Unusual boost readings.....

IronMonkeyL255 · Post by **IronMonkeyL255** » Tue Jan 29, 2008 11:03 pm

I have been having an issue regarding boost for some time now.

It seems as though whenever I am on boost, the reading my gauge sees flutters very quickly. On my old Prosport mechanical gauge (awesome quality gauge and very accurate), this caused the gauge to rattle something terrible. On my new AEM Tru-Boost gauge/EBC (good gauge/controller with lots of neat features), this causes it to flutter the wastegate open and closed when right at the Spg pressure I have input (it keeps the WG closed until the entered value, then cycles the solenoid at the selected duty cycle).

I have installed an inline restrictor in the line going to the gauge, and it helped a bit, but it still does it. I was running my old Autometer off the line leading to the BPV, then plumbed my Prosport gauge into the brake booster line (when I finally figured out that the BPV line doesn't see true vacuum). When I installed my Tru-Boost, I moved the location to a 'T' (really more like a y with the fitting I used) in the line leading to the factory MAP sensor.

Has anyone else experienced this? It doesn't appear as though this is a common occurrence, since I am sure someone else would have posted a thread about it.

asc_up · Post by **asc_up** » Wed Jan 30, 2008 12:30 am

Hmmm I have the same AEM boost gauge (awesome gauge/controller BTW) and I don't have that problem.

I installed my boost gauge off of the line that comes off of the intake manifold (that way you get a true boost/vacuum reading).

Try teeing in there, if you haven't already. Hope this helps out.

Arctic Assassian · Post by **Arctic Assassian** » Wed Jan 30, 2008 12:31 am

This happened to me, I faulted the BOV that I put on, because the stock BPV fixed the problem. I also had "turbo-surge".

IronMonkeyL255 · Post by **IronMonkeyL255** » Wed Jan 30, 2008 4:58 am

That is exactly where I have mine teed into right now.

I am running the stock BPV. Maybe it's worn out......

If I could find a WRX stocker with the elbow still attached for a reasonable (cheap) price I would swap for that instead ('cuz it'll bolt right up to my WRX i/c and I no longer have cruise).

IronMonkeyL255 · Post by **IronMonkeyL255** » Thu Jan 31, 2008 2:33 am

Anyone else have any ideas?

SubaruNation · Post by **SubaruNation** » Thu Jan 31, 2008 3:22 am

my money's on asc and what was already said,
maybe a leak somewhere?

Arctic Assassian · Post by **Arctic Assassian** » Thu Jan 31, 2008 3:45 am

OH...Make sure you have an awesome vacuum source to your bpv. For awhile I had a hole that was rubbed in by my hood, I had to rotate my BOV.

555BCTurbo · Post by **555BCTurbo** » Thu Jan 31, 2008 7:59 am

I wouldn't use that spot for the gauge reference...as it is the line that leads to the MAP sensor...and could potentially mess with it. My gauge is teed off the vacuum reference under the brake booster line on the intake manifold.

My guess is that you have a boost controller problem, as it is most likely causing wastegate flutter, due to an inconsistent signal.

IronMonkeyL255 · Post by **IronMonkeyL255** » Thu Jan 31, 2008 8:30 am

But that's the thing.... It does it when running wastegate boost, and while under vacuum as well. Has also done it using 2 different factory boost control solenoids under factory ECU control.

It has done it with 3 different gauges as well.

Arctic Assassian · Post by **Arctic Assassian** » Thu Jan 31, 2008 10:34 pm

Maybe adjust the wastgate? Is it closing all the way?

asc_up · Post by **asc_up** » Fri Feb 01, 2008 12:05 am

Maybe the actual wastegate spring is bad. Could that be a possibility?

IronMonkeyL255 · Post by **IronMonkeyL255** » Fri Feb 01, 2008 3:52 am

It is closing all the way, and still has plenty of tension. I will see what pressure it opens at a bit later, just to be sure.

I am going to try to get my hands on a WRX BPV and see if that does the trick. If not, then I am at a loss.

asc_up · Post by **asc_up** » Fri Feb 01, 2008 5:31 am

Yeah that would be the thing to do, I suppose. WRX BPVs aren't cheap though. Can you find a stock SS one?

IronMonkeyL255 · Post by **IronMonkeyL255** » Fri Feb 01, 2008 5:43 am

Probably.

I wonder if BlackBart is back yet.......

asc_up · Post by **asc_up** » Fri Feb 01, 2008 5:45 am

I'm pretty sure he is.
Shoot him a PM.

I went to the Subaru dealer to see about a new WRX BPV and they wanted $175.00

555BCTurbo · Post by **555BCTurbo** » Fri Feb 01, 2008 7:52 am

asc_up wrote:I'm pretty sure he is.
Shoot him a PM.

I went to the Subaru dealer to see about a new WRX BPV and they wanted $175.00

Or you can get one on Nazicock for like $20

asc_up · Post by **asc_up** » Fri Feb 01, 2008 8:46 am

Brand new?!

555BCTurbo · Post by **555BCTurbo** » Fri Feb 01, 2008 9:04 am

Probably barely used...

And it's not like they really wear out...

My SS still has its original bypass valve, and it has 216,000 on it.

I have some Bosch ones if you are interested...they work fantastically.

[/end hijack]

IronMonkeyL255 · Post by **IronMonkeyL255** » Fri Feb 01, 2008 5:49 pm

I have another OEM one on the way from BB, so I will give that a try and post the results.

IronMonkeyL255 · Post by **IronMonkeyL255** » Sat Feb 02, 2008 6:41 am

n/m

I have a line on a WRX one I'm gonna pick up next week.

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Unusual boost readings.....

Unusual boost readings.....