Boost Gauge w/Procharger?
07-01-2002, 08:42 AM
#1
Guest
Posts: n/a
Boost Gauge w/Procharger?
Has anyone used a Gaffrig boost gauge on a Procharger application with the gauge plumbed into the manifold?
I just installed a gaffrig 0-15 PSI boost gauge and it occurred to me that since I plumbed it to the manifold (instead of the carb box) that the gauge would likely be seeing vacuum during idle.
Does anyone know if the gauge can take the engine vacuum? I have not run it yet but I didn't want to ruin the gauge.
thanks, Paul
I just installed a gaffrig 0-15 PSI boost gauge and it occurred to me that since I plumbed it to the manifold (instead of the carb box) that the gauge would likely be seeing vacuum during idle.
Does anyone know if the gauge can take the engine vacuum? I have not run it yet but I didn't want to ruin the gauge.
thanks, Paul
07-01-2002, 08:51 AM
#2
Registered
Join Date: Sep 2001
Location: Houston, TX, USA
Posts: 2,287
Likes: 0
Received 0 Likes
on
0 Posts
I do not know about your gauge. I would call manufacture. I have Vac-boost gauge plumbed to the intake. With this I can see exactly what motor is doing. Plumbing to the box will not give you reading what motor is doing. I have gauge in box & in intake. When crusing intake will show 6-5" vac but box will show 3 lbs boost.
07-01-2002, 10:01 AM
#4
Guest
Posts: n/a
Thanks guys,
Yeah I really want to watch the manifold pressure. I just checked the Gaffrig website and they have a combo gauge. The only drawback is that it is 0-30" vac/0-30 psi Boost. On a 2" face, that will translate to pretty hard to read and not so much resolution.
Have not run it yet (just got the motor back together w/procharger kit) but I'm guessing that I'll be looking at less than 5 PSI max pressure in the manifold so I'll be in the bottom range of the gauge.
The Procharger Stage II kit is belted to run @ 5 PSI. I'm sure that meand 5 PSI in the box!
I'll call Gaffrig this AM.
Paul
Yeah I really want to watch the manifold pressure. I just checked the Gaffrig website and they have a combo gauge. The only drawback is that it is 0-30" vac/0-30 psi Boost. On a 2" face, that will translate to pretty hard to read and not so much resolution.
Have not run it yet (just got the motor back together w/procharger kit) but I'm guessing that I'll be looking at less than 5 PSI max pressure in the manifold so I'll be in the bottom range of the gauge.
The Procharger Stage II kit is belted to run @ 5 PSI. I'm sure that meand 5 PSI in the box!
I'll call Gaffrig this AM.
Paul
07-01-2002, 11:45 AM
#7
Guest
Posts: n/a
turbojack,
Hope you are right. I have no experience with the Procharger yet but I was expecting the 5 PSI to be the max pressure in the carb box. I'm going to prop the boat for ~5200 rpm. I don't have any idea what the boost profile is like for my set up, but I think they rate the M1-SC at 5 #'s at 4800 engine RPM's. I'll let you know.
More is better!
thanks for the info!
Paul
Hope you are right. I have no experience with the Procharger yet but I was expecting the 5 PSI to be the max pressure in the carb box. I'm going to prop the boat for ~5200 rpm. I don't have any idea what the boost profile is like for my set up, but I think they rate the M1-SC at 5 #'s at 4800 engine RPM's. I'll let you know.
More is better!
thanks for the info!
Paul
07-01-2002, 12:03 PM
#8
Registered
Join Date: Sep 2001
Location: Houston, TX, USA
Posts: 2,287
Likes: 0
Received 0 Likes
on
0 Posts
This is my first year with procharger but good buddy of mine is on his 4th year. I am suprised his motors are still togeter since he runs wide open all the time.
Most important thing if you are setting up is get jetting right, This means on rich side. Check plugs at a number of different rpms to make sure you have jetting right at part & full throttle. If wrong motor will detonate itself apart & you will be doing motor work real soon.
Most important thing if you are setting up is get jetting right, This means on rich side. Check plugs at a number of different rpms to make sure you have jetting right at part & full throttle. If wrong motor will detonate itself apart & you will be doing motor work real soon.
