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Old 12-02-2012, 11:07 PM   #1
mikemike616
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Default Peak Boost Levels Dropping

A few months ago I got my WRX road tuned by IA Performance and we had it peaking at about 16.5 psi. I swapped in the GS EBCS just before the tune and on the first WOT run I was only hitting 10 pounds. He had me double check that the EBCS was hooked up correctly and I triple checked that it was. He had me tighten up the wastegate actuator arm a bit and that still didn't help achieve higher boost levels. So he cranked up the wastegate duty cycle to around 90% which had me a bit worried. But being that I am pretty new to turbo cars and know nothing about tuning, I asked him and he reassured me that it would be fine. I've noticed over the last few months that I'm hitting lower and lower peak boost levels at WOT and now I'm maxing it at about 12-13 pounds.

Is running the wastegate at 90% duty cycle wearing it out and making the wastegate door open sooner or wider or something and dropping my boost levels? Does this IA Performance guy have no idea what he's doing or what? And if the wastegate is bad, can I replace it or fix it?

Thanks.

/Long story bro.
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Old 12-02-2012, 11:23 PM   #2
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I'd be looking for something mechanical going on. The tune shouldn't be an issue. Check for boost leaks and pre-turbo exhaust leaks.
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Old 12-03-2012, 07:28 AM   #3
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Did u swap to new vacuum lines when u installed Ebcs? Not sure if restrictor pill from stock lines wld cause problems but I know the pill isn't needed for ebcs
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Old 12-03-2012, 09:44 AM   #4
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Originally Posted by drewvdw View Post
I'd be looking for something mechanical going on. The tune shouldn't be an issue. Check for boost leaks and pre-turbo exhaust leaks.
Thats what I'd be looking for. OR you could have a seriously clogged up intake. I'm taking an entire state worth of mice in the airbox.
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Old 12-03-2012, 10:38 AM   #5
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From the sound of it, something was not right since the EBCS was installed. You should actually need LESS WGDC using a Grimmspeed EBCS to reach the same target boost.
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Old 12-03-2012, 11:17 AM   #6
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Did u swap to new vacuum lines when u installed Ebcs? Not sure if restrictor pill from stock lines wld cause problems but I know the pill isn't needed for ebcs
Yes. I used the vac hoses that were included with the kit. I know the restrictor pill is removed.

I'll check the intake today. I can do a datalog and upload it here if anyone thinks they can diagnose the problem that way.

Quote:
Originally Posted by Tripintaz View Post
From the sound of it, something was not right since the EBCS was installed. You should actually need LESS WGDC using a Grimmspeed EBCS to reach the same target boost.
Is it possible that I have a bad EBCS?
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Old 12-03-2012, 12:17 PM   #7
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Originally Posted by mikemike616 View Post
Yes. I used the vac hoses that were included with the kit. I know the restrictor pill is removed.

I'll check the intake today. I can do a datalog and upload it here if anyone thinks they can diagnose the problem that way.



Is it possible that I have a bad EBCS?

It's possible I suppose. More likely that its hooked up incorrectly or there is a vacuum line popped off somewhere.
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Old 12-03-2012, 01:20 PM   #8
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Originally Posted by Tripintaz View Post
From the sound of it, something was not right since the EBCS was installed. You should actually need LESS WGDC using a Grimmspeed EBCS to reach the same target boost.
^This. Something in the install or hardware doesn't sound right.
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Old 12-03-2012, 02:21 PM   #9
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Okay I'll have a look again at it today but I'm certain I hooked up the EBCS correctly during the install. I checked and rechecked and rechecked. I did a datalog earlier and now I'm peaking at 61% WGDC and 14.1 psi while target boost is 17.5 psi.
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Old 12-03-2012, 02:51 PM   #10
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Do you have a wideband? What's your AFR?
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Old 12-03-2012, 03:52 PM   #11
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Do you have a wideband? What's your AFR?

His AFR would have zero bearing on his inability to reach boost target.
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Old 12-03-2012, 03:53 PM   #12
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Originally Posted by mikemike616 View Post
Okay I'll have a look again at it today but I'm certain I hooked up the EBCS correctly during the install. I checked and rechecked and rechecked. I did a datalog earlier and now I'm peaking at 61% WGDC and 14.1 psi while target boost is 17.5 psi.

Boost leak?
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Old 12-03-2012, 03:55 PM   #13
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His AFR would have zero bearing on his inability to reach boost target.
So a boost leak wouldn't affect AFR?
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Old 12-03-2012, 05:04 PM   #14
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A boost leak will def change the afr. Your pulling in unmetered air so if you got a leak your going to run lean.
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Old 12-03-2012, 06:29 PM   #15
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According to my datalog, I'm staying at 11.14 AFT at WOT but that's using the stock O2 sensor so I'm assuming 11.14 is the lowest it can read.
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Old 12-03-2012, 07:54 PM   #16
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So a boost leak wouldn't affect AFR?
Of course it would. But checking his AFR won't determine why he cant reach target boost. I was already suggesting he should check for boost leaks.
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Old 12-03-2012, 08:05 PM   #17
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Yes, checking his AFR is a very easy way to see if there's a possibility of a boost leak. It's a hell of a lot easier than manually checking each connection, especially if you've got a front mount.
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Old 12-04-2012, 09:57 AM   #18
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Originally Posted by drewvdw View Post
So a boost leak wouldn't affect AFR?
Quote:
Originally Posted by drewvdw View Post
Yes, checking his AFR is a very easy way to see if there's a possibility of a boost leak. It's a hell of a lot easier than manually checking each connection, especially if you've got a front mount.

