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Old 09-10-2017, 03:06 PM   #1
erabung
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Default Change in altitude

So I got my 2012 wrx pro tuned in Scottsdale AZ where I was pushing boost at around 19. I just moved to Denver CO and I'm maxing out at 15 while feeling a decrease in power. Is there anything I can do besides getting it re-tuned for higher altitude ?
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Old 09-10-2017, 03:37 PM   #2
chillywit
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The ECU will compensate for altitude and temperature. Note that you will get less boost from your turbo at altitude than at sea level from decreased air density. I copied the following from Cobb Tuning:

"It is common for turbocharged cars at higher altitudes to run less boost pressure due to lower air pressure and air density. Your turbocharger has to work harder to compress a less dense air mass compared to the same turbocharger at sea level. This must be factored in when determining if your turbocharger is running the proper amount of boost pressure and not being pushed beyond its efficiency range. For example, if you live in Denver at 5280 ft and are trying to run a peak boost pressure of 15 psi, your turbocharger has to work the equivalent of making ~17.5 psi at sea level. There are barometric compensations within the factory ECU that lower boost targets as you climb in altitude in an effort to keep the turbocharger in its optimal range. The COBB performance maps utilize these compensations and therefore, it is perfectly normal for the final boost target to be lower than what is listed for your map."
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Old 09-10-2017, 04:25 PM   #3
Charlie-III
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Quote:
Originally Posted by chillywit View Post
The ECU will compensate for altitude and temperature. Note that you will get less boost from your turbo at altitude than at sea level from decreased air density. I copied the following from Cobb Tuning:

"It is common for turbocharged cars at higher altitudes to run less boost pressure due to lower air pressure and air density. Your turbocharger has to work harder to compress a less dense air mass compared to the same turbocharger at sea level. This must be factored in when determining if your turbocharger is running the proper amount of boost pressure and not being pushed beyond its efficiency range. For example, if you live in Denver at 5280 ft and are trying to run a peak boost pressure of 15 psi, your turbocharger has to work the equivalent of making ~17.5 psi at sea level. There are barometric compensations within the factory ECU that lower boost targets as you climb in altitude in an effort to keep the turbocharger in its optimal range. The COBB performance maps utilize these compensations and therefore, it is perfectly normal for the final boost target to be lower than what is listed for your map."
Excellent quote from a group that has a clue on Subaru tuning, good on you!

Quote:
Originally Posted by erabung View Post
So I got my 2012 wrx pro tuned in Scottsdale AZ where I was pushing boost at around 19. I just moved to Denver CO and I'm maxing out at 15 while feeling a decrease in power. Is there anything I can do besides getting it re-tuned for higher altitude ?
While you "could" get a retune for your altitude, you may run into issues when going towards sea level.
So, ask yourself, "am I staying here, or may I go towards sea level?".
At some point, you may need less intake restriction or larger turbo for similar performance at Denver altitude.

"Speed is money, how much do you want to spend?".
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Old 09-11-2017, 07:28 AM   #4
rtv900
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keep in mind there are countless turbo vehicles on the market nowadays.
They all come with the same 'tune'
When they leave the factory nobody knows whether they are going to Denver or Miami or Alaska.
Temperature has the same affect on density too, and cars work fine in 10 degree weather or 110 degree weather.
ECU's work.
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Old 09-11-2017, 07:01 PM   #5
erabung
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Quote:
Originally Posted by rtv900 View Post
keep in mind there are countless turbo vehicles on the market nowadays.
They all come with the same 'tune'
When they leave the factory nobody knows whether they are going to Denver or Miami or Alaska.
Temperature has the same affect on density too, and cars work fine in 10 degree weather or 110 degree weather.
ECU's work.


Thanks for the advice. As much as I don't see myself leaving Denver, I don't want to be limited myself from going somewhere because I tuned my car a certain way. As the money part of it goes I don't think it's worth it
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