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 Post subject: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Tue Nov 07, 2017 8:10 pm 
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Joined: Thu Oct 26, 2017 12:32 am
Posts: 5
Hi,

I've recently started looking into my ECU a little in order to improve some things.
My car is a 2008 WRX (EDM), stock except for a 2.5'' catback, with 110k miles on it. It runs alright, but feels quite sluggish. I don't have another WRX to compare it to, but it sure doesn't feel like the 230 hp it should have.

So I've been doing some datalogging with the stock map to try and understand what it's doing, how the tables work and how they translate into running the engine.

These are the results:

Attachment:
graph.JPG
graph.JPG [ 81.21 KiB | Viewed 243 times ]


I've attached the full log if anyone wants to take a closer look, but the graph works fine to show my point.

As you can see, the Boost Error is substantial throughout most of the pull. WGDC isn't adjusting accordingly, but actually decreasing way below initial WGDC values.
I took the Init and Max WGDC values from the rom's tables and put them into the graph as well to show what I mean. I do realize those will have been adjusted slightly by the low IAT - still, the actual WGDC curve should at least somewhat resemble the other two WGDC curves, right?

So, what's going on here? Why is the WGDC dropping like this?

I've already checked the BCV, it works fine. The vac lines are in good condition and the restrictor pills are in there as well. Initially, I thought that was the issue because 8.5 psi max boost to me sounded a lot like the BCV not working properly. But that still doesn't explain the WGDC curve, right?


If you open the log, be aware that I am from Europe and we use a comma instead of a point for decimals (sorry... gotta fix that for future logs). When opening the log, it should give you an option that'll make it look right.


Attachments:
romraiderlog_20171106_120332.csv [6.51 KiB]
Downloaded 9 times


Last edited by Eufred on Wed Nov 08, 2017 7:41 am, edited 1 time in total.
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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Wed Nov 08, 2017 5:19 am 
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Posts: 2038
Location: NI
have a look at your TD blah compensation (IAT) tables - your IAT is reading 59 down to 52 (f) which puts you in the -34% region of turbo dynamics correction most likely the ECU is pulling a load of duty for you and more as the temps drop even more.

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MY06 EDM STi Type UK Spec D
============================
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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Wed Nov 08, 2017 8:09 am 
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Joined: Mon Jun 08, 2015 4:52 am
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What's your altitude?

Our 08 WRXes cut WGDC (thus boost) substantially above 4000rpm if at some kind of altitude (Atm.press below 0.96 bar or something) because of our tiny turbo. :roll: Your graph looks like this is the issue.

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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Wed Nov 08, 2017 9:53 am 
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Joined: Sat Oct 29, 2016 5:40 pm
Posts: 61
That's the best I can do.. with minor issues I had to fix manually but I'm too lazy today :(

Attachment:
edited.csv [6.6 KiB]
Downloaded 5 times


However I think the WGDC is not the issue. You should hit target a lot earlier than the WGDC started to drop. Are you sure you don't have leaks for example? It can be a lot more things that you can imagine. You should log few more parameters next time.


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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Wed Nov 08, 2017 7:34 pm 
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Joined: Thu Oct 26, 2017 12:32 am
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Wow - good info in your replies, thanks.

Looks like there are three tables playing a role here:

- Turbo Dynamics Proportional Compensation (IAT):

IAT was between 11°C and 14°C, resulting in Target Boost reduction somewhere around 20-30%.
When logging Target Boost, are the values pulled straight from the Boost Table or does TD Compensation get factored in as well?


- Initial/Max Wastegate Duty Compensation (IAT):

Again, IAT between 11°C and 14°C means WGDC reduced by 20-30%. This is definitely not represented in my graph because I pulled the WGDC values from the Rom.


