Welcome to the North American Subaru Impreza Owners Club Friday May 29, 2015
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Engine Management & Tuning > Open Source Reflashes

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 10-29-2008, 11:07 AM   #26
the suicidal eggroll
Scooby Guru
 
Member#: 51961
Join Date: Jan 2004
Chapter/Region: RMIC
Location: Broomfield, CO
Vehicle:
2005 STi
2012 WRX

Default

Good writeup, but some sections need working.

In particular, your description of how a wastegate works is incorrect, actually it's backwards. The input port on the wastegate is on the OTHER side of the diaphragm from your description, the pressure applied to this port is what opens the wastegate. Without this line attached, the wastegate would never open.

Your explanation of how to tune the wastegate duty cycle is correct, but what those changes are actually doing is again, backwards. There are three basic types of boost controllers, bleed-style electronic, interrupt-style electronic, and manual.

Bleed-style electronic - This is what the stock BCS is on our cars. The line coming from the turbo compressor outlet goes to T, one leg of the T goes to the wastegate, the other leg goes to the BCS. The other end of the BCS runs to the intake. With a wastegate duty cycle of 100, the BCS is open, allowing the air coming from the turbo's compressor outlet to flow through the T, through the BCS, and back into the intake. The wastegate sees very little pressure, so it does not open. When the wastegate duty cycle is 0, the BCS is closed, forcing the air coming from the turbo's compressor outlet to flow through the other leg of the T and straight into the wastegate. When the pressure applied to the wastegate is equal to the wastegate spring pressure, the wastegate will open. The bleed-style BCS controls how much pressure the wastegate sees by pulsing quickly, venting off some of the air coming from the turbo back to the intake, lowering the pressure seen by the wastegate.

Interrupt-style electronic - This is the Prodrive, Perrin, GM, etc. These are 3-port units (whereas the OEM is a 2-port). When the BCS is at rest, air can pass between port 1 and port 2, but not 1-3 or 2-3. When the BCS is energized, air can pass between port 2 and 3, but not 1-2 or 1-3. By attaching the turbo outlet to port 1 and the wastegate to port 2, we get the interrupt-style BCS. When the wastegate duty cycle is 0, the BCS is at rest, so air can pass freely between ports 1 (turbo) and 2 (wastegate). This means the wastegate sees the full boost pressure and will open as soon as it hits the wastegate spring pressure. When the wastegate duty cycle is 100, the BCS is energized, so air can pass freely between ports 2 (wastegate) and 3 (outside air). The wastegate sees zero pressure, and will not open. The advantage of this type of BCS is at high duty cycles, when the BCS is trying to keep the wastegate closed. In the bleed-style, the wastegate will ALWAYS see some boost pressure, the farther the WGDC is from 100, the more pressure it will see, which means it will begin to crack open pretty soon, well before you reach target boost. In the interrupt-style, the wastegate sees no boost pressure until the BCS wants it to, allowing you to build boost faster.

Manual - This is a very simple, very robust style boost controller. It is simply placed in the line between the compressor outlet and the wastegate (compressor outlet to BC, BC to wastegate). The BC creates a pressure drop in that line, essentially creating a pressure drop at the wastegate. This means that if the turbo is putting out 15 psi, and the BC is set at +5 psi, the wastegate will see 10 psi. The setting of the boost controller is always "+X psi", X being the amount of pressure the the BC drops. They are not complicated, but they get the job done very effectively. The only downside to them, is you are always set up to run the full boost that the MBC is set for. Partial throttle, 3/4 throttle, full throttle, your target boost is always the same. With a large turbo where you can control the boost pressure through the throttle quite easily this is fine, but for a small turbo that hits full boost early and easily, it can be a PITA to drive around. The EBC lets you set different target boost levels based on RPM and throttle position, the MBC does not.
* Registered users of the site do not see these ads.
the suicidal eggroll is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 10-29-2008, 11:09 AM   #27
mxpunk
Scooby Specialist
 
Member#: 132130
Join Date: Nov 2006
Chapter/Region: TXIC
Location: Austin, Texas
Vehicle:
2002 Ford F-150
Graphite Gray

Default

Quote:
Originally Posted by williaty View Post
You should post a this on RomRaider's forum as well for peer review. You got a couple of details wrong but those guys would do a MUCH better job of explaining all of it that I can.

