Autometer boost gauge reads high. - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


DIY Turbo Discussion greddy on a 1.8? homebrew kit?

Reply
 
 
 
LinkBack Thread Tools
Old 03-23-2014, 11:38 AM   #1
Senior Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2012
Location: New Braunfels,TX
Posts: 1,141
Total Cats: 51
Default 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.
ScottyP3821 is offline   Reply With Quote
Old 03-23-2014, 12:13 PM   #2
Elite Member
 
DNMakinson's Avatar
 
Join Date: Jan 2013
Location: Seneca, SC
Posts: 2,698
Total Cats: 267
Default

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.

Last edited by DNMakinson; 03-23-2014 at 01:13 PM.
DNMakinson is offline   Reply With Quote
Old 03-23-2014, 01:16 PM   #3
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,105
Total Cats: 518
Default

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.
curly is offline   Reply With Quote
Old 03-23-2014, 08:27 PM   #4
Senior Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2012
Location: New Braunfels,TX
Posts: 1,141
Total Cats: 51
Default

Cool thanks for the replys. Im going to borrow one and see if it changes.
ScottyP3821 is offline   Reply With Quote
Old 03-23-2014, 08:49 PM   #5
Senior Member
iTrader: (1)
 
Onyxyth's Avatar
 
Join Date: May 2013
Location: Boyertown, PA
Posts: 719
Total Cats: 55
Default

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.
Onyxyth is offline   Reply With Quote
Old 03-23-2014, 10:21 PM   #6
Senior Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2012
Location: New Braunfels,TX
Posts: 1,141
Total Cats: 51
Default

Quote:
Originally Posted by Onyxyth View Post
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.
ScottyP3821 is offline   Reply With Quote
Old 03-23-2014, 10:25 PM   #7
Elite Member
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default

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.
concealer404 is offline   Reply With Quote
Old 03-24-2014, 11:12 AM   #8
Senior Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2012
Location: New Braunfels,TX
Posts: 1,141
Total Cats: 51
Default

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.
ScottyP3821 is offline   Reply With Quote
Old 03-24-2014, 11:28 AM   #9
Elite Member
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default

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.
concealer404 is offline   Reply With Quote
Old 03-24-2014, 11:34 AM   #10
Junior Member
 
Join Date: Nov 2009
Location: Jax Fl
Posts: 469
Total Cats: 30
Default

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.
Tw34k is offline   Reply With Quote
Old 04-03-2014, 05:04 PM   #11
Junior Member
iTrader: (2)
 
Join Date: Jan 2007
Posts: 329
Total Cats: 16
Default

it is very common for MAP sensors to always read slightly lower than boost gauges....something about the diaphragm
Alejo_NIN is offline   Reply With Quote
Old 04-04-2014, 06:42 PM   #12
Senior Member
Thread Starter
iTrader: (2)
 
Join Date: Jun 2012
Location: New Braunfels,TX
Posts: 1,141
Total Cats: 51
Default

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
ScottyP3821 is offline   Reply With Quote
Old 04-04-2014, 06:45 PM   #13
Elite Member
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default

Crimp won't magically create more or less boost, but can affect reaction speed.
concealer404 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 57 07-19-2017 05:11 PM
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
Going back to stock. Need some 1.6 parts. Trent WTB 2 10-01-2015 01:15 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 06:58 AM.