Autometer boost gauge reads high.
 

I wanted to clarify this before I go replacing my boost gauge or something. My current boost gauge is t'd into my map that goes to the ms. I tuned my ebc pid and I am at 180 kpa or about 11 psi in all gears at all speeds according to the map ms boost gauge. My vaccum on my autometer gauge reads correctly however in boost it reads 3-4 psi higher than what my map is seeing. Could this be a bad gauge or do you think it has to do with the lack of velocity caused by air traveling around a 90 degree bend in the T. I am sorry if this sounds confusing. It's just something I'm a little OCD about and would like my analogue boost gauge to read the same. Would a Electronic boost gauge make a difference? Or would switching the boost gauge to its own source rather that T'd on the map line help.

Virtually no flow at steady state. Once the MAP sensor and gauge bourdon tube are at registering state, there is no velocity at the tee.

Where I work, we have an old saying, "the man with two watches never knows what time it is."

Point is, you must determine which, if either, is correct. There may be some with experience as to how accurate the MS MAP sensors are. Realize also that the MS is calibrate-able and the calibration (span) could be off. There should be a tool that has a trust-able gauge that can be used to pressurize the line (from the end that is connected to the manifold), and then you can bring it up to, say, 15psi and compare that "standard" against the MS reading and the Autometer reading. Then you know how to proceed.

I T off my FPR line for the MS, then off that line once it's in the cabin for the boost pressure gauge, they're both fairly identical. If I were you, I'd borrow/steal/buy another boost gauge and see if it reads better.

Cool thanks for the replys. Im going to borrow one and see if it changes.

My FM boost gauge always reads 1-2 psi over. MS sees 148kpa which about what the wastegate should be at. FM gauge will read ~9 psi. Never really bothered me.

Yeah that's what I have. It came with the used turbo kit I bought.

Our FM boost gauge was never the most accurate thing in the world either.

Also have to consider gauge pressure vs absolute.

At 12,000 ft, a mechanical gauge will still read "0," even though that's not accurate.

So I borrowed one and by borrow I mean went to oreilys and asked my buddy Ramon if I could use the one on display. I went around the block and sure enough it reads correct. Ill be getting another autometer but this time through autometer. Usually my logic would say go sunpro as it worked just fine but I have heard some bad things so Ill stick with a new autometer. Who knows what happened to or how old the FM gauge is anyway.

It's just a mechanical gauge thing. They go out of adjustment eventually.

I have a box with old gauges in it... probably 8-10 old Autometers. At least half of them don't return to "0."


If you like the FM gauge, you can call Autometer and see if they'll service it. It's a thing.

Ive noticed in the past that sometimes people over tighten the fitting on the back of the gauge and this I think causes the offsetting of the mech needle.

I've seen it happen quite easily and straight out of the box with some super cheap gauges.

it is very common for MAP sensors to always read slightly lower than boost gauges....something about the diaphragm

I am in the process of adding an oil temp gauge and am relocating my boost gauge next to my wideband. I noticed a small crimp in the tube to the boost gauge. I went ahead and cut it out and re sealed . After I finish my oil cooler ill post on wither or not that fixed it

Crimp won't magically create more or less boost, but can affect reaction speed.