One thing I will touch on, though, is your section on AFRs. Stoich is not ideal for anything other than emissions. Stoich produces the lowest sum of hydrocarbons and oxides of nitrous. It's not the best for fuel economy (leaner than stoich is) and it's not the best for power (richer than stoich is). The reason that richer than stoich is best for power is that, due to real-world imperfections in charge mixture, running an engine at stoich results in both excess oxygen and fuel in the exhaust stream. This is due to some of the oxygen and some of the fuel not being able to find each other in the combustion chamber. Oxygen is the thing it's hard to get into an engine so we want to be damned sure that we burn every last one of the buggers. To ensure this, we add extra fuel to make sure that none of the oxygen escapes alive. For "normal" engines, this results in Mean Best Torque being somewhere in the ballpark of 13 to 13.5 AFR. Now, many engines, especially forced-induction engines, will have problems with knock at that AFR. By further enriching the mixture, the efficiency of the combustion can be reduced to the point that knock is easier to control. Make sure you read that carefully, though. The increased resistance to knock is a result of reduced efficiency. So over-enrichment (richer than 12.5 or so) costs both fuel efficiency and power. However, it allows for higher boost and/or more timing. It's a trade off and different tuners will prioritize different aspects of that trade off. In the end, most theories on that compromise will end up making roughly the same power, just in different ways.
i agree, getting an experts opinion and revision would be very beneficial. the OP clearly stated that he is NOT a tuner and that's fair.

Quote:
Originally Posted by lambdamaster View Post
wow...this really needs to be a sticky!
x454643434234 elevently billion
mxpunk is offline   Reply With Quote
Old 10-29-2008, 11:11 AM   #28
boostdog
Scooby Specialist
 
Member#: 149752
Join Date: May 2007
Location: NW Arkansas
Vehicle:
07 wrx tr
rr tuned stg2 12.8@105mph

Default

This is great. keep making the needed revisions to info noodle...... man this is what i needed! thanks again!!!!!
boostdog is offline   Reply With Quote
Old 10-29-2008, 11:15 AM   #29
mxpunk
Scooby Specialist
 
Member#: 132130
Join Date: Nov 2006
Chapter/Region: TXIC
Location: Austin, Texas
Vehicle:
2002 Ford F-150
Graphite Gray

Default

sucide eggroll..

there are ways to tune around a MBC with small turbos, via runing a parallel boost setup using an boost solenoid or you can just set the cl/ol delays so that it starts running rich as soon as it spools, atleast thats how im interpretting it.
mxpunk is offline   Reply With Quote
Old 10-29-2008, 11:16 AM   #30
10-56
Scooby Newbie
 
Member#: 144436
Join Date: Mar 2007
Chapter/Region: E. Canada
Location: NB
Vehicle:
2007 WRX GRP
1995 Justy GL AWD

Default

Thread of the Year!!
10-56 is offline   Reply With Quote
Old 10-29-2008, 11:18 AM   #31
Bad Noodle
Scooby Specialist
 
Member#: 174442
Join Date: Mar 2008
Chapter/Region: Tri-State
Location: NNJ
Vehicle:
2007 SuperWagon
I don't spell well

Default

thanks for the feedback guys. Like I said, any info that needs to be corrected, let me know, I'll be happy to do it. And if you agree with someone else's correction, back them up so I know it's not just one person that thinks the info is wrong.

