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Discussion Starter #1
That is all the boost I get! And all this time I just thought I was getting used to my car's fierceness.

So I got on the highway and payed closer attention to my boost guage:

1st gear = .07 MPa = 10.15 psi
2nd gear = .075 MPa = 10.88 psi
3rd gear = .08 MPa = 11.6 psi
4th gear = as soon as it gets to .09, it drops to .08 MPa = 11.6 psi
5th gear = same as 4th

This sucks. I thought that the factory ECU sets the boost at ~14 psi in 4th and 5th gears. What could have caused this loss of boost? I only have 27,000 miles on the stock turbo. What should I do to fix it? I'm thinking the Cobb AP. Thanks for your thoughts.

Mods: Catless UP/TBE, rampod
 

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Discussion Starter #4
I'm not sure if it is normal. I know my car was pulling harder when I got the exhaust complete. And only until recently I've noticed the power loss. As far as the MBC goes, is it simply a matter of turning up the boost to compensate, or is there a more serious problem with boost loss?
 

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Sounds normal to me too. I had an MBC set to about 15psi, it worked great. Even if you use an MBC and set it to the stock boost level it really helps the boost come on and smoothes it out quite a bit.
 

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stalefish19 said:
I'm not sure if it is normal. I know my car was pulling harder when I got the exhaust complete. And only until recently I've noticed the power loss. As far as the MBC goes, is it simply a matter of turning up the boost to compensate, or is there a more serious problem with boost loss?
The turboback and uppipe will help the turbo spool sooner and last longer. There is HP gains but nothing drastic. Your stock boost solenoid(sp) could be going bad? Mine car has a turboback and uppipe with no MBC, still running the stock solenoid(sp) and I boost at 17psi from 3rd thru 5th. But then again my car has been modded and unmodded severeal times, so my solenoid(sp) is bad I'm sure.

I really don't have an answer for you, from what I have read on here many people experiance different boost levels. Best guess is to take it in and have them check it out. Or maybe one of the guys like Pace, David can help you figure it out.
 

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Discussion Starter #8
What makes you think that the solenoid is bad? Would the bad solenoid be covered under warranty if I took it in? Also I'm amazed that you get 17 lbs of boost on your turbo without a MBC. What turbo do you have in there?
 

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The WRX is rated for 13.5 Max boost. That most likely will occur in the higher gears. When you factor in altitude your boost isn't too bad at all. Plus your boost guage could be off, and if you have the stock one it is really hard to read. .01 MPA is like 1.5 pounds so misreading it slightly could set you off too....

I would do a MBC regardless though.... :D
 

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boost gauges..

crazycam31 said:
The WRX is rated for 13.5 Max boost. That most likely will occur in the higher gears. When you factor in altitude your boost isn't too bad at all. Plus your boost guage could be off, and if you have the stock one it is really hard to read. .01 MPA is like 1.5 pounds so misreading it slightly could set you off too....

I would do a MBC regardless though.... :D
don't mean to hijack the thread, but what's a good boost gauge that would fit where the stock gauge goes.. preferrably something that reads in psi and might be a little more accurate? anyways, back to the low boost discussion! :)
 

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Re: boost gauges..

elijahwrx said:
don't mean to hijack the thread, but what's a good boost gauge that would fit where the stock gauge goes.. preferrably something that reads in psi and might be a little more accurate? anyways, back to the low boost discussion! :)
Omori make 45mm boost gauges that would fit in your stock boost gauge holder with some lubricant, hehe. They come with 02/03 orange/green colors or red/green for 04/05.

http://www.j-spectuning.com/omori_rg.htm

Those are the boost numbers I get stock as well. Altitude.
Word.
 

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stalefish19 said:
What makes you think that the solenoid is bad? Would the bad solenoid be covered under warranty if I took it in? Also I'm amazed that you get 17 lbs of boost on your turbo without a MBC. What turbo do you have in there?
The stock solenoid could be just fine and most likely is. I mentioned it because that was the first thing that poped into my head in regards to your issue. But from your numbers you are right on for stock turbo and altitude. I suggest like the rest of the guys is to put on an MBC and see your results from there.

