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#1 |
Former Vendor
Member#: 241881
Join Date: Mar 2010
Chapter/Region:
AKIC
Location: 907-355-6655 text or phone
Vehicle:2014 P3 Import Auto AWD Dyno, Mods, etc |
![]() Open thread to discuss tunes, answer questions, and advise.... Anyone?
Bring it on... Last edited by P3Auto; 03-23-2010 at 08:13 PM. |
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#2 |
Scooby Specialist
Member#: 189926
Join Date: Sep 2008
Chapter/Region:
International
Location: Okinawa, Japan
Vehicle:2000 RHD STi |
![]() Surging boost under 3/4-full throttle. Causes?
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#3 |
Former Vendor
Member#: 241881
Join Date: Mar 2010
Chapter/Region:
AKIC
Location: 907-355-6655 text or phone
Vehicle:2014 P3 Import Auto AWD Dyno, Mods, etc |
![]() Before I go into too much detail its important to understand that most turbo charged engines with larger high pressure turbos don't like part throttle boosting and control can be a real pain. I'm not saying it cannot be done but let me throw out some of the factors.
MAIN PROBLEM: The gain or duty cycle of the boost control to reach desired boost is usually drastically different at part throttle vs. wide open. Lets assume were talking about an IWG (internal wastegate) which is what stock Subarus and a lot of bolt on turbos use. The IWG has a WGA (waste gate actuator). The WGA has a spring that is designed to keep the waste gate shut up to a certain pressure load. What ever the WGA spring is set to is what your min. boost will be. In other words if you told your boost controller that you want zero boost you would still get what we call "Spring pressure" which might be 6-11PSI in the case of a Subaru typical turbo setup. So the first problem is you cannot make zero pressure at part throttle or below min at part throttle. Now lets look at a lot of guys/gals that run manual or added on electronic boost control. Does the boost controller know the difference between part throttle and wide open or even off throttle? A good boost controller will monitor throttle position for this very reason. Does yours? Part throttle boost control issues can also stem from you point of boost control signal. Where do you pick up a boost signal to control your WGA, are you getting it pre-throttle body or post. When your at part throttle there can be differences between the manifold pressure and the pressure you might read at the turbo outlet nipple for instance. In fact there may be a pressure drop after you intercooler as well, but thats another discussion. So you really should be getting your boost control signal from the manifold post throttle body. The ultimate setup would be two boost gauges one from the turbo outlet region and one from the manifold, then you could monitor for leaks, blocks, or large pressure drops due to restriction in the intercooler. Cool huh? There can also be some other strangness like turbulence, compressor stalling, etc which will cause the boost to spike and dip as the controller tries to keep up with the changes. Remember a boost controller (electronic style anyway) is constantly changing the duty cycle that it pulses the signal to the WGA. It has to look at the boost currently and figure out what changes to make to hit the desired levels. Sounds simple but its not considering every change is not instant due to turbo lag, delay from longer pipes, and other factors like what I mentioned above. The boost controller is also only allowed to make so much change at one time. You controller problably isn't allowed to pull enough duty cycle off the WGA to lower the boost where you want it. There is tons more to this and I suggest some reading on how boost control works in general. I know your running an EBC so check all the hoses and make sure you have it connected the best way. If it has no idea of throttle position then you may not be able to solve this problem. I would need to know more about the EBC to answer better. I think the best solution would be to go back to using the stock boost control system. It knows throttle position and can control part throttle boost much better than any MBC or most EBC's. Other wise drive with a heavier or lighter foot and stay away from that sweet spot that it spikes at. Also allowing the car to control the boost gives you another failsafe in case of problems the ECU you set you back to spring pressure. Oh another thought, with Subarus I have noticed the by pass valve or blow off valve will crack open at part throttle boost some times. This can cause all kinds of issues as well and it is due to where it gets its vacum signal from to open and how much pressure it has to keep it shut. |
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#4 |
Scooby Specialist
Member#: 94836
Join Date: Aug 2005
Chapter/Region:
AKIC
Location: Anchorage
Vehicle:2oo5 STi Aspen 2o12 PiLoT CherrY |
![]() Awesome idea.