I've posted a link to this in the RomRaider forum. I want to get all the details hammered out here first. The idea is that once the majority think the info is correct, we can move it to RR for a more indepth review. Most of the info is from RR anyway.
Bad Noodle is offline   Reply With Quote
Old 10-29-2008, 11:51 AM   #32
eduSti
Scooby Specialist
 
Member#: 136503
Join Date: Jan 2007
Chapter/Region: MAIC
Location: MD
Vehicle:
08 STI

Default

VERY NICE......ill have to read it about 20 times before I can actually say I can understand but VERY NICE.......thanks for the writeup
eduSti is offline   Reply With Quote
Old 10-29-2008, 12:35 PM   #33
10-56
Scooby Newbie
 
Member#: 144436
Join Date: Mar 2007
Chapter/Region: E. Canada
Location: NB
Vehicle:
2007 WRX GRP
1995 Justy GL AWD

Default

Quote:
Originally Posted by williaty View Post
You should post a this on RomRaider's forum as well for peer review. You got a couple of details wrong but those guys would do a MUCH better job of explaining all of it that I can.

One thing I will touch on, though, is your section on AFRs. Stoich is not ideal for anything other than emissions. Stoich produces the lowest sum of hydrocarbons and oxides of nitrous. It's not the best for fuel economy (leaner than stoich is) and it's not the best for power (richer than stoich is). The reason that richer than stoich is best for power is that, due to real-world imperfections in charge mixture, running an engine at stoich results in both excess oxygen and fuel in the exhaust stream. This is due to some of the oxygen and some of the fuel not being able to find each other in the combustion chamber. Oxygen is the thing it's hard to get into an engine so we want to be damned sure that we burn every last one of the buggers. To ensure this, we add extra fuel to make sure that none of the oxygen escapes alive. For "normal" engines, this results in Mean Best Torque being somewhere in the ballpark of 13 to 13.5 AFR. Now, many engines, especially forced-induction engines, will have problems with knock at that AFR. By further enriching the mixture, the efficiency of the combustion can be reduced to the point that knock is easier to control. Make sure you read that carefully, though. The increased resistance to knock is a result of reduced efficiency. So over-enrichment (richer than 12.5 or so) costs both fuel efficiency and power. However, it allows for higher boost and/or more timing. It's a trade off and different tuners will prioritize different aspects of that trade off. In the end, most theories on that compromise will end up making roughly the same power, just in different ways.
The best torque mix range is between 11.76 and 12.8.

Mean best torque is 12.28.

A good compromise Torque/Fuel Economy is 12.5
10-56 is offline   Reply With Quote
Old 10-29-2008, 12:56 PM   #34
Bad Noodle
Scooby Specialist
 
Member#: 174442
Join Date: Mar 2008
Chapter/Region: Tri-State
Location: NNJ
Vehicle:
2007 SuperWagon
I don't spell well

Default

Quote:
Originally Posted by the suicidal eggroll View Post
Good writeup, but some sections need working.

In particular, your description of how a wastegate works is incorrect, actually it's backwards. The input port on the wastegate is on the OTHER side of the diaphragm from your description, the pressure applied to this port is what opens the wastegate. Without this line attached, the wastegate would never open.
Hey, I just looked it up:
http://www2.turbov6camaro.com:443/gate.htm

I'm not sure I understand. You're saying that the only reason the wastegate opens is because boost helps overcome the spring tension?

What happens when you pull the boost reference line off? You're saying it wouldn't open, but my gate opens at the spring pressure. I can only make ~7 psi then. Also, the boost reference nipple is at the top of the wastegate, not near the exhaust side.

I'm a little confused. please explain further.
Bad Noodle is offline   Reply With Quote
Old 10-29-2008, 01:09 PM   #35
10-56
Scooby Newbie
 
Member#: 144436
Join Date: Mar 2007
Chapter/Region: E. Canada
Location: NB
Vehicle:
2007 WRX GRP
1995 Justy GL AWD

Default

The spring pushes the wastegate shut. If pressure inside the diaphragm is higher than the pressure of the spring the wastegate opens.

The pressure inside the diaphragm is controlled by the boost control solenoid, that is itself controlled by the WDC.

