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Old 02-15-2013, 03:19 PM   #1
paN1k
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Default Question about boost levels

Hey guys..

I've had this 2006 WRX for a few months. She runs pretty dang good but I had a question about boost levels. I have the stock Lamco crappy mPA gauge and I can get up to .07/.08 in third gear. 4th gear sees about .07 and 5th gets about .05. So I'm seeing about 10PSI in third and fourth and about 7PSI in fifth. What could be causing this? Stock TD04 turbo. The previous owner admitted to having an Cobb Accessport and a aftermarket downpipe. Do you think I need to reflash the ECU with a stock tune? Or could my turbo possibly be getting tired, car has about 78k on the clock.
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Old 02-15-2013, 03:28 PM   #2
Mr Wrex
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Lets start with the basics before jumping to conclusions... Is the car tuned for that downpipe? If so, who did the tune and what did they set the target boost to?
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Old 02-15-2013, 03:29 PM   #3
HinshawWRX
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If he unmarried the AP (which he would be dumb not to because it's worth more that way) then the stock tune would be put back on the car.

What could cause 10ish psi max? A lot of things. Start small and replace all your vacuum hoses.
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Old 02-15-2013, 03:30 PM   #4
paN1k
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I don't know. The stock downpipe is on now. I don't know what it's tuned for at the moment. Stock turbo, stock downpipe, stock TMIC.
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Old 02-15-2013, 03:35 PM   #5
marcymarc
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iirc you should be hitting around 12.5-13.5 on a stock tune.. it will peak at these numbers, and not hold steady FYI.
before doing anything, i would double check your calculations from mpa > psi...

if your numbers seem correct, i would perform a leak down test to see what/where your leaking boost at.
dont go replacing stuff until you know what needs to be replaced.

marc
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Old 02-15-2013, 03:40 PM   #6
Mr Wrex
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Find out the mods and tune on your car. If those check out to be stock, do the leak test like marc suggested. That should help you figure out what's going on.
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Old 02-15-2013, 04:16 PM   #7
paN1k
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Yeah, i'll get the leakdown done. I know some of the vacuum lines tend to harden due to heat.
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Old 03-01-2013, 03:58 PM   #8
paN1k
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Gonna hook it up to a smoke machine this weekend. I've been keeping an eye on the boost gauge, it fluctuates a little bit on idle. Another thing I have been noticing is that the brake pedal seems to lose a bit of pressure when the idle fluctuates. I only notice it at stoplights when I am holding down the brake pedal for a bit. I went through the vacuum lines and everything is attached, don't know if there are cracks though.

I also have noticed that when going uphill the car seems to lose a bit of boost it kind of shudders a bit.


We'll see...
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Old 03-01-2013, 04:19 PM   #9
DHRDAN
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2 things.


1. If your car is tuned... it's limited by boost controller.


2. If it's not tuned... it's your turbo.



Hook up a computer to your car and find out what's up.
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Old 03-13-2013, 12:37 PM   #10
paN1k
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I'm closer to getting my laptop fixed. I did find the airbox was not completely closed, fixed that and I have more vacuum on idle. I also found the hose from the intercooler has insulation coming off it and wrapped in electrical tape. Going to replace the intercooler hoses this weekend.
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Old 03-13-2013, 12:47 PM   #11
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The insulation and electrical tape are normal, and it's like that from the factory, despite how ugly it looks. You don't need to replace those hoses, but it is a good idea to make sure that the clamps are on tight, and that you don't have any boost leaking from where the hose joins the turbo.

It's possible that the boost gauge is reading incorrectly, as it relies on flimsy little hoses to get its reading. Do you know if the previous owner unmarried the AP?
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Old 03-13-2013, 12:47 PM   #12
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The insulation and electrical tape are normal, and it's like that from the factory, despite how ugly it looks. You don't need to replace those hoses, but it is a good idea to make sure that the clamps are on tight, and that you don't have any boost leaking from where the hose joins the turbo.

It's possible that the boost gauge is reading incorrectly, as it relies on flimsy little hoses to get its reading. Do you know if the previous owner unmarried the AP?
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Old 03-13-2013, 01:15 PM   #13
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I had this same problem on my 05 wrx some years ago. The spring in the wastegate actuator broke or bent causing the WGA to open under far less boost signal than stock. I got a new one and the issue went away.

If the car was stage 2 before, they probably set a good amount of preload on the WGA which could cause gradual damage to the spring or perhaps they adjusted the arm too far in the other direction when they put it back to stock.

Just tug on that little arm with one hand, it shouldn't move without really having to pull. If you can pull the arm with one hand and a couple fingers then you just need a new WGA or just need to adjust the preload.
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Old 03-13-2013, 02:44 PM   #14
paN1k
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I'm gonna remove the intercooler this weekend anyway, i'll check the WGA. Can I check the WGA without removing the heatshield? Just for movement... ? I'm gonna fix my laptop this weekend, just needed a cdrom drive, that way I can hook up my tactrix and see what's up. I would think he unmarried the AP.. should be a fun Subaru Saturday***8482;

Last edited by paN1k; 03-13-2013 at 06:10 PM.
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Old 03-17-2013, 11:12 AM   #15
paN1k
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Found a vacuum leak on the vacuum line that goes to the boost gauge. Patched that up and checked the gasket for the BPV. I also cleaned the BCS with some MAF cleaner. I'm still peaking at 10psi but she holds steady at 7PSI. I even saw 5th go into 10PSI now. I checked the WGA and the arm moved fairly easy. Do you think the WGA is why I am hitting 10PSI max?

Question to all you guys is why would someone adjust the WGA for a stage 2 tune? My thinking is you would want the waste gate to hold more pressure??
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Old 03-17-2013, 03:45 PM   #16
corvallisbattery
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You can adjust the Watergate for many reason. For me I was seeing boost creep. Too much preload causing the actuator to not open up enough/ on time. One full rotation fixed me right up.. but now I run ewg. you could be having the complete opposite problem.
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Old 03-18-2013, 08:03 PM   #17
paN1k
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OK, took the WRX to Infamous Performance. Mike is awesome. Hooked up the smoke machine, I am leaking off the PCV hose. Easy enough fix. Mike took the time to take of the heatshield and informed me my WGA is pretty much toast. It's probably the cause of my low boost levels. At least I took the time to check my vacuum lines, i don't feel like a total n00b. Time to order a WGA and see what it will do!
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Old 03-25-2013, 08:25 PM   #18
paN1k
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Problem solved. It was not the WGA but the BCS. I'm boosting fine now.
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