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Old 04-01-2013, 09:34 PM   #1
tec_41
Scooby Newbie
 
Member#: 346278
Join Date: Feb 2013
Chapter/Region: MWSOC
Location: Wisconsin
Vehicle:
04 WRX
WRB

Default First Log, Boost Surge/Spike

https://docs.google.com/file/d/0B46b...it?usp=sharing

I just got my AP today for my 04 WRX. Using the Cobb OTS Stage 2 93 octane map.

I took a quick log of a 3rd gear pull, it's the best I could do since I had to run out the door. Please just let me know if you guys would benefit from adding/removing anything to the included data. It's not a hassle to go take another...just hoping someone can make something of this.

The car has TBE (Perrin catted DP), Turbo XS TMIC, and those are all the relevant upgrades I know. Stock intake. As you can see from the log, the boost is surging like crazy- Spiking up to 22psi at one point. And the inj. duty cycle is not looking good.

I guess I'll just leave it at that...where the heck do I start? I'm new to this, go easy on me . But if you ask me for more info, I'll get it. Thank you very much for any input!
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Last edited by tec_41; 04-01-2013 at 09:57 PM.
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Old 04-02-2013, 10:54 AM   #2
Cobb Tuning
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Join Date: Mar 2001
Location: Austin, DFW, Portland, SOCAL
Default

Quote:
Originally Posted by tec_41 View Post
https://docs.google.com/file/d/0B46b...it?usp=sharing

I just got my AP today for my 04 WRX. Using the Cobb OTS Stage 2 93 octane map.

I took a quick log of a 3rd gear pull, it's the best I could do since I had to run out the door. Please just let me know if you guys would benefit from adding/removing anything to the included data. It's not a hassle to go take another...just hoping someone can make something of this.

The car has TBE (Perrin catted DP), Turbo XS TMIC, and those are all the relevant upgrades I know. Stock intake. As you can see from the log, the boost is surging like crazy- Spiking up to 22psi at one point. And the inj. duty cycle is not looking good.

I guess I'll just leave it at that...where the heck do I start? I'm new to this, go easy on me . But if you ask me for more info, I'll get it. Thank you very much for any input!
The nature of the radically wavering boost and boost spikes indicates that there is likely some kind of mechanical issue with the car. This could be any number of things from damaged wastegate vacuum lines, wrong restrictor pill, etc. You can confirm this by downloading the fuel economy map from the maps section at cobbtuning.com, reflashing to car, and then do a run (but don't go up to as high as an RPM as last run - keep it under, say 4500 RPM). The fuel economy map will disable boost control - if the boost still wavers/spikes out of control, then you know you have a mechanical issue with the car.

Bill
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Old 04-02-2013, 11:07 AM   #3
tec_41
Scooby Newbie
 
Member#: 346278
Join Date: Feb 2013
Chapter/Region: MWSOC
Location: Wisconsin
Vehicle:
04 WRX
WRB

Default

Thanks a lot, Bill. I'll give that a shot...I almost suspect the restrictor pill as a possible issue. I found a pill on the line going to the factory boost gauge a few weeks ago that really shouldn't have been there, so maybe it is supposed to be for the wastegate. I'll check that out for sure.
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Old 04-02-2013, 08:45 PM   #4
tec_41
Scooby Newbie
 
Member#: 346278
Join Date: Feb 2013
Chapter/Region: MWSOC
Location: Wisconsin
Vehicle:
04 WRX
WRB

Default

https://docs.google.com/file/d/0BwTr...it?usp=sharing

Here is a log using the Economy tune. As you can see, it didn't surge on this one, so I'm going to start by checking for the pill.
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Old 04-03-2013, 01:48 PM   #5
mikeydrives1
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Member#: 262117
Join Date: Oct 2010
Chapter/Region: Tri-State
Vehicle:
2001 Forester
STi II type M

Default

2nd Log looks decent. I dont see anything wildly alarming yet on it. The first one looks similiar to an issue i dealt with with boost overshooting, then undershooting, then overshooting again and again until it hit target boost.

In my experiences with working out boost surging and spikes, it ended up being an overly sensitive turbo-dynamics table(s). The numbers were set too high for correction, so on cold mornings, boost would often overshoot its target, then it would cut the wastegate back too much, it would undershoot, then it would increase the wastegate again, causing an overshoot, and would repeat itself over and over.

The way my tuner and i approached it was by Zero'ing out all the TD tables, and starting from scratch by setting one set Wastegate duty cycle number for the car to achieve, and worked around getting a number that reached our target boost, as if it were a manual controller (say, 55% for the whole high WGDC table). Once we found a number that got to our target boost (letting it taper off by redline), we slowly worked in the TD table corrections bit by bit until it no longer would cause surging or overboosting on cold mornings. It took a few trys before we got it down pat, but i hope this process will help you at least get to a starting point if it is infact a tuning issue, and not mechanical.
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Old 04-03-2013, 03:11 PM   #6
tec_41
Scooby Newbie
 
Member#: 346278
Join Date: Feb 2013
Chapter/Region: MWSOC
Location: Wisconsin
Vehicle:
04 WRX
WRB

Default

Thanks a lot for the input! That's very interesting...I think my issue is related to a missing restrictor pill, though. At least that's what I'm starting with.

I created a thread in another section asking for help on that, here's a link to it-
http://forums.nasioc.com/forums/show....php?t=2488789
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