Boost Gauge Install

[flatblack]

Do the gauges come with instructions, when you buy them from the s10 planet store, and what is the difference between mechanical and electrical gauges?? what kind should i get when we move on the group purchase?? :info:

[Jerrylm]

I don't know about when you buy them from the s10 planet store, but I bought an AutoMeter boost gauge and fuel pressure gauge for my Blazer. The instructions were plain and easy to follow. My boost gauge is mechanical. It's actually plugged into the manifold vacuum and the pressure change mechanically operates the needle on the gauge. The fuel pressure gauge is electronic. There is a sensor (or pressure transducer) that screws onto the fuel return line and it varies a voltage signal back to the gauge that is interpreted as pressure on the gauge. Bottom line, mechanical gauges tend to be less expensive, electronic more expensive. Quality of whatever you choose will have a bearing on accuracy and how long it lasts.

[flatblack]

i understand the electrical gauges, pretty simple how they work, but how do the mechanics of the boost gauge work? is it like a cable that is inserted into the manifold vacuum and a tab that i pushed over with the more boost that is pushed?

[Jerrylm]

I've always been curious about how things worked so on more than one occasion I've taken old pressure gauges apart to see what's inside. They're really pretty simple. Normally a gauge is connected to the pressure source either directly or with piping or tubing. Inside the gauge, the part that the pressure goes into is called a bourdon tube. It's a flexible, C shaped, brass (or simular material) tube. As the pressure increases, it causes the tube to try and straighten out. The opposite happens when the pressure decreases. The bourdon tube movement is attached to something like a rack and pinion gear setup. The gauge needle is attached to the pinion part, so it rotates when the bourdon pulls on the rack. This is kind of hard to explain without pictures but if you ever find an old gauge you can tear apart it's easy to see how it works. Sorry for the long explanation and I hope this gives you some idea how a mechanical pressure gauge works.

[joker2040]

Any thoughts Super?

[flatblack]

well thats cool, i need to tear one apart...thanks for the info...

[Jerrylm]

I found this after looking around a little bit. This explains it pretty well. Keep in mind this is one way mechanical gauges are made. There are other ways to make them but this is among the most common.
http://www.engineersedge.com/instrumentation/bourdon_pressure_detector.htm

[flatblack]

ok...that makes some good sense...thanks for the info guys...now for the million dollar question, if you were to purchase a boost gauge would it be mechanical or electical with out money in mind...which is an easier install? and which gives a better read of pressure?

[Jerrylm]

If I had to do it again, I'd still go with the mechanical. It's hard to beat a good quality mechanical gauge and it will give accurate readings for a long time. Installation is easier too. Just mount the gauge, run the tubing between the gauge and engine and then use a tee fitting to tap into a vacuum line close to the manifold. The only wiring required is tying the gauge light into the dash lights. Get a gauge with a range as close to the max pressure you expect to see. If you're going to run 6 - 7PSI boost you'll get more accurate gauge readings with a gauge that goes from 30" vac to 20 PSI than a gauge with a range of 30" vac to 30 PSI.

[flatblack]

aight i installed the boost gauge halfway lastnight, and i was looking at instructions and it shows a T fitting on the vacuum hose? i didnt get a T fitting along with the gauge...and i dont have the S/C yet but when i do will i then have this vacuum hose then? or do i already have it??

[flatblack]

bump...