- Initial/Max Wastegate Duty Compensation (atm. pressure):

I'm about 1000 ft above sea level, nothing unusual.
I did actually log atmospheric pressure in that pull, just deleted it from the log because i didn't think it was important. It was at 13.93 psi, which means WGDC gets reduced by 12.5% up to 4k rpm, up to to a whopping 70.3% reduction at 5k rpm! :shock: :shock:


Results:

Attachment:
graph2_post_compensation.JPG
graph2_post_compensation.JPG [ 96.16 KiB | Viewed 219 times ]



Now, this still isn't 100% correct because I only added atm pressure compensation to Init/Max WGDC curves. They should be even lower with the IAT compensation added.


While it all makes a lot more sense now, I'm wondering if those WGDC Compensation values aren't a little too aggressive? I'm looking at a quite popular base map for an '09 wrx, atm. pressure compensation is set to -18% instead of the original -70.3%, and IAT compensation is set to -10% instead of -34.4% (at 10°C).

How far should I be able to go safely, without risking the turbo? Is it the simple matter of making sure I don't over-boost or is there more to it?
I will definitely have to do something about that...


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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Thu Nov 09, 2017 4:51 am 
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Joined: Mon Jun 08, 2015 4:52 am
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Eufred wrote:
While it all makes a lot more sense now, I'm wondering if those WGDC Compensation values aren't a little too aggressive? I'm looking at a quite popular base map for an '09 wrx, atm. pressure compensation is set to -18% instead of the original -70.3%, and IAT compensation is set to -10% instead of -34.4% (at 10°C).

How far should I be able to go safely, without risking the turbo? Is it the simple matter of making sure I don't over-boost or is there more to it?


Atm.compensation is not to prevent overboost, it's to avoid what i think is called "compressor surge", and thus to save the turbo itself.
09 wrx uses a different (bigger) turbo that works better at altitude, that's why there's less atm.pressure compensation.

I think you should focus on the area below 4000rpm first. You should be able to get much closer to target boost in that area, regardless what altitude you're at. 8 psi is barely above wastegate spring pressure, so if this really is what you get, there has to be a mechanical issue, and i would be careful messing with WGDC in that case. ;)

Maybe try logging MAP (Manifold absolute pressure) and Atm.pressure as well, that's how i usually do it.
You could also try to zero your WGDC (set "Max Wastegate Duty Limit Post-Compensation" to 0) to see if you get wastegate spring pressure boost correctly. (should be around 6-7 psi).

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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Thu Nov 09, 2017 5:53 am 
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Joined: Sat Oct 29, 2016 5:40 pm
Posts: 61
In such cases I would first look at the learning view. If there is a leak .. it should be shown out there first for example. It can be something quite simple than we're thinking.


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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Thu Nov 09, 2017 6:57 pm 
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Joined: Thu Oct 26, 2017 12:32 am
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A/F learning looks alright to me..?

The only way I'll know 100% for sure is to do a pressure test, correct?


Just to be sure: I'm assuming the knock sensor does pick up engine misfires as well? Because I got a P0301 code with the car running only on three cylinders about two months ago that lasted about 15 miles. I didn't have my tactrix back then and the car fixed itself before I even got back to the house, but that is definitely something I'll have to look into.


Attachments:
romraiderLTV_20171101-153540.png
romraiderLTV_20171101-153540.png [ 21.26 KiB | Viewed 191 times ]
romraiderLTV_20171106-115315.png
romraiderLTV_20171106-115315.png [ 21.26 KiB | Viewed 191 times ]
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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Wed Nov 15, 2017 10:58 am 
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Joined: Thu Oct 26, 2017 12:32 am
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Although I haven't been able to look into it much more (busy with work), I did manage to get a few more logs with the stock rom last weekend.
Logged a bunch more stuff this time, including Max WGDC.

All 5 logs were consistent, max boost starting at 3500 rpm, WGDC pretty much riding the max values all the way to redline.

Attachment:
11-11-pull1.JPG
11-11-pull1.JPG [ 89.05 KiB | Viewed 137 times ]


Again, boost/WGDC is restricted significantly by low barometric pressure (13.78 psi). I checked the pressure recordings for my city on that day and 14.6 psi was the lowest!
So today I checked atmospheric pressure and manifold pressure without the engine running, both were reading low. 14.36 psi at the manifold and 14.07 psi atmospheric while the city recorded 14.9 psi. This difference of 0.8 psi is consistent with my previous logs.
I assume this is part of my problem? The ecu starts cutting boost and WGDC below 14.3 psi and the sensor always reads below that. I'd prefer not having to buy a whole new secondary air pump just because of that sensor, are there any other options?


