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Old 08-08-2018, 10:16 AM   #1
rmb2485
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Default 2011 WRX boost building very slow (w/ datalog)

2011 WRX, stock except for SPT catback exhaust and COBB OTS Stage 1 91 octane map. Boost seems to be building very slowly, as seen in the below datalog from a third gear pull. I haven't had the time to really crawl around and under the car yet and look for boost or exhaust leaks, but there is nothing obvious visually and everything sounds fine.

Possibly a wastegate issue? The wastegate duty cycle in the datalog shows it never really getting over 67%; shouldn't it be at 100% at wide open throttle?


https://docs.google.com/spreadsheets...it?usp=sharing
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Last edited by rmb2485; 10-10-2018 at 09:25 AM. Reason: Updated datalog link
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Old 08-09-2018, 12:21 PM   #2
rmb2485
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Anyone able to help out here?

The car doesn't reach max boost until about 5500rpm, and it takes over 7 seconds to get there at wide open throttle. Not sure where to start...
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Old 08-09-2018, 12:22 PM   #3
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Delete...accidentally double posted somehow.

Last edited by rmb2485; 08-09-2018 at 02:51 PM.
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Old 08-09-2018, 01:04 PM   #4
Turpid Porpoise
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Flash back to the stock map and see if the problem is still there
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Old 08-09-2018, 01:26 PM   #5
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Double post

Last edited by Turpid Porpoise; 08-11-2018 at 01:15 PM.
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Old 08-11-2018, 11:00 AM   #6
blue sedan
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Check your AF LEARNING values on Accessport !
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Old 09-24-2018, 04:00 PM   #7
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Update on this, still need some help.

I found and fixed a boost leak at the intercooler to throttle body hose and don't see any other boost or exhaust leaks. The car is building boost better now, but still slow; it hits max at at 5000rpm and takes 6 seconds to get there. New datalog is below. Does the same with the stock map.

https://docs.google.com/spreadsheets...it?usp=sharing

Any suggestions on what else to check?
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Old 09-24-2018, 04:06 PM   #8
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Quote:
Originally Posted by blue sedan View Post
Check your AF LEARNING values on Accessport !
This. Specifically, A/F learning A-D, or at least A-C.
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Old 09-24-2018, 04:22 PM   #9
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Quote:
Originally Posted by blue sedan View Post
Check your AF LEARNING values on Accessport !
Quote:
Originally Posted by relative4 View Post
This. Specifically, A/F learning A-D, or at least A-C.
AF Learning 1 is in the datalogs. It's 0 throughout the WOT third gear pulls. Never goes outside of the +/- 8 range that COBB suggests from what I've seen just driving around.

Are AF Learning A-D something different? I can datalog them tomorrow.
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Old 09-25-2018, 09:27 AM   #10
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Datalog with the AF values is below. AF Learning A-D are -1.5, 0.7, -3.9, and 0...what should they be?

https://docs.google.com/spreadsheets...it?usp=sharing

Last edited by rmb2485; 10-10-2018 at 09:27 AM. Reason: Updated datalog link
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Old 09-25-2018, 10:46 AM   #11
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Those fuel trims are great; anything within 5% of zero is fine.
Check your boost control hoses and wastegate actuator operation. Pull the downpipe to check wastegate seating and turbo condition.
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Old 09-25-2018, 12:06 PM   #12
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Quote:
Originally Posted by relative4 View Post
Those fuel trims are great; anything within 5% of zero is fine.
Check your boost control hoses and wastegate actuator operation. Pull the downpipe to check wastegate seating and turbo condition.
Thanks for the help.

The hoses between the wastegate actuator and boost control solenoid all look and feel fine. I haven't tested the solenoid yet but will. How do I test the wastegate actuator?

As for pulling the downpipe...I eventually will but I'm a little scared to do that, haha. I have a Cobb downpipe I've been meaning to put on, but I'm fairly certain I'm going to snap bolts when trying to remove the stock downpipe. I already snapped one of the bolts holding the intercooler to the turbo and the lower bolt holding the heatshield on (the car came with an SPT heatshield, so it's just one bolt up top and one down below on the side). The turbo to intercooler bolt was easy enough to drill out, but that lower headshield bolt has no access and the downpipe bolts will have no access as well without removing the turbo from the car.
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Old 09-25-2018, 02:33 PM   #13
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Spray all of the bolts with lots of penetrating lubricant the night before you attempt to remove the downpipe. When you do go to remove them, use heat to help break them loose.

The way you describe it leads me to believe you have a restriction or leak pre turbo or something faulty in your boost control equipment(flapper not closing, actuator not functioning properly, etc.).

Last edited by Turpid Porpoise; 09-25-2018 at 02:47 PM.
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Old 09-25-2018, 05:04 PM   #14
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Your "TD Boost error" is under negative one (-1). So the car is overboosting. Do you have the high waste gate map on it?
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Old 09-26-2018, 09:36 AM   #15
rmb2485
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Quote:
Originally Posted by mustangtyson View Post
Your "TD Boost error" is under negative one (-1). So the car is overboosting. Do you have the high waste gate map on it?
It has the normal map right now, and I know I need to change it to the low wastegate map because of that TD Boost Error, now that I fixed the small boost leak at the throttle body. I don't think that has anything to do with the slow boost issue though.
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Old 10-10-2018, 09:23 AM   #16
rmb2485
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So to wrap this up, this turned out to be a wastegate issue, although I'm still not sure exactly what the problem was. Playing with the wastegate linkage by hand I couldn't move it at all, however when I tapped it with a wrench it moved ever so slightly more in the closed direction than it was initially. So I disconnected the actuator arm from the wastegate arm and both moved freely on their own. Put it back together and everything moves and the car is boosting properly. So something was bound either in the actuator, linkage, or wastegate and the wastegate wasn't closing all the way.

New datalog is below if anyone is interested. The car is underboosting now, so either it needs to learn a little since the wastegate now closes fully or I need to change to the high wastegate map. I'll keep an eye on it.
https://docs.google.com/spreadsheets...it?usp=sharing

Downpipe bolts did come out without breaking, but only with using a two foot breaker bar and way more force than I was really comfortable with. And it turns out that lower heat shield bolt that had snapped is in a bracket that's fairly easy to remove, so I was able to pull that off and drill out the broken bolt and tap new threads.

Thanks for the help along the way!
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