Removing the boost line from the wastegate will cause the wastegate to never open. Bypassing the line from the BCS will make the wastegate to stay open when boost is above spring pressure.
10-56 is offline   Reply With Quote
Old 10-29-2008, 01:11 PM   #36
williaty
Scooby Guru
 
Member#: 71092
Join Date: Sep 2004
Chapter/Region: MWSOC
Location: Delaware County, Ohio
Vehicle:
2005 2.5RS Wagon
Regal Blue Pearl

Default

Quote:
Originally Posted by 10-56 View Post
The best torque mix range is between 11.76 and 12.8.

Mean best torque is 12.28.

A good compromise Torque/Fuel Economy is 12.5
The two textbooks I've got in front of me disagree with you, placing it learner than that.
williaty is offline   Reply With Quote
Old 10-29-2008, 01:28 PM   #37
Bad Noodle
Scooby Specialist
 
Member#: 174442
Join Date: Mar 2008
Chapter/Region: Tri-State
Location: NNJ
Vehicle:
2007 SuperWagon
I don't spell well

Default

Quote:
Originally Posted by 10-56 View Post
The spring pushes the wastegate shut. If pressure inside the diaphragm is higher than the pressure of the spring the wastegate opens.

The pressure inside the diaphragm is controlled by the boost control solenoid, that is itself controlled by the WDC.

Removing the boost line from the wastegate will cause the wastegate to never open. Bypassing the line from the BCS will make the wastegate to stay open when boost is above spring pressure.
Ahh got it. That diagram confused me. Updating info now
Bad Noodle is offline   Reply With Quote
Old 10-29-2008, 01:30 PM   #38
saab-on-the-cobb
Scooby Specialist
 
Member#: 116330
Join Date: May 2006
Chapter/Region: South East
Location: He sits AROUND the house...
Vehicle:
1999 Lincoln Nav
hooker's lipstick red

Default

Quote:
Originally Posted by williaty View Post
The two textbooks I've got in front of me disagree with you, placing it learner than that.
Can we get a reference?

What books?

Thanks,

sotc
saab-on-the-cobb is offline   Reply With Quote
Old 10-29-2008, 01:39 PM   #39
williaty
Scooby Guru
 
Member#: 71092
Join Date: Sep 2004
Chapter/Region: MWSOC
Location: Delaware County, Ohio
Vehicle:
2005 2.5RS Wagon
Regal Blue Pearl

Default

Friggen Duped.
williaty is offline   Reply With Quote
Old 10-29-2008, 01:39 PM   #40
williaty
Scooby Guru
 
Member#: 71092
Join Date: Sep 2004
Chapter/Region: MWSOC
Location: Delaware County, Ohio
Vehicle:
2005 2.5RS Wagon
Regal Blue Pearl

Default

Well, I'll give you two that are easy to get at the library rather than the books of doom (most of it's over my head). I got from an auto-e major friend.

Try Engine Management: Advanced Tuning by Greg Banish as well as the less useful How to Tune and Modify Engine Management Systems by Jeff Hartmann. Both discuss LBT/MBT/RBT. Banish does it more in terms of the theory of why you should do it that way, Hartman does it more from the perspective of finding the actual value for that car on the rollers.


Additionally, Innovate Motorsports has some very good whitepapers on their site about it.
williaty is offline   Reply With Quote
Old 10-29-2008, 02:26 PM   #41
the suicidal eggroll
Scooby Guru
 
Member#: 51961
Join Date: Jan 2004
Chapter/Region: RMIC
Location: Broomfield, CO
Vehicle:
2005 STi
2012 WRX

Default

Quote:
Originally Posted by mxpunk View Post
sucide eggroll..

there are ways to tune around a MBC with small turbos, via runing a parallel boost setup using an boost solenoid or you can just set the cl/ol delays so that it starts running rich as soon as it spools, atleast thats how im interpretting it.
Yeah, you can do a hybrid setup with an EBC, so the EBC controls boost at partial throttle and the MBC controls boost at full throttle, but I just wanted to touch on the 3 main types.

