Boost gauge question

[HawkZ71]

I'm planning to get a whipple and Autometer boost gauge. However, I've found two types of boost gauges.

AUT4103 Boost 30" Hg./30 PSI
AUT4104 Boost 35 PSI

Click Here (http://www.rpmoutlet.com/aut4100.htm) to see.

What is the difference between these. I think all I need is the 35PSI, but was wondering what the other one was.

Thanks for your help.

[ibthumpin]

One of them shows you just boost, 0-35psi.
The other shows vacuum and boost - with zero appearing in the middle. I forget what the "Hg" measuring increment stands for - maybe its the symbol for mercury, because I think vac. is measured in "inches of mercury". Its determined by how far up a tube the liquid is sucked. Or something like that ... lol.
The terms negative boost and vacuum are sometimes thrown about and mean the same thing. The second gage jsut gives you the ability to see vacuum, whereas the other gauge would jsut rest on the pin when there is no boost.

Which one do you want?? Hell if I know :D

[James B.]

Get one that only goes up to 15psi. It will give you more sweep and greater resolution.

[CoonToot]

Originally posted by James B.
Get one that only goes up to 15psi. It will give you more sweep and greater resolution.

Once again, James is dead-on. I have the Ultra-Lite series model #4301 that goes from -20 on the vacuum side to +20 on the boost side, which is perfect for my needs with the Whipple. I like that it has the aforementioned sweep and resolution that is better than the 30 psi model, although you don't have much a choice in the Lunar series.

Scott

[HawkZ71]

:word: For now I'm stuck with just the one 2-1/16 mechanical boost gauge. I already have three Lunar gauges and don't like the idea of have an odd gauge in the cluster...

Maybe I'll get lucky and by the time I get the Whipple, they'll add more offerings to the lunar series.