I've been reading up on how the injectors being Maxed out? Would it be a good idea to upgrade those before going for a protune? Currently stage two using the ots Cobb tune. I do want to protune but just thinking what to do so I'm not paying for every little part. |
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#5 | |
Scooby Specialist
Member#: 197928
Join Date: Dec 2008
Chapter/Region:
AKIC
Location: anchorage
Vehicle:2019 F-350 White |
![]() Quote:
Very good idea. BTW i have my stockers for sale hahaha. |
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#6 | |
Former Vendor
Member#: 241881
Join Date: Mar 2010
Chapter/Region:
AKIC
Location: 907-355-6655 text or phone
Vehicle:2014 P3 Import Auto AWD Dyno, Mods, etc |
![]() Quote:
Injectors need to be upgraded anytime you increase air flow much beyond stock levels with the Subarus. This might be from more boost, bigger turbo, intake changes, cams, etc. I find that the STI is good to about 18-20PSI on the stock turbo with min mods before you really should size up the injectors. Due to the fact our octane is low up here we tend to have to run rich which means more fuel then others run. COBB OTS tunes have you covered with a very rich tune typically, good and bad. Last edited by P3Auto; 03-23-2010 at 07:44 PM. |
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#7 |
Scooby Specialist
Member#: 142304
Join Date: Mar 2007
Chapter/Region:
E. Canada
Location: Ontario
Vehicle:2007 Impreza WRX Obsidian Black |
![]() can we have an Ask a Ninja corner too??
![]() congrats P3!!! |
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#8 |
Scooby Newbie
Member#: 32908
Join Date: Feb 2003
Chapter/Region:
AKIC
Location: Alaska, Anchorage
Vehicle:2005 Impreza WRX STI BLUE |
![]() I must have missed the announcement, whats P3 Stand for Seth?
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#9 |
Former Vendor
Member#: 241881
Join Date: Mar 2010
Chapter/Region:
AKIC
Location: 907-355-6655 text or phone
Vehicle:2014 P3 Import Auto AWD Dyno, Mods, etc |
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#10 |
Scooby Newbie
Member#: 32908
Join Date: Feb 2003
Chapter/Region:
AKIC
Location: Alaska, Anchorage
Vehicle:2005 Impreza WRX STI BLUE |
![]() Great information, but what does P3 stand for?
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#11 |
Scooby Newbie
Member#: 205902
Join Date: Mar 2009
Chapter/Region:
TXIC
Location: Fort Worth TX
Vehicle:2008 sti - all year 08 CBR1000RR-summer- Sold |
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#12 |
Scooby Specialist
Member#: 192358
Join Date: Oct 2008
Chapter/Region:
AKIC
Location: Palmer,AK
Vehicle:MANY P3 Import Auto 907 355 6655 |
![]() P3 name up to speculation and imagination...lol
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#13 |
Former Vendor
Member#: 241881
Join Date: Mar 2010
Chapter/Region:
AKIC
Location: 907-355-6655 text or phone
Vehicle:2014 P3 Import Auto AWD Dyno, Mods, etc |
![]() Yes it is...Wait a second...Multiple personality disorder kicking in again...BTW I am or was Turbosetch for those who missed that part.
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#14 |
Scooby Newbie
Member#: 32908
Join Date: Feb 2003
Chapter/Region:
AKIC
Location: Alaska, Anchorage
Vehicle:2005 Impreza WRX STI BLUE |
![]() 1999 Subaru legacy Outback SUS Limited 30th Anniversary Addition.
When I used to drive my wifes car, if I drove it too rough directly after starting it, the car would seem like it want to lurch forward still, RPM's would be very high, then all of a sudden the car would just die. Would could cause that? |
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#15 |
Scooby Specialist
Member#: 78982
Join Date: Jan 2005
Chapter/Region:
AKIC
Location: Car.
Vehicle:1992 NFSVX LSL 5mtGT Long name, short temper. |
![]() Is this thread going to focus primarily on engine management issues or do you feel up to takin' a whack at a couple very unique problems with my SVX?
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#16 |
Former Vendor
Member#: 241881
Join Date: Mar 2010
Chapter/Region:
AKIC
Location: 907-355-6655 text or phone
Vehicle:2014 P3 Import Auto AWD Dyno, Mods, etc |
![]() Its not really a supposed to be for major diagnostics on a specific problem. I intended to make it more of a Q&A for people that are tuned or wondering about tuning for adding power or mods. If you want to bring the car to the shop or send me some PM's I might be able to help.