As to why I'm hitting boost so late, I guess what I'll do next is to run with 0% WGDC to see how it builds boost on spring pressure alone.
Just to clarify, do I have to zero the WGDC tables and flash the ecu or can I just temporarily block off the vac line going to the EBC valve so that only the inlet and actuator are connected directly? That should have the same effect, right?


Attachments:
pull1.jpg
pull1.jpg [ 155.85 KiB | Viewed 137 times ]
11-11-pull1.csv [15.89 KiB]
Downloaded 3 times
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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Sat Nov 18, 2017 2:49 pm 
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Joined: Mon Jun 08, 2015 4:52 am
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13.8 Psi doesnt seem unrealistic at almost 500 m Elevation. 14.9 Psi does though.
Btw, in which gear do you take your logs?

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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Mon Nov 20, 2017 11:40 am 
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Joined: Thu Oct 26, 2017 12:32 am
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Same thing today - the official German Weather Service reported 14.8 psi, while my car's pressure sensor only read 14.07 psi. I get your point, my elevation is 341m and atm. pressure should be a little under 14.7 psi. But I doubt the Weather Service could be off by that much..??

All my logs are in 3rd gear.


Today I pulled the vac line off the EBC and plugged it. Max boost with spring pressure alone is at 5.5 psi. I've attached the logs, one with the stock setup and one with spring pressure boost.
I'll go ahead and tighten the WG arm to see if i can get it to about 8 psi. Maybe that'll help.


Attachments:
11-20-pull3_stock.csv [10.69 KiB]
Downloaded 2 times
11-20-pull1_spring pressure.csv [10.53 KiB]
Downloaded 3 times
11-20-pull3_stock.JPG
11-20-pull3_stock.JPG [ 87.53 KiB | Viewed 93 times ]
11-20-pull1_spring pressure.JPG
11-20-pull1_spring pressure.JPG [ 79.6 KiB | Viewed 93 times ]
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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Fri Dec 08, 2017 3:59 pm 
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Joined: Mon Sep 19, 2011 4:39 pm
Posts: 79
I've been finding the 2008 EU WRX a tricky beast to improve. Stock its now where near as responsive as my 2006 wrx. My experience of the stock map is that the actual boost never reaches the target boost. This is mostly due to the compensation tables for IAT like already mentioned, and when tweaked this will help. I'm making progress but its slow and frustrating. I've not seen the atmosphere issues you are seeing but I'm pretty much at sea level with 1.0 bar.


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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Fri Dec 08, 2017 4:39 pm 
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Joined: Sat Oct 29, 2016 5:40 pm
Posts: 61
The compensation is definitely not the problem with the car tho. It looks like the solenoid is not working properly. I would suggest switching the lines. Try it out.


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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Sat Dec 09, 2017 5:34 pm 
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wouldn't be the first hatch WRX i've seen with a crap solenoid for some reason. Fitting a 3 port plus a few turns on the arm and it should start to pick up quite nicely. Watch out for boost leaks at the recirc valve as well - could be the turbo is making boost but its getting circulated back into the turbo intake instead of the manifold.

_________________
Good luck and may the logs be ever in your favour!


MY06 EDM STi Type UK Spec D
============================
Panel Filter/2.5" Decat/Prodrive Springs/Leather Seats


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 Post subject: Re: Stock '08 WRX not hitting target boost - WGDC issue??
PostPosted: Sat Dec 09, 2017 6:20 pm 
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Joined: Sat Oct 29, 2016 5:40 pm
Posts: 61
As bludgod said I remembered a case I had few weeks ago. Check if you have a restrictor pill and try with 3 port. You can easily buy a mac solenoid which works great as bludgod said. I would first swap the hoses and check for pill though.


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