[sshea45]

I just recently bought an 06 wrx, it's the first car I've owned that is turbocharged. Until recently it was running great, but with really low temperatures outside (-5f) it surges under acceleration and doesn't seem to be running full boost! Is it from the extremely low temp or is there something else going on I need to be concerned about? Thanks!

 

[teflon_jones]

I doubt it's from the temp. Is the car stock? How many miles on it?

 

[Donkey]

Impossible to tell with no other data. What octane gas do you run? Is there a CEL?

 

[sshea45]

I run 91 octane no ethanol. I've so far only put catback exhaust on it, it just rolled over 67k miles. The CEL hasn't come on.

 

[Sinister]

is that with your foot half way down? Or all the way?

 

[wrxdrvr]

The oscillation probably has to do with the wastegate to FBC solenoid vacuum lines ID being a little too big allowing too much air to be released and the boost goes up too high for a sec than the FBC solenoid tries to lower it but it drops too low and it starts to oscillate... The cold air put it over the top as boost is reached faster than when hot air is compressed.

 

[Sinister]

what makes you think that?

 

[sshea45]

I first noticed it fall on its face when I was accelerating normal, but it seemed to do it no matter how I drove! The more I got on it the more noticeable it was!

 

[wrxdrvr]

what makes you think that?

Because that's what happened to my '02 WRX when I did the 1/8" or 3/16" boost control mod way back when, I put the stock in-line restrictor back in and everything got normal again...

 

[Sinister]

his car is stock though.

 

[Mikie13]

or its just that cold out and the turbo just runs out of breath because its tiny and you notice it dropping off quickly after 5k rpm...(stock maps taper quite a bit actually)

 

[wrxdrvr]

his car is stock though.

Yes, but if someone changed the vac lines before him to a non stock one... Just saying what caused boost hunting on my car...

 

[GarrettKoonsman]

Did you let the car warm up entirely before getting on it to where you noticed this?

 

[sshea45]

Yeah it was completely warmed up. I drove about 30 miles at 70. Should I put something to block the inter cooler when it's that cold?

 

[Sinister]

no. It should be fine. I drove at 5 degrees the other day and had no problems.

 

[GarrettKoonsman]

Yeah it was completely warmed up. I drove about 30 miles at 70. Should I put something to block the inter cooler when it's that cold?

No don't do that. if you were warmed up then that eliminates one of my thoughts.

 

[sshea45]

Is there something wrong I should look for?

 

[theblurz]

I know some other turbo cars or trucks have a boost limiter that restricts boost at that level. Until the sensors get up to temp you don't get the extra boost. Don't know about the suby though.

 

[teflon_jones]

If you're not getting a CEL, and the car is stock, then this is going to be very hard to figure out.

I'd start with checking all of your wiring and hoses under the hood.