And sorry my profile mis lead you, I have not updated it in some time. that was my old build, currently I sold all that stuff. Right now I am on the stock turbo and running the APS turboback with a gutted stock uppipe. The reason I am getting such high boost levels is most likely my solenoid. Its not the most efficant(sp) IMO to control boost. and for some reason my likes to boost hard. Its going to kill my stock turbo but I'm not worried about it. I am putting in a 2.5 and 6 speed shortly.

Again, sorry for the lack of important info, try the MBC and lets us know.
 

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Normal--- altitude sucks

Its normal, -- due to altitude.

Your normal air pressure here at altitude can be as low as 11.5 psi. Even less during stormy weather. Thats at least a 3.2 psi deficit over sealevel boost levels.

Add that 3.2 psi to your boost numbers and you come right up to normal design sealevel boost levels.

I show a max manifold boost of 13.5 psi with a boost setting of 17+ psi on my electronic boost controller.

Don't worry your car is working just fine.

Larry
 

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Re: Normal--- altitude sucks

hotrod said:
Its normal, -- due to altitude.

Your normal air pressure here at altitude can be as low as 11.5 psi. Even less during stormy weather. Thats at least a 3.2 psi deficit over sealevel boost levels.

Add that 3.2 psi to your boost numbers and you come right up to normal design sealevel boost levels.

I show a max manifold boost of 13.5 psi with a boost setting of 17+ psi on my electronic boost controller.

Don't worry your car is working just fine.

Larry
You can always count on Larry to give you correct info.

:wiggles:
 

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To add what has already been [correctly] stated..

Your Subaru ECM is programmed to reduce boost levels with increasing elevation, it order to maintain a 'safe' pressure ratio and not over work the turbo. To do otherwise would compromise turbocharger longevity.

While 13.5psig in Denver will net you less mass of air in the combustion chamber than 13.5psig of boost at sea-level, it would in fact result in a higher compressor pressure-ratio. That's the high elevation double-whammy. Bottom line is our turbos work harder to produce less.

-Pace
 

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Discussion Starter #18
Thanks for all the info and proving that the only problem is with me, not the car. But can you blame me for wondering if my car is pulling as hard as it used to? We all want the most out of our mods (and the stock turbo in my case). When I calculated just over 10 psi in the first 2 gears and 11 psi in the last 3 I nearly crapped myself. I automatically assumed something was wrong, which is what you'd expect with the first car you've ever bought on your own. I ended up driving a stock WRX for the sake of comparison which is all that I needed to know to realize that my car is still fast as hell. My car definitely has a more linear power to it though, with not as much turbo lag. Probably becasue everything is catless. I guess I miss having that lag where the turbo kicks in and nearly rips your head off.

I still see this low boost as a problem though. Next on the mod list: Cobb AP stage 2. It sucks I have to wait so long for it, but I'm sure it's well worth it. With the help of engine management, I should definately get the most out of my engine, even at altitude. Damn the Rocky Mountains! That is all.
 

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I still see this low boost as a problem though. Next on the mod list: Cobb AP stage 2. It sucks I have to wait so long for it, but I'm sure it's well worth it. With the help of engine management, I should definately get the most out of my engine, even at altitude. Damn the Rocky Mountains! That is all.
I noticed similar issues with my boost levels.. i think my stock boost gauge might be a bit inaccurate. since i got the cobb accessport, i've been able to get the digital boost readout, and it's showing roughly 12 lbs in first and second and closer to 14 lbs in 3rd, 4th and 5th. when i was reading the stock gauge, things appeared to be the same as or similar to stock, even though the butt dyno was telling me different.

i can't wait for my tbe and up-pipe.. next week! you'll be VERY happy with your accessport. :) FWIW, if you can deal with paying sales tax, i was able to find an AP locally down in aurora.. not sure if he's got anymore, but the shop is listed on the cobb website 'speedy roopair'..

EDIT: i've also got 37k on the factory turbo.. roughly 1500 miles with the AP
 
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