And it's not the fueling that's a problem with an MBC, if your car has a fueling problem that needs to be taken care of in the fuel tables, the only downside of an MBC is that you can't hold boost below max during partial throttle. To take care of this you can do a few different things, including running an EBC in parallel to handle boost at partial throttle or just feathering the gas to get your desired boost (more difficult with smaller turbos).

Personally, I'm a fan of MBCs. Set it once, and the car will run the same boost today, tomorrow, at 30 degrees, 100 degrees, whatever. When I was using the EBCS it was SUCH a pita...one day it would drive fine, a week later when it's 30 degrees outside it would overboost by 4 psi. Try to tune it on the dyno and first it ignores the max wastegate duty field and goes much higher, overboosting by 5 psi, then it decides to dump everything off, going below target boost by 4 psi, and then it just feels like lowering the WDC more and more (even though it's below initial WDC, below max WDC, and below target boost with no knocking), lowering the boost further and further below the target, for no reason at all. I don't miss my EBCS one bit.
the suicidal eggroll is offline   Reply With Quote
Old 10-29-2008, 02:26 PM   #42
the suicidal eggroll
Scooby Guru
 
Member#: 51961
Join Date: Jan 2004
Chapter/Region: RMIC
Location: Broomfield, CO
Vehicle:
2005 STi
2012 WRX

Default

Quote:
Originally Posted by 10-56 View Post
The spring pushes the wastegate shut. If pressure inside the diaphragm is higher than the pressure of the spring the wastegate opens.

The pressure inside the diaphragm is controlled by the boost control solenoid, that is itself controlled by the WDC.

Removing the boost line from the wastegate will cause the wastegate to never open. Bypassing the line from the BCS will make the wastegate to stay open when boost is above spring pressure.
Correct
the suicidal eggroll is offline   Reply With Quote
Old 10-29-2008, 02:32 PM   #43
Bad Noodle
Scooby Specialist
 
Member#: 174442
Join Date: Mar 2008
Chapter/Region: Tri-State
Location: NNJ
Vehicle:
2007 SuperWagon
I don't spell well

Default

Thank for pointing out the wastegate stuff guys. I updated the original post to reflect the correct description.

Keep the good info coming
Bad Noodle is offline   Reply With Quote
Old 10-30-2008, 10:23 AM   #44
EGY5
Scooby Specialist
 
Member#: 165206
Join Date: Nov 2007
Chapter/Region: MAIC
Location: Columbia, MD
Vehicle:
2006 WRB DPSti
w/ white shoes

Default

i just got a boner from reading this.

thanks guy
EGY5 is offline   Reply With Quote
Old 10-30-2008, 11:34 PM   #45
hostile silence
Scooby Specialist
 
Member#: 163878
Join Date: Nov 2007
Chapter/Region: MAIC
Location: Pittsburgh
Vehicle:
05 STi & CBR1000rr
OBP & Blue and Yellow

Default i felt it move too....

yeah, i might have climaxed if i really had greater understanding of how open tuning works...but i was refered to a few books on romraider by a buddy of mine who is helping me tune my car, so i will be studying the books and posts like this to get an understanding of how my car works (along with picking my buddies brain).... great write up gentleman, us common knowledge men really appreciate all of you for spitting this kind of information out... thanks again


Quote:
Originally Posted by EGY5 View Post
i just got a boner from reading this.

thanks guy
hostile silence is offline   Reply With Quote
Old 10-31-2008, 11:19 PM   #46
EGY5
Scooby Specialist
 
Member#: 165206
Join Date: Nov 2007
Chapter/Region: MAIC
Location: Columbia, MD
Vehicle:
2006 WRB DPSti
w/ white shoes

Default

Yea I mean its like Unabombers stuff. Everything can be really intimidating if you have to search for it everywhere and judge where the threads/posts are misinformation.