What I'm getting at is checking AFR will not confirm nor deny boost leaks. He should check for boost leaks regardless of what his AFR reads. Boost leaks do not always have a huge affect on WOT AFR. As OP stated above his AP is reading 11.14 which is safe, however this does not prove there are no boost leaks.


The fact that the peak boost as slowly lowered over time makes me think some sort of boost leak has developed.

OP, when you are see 61% WGDC what is your turbo dynamics doing? Trying to add more boost? If you peaked at 61% then your tuner is not using 90% in the WGDC tables. He must have gotten it worked out or gave you some incorrect info. Maybe he set the max allowed WGDC to 90% but that does not mean the ECU will always go that high. Its WGDC table + Turbo Dynamics = final WGDC.

If you had a boost leak somewhere and your max WGDC was 50% in the table at WOT then turbo dynamics added 11% (max) trying to reach boost target and still cant reach target. That sounds a lot like a boost leak. I would be curious to see a log of a WOT run in 3rd that shows Boost, Target Boost, TD error, TD Integral, TD Proportional, and MAF grams per sec.
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Old 12-04-2012, 10:47 AM   #19
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Okay I did a datalog this morning, pulling from 2500rpm to about 6000 rpm. Boost peaked at 15psi (still 2 pounds below target) and I did hit 90% WGDC. It seems I can only build that much boost when I go WOT lower in the rpm band and build it up. I'm uploading three datalogs. The first is the one from this morning, the second is from yesterday morning showing lower boost and lower WGDC and the last is a datalog I did right after I got the car tuned a few months ago.

WOT 3rd Gear Pull
Driving Pulls
Tuning Pull
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Old 12-04-2012, 11:31 AM   #20
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The first one from this morning shows your Turbo Dynamics pegged at maximum trying to reach boost target. However you peak WGDC is staying in the low 60's. So it seems your WGDC table is tuned in the lower 50's and the Turbo Dynamics is adding its maximum amount (proportional is pegged at max all the way thru that pull) and the total is coming out to about 61%. This possibly shows your do not have enough WGDC set in the high table or your have a boost leak.

Interestingly enough, your log from right after the tune from a long time ago shows the WGDC's going into the 80's. Quite frankly this seems very odd. I don't see how both logs are from the same tune.
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Old 12-04-2012, 01:18 PM   #21
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Okay man. I'll try to get it leak tested. Should I be prepared for the need for a retune after the leak is fixed being that it's possible the leak was there when it was tuned? It shows my target boost is almost 18psi which I've never seen even right after the tune.

Thanks so much for all the help. I'll let you know what the outcome is.
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Old 12-04-2012, 02:39 PM   #22
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Sounds like you had a leak all along. I would fix and lid to see what your boosting at.
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Old 12-04-2012, 02:41 PM   #23
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Originally Posted by mikemike616 View Post
Okay man. I'll try to get it leak tested. Should I be prepared for the need for a retune after the leak is fixed being that it's possible the leak was there when it was tuned? It shows my target boost is almost 18psi which I've never seen even right after the tune.

Thanks so much for all the help. I'll let you know what the outcome is.
It might need to be adjusted, but it will probably be ok since the WGDC's seem to be in the right area to reach your boost target if there was no boost leak. I happen to know that 50-60% WGDC is sufficient enough to hit 18psi with stock turbo, stock TMIC, and Grimmspeed EBCS.

You should go over all of your vacuum lines, TB to IC hose, and BPV hose to see if anything is obvious. If you search the forum here there are a few different threads explaining different ways to perform a boost leak test. I would rule out a boost leak before entertaining other possible causes of your symptoms.

None of this explains how your WGDC was maxed out at 61% on your most recent log, but was hitting in the 80%'s in the log you claim was from right after your tune.....actually come to think about it....does it only not reach boost target as the weather gets colder? It could be that your tuner did not tune the tables that reduce the WGDC's as intake temps get colder. Factory values in these table will cause a big loss in peak boost once the intake temps start dropping below ~60F. Since the EBCS is more sensitive, if those tables were left at factory values it would be pulling out too much WGDC. It could be this instead of a boost leak. Is your tune locked? Can you ask your tuner for a screen shot of the WGDC compensation vs IAT tables?
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Old 12-04-2012, 09:52 PM   #24
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Originally Posted by Tripintaz View Post
...actually come to think about it....does it only not reach boost target as the weather gets colder? It could be that your tuner did not tune the tables that reduce the WGDC's as intake temps get colder. Factory values in these table will cause a big loss in peak boost once the intake temps start dropping below ~60F. Since the EBCS is more sensitive, if those tables were left at factory values it would be pulling out too much WGDC. It could be this instead of a boost leak. Is your tune locked? Can you ask your tuner for a screen shot of the WGDC compensation vs IAT tables?
Yeah I actually thought that might be the problem initially but it just didn't make sense to me that colder temperatures would result in lower boost. The weather has gotten continually colder since the tune was done. I'll email the tuner. How do I know if my tune is locked?
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Old 12-04-2012, 10:10 PM   #25
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Originally Posted by jrodm12 View Post
A boost leak will def change the afr. Your pulling in unmetered air so if you got a leak your going to run lean.
Confused by this...a boost leak means metered air is escaping which means the motor is getting less air than it thinks and you will be running rich.
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