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#17 | |
Former Vendor
Member#: 241881
Join Date: Mar 2010
Chapter/Region:
AKIC
Location: 907-355-6655 text or phone
Vehicle:2014 P3 Import Auto AWD Dyno, Mods, etc |
![]() Quote:
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#18 |
Scooby Specialist
Member#: 137569
Join Date: Jan 2007
Chapter/Region:
AKIC
Location: East SIDE! of anchorage
Vehicle:WRX Twinscroll Dez in yo mouth! |
![]() why is my cel on for missfire but no codes show? why does it flassh atl low rpms but not at high rpms?
I have changed plugs, fuel filter, checked lines, cleaned MAF, ....what else should i do? car runs normal just this flashing cel? my gas mileage is **** so does that point to my front O2 sensor? |
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#19 | |
Former Vendor
Member#: 241881
Join Date: Mar 2010
Chapter/Region:
AKIC
Location: 907-355-6655 text or phone
Vehicle:2014 P3 Import Auto AWD Dyno, Mods, etc |
![]() Quote:
Again were getting into diags not tune specific from what I can tell. The car is more likely to misfire or detect misfire in lower rpms because the load is higher on the motor and the sensitivity of the detection circuit is better. Some code will actually not even try to detect a misfire at higher rpms. Not sure on yours would have to research but its not really important at this stage. As for the O2 sensor(front one anyway) the car uses this to fine tune closed loop mode. So when your idle or just cruising the ECU will read the from the front wideband and adjust the trims to match 14.7:1 AFR. Usually when they go bad you get a check engine light, or surging while cruising, hunting idle, smells rich, black smoke, etc. It could be possible that yours has skewed somehow to give off readings making your car richen up the mix thinking its hitting 14.7:1. I would say this is very unlikely but a very rich idle would cause misfires. You could figure it out by logging or using learningview.exe. The learned trims will be positive numbers over 6-8%. I seem to remember you had the misfire issues on your old motor as well. I would suspect a part you swaped. |
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#20 |
Former Vendor
Member#: 241881
Join Date: Mar 2010
Chapter/Region:
AKIC
Location: 907-355-6655 text or phone
Vehicle:2014 P3 Import Auto AWD Dyno, Mods, etc |
![]() So it was brought to my attention that some Cobb tunes for 90-91 octane run the injectors at 100% . I just got done doing some checking on this and also looking at some logs from when I tried one of these tunes in one of my cars.
It does seem in fact that specifically Stage 2 90-91 octane pre-2009 STI tunes do run the injectors to 99% or more. So is this really bad you may wonder, well let me walk you through the steps of what happens when there is trouble. So when the car is completly happy your running 18lbs or so of boost and maxxing the injectors out at or close to redline. In the event of severe enough knock or very cold conditions the car will switch to different fuel maps or add fuel. Seems like a no brainer right? You must need bigger injectors! Well let see... A big piece of Subarus "fail safe" technology is based on something called IAM (ignition adavance multiplier) or the same DAM (dynamic advance multiplier). On an STI when all is happy and there is no knock this number is at 1.0 got it? 1.0 is best and 0.1 is worst. Now when there is a knock event for any reason if its bad enough the car will drop the IAM down a certain amount depending on various factors. So lets just say the IAM has dropped, here is a chart for what happens on an 05 STI with Cobb Stage 2 90-91 octane: 1.00 Very happy car. 0.75 Global timing reduced. 0.50 Global timing reduced. 0.35 Switch to failsafe fuel maps, Global timing reduced 0.20 Boost control shut down (min boost), Global timing reduced So when we switch to failsafe maps we see the car wants to add in some fuel with a failsafe map, it adds as much as 5% more fuel for an STI. But here is the catch. The Cobb tune doesn't max out injectors until close to redline. The failsafe tables only add fuel in the peak tq regions and look the same as the normal fuel maps towards redline. There is JUST enough room to add the fuel needed. The other part is the fuel tables are calling for 10.6:1 at redline, the reality we see on the wideband is close to 10:1 which is VERY rich at redline. You actually don't need near that amount of fuel past peak TQ. Peak TQ ranges is where the knock tends to be not at peak HP range. So leaning out at redline as long as it doesn't exceed 11.5:1 *should* be ok. More catch, if the knock is bad enough and your using the factory boost control then the car also pulls the boost out which means......Yep less fuel needed. So if I have completly confused you now the original question was does my STI need bigger injectors to be safe? Yes and no: No -- If you run stock boost control, don't go below sea level and redline it, will never run over 18.5PSI, and feel your car will never blow a hose or loose boost control. Yes -- If you run after market boost control, and if you want to be absolutely sure to be safe. The possibility for spikes in air flow due to boost control failure or other condition are real! All it takes is one good pull in a lean condition and your piston is done in most cases due to severe knock. Some injector overhead would be nice to have but won't solve all problems, at least it would be one thing less to worry about. |
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#21 |
Scooby Newbie
Member#: 222520
Join Date: Sep 2009
Chapter/Region:
AKIC
Location: Soldotna
Vehicle:07 Sti SWP |
![]() Heres a question for you. What would be two of the most beneficial books to someone wanting to learn about tuning on modern engines, but lacking much of a background on the subject? Where is a good place to start?
