Subaru WRX Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #1 ·
Hello all, and thanks in advance for any help. I've got a 2010 WRX wagon, only performance mod being an AP with the 91 tune (wish we had 93 here in california) Anyway, been having an issue where sometimes 1st/2nd don't get full boost, capping out at 10-12 psi. When the car is working perfectly and running at full boost, which I might add is usually the case, it reaches 15-16 pounds of boost in these gears. It feels noticeably slower when it's not getting the full 15-16, and I am wondering what could be causing this. It's only once every 10 starts or so that it runs at the lower boost and has much less pull. If it were a boost leak, wouldn't the loss of boost in those gears be constant, rather than only an occasional issue? Thanks again for the help
 

·
Super Moderator
Joined
·
10,985 Posts
Be sure you are using the 91ACN tune, and you shouldn't be making full boost in 1st or second really.

Sent from my SAMSUNG-SM-G935A using Tapatalk
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #3 ·
Be sure you are using the 91ACN tune, and you shouldn't be making full boost in 1st or second really.

Sent from my SAMSUNG-SM-G935A using Tapatalk
I am, and this problem existed before I added the AP and was running the stock ECU settings. The gauge from the AP just confirmed my suspicions. Again, on some starts 1st/2nd are much slower than 1st/2nd normally are in my car. And as mentioned in the OP I do usually get 14-16 psi boost in 1st/2nd.
 

·
Super Moderator
Joined
·
10,985 Posts
You shouldn't achieve full boost in first or second. If you are you may be experiencing some overboost.

Sent from my SAMSUNG-SM-G935A using Tapatalk
 

·
Super Moderator
Joined
·
10,985 Posts
It is completely normal. There is less load on the engine in first and second so you won't make as much boost. The higher gear the more did advantage your engine is at and that's why it builds boost faster and builds more boost. It is also the exact same mechanism that makes overboost such an issue in od gears.

Sent from my SAMSUNG-SM-G935A using Tapatalk
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #7 ·
Really? Okay. I'm just surprised because it feels very sluggish when it doesn't feel normal. It also almost feels kinda notchy in and out of gear changes, but only when it does the sluggish act.
 

·
Super Moderator
Joined
·
10,985 Posts
How long have you had the car? How many miles are on it? You may be suffering heat soak

Sent from my SAMSUNG-SM-G935A using Tapatalk
 

·
Super Moderator
Joined
·
10,985 Posts
It's where the intercooler gets hot and doesn't properly cool the intake charge. It's super common on top mounts when not moving constantly.

Sent from my SAMSUNG-SM-G935A using Tapatalk
 

·
Registered
Joined
·
142 Posts
Are u tryna pull these runs during the day? Cuz if you are xj is right on the money. If I do a pull during the day max boost I see is about 14.5psi at 89 degrees and up. If I do one in the late afternoon/night I'll hit 16.8psi sometimes easily. And I'm in SoCal as well
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #12 ·
Okay, sounds like there's nothing you can do to avoid heat soak? And actually believe it or not, the problem seems to occur more frequently when it's cold. Over winter it happened a lot more than it does now.
 

·
Super Moderator
Joined
·
10,985 Posts
You can add a water sprayer it helps a little bit. Over the years I've seen people hodgepodge together all sorts of things but the water sprayer is probably the most helpful.

There could be a myriad of issues with your car that would make it feel a little sluggish. However 10psi in first is not your issue. It could be plugs, coils, dirty maf, old airfilter, bad gas, or in some folks vehicles. Incorrect equipment for the tune on the car.

Start simple. Oil, air filter, hit the maf with some cleaner.

Sent from my SAMSUNG-SM-G935A using Tapatalk
 
1 - 14 of 14 Posts
Top