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10 XT 4EAT
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Discussion Starter · #1 ·
Basically just looking for a confirmation that I am not crazy or mistaken, but right now I am in the minus 20's C, and my peak boost has been going down.

I am pretty sure I didn't notice this behaviour last year, which lends probability that something may be off.

Basically yesterday at -20C ambient, I noticed that all I could hit for boost was 10-12psi range, and today at -25C ambient, all I was hitting was maybe 7-9psi, on both my commute to work and commute home (mostly highway, one way trip of 50km). On my way home today, definitely felt like just waste gate boost power levels.

So, confirmation that am I right that something is likely off and that the cold temperatures shouldn't be affecting boost target this much?
 

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2001 Forester STi 6spd with MapDCCD and 535hp
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4,708 Posts
There are some Tables in the ECU that deal with compensation in boost for changes in coolant and intake temperature. To be honest, ive never made an effort to make any adjustments to them. My guess would be that it is so cold that it is telling the ECU to draw back on the wastegate duty cycles using the Turbo Dynamics compensation for fear of accidentally overboosting, which is a natural problem for some setups when the temperatures drop down low.

If you can, post up some Datalogs of pulls when it is not hitting peak boost , and then nab some other logs where you are seeing it hit peak boost, and (we) can determine what your wastegate is doing during these times.
 

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10 XT 4EAT
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893 Posts
Discussion Starter · #3 ·
pretty sure now that it does appear to be intake temp compensation. I just didn't expect that much boost cut. In previous years I guess I just didn't notice it as I tend to drive more sedate the colder it gets.
 
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