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Problem with new Boost guage, Reads 14 pounds!! Whaaa

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White91TalonTsi

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Discussion starter · #1 ·
Alright so i got my new Autometer Carbon Fibre series boost guage today and looks great :cool: . But when I ran the Turbo is read 14 maybe even 15 psi :eek: and My MBC isnt even on.

It will not hold the boost though, it shoots up to around 15 then drops to about 11 at high rpm's. :confused:

So...is this normal?? Im really confused if I just have some mad boost creep (Its a really cold day, maybe turbo running really good?), or is the Guage not accurate or what? :mad:

Please help guys I dont want to wreck my car! :)
 
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#3 ·
White91TalonTsi said:
Alright so i got my new Autometer Carbon Fibre series boost guage today and looks great :cool: . But when I ran the Turbo is read 14 maybe even 15 psi :eek: and My MBC isnt even on.

It will not hold the boost though, it shoots up to around 15 then drops to about 11 at high rpm's. :confused:

So...is this normal?? Im really confused if I just have some mad boost creep (Its a really cold day, maybe turbo running really good?), or is the Guage not accurate or what? :mad:

Please help guys I dont want to wreck my car! :)
Click to expand...

you got nothing to worrie about, a stock dsm can hold 16 psi safley. aslond as you dont go over that you should be fine.

I would bet that your gauge is just fine but just to be sure when you turn the engine off it should go to 0 and when idling it should read between 15-20 units vaccum. If it does this chances are you are boosting that much

Do you have an exaust or intake mod? That could raise boost from factory levels. I have a turbo back exaust on my car thats all and i run 12 psi till 5000 rpm then i spike to 15 psi just to give an example.

If you dont then it could be a problem with your acuator not opening the wastegate as quick as it should. like a leak in the vac line going to the acuator or in the acuator itself.
 
Discussion starter · #5 ·
Lol yes My steering wheel is worn but oh well :)

axemurderer said:
you got nothing to worrie about, a stock dsm can hold 16 psi safley. aslond as you dont go over that you should be fine.

I would bet that your gauge is just fine but just to be sure when you turn the engine off it should go to 0 and when idling it should read between 15-20 units vaccum. If it does this chances are you are boosting that much

Do you have an exaust or intake mod? That could raise boost from factory levels. I have a turbo back exaust on my car thats all and i run 12 psi till 5000 rpm then i spike to 15 psi just to give an example.

If you dont then it could be a problem with your acuator not opening the wastegate as quick as it should. like a leak in the vac line going to the acuator or in the acuator itself.
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No exhaust mods but all I have is a K&N Filter. My car seems REALLY fast today though, faster than any normal day :confused: , hmm I hope this wont turn into a wastegate problem.
Also My boost guage has no Vaccume, its all psi.
 
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Discussion starter · #6 ·
Any more Diagnonis's guys? Im really concerned/worried that I am loosing compression :(
 
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#7 ·
what line did you tap into for your gauge source??? On my 91, i tapped into the line coming off of the intake manifold to the fuel pressure regulator solenoid....It reads near 100% accuracy with both vacuum and boost.....plus it's nice and close to the fire wall......just curious......
 
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#8 · (Edited)
tap into the fuel pressure solenoid at the top right hand of the engine (look up in 1000Q's it will have a map of the engine bay) also It may be you have a boost leak, but I doubt it. As in the boosting high, my 92 has a few mods but when i just had a k&n I was boosting at 15, make sure your BCS is hooked up properly or else you have nothing limiting the boost. Mine was (and still is ) dissconnected becuase the shop that put my JDM in didnt hook it up. = 21Psi boosting on a 14b! boom, im waiting to put in my new turbo, luckily nothing else was screwed up. Good luck bro.
-Eric
-Its prolly nothing big No part costs more than $400 under our hood luckily.
 
Discussion starter · #9 ·
Hmm thanks guys. I have no clue where its hooked up too, I looked under the hood and couldnt find any wires anywhere. But I will take a look now that you have given me some directions :)

It was reading about 14 pounds today also on a very cold day. Im curious to see what it reads when its warmer and the car is a little slower.
 
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#10 ·
You will not find wires because it is most likely mechanical (or so I hope). Look for tubes coming from your drivers side firewall (near the throttle cable area) and teeing into a vaccum line somewhere near the intake manifold.

This spike is kind of common, however shitty it can be. The only thing you can really do is increase exhaust size, port wastegate runners, bigger o2 housing etc.
 
Discussion starter · #11 ·
laxdudeee said:
You will not find wires because it is most likely mechanical (or so I hope). Look for tubes coming from your drivers side firewall (near the throttle cable area) and teeing into a vaccum line somewhere near the intake manifold.

This spike is kind of common, however shitty it can be. The only thing you can really do is increase exhaust size, port wastegate runners, bigger o2 housing etc.
Click to expand...
It sucks for the engine...but its fun :) . But that 14psi will see the pavement alot better with a Apexi Turboback soon :)

How exactly does a Mechanical Boost guage work?
 
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#12 ·
The gauge gets a direct reading from the flow of air...The air goes into the gauge and pushes down on a spring that is calibrated to PSI and the more pressure that pushes down on the spring the farther the needle goes up (MORE BOOST!). That is a guess but I cannot see it working any other way.
 
#13 ·
if you have a vac line running to the wg actuator with a tee in it, it is possible that the tee is a restriction and is causing the boost to get up to 15. happened on my 98gst. was pretty sweet, and i didnt have to buy a MBC untill i was fed up with the boost falling off at high rpms
 
#15 ·
White91TalonTsi said:
This is My MBC set up guys...
Click to expand...
Only problem with that is that is is reading the pressure right after the turbo...In order to get the best reading at the closest possible place to the actual cyliners (where the pressure really matters) you want to take it from the intake manifold and that is why most people split it off of the BOV to intake manifold line.
 
Discussion starter · #16 ·
laxdudeee said:
Only problem with that is that is is reading the pressure right after the turbo...In order to get the best reading at the closest possible place to the actual cyliners (where the pressure really matters) you want to take it from the intake manifold and that is why most people split it off of the BOV to intake manifold line.
Click to expand...
So how could I exactly set that up? Reroute the Boost guage or the MBC?
 
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#17 ·
That was sort of unclear, when I said reading I did not mean boost gauge I meant MBC, so re-routing the mbc to go from the BOV line to the wastegate is theoretically better (and what most people do) then cap the nipping on the compressor housing elbow.
 
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