What's my new Boost Gauge telling me?
 

Just finished installting my Stewart Warner Boost Gauge (lights not spliced in yet but gauge is working) and I am wondering what are normal readings for a Boost gauge?

At idle I'm showing 20/21 Hg Vacuum and at Boost say 5000/6000 RPM's I'm showing 16/17 psi.

Currently the mods I have installed for performance are an Alta IC Diverter, Engine Damper, Helix 17% pulley and a Webb/Helix clone CAI. Just want to know what normal is... TIA Michael

Sounds perfectly normal to me. :thumbsup:

yep from all i've read here ;that's correct!!

Where are you measuring the boost?
cheers,

Not sure what you mean when you say, "Where are you measuring the boost?"

I didn't see many pictures on their site, can you post some of your new installation?

I'm not measuring boost myself, but I can put a probe in before the IC, after the IC or from any of the vacuum tubes (like the one coming off the intake manifold near cylinder 4 (the one at the left). Hence my question: where in the intake path are you measuring boost? My experience measuring temperatures suggests that temperature varies considerably along the intake path and requires at least 4 probes to understand what is happening (I currently only have 3...damnit).

cheers

Sorry to highjack the thread, but where should one measure boost from? Say, if someone recently installed a DFIC?

Thank you,
JBravoMC

I think most with the DFIC are measuring boost at the bungs on the in- and out- cavities of the IC. They are standard 1/8" NPT females.

cheers,

So, assuming I have one boost gauge needle, do I tap into the IN, OUT or both bungs to get the boost reading? With both bungs possibly giving me the average? Is that even wise to do?

TIA,
JBravoMC

For a boost gauge...
 

the best place to tap is the existing tap used for the VGS mod, down by belt end of the engine on the intake manifold. This is the vacuum line that controls the fuel regulator, and while not exactly where the T-MAP sensor is, is representative of what the ECU sees to run the motor. Really, a boost gauge is there not to diagnose the pressure losses in the intake path (a good thing to do) but to measure the pressure that's forcing the charge into the cylinders. And the intake manifold is the best place to do that.

But Phil, you're quickly comming to understand what's true on diagnostics. You can't have too many data channels, but you sure can have too few! For a good Intake characterization, you either have to move one or two probes around in a repeatable environment (read good dyno room) or you have to have enough channels to get everything you want at once, to get good snapshots of the action in real world conditions..... Wouldn't it be sweet to have a min of 4 each temp and pressure? more would be even better.

Costs less than an M62 kit, but I think I'd rather have the blower!:lol:

Matt

I also have the Stewart Warner gauge, which was installed by the dealership. With a 15% and intake I get 15psi at redline in 4th gear. So yours seems just about right with the larger pulley.