[Stein]

I've posted a lot recently about the pulsing acceleration that I have under moderate acceleration. This log shows not only a cycling of boost, but also engine rpm. Throttle pressure was held quite constant, and the car does not accelerate smoothly. Automatic transmission in 3rd and didn't downshift. Comments are very welcomed.

2007 Forester XT automatic
Mods:
TurboXS 4" downpipe, catless 3" midpipe, and stock axleback
Cobb stage 2 91 reflash with 91 octane ethanol free gasoline (same symptoms in stage 1 also)
Stock inbox less resonator box, using stock style paper filter.

View attachment 22430

 

[2.5x_sleeper]

Have you tried reflashing to the AP married stock map to see if your problem clears.

Bobby...

My MODding Journal

 

[Stein]

No, I haven't. It's really not a stock car at this point...that was my logic at least. It definitely seems like a boost control issue. I don't know how the pills work, etc, but it goes woosh woosh woosh as the car thrusts down the road.
Big boost, loss of boost, big boost, loss of boost until it gets into the 4500 rpm range, then it all smooths out, but I RARELY take the RPM that high because it just doesn't feel good.

 

[2.5x_sleeper]

I tried running Stage1, which improved performance, but also caused engine cutouts. I was told it was caused by over boosting, a commom problem with the OTS tune. I'm running the married stock map until my scheduled dyno protune, later this month. :smile:

Bobby...

My MODding Journal

 

[Stein]

I'm sure the flood of "get tuned" responses are just a bit away...
With the wealth of self tuners and mechanical people here, I'm hoping to hear about changing the pill, or something relatively mechanical in nature that I can do without racing to a tuner.

 

[2.5x_sleeper]

I'm sure there are those that love the OTS tune maps, but you've got to be pretty lucky to have one that closely matches your specific build. :frown:

I'm running almost stock, so I'm going for a dyno protune for the experience, fun & more crap to put in my Member Journal! :biggrin:

Bobby...

My MODding Journal

 

[Stein]

Yeah, I do agree that OTS maps are junk, but really just using it for the couple months during the build up, hoping to finish up the exhaust shortly, TMIC shortly, and potentially cap it all off with possible turbo and injectors, and then really call it quits and get tuned with the turbo, and injector setup, but really concerned with the current state... Driveability is BAD for VERY basic mods.

 

[scubadoober]

Remove the pill all together, that will illustrate if it is mechanical. Your WGDC look pretty stable so it doesn't look like a boost control issue. I'm saying leak, more specifically the y-pipe (either the y-pipe itself or at the turbo). That would give the whoosh sound and explain why the ecu is pulling fuel since it thinks more air is getting in.

 

[Stein]

I did have the intercooler off when I installed the exhaust. I definitely struggled when I re-installed the intercooler, but was happy when it went back together. I do get "full" boost under full throttle, it's just the mid-range that's goofy. There is a very pronounced "whoosh" sound, I left the leak theory alone due to still hitting boost, but you have a good point. Removing the pill, I can do this, just wondering if this is simply a step to diagnose the issue, or permanent?

 

[scubadoober]

Removing the pill is just to diagnose, if you left it out you would run on WG boost, about 9 psi IIRC. The fact that you are still hitting full boost illustrates even more that it isn't a boost control issue.

 

[stan_t]

I believe you are describing the same choppiness I have. What was the weather like? I think mine gets worse when it's 50 and below.

Stan

 

[Stein]

Is it possible to still hit boost with a leak? I would assume so. It'll just keep the WG closed or open less to maintain boost, correct?

 

[Stein]

Yeah, it's warm...it finally hit 50 today! Life in the northern climate!
I know air density plays a pretty big factor in forced induction, but I don't know...Frustrating to say the least.
Stan, have you logged numbers at all with an AP? I should really shoot a video, you guys would not believe it if the video turned out.

 

[stan_t]

I have this log from a while back. I can make a more-recent one.

Stan

 

[Stein]

Boy, you gotta be good to read logs, don't you. Mind boggling.

 

[stan_t]

Yeah, that one is kinda long.. basically, there are 2 pulls in there, up and down the same empty strip with a u-turn in the middle. I left all the non-WOT stuff in there, it could be cleaned up. I think it was 1st through 4th.

Stan

 

[Arthrogrian19]

My guess is wastegate flutter. Look at the boost and WG duty columns - they're oscillating, which means the WG isn't staying closed. It isn't staying closed because the actuator is meant to operate at lower boost levels.

You can manually adjust the tightness of the WG actuator by disconnecting the actuator arm and turning it. There are some more detailed write-ups on Nasioc on adjusting the actuator.

 

[thefoos]

My guess is wastegate flutter. Look at the boost and WG duty columns - they're oscillating, which means the WG isn't staying closed. It isn't staying closed because the actuator is meant to operate at lower boost levels.

You can manually adjust the tightness of the WG actuator by disconnecting the actuator arm and turning it. There are some more detailed write-ups on Nasioc on adjusting the actuator.

Yep, thats where I was going to start...

Did you already tighten the WGA when you installed the TBE? If not, thats the first thing you need to mess with. You want to sneak up on things here, 1 turn at a time. But I think I ended up (and most do) around 2.5-3 turns. You want to shorten the arm, fyi...

 

[Stein]

Sounds great. I found a big printout from COBB on this, and I'll check NASIOC too. Will this need to be lengthened again for a "return to stock"?

 

[Stein]

Edited...