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#22 | |
Former Vendor
Member#: 241881
Join Date: Mar 2010
Chapter/Region:
AKIC
Location: 907-355-6655 text or phone
Vehicle:2014 P3 Import Auto AWD Dyno, Mods, etc |
![]() Quote:
First read should be: http://www.amazon.com/Engine-Management-Advanced-Greg-Banish/dp/1932494421/ref=sr_1_2?ie=UTF8&s=books&qid=1269915658&sr=8-2 This book even has Subaru WRX/STI pics in it with some talk about them. I think you have an 07 STI. If you already have a tune you should take a look at it and start to examine the tables one at a time and learn what they all do. If you have a Cobb AP2 you can download free software from Cobb to actually view and change your own tune. If you want to use OpenECU thats a great choice as well to view and edit your tune. The forums have great information if you can pick over the noise and they also go over the tools needed to start going. If you can get a handle on the fundamentals and how the engine works then understand timing and fuel you can start to tune anything. Every ECU has its own specilized logic that you have to learn but the more you do it the easier it is to learn new or different ECUs. The other part of course is understanding the limits of what your tuning and this part is where it gets tricky. Lots of reading and research must be done on the specific model of car to understand things like drivetrain weakness, common points of failure, fuel and timing limits, etc. The bad part about this for any tuner is doing something new. We have to learn by trial and error of the weakness of the systems if they are not already known. Usually someone else has broken it first and wrote about it some where! Finally you have to be able to identify existing issues not related to the tune. This is the biggest headache for any tuner. Its common for some one to call me and say some thing like "My car isn't hitting boost any more, I need it to be retuned.", or "My car has a rough idle and feels slower, I need you to retune it.". 9 times out of 10 there is a mechanical issue like a hose is loose, internals are failing, the list goes on and on. Problems like that should not be tuned out but rather identified and fixed prior to a tune. An easy example would be a person with a stock tune that claims issues and wants them fixed via a tune. Bad plan. You should never tune a car that you can't verify is properly working from the start. This all requires knowlege of whats normal and whats not. Something I have to repeat to customers all the time is that a tune doesn't change over time, the car and the enviroment do. I personally will turn away work if the car does not meet my standards or is a "hack job". I would offer to fix mechanical issues but not band-aid them. I simply won't participate in blowing their car up any faster. I have started to produce some videos for tuning Subarus but have failed in terms of time to get them done. I think others have some stuff out there if you search youtube. |
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#23 | |
Scooby Guru
Member#: 22923
Join Date: Aug 2002
Chapter/Region:
International
Location: above 8000 rpm!
Vehicle:2002 EJ207 V8 1.5xtr TWIN-SCROLL Black Bugeye |
![]() Quote:
Probably a bit dated now but it really helps promote the idea of keeping the natural balance of the car. Of course, it is specific to the WRX/STI . |
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#24 |
Scooby Newbie
Member#: 222520
Join Date: Sep 2009
Chapter/Region:
AKIC
Location: Soldotna
Vehicle:07 Sti SWP |
![]() Thank you for the advice and the convenient links. I am currently on a AP V2 but am looking at converting over to open source. Haven't had much of a chance to play with the AP yet but it is pretty high up on my list now. Just want to start to get used to data logging and what not. I don't know near enough and would not be comfortable even thinking about messing with the actual tune just yet.
Looks like I'll have a couple of books to kill my flight time with now. |
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#25 |
Scooby Newbie
Member#: 32908
Join Date: Feb 2003
Chapter/Region:
AKIC
Location: Alaska, Anchorage
Vehicle:2005 Impreza WRX STI BLUE |
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