3.07 or not)
> -toad or no toad
>
> If you dont have all this info thats OK, just a normal highway speed
> reading will suffice- Just trying to get a feel for a basic range, as I am
> going to be rebuilding this dudes carb in the next week or two and want to
> get it right for him. I'll report what results I get to the GMC net;-)
>
> Please reply either on-list or privately to
>
> deville
>
> Thanks!
>
> Brent Covey
> Vancouver
>
> PS apparently theres a GM 3.36 ring and pinion for the GMC, I'm digging
for
> more info.
>
>
 
I have a vacuum guage, and I live in New Mexico. I have about 17 to 18 inches
of vacuum at idle, and when I am going down the road at a level road, I too
get around 13 " and it goes down from there when I climb hills.
al

> Hi Everyone-
>
> Yet another informal survey ;-)
>
> I was talking with a local GMC owner who says he's seeing about 12" Hg
> vauum at highway speed, and this sounds darn low to me-
>
> If you have a vacuum guage in your GMC, I'd be interested in knowing what
> is a typical range-
>
> Here's what I need to know-
>
> -Vacuum reading in inches Hg
> -name of the city/state you usually are driving in at this reading, if
> relevant
> -axle ratio (factory 3.07 or not)
> -toad or no toad
>
> If you dont have all this info thats OK, just a normal highway speed
> reading will suffice- Just trying to get a feel for a basic range, as I am
> going to be rebuilding this dudes carb in the next week or two and want to
> get it right for him. I'll report what results I get to the GMC net;-)
>
> Please reply either on-list or privately to
>
> deville
>
> Thanks!
>
> Brent Covey
> Vancouver
>
> PS apparently theres a GM 3.36 ring and pinion for the GMC, I'm digging for
> more info.
 
Rest of answer. Have 3.42 final drive, yes pull toad - wv thing around 1700
lbs.
al

> Hi Everyone-
>
> Yet another informal survey ;-)
>
> I was talking with a local GMC owner who says he's seeing about 12" Hg
> vauum at highway speed, and this sounds darn low to me-
>
> If you have a vacuum guage in your GMC, I'd be interested in knowing what
> is a typical range-
>
> Here's what I need to know-
>
> -Vacuum reading in inches Hg
> -name of the city/state you usually are driving in at this reading, if
> relevant
> -axle ratio (factory 3.07 or not)
> -toad or no toad
>
> If you dont have all this info thats OK, just a normal highway speed
> reading will suffice- Just trying to get a feel for a basic range, as I am
> going to be rebuilding this dudes carb in the next week or two and want to
> get it right for him. I'll report what results I get to the GMC net;-)
>
> Please reply either on-list or privately to
>
> deville
>
> Thanks!
>
> Brent Covey
> Vancouver
>
> PS apparently theres a GM 3.36 ring and pinion for the GMC, I'm digging for
> more info.
 
Brent Covey asked :If you have a vacuum guage in your
GMC, I'd be interested in knowing what is a typical
range-

Results from my POOR MAN's DYNO TESTING BELOW
(including vacuum)



Coach Type ---- '73XPD - 26'
Engine ---- 455
Year ---- '73
heads ---- "j" (just rebuilt)
oil ---- Mobil 1 15W/50
ignition ---- "HEI" (Springfield)
initial---- 10 degrees
advance---- ported vacuum
comp. ---- 170 psi (approx - all cylinders)
vacuum ----
idle ---- 20" (neutral 850 rpms approx no a/c)
50mph ---- 16"
60mph ---- 14"
70mph ---- 12"

drive ratio---- 3.07 (OEM) Mobil 1
shift kit ---- no (OEM)
tires ---- XPS RIB
---- 8.75 X 16.5
---- 65 lbs (all)

load gas ---- full
L/P ---- 90% full
waste ---- empty
water ---- full
cargo ---- 150lbs tools/supplies ?

Gas ---- 87 octane (true gasoline)
A/C ---- 1/center - off
road ---- level
air temp ---- 70 degrees (love Florida weather)

DYNO TEST ----
method---- STANDING START - pedal to the floor -
record times for
0 - to 30 / 40 / 50 / 60 / 70 mph

RESULTS
0-30 ---- 7 seconds
0-40 ---- 11 seconds
0-50 ---- 18 seconds
0-60 ---- 27 seconds
0-70 ---- 40 seconds

=====
Pete Papas-->http://members.tripod.com/~mehawk_ii/index.html
. ___________ (MY TOYS) (904)672-0571
./_][__][] []| 1973 GMC M/H 1976 Bi-Centennial Harley M/C
.*O-------OO-* Painted Desert 1979 280ZX Datsun (1 of 1000)
Photos--> http://albums.photopoint.com/j/AlbumList?u=192176
__________________________________________________
Do You Yahoo!?
Talk to your friends online with Yahoo! Messenger.
http://im.yahoo.com
 
HOWELL TBI
FARMINGTON N.M. elevation 5000 ft
CASPRO POWER DRIVE 3.50
TOWING VW BEETLE
60 MPH FLAT GROUND
VACUUM 12
 
You are getting this message from sprint pcs, connected to a mac...
so there
send this to the net... works
>
>al
I sent this message to gene just a few minutes ago...

got the sprint free web services as part of my sprint pcs... got the
cable and software and installed on my MAC ( actually the mac is running
windows - sigh) had to stoop to that to get it to work. But it does.
so those of you who are thinking about the sprint etc, might want to
consider.
cable now runs $99 vice $199 yesterday. I signed up for 1000 minutes
shared with my son, so each of us has 500 minutes... they now can be
used for phone etc, plus web and internet connections.
speed is slowwwwwww 14.4 but plans are to go to 28.8 in the summer.

any questions - just email.

as a contest between gene and I, I won as he is still trying to
connect...
al
 
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