07-01-2002, 01:02 PM
#9
Guest
Posts: n/a
Paul,
Not sure if anyone has mentioned this yet, but you might want to consider running the boost gauge to the box, and not into the intake manifold. The reason I say this, is because the boost reading from the intake will have an air / fuel mixture. If the line pops off the gauge while running under boost, there is a potential for air / fuel mixture to escape into the helm area. Also, in the carb box, there won't be a (significant) vacuum to worry about. But like Turbojack said, expect 1 - 2 psi drop across the carb.
As for gauges, I would not hesistate to look at (dare I say it...) Automotive style gauges. I went with a set ot Autometer "Classic Rod" boost gauges. Haven't had any problems with them. Also, the vacuum goes to 30 in/Hg while the Boost only goes up to 15 psi. Plus, the gauges don't look like your typical Autometer gauges. They actually fit the Gaffrig Speedo and Tach better than the other Gaffigs. I've been thinking about swapping out the oil, water, and voltage gauges with matching Autometers for better looks and accuracy.
-Bayley
Not sure if anyone has mentioned this yet, but you might want to consider running the boost gauge to the box, and not into the intake manifold. The reason I say this, is because the boost reading from the intake will have an air / fuel mixture. If the line pops off the gauge while running under boost, there is a potential for air / fuel mixture to escape into the helm area. Also, in the carb box, there won't be a (significant) vacuum to worry about. But like Turbojack said, expect 1 - 2 psi drop across the carb.
As for gauges, I would not hesistate to look at (dare I say it...) Automotive style gauges. I went with a set ot Autometer "Classic Rod" boost gauges. Haven't had any problems with them. Also, the vacuum goes to 30 in/Hg while the Boost only goes up to 15 psi. Plus, the gauges don't look like your typical Autometer gauges. They actually fit the Gaffrig Speedo and Tach better than the other Gaffigs. I've been thinking about swapping out the oil, water, and voltage gauges with matching Autometers for better looks and accuracy.
-Bayley
07-01-2002, 02:33 PM
#10
Guest
Posts: n/a
Wooaah Bayley,
Nice instruments! Quite the contrast to my 1990 Baja. Those look great. I wouldn't expect you to have isues with the automotive gages anyway. When you think about it, you can have plenty of humidity locked up in a car and besides, who puts as many hours on their boat as their car?
On the gauge plumbing/fitting, you have a good point with the air/fuel mixture. I ditched the 1/8th line that came with the gauge and used 1/4 Polypropylene with high quality stainless fittings (Swagelok) with tubing barb inserts to support the tubing where the compression ferrule locks onto the tubing. It's pretty secure.
What are you guys running for Timing? I just installed an MSD system with the pro-billet distributor. I have the black bushing in it with one heavy and one light spring. The advance curve looked pretty linear right on up to 5000 RPM. Do you have to check the timing @WOT? Or can you just set timing @ idle and count on the bushing stop to limit timing? I was told to run 30 deg total advance. I saw some posts that indicated 28-29 deg. total timing.
I also bought and had the carb. set up by Dean Nickerson and he said that the jetting should be OK. We'll see.
Man, I am hoping I don't have to keep pulling plugs to look at them bacause it is a royal pain in the a..... to get at the starboard side ones. I'm geting ready to put the back seat in and I can't imagine getting at those plugs once it is back together!
Nice instruments! Quite the contrast to my 1990 Baja. Those look great. I wouldn't expect you to have isues with the automotive gages anyway. When you think about it, you can have plenty of humidity locked up in a car and besides, who puts as many hours on their boat as their car?
On the gauge plumbing/fitting, you have a good point with the air/fuel mixture. I ditched the 1/8th line that came with the gauge and used 1/4 Polypropylene with high quality stainless fittings (Swagelok) with tubing barb inserts to support the tubing where the compression ferrule locks onto the tubing. It's pretty secure.
What are you guys running for Timing? I just installed an MSD system with the pro-billet distributor. I have the black bushing in it with one heavy and one light spring. The advance curve looked pretty linear right on up to 5000 RPM. Do you have to check the timing @WOT? Or can you just set timing @ idle and count on the bushing stop to limit timing? I was told to run 30 deg total advance. I saw some posts that indicated 28-29 deg. total timing.
I also bought and had the carb. set up by Dean Nickerson and he said that the jetting should be OK. We'll see.
Man, I am hoping I don't have to keep pulling plugs to look at them bacause it is a royal pain in the a..... to get at the starboard side ones. I'm geting ready to put the back seat in and I can't imagine getting at those plugs once it is back together!
Last edited by NEVRENUFF; 07-01-2002 at 02:36 PM.