But when someone unifies or collaborates to get all the information in one spot, it makes it so much easier to get the information right, as well as helping the new guys learn.
EGY5 is offline   Reply With Quote
Old 11-01-2008, 09:14 PM   #47
mug23
Scooby Specialist
 
Member#: 97841
Join Date: Oct 2005
Chapter/Region: NESIC
Location: Back to Boston
Vehicle:
2005 STI Race Ready
OBP/Orange

Default

If they don't make this into a sticky, the author should post it on Wikipedia.

Please make it into a sticky.
mug23 is online now   Reply With Quote
Old 11-02-2008, 10:10 AM   #48
breezeby
Scooby Specialist
 
Member#: 132658
Join Date: Nov 2006
Chapter/Region: South East
Location: jacksonville
Vehicle:
07 TR vf39ed
RomRaided!!!! Oh Yeah!!

Default

pretty good stuff
breezeby is offline   Reply With Quote
Old 11-04-2008, 12:02 AM   #49
Disaster646
Scooby Specialist
 
Member#: 135382
Join Date: Dec 2006
Chapter/Region: South East
Location: Hollywood, FL
Vehicle:
02 6spd hybrid wrx
fpgreen+E85 ftw 7.5@95.7

Default

just bookmark this page..lol.. i just started tuning my hybrid build.. and with this post it has answered a couple questions.. . nobody seems to have a damn hybrid tune.. but so many always say.. oh if u blow ur 2.0liter go hybrid with wrx heads.. but what about the tuning?.. im currently making a very safe base map.. and one for my needs.. cuz when im done im posting my maps to the ppl in need..
Disaster646 is offline   Reply With Quote
Old 11-04-2008, 06:56 AM   #50
Bad Noodle
Scooby Specialist
 
Member#: 174442
Join Date: Mar 2008
Chapter/Region: Tri-State
Location: NNJ
Vehicle:
2007 SuperWagon
I don't spell well

Default

Some feedback from the romraider forum from benw:

Quote:
The tuning guide as you have written it, is inherently flawed, and it's not your fault. The nature of custom tuning is that each car receives special treatment according to its modifications, fuel, altitude, driver preferences, primary usage, et al.

The guide, as it exists currently, attempts to go into details that are much too fine for the broad spectrum of people who will read it. I think the best method of creating a tuning guide for such a wide range of users, cars, and technical abilities, would be to start basic, and only cover the points which are simple and consistent across most tuning endeavors. The UTEC tuning guide is a good example of this.

If it were me, I'd have a few key areas of the guide, and strip everything else out. I'd start by linking all of the good stickies, for things like Subaru's timing strategy and boost control. Here are some areas I'd describe the known good process(es) for, and link to popular threads on RomRaider.com and OpenECU.org where more information and discussion can be found:
- how to properly scale fuel injectors
- how to properly scale a new MAF/intake
- how to map target boost and tune WGDC/turbodynamics
- basics of fueling strategy
- basics of timing strategy (broken down into 2.0L, 2.5L, and STI if necessary)

And more as needed. I think that keeping things as simple as possible is ultimately more effective than inundating new users with a guide that is simply too large, and too specific to be of any use. Specific advice or details only works when everyone's working with the same hardware (car) and that's just not possible in our world!
So keep in mind this guide isn't the 10 commandants on how to tune your car...it's more like the pirate's code... which isn't really a code but more of a guideline.
Bad Noodle is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
My Swap: 1999RS to 2002WRX. Complete Wiring Guide Inside 99 rs Subaru Conversions 231 05-12-2015 03:51 AM
A complete n00b's guide to changing the oil in your WRX (with pics!) perret318 Service & Maintenance 153 11-28-2013 01:17 AM
Complete open source tuning guide shutupnshift04 Commercial ECU Reflashes 19 05-10-2007 05:16 PM
Updated StreetTUNER Tuning Guide and Tuning Guide Worksheets... Christian. AccessPort 0 04-17-2007 05:24 PM
Complete Price Guide. Diabolical1 CC Canada Region Forum 0 06-20-2006 02:40 AM


All times are GMT -4. The time now is 01:18 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2015 Axivo Inc.
Copyright ©1999 - 2015, North American Subaru Impreza Owners Club, Inc.