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Discussion Starter · #1 ·
What do all you fa20dit owners get for peak boost in your 15+ rex? I was doing some racing in Mexico tonight and was only hitting 12.5psi in 2,3, and 4. Should I not be hitting more then that in WOT?
 

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That strikes me as odd. The number of threads posting 20+ psi as a max or spike vs your 12.

Where did you buy your fuel?
 

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Discussion Starter · #3 ·
Yea it seems odd, I was hitting 23.4 but I had my wastegate hose fixed cause it was overboostimg but I was still hitting 17 and higher. Ever since I got the car back from dealership I can barely get past 12.5-13.0 and that it WOT.

And I’ve been going to the same station for my gas and using Shells 91 nitro +
 

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There are environmental variables however I still feel you should be seeing near 20 with spikes.

I would contact the dealer again. I wonder if they left something undone. Do you have a way to datalog?
 

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Discussion Starter · #5 ·
Well isn’t psi reach higher numbers in colder weather conditions?

And yea I’m gonna give them a call Monday morning cause it’s been acting weird ever since I got my car back.

I don’t have a COBB access port or anything so I’ll have to find a way that doesn’t affect warranty and such.
 

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It can. Your boost pressure is the pressure above ambient pressure. So if you have 10psi of air pressure plus 15psi of boost pressure there will be 2 readings. The boost pressure of 15 and the map reading of 25
 

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Discussion Starter · #7 ·
Was able to hit 14.9 today but shouldn’t I still have more boost? And also the overboost where it can goto 20+ for a spike, do I still take this to the dealership?
 

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I cannot explain why, but mine sounds exactly the same as yours. When mine was new, I'd get that 20ish spike but now I never get that high. For me, it is not an issue. I actually prefer to not have the high spike.

Maybe these cars are like Apple devices where they purposely slow down as they age.
 

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in my 17 WRX Id peak at 20-21 psi in warm weather, but in winter or colder weather, esp under 30 deg F Id see peak boost 15-17 maybe. Figured the ECU limited boost depending on temps. It was pretty consistent.

In my 18 STI, peak boost in cold weather (30s) is like 14-15, when it hit 70 for a few days I saw 16-17
Its consistent.

Yours however sounds like they left a rag in the intake or something. Just not right
 

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Discussion Starter · #11 ·
Yea before I brought it in to the dealership to fix a wastegate hose, I was hitting that spike boost and getting higher numbers like most all other wrx owners are getting also. Now I can barely get 14 which seemed off. Car is also fairly new with only 2000 km.
 

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I think that sounds about right. My peak boost shows as 22 but on a daily basis I am hitting around 15 between 2.5k and 4k RPM. Seems like a good safe number when the car is already performing well
 

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I’d take it back. And especially since they run a computer search to catch warranty issues (PM me on any questions on that), they should be able to tell something’s not right.
 

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Over a year old. I'd venture the problem was solved.
 
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