Author Topic: boost issues: 1/4 throttle and boost goes from 10 to 20  (Read 2273 times)

Offline its allgood

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boost issues: 1/4 throttle and boost goes from 10 to 20
« on: March 09, 2012, 07:46:01 PM »
I'm having issues at quarter throttle to half throttle, if i start out and into it about a quarter throttle my boost goes from 10 to 20 back to 10 back to 20 and will just keep surging. I never really noticed it till about a week ago. im kinda a fuel mizer and dont  accelerate much past an 1/8th. I have a a turbo back exhaust, cobb stage 2 91 fuel. i put the tune back to stock and  didnt notice the surge until about 2/3 to 1/2  throttle. I have no boost controller or blow off valve. I did run a blow off valve for  a few weeks. after i realized it was not a smart thing to have on my car. anyone have any ideas? And yes, i a noob to import turbo cars. Curt

I do have the pill in vac line.
02 WRX

Offline poohbear

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #1 on: March 09, 2012, 09:42:42 PM »
Can you post some logs please...

Offline its allgood

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #2 on: March 09, 2012, 10:32:58 PM »
i actually data logged while this situation was going on. I just have to figure out how to post it one here, or for that point get it out of access port manager. any help would be cool. Sorry, but a comp nerd.
02 WRX

Offline arau

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #3 on: March 09, 2012, 11:05:07 PM »
I'm thinking its boost controller... Best bet go with a 3 port and ditch the stock 2 port :)
1998 GW   Legacy GT LTD. -SOLD
2003 WRB Impreza WRX W/STI mods.
1999 RBP  Impreza 2.5 RS-SOLD
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Offline poohbear

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #4 on: March 10, 2012, 06:36:15 AM »
You should be able to copy and save into excel... If not I have the manager on my laptop... You can email it to me if need be...
What all did you log? Next time your plugged in log the following -
WGDC
INJ PW
FBKC
FLKC
Fuel learning (in areas a b c d)
WIde band please :)
target boost
Manifold relative pressure corrected
turbo dynamics (both proportional and integral)
Total timing
calculated engine load
revs
throttle positioning
and CL/OL status

That should get me started and we can work from there... Depending on what is seen in the log we will remove and replace some of those params...

Did this just start happening?
I have seen this a few times before, one was just due to a crappy tune (the car under boosted, then over boosted, then under boosted, and just chased its tail trying to reach target) another was a bad waste gate actuator (created the same issue having the ecu chase its tail) and I have seen leaks cause this issue... 

The logs will help us narrow down the issue

Boost oscillations like this would not be caused by a faulty solenoid... Generally when the solenoid goes bad the car will run on spring pressure only... This usually means sub 10 PSI with slow onset of boost...

Offline its allgood

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #5 on: March 10, 2012, 07:56:36 AM »
thanks pooh! when i get off today i will down load the new data logs. and get them sent.
02 WRX

Offline its allgood

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #6 on: March 11, 2012, 01:26:21 PM »
data logs:

02 WRX

Offline its allgood

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #7 on: March 11, 2012, 01:28:38 PM »
part throttle log:

02 WRX

Offline poohbear

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #8 on: March 11, 2012, 03:07:54 PM »
That tune is not healthy... You're running 9 IAM and still knocking... You are spiking in the low revs and td compensates and you begin to surge... Are u sure you are running a stage 2 map? Your wgdc is also very low to be hitting 21 psi at 3500 revs or less
Did you ever shorten your actuator arm? Try lengthening it if so... If not maybe a low wgdc map from cobb is in order
« Last Edit: March 11, 2012, 04:07:30 PM by poohbear »

Offline its allgood

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #9 on: March 11, 2012, 07:00:51 PM »
That tune is not healthy... You're running 9 IAM and still knocking... You are spiking in the low revs and td compensates and you begin to surge... Are u sure you are running a stage 2 map? Your wgdc is also very low to be hitting 21 psi at 3500 revs or less
Did you ever shorten your actuator arm? Try lengthening it if so... If not maybe a low wgdc map from cobb is in order

its the cobb stage 2, i did install the stock map and it still seemed to have to much boost. I have not touched the actuator arm.
I guess im lost. I'm glad i have taken it easy on this car. What do i do next?
02 WRX

Offline its allgood

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #10 on: March 11, 2012, 07:05:41 PM »
could a pill that is to small cause the high boost at low rpms? I guess i did not notice that i had knock. I really need to learn how to read the data log. thanks again
02 WRX

Offline poohbear

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #11 on: March 11, 2012, 07:15:44 PM »
If u didnt change out pills the no... What mods are om the car? Try a low wgc map from cobb

Offline its allgood

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #12 on: March 12, 2012, 03:31:37 AM »
If u didnt change out pills the no... What mods are om the car? Try a low wgc map from cobb

turbo back exhaust no cat, cobb stage 2 91 oct. I did have to get a new pill for the vac line and not sure if it stock size or not. I'll order the stock size from subaru so i know for sure i have the stock size. What is a wgc map?
02 WRX

Offline MasterForce

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #13 on: March 12, 2012, 06:27:11 AM »
If u didnt change out pills the no... What mods are om the car? Try a low wgc map from cobb

turbo back exhaust no cat, cobb stage 2 91 oct. I did have to get a new pill for the vac line and not sure if it stock size or not. I'll order the stock size from subaru so i know for sure i have the stock size. What is a wgc map?

a low wastegate map is for cars that are overboosting over the acceptable range target boost. which is about -/+ 1psi.

http://www.cobbtuning.com/AccessPORT-Off-The-Shelf-Maps-s/40100.htm#/v/accessport/maps/subaru/wrx/WRX-Maps-02-03-Stock-SF-Intake
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Offline its allgood

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #14 on: March 12, 2012, 07:07:56 PM »
i tried the lwg map and seems to make no difference. in fact it boosts faster, or it seemed. it almost seems like i have a manual boost controller on.
02 WRX

Offline poohbear

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #15 on: March 16, 2012, 07:07:57 AM »
Try running on spring pressure... Then if that helps you may think about cleaning your lines with the restrictor pill...

Offline its allgood

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Re: boost issues: 1/4 throttle and boost goes from 10 to 20
« Reply #16 on: March 16, 2012, 06:53:19 PM »
I just found a small vac leak on one of the vac lines. it looked fine but when i sprayed some water on it i could hear it. i re capped it, drove it and seems all is good so far. i will up date tomorrow and see how it goes. thanks for all the help guys. curt
02 WRX