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Old 10-06-2011, 11:02 AM   #301
Bad Noodle
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It sounds like your missing the point of TD. As written in the guide, TD is meant to correct for overboosting or underboosting after you have your WGDC dialed in correctly. So if you are tuning in the current weather conditions, you should be able to get your boost correct by adjusting the WGDC tables only and have TD set to 0. Adjust both WGDC tables. If your initial value is 30 and your max is 50 and you are overboosting, move them to 25 and 45. That leaves the gap between them for TD corrections when you start using them again.
If you tune your car now with your WGDCs dialed in and everything is working with the TD zeroed out, in July you won't be hitting your target boost because the atmosphere has changed and the air has become less dense. Then TD should step in and work to correct for the boost error. Otherwise you'd have to retune your boost every time the weather changes.

It sounds like you're expecting to see a direct correlation between 1 table and 1 effect when it doesn't work like that. It's a dynamic self correcting system and you need to understand it's individual parts as well as the whole to really know what to change. Otherwise you make a change, you don't see the effect you were expecting, and end up getting frustrated because there isn't a directly cause-effect relationship.
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Old 10-06-2011, 11:15 AM   #302
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Quote:
Originally Posted by AB-737 View Post
One other question on tuning in the WGDC tables... Should my Target primary wastegate be my the value in my initial table? Or between the Initial and Max? this is where I'm still slighly confused on what table should read what.

I'm guessing the Initial should be the lowest WG value needed to reach that target boost in any of the gears since that varries, and then your max is the highest WG necessary to reach the target boost in any of the gears. Am I correct in that thinking?
Under ideal conditions, your car would always run the initial WGDC, and TD Int and TD Pro would be 0, because your boost error would be zero. The WGDC max table is just there as a safety net to keep things from going out of control, you should never actually have to use it. You want it to be high enough where it doesn't interfere with TD Int and TD Pro as they're doing their job fixing any boost problems you might have, but you don't want it to be so high where if something goes wrong, your WGDC isn't allowed to push all the way to 100 and cause a huge boost spike. Your WGDC max table should never actually be used for tuning, just as a safety net.

Without per-gear WGDC compensations, I would probably tune the initial WGDC table in 3rd or 4th, and let the turbo dynamics modifiers do their job in the other gears.
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Old 10-06-2011, 11:24 AM   #303
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I'm understanding how it works and see how it works, but when I read this

Quote:
"Look at the TDI being added in at the RPM you want to achieve full boost. Add that amount to your 100% WGDC column.
9) Rinse and repeat.
a. As you do this, you will start getting a better idea of how the turbo is working and that will help you find exactly where the turbo is happiest in the RPM range. Seeing how the turbo is behaving will help you confirm the RPM you want full boost at or revise it.
b. Do this until you reach your target boost (this was set at 75% of your theoretical) at some rpm
c. Once you are hitting boost value you have in your boost map, your TDIC should start building up and your TDI should be maxed out as your spool.. Then as you hit the target boost, your TDI should drop to 0 and your TDIC should stay constant."
I get confused again because its telling me to leave that correction system in place while I'm trying to dial in my WGDC

I new to boost tuning yes, but not new to tuning as a whole so I understand where corrections come into play and why they are needed in climates where your weather changes drastically.

From what I'm reading, I'm gathering that I need to dial in my WGDC's WITHOUT any correction being done so I know what they need to be to hit a target boost and then re-enable that correction system to keep that boost stable when the air changes. With reading the guide it reads as if you are USING the correction system to reach target boost all the time since you never disable it, you only use it's numbers to add to your WGDC till you hit target and if you ask me the correction system will get you to target WELL before your WGDC table is close enough to do it on its own... Right?

My biggest issue is I have 3 different explanations as to how to tune it and none match what the guide reads, and you stated to have the WGDC at 30 and 50 and if you over boost to drop to 25 and 45, now where did you come up with the 20 split between the two tables? thats not noted anywhere and really can drive someone nuts if they can't figure out where people are getting these values from. Especially when terms used don't match any tables or pids that you can scan for your model year.

TD is a correction system to stabilize boost when air conditions change and get you to target boost when there is a drastic change in TP? simply answer that as a yes or no question.

WGDC is a range of where your wastegate needs to be for a lower gear and a higher gear to produce X boost at X RPM. Is that also right?

Right now TD is off, so why shouldn't a change done to the WGDC table directly affect my boost levels? Is there another table thats correcting for something else that I'm not aware of and isn't stated anywhere?

I feel that there is tons of knowledge on the tuning of these cars but a lot of the basics are just left out, or some of the stuff may of the advanced users just take as common knowledge isn't noted so those starting out have to dig and "ask stupid questions" to figure out whats going on, and at that point in time they just keep getting told they don't understand this or that, when really its lack of information causing their confusion.
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Old 10-06-2011, 11:31 AM   #304
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Quote:
Originally Posted by the suicidal eggroll View Post
Under ideal conditions, your car would always run the initial WGDC, and TD Int and TD Pro would be 0, because your boost error would be zero. The WGDC max table is just there as a safety net to keep things from going out of control, you should never actually have to use it. You want it to be high enough where it doesn't interfere with TD Int and TD Pro as they're doing their job fixing any boost problems you might have, but you don't want it to be so high where if something goes wrong, your WGDC isn't allowed to push all the way to 100 and cause a huge boost spike. Your WGDC max table should never actually be used for tuning, just as a safety net.

Without per-gear WGDC compensations, I would probably tune the initial WGDC table in 3rd or 4th, and let the turbo dynamics modifiers do their job in the other gears.
That helps in explaining my boost levels in different gears... But I can only assume that I would have to tune my WGDC max table higher if I'm not reaching target boost but hitting that max level right? Or the other way, overboosting and the WGDC is below that Max number.

Once again maybe It's terms I'm lost at again...

My map has

Initial WGDC
Max WGDC
MAX WGD Limit Post-Compensation
Initial/Max WGD Compensation IAT
Initial/Max WGD Compensation ECT
Initial/Max WGD Compensation Atm. Pressure

When you say Max WGDC shouldn't be tuned, which table from the above are you referring to? Your statment of that contradicts what Bad Noodle said about changing from 30-50 down to 25-45.

Both the Initial and Max WGDC tables say that wastegate compensation tables are applied to those values, so in my map I'm guessing MAX WGDC is not as high as it can go. But the Max WGD Limit table is the one that does that.
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Old 10-06-2011, 11:35 AM   #305
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The problem is you'll find a million different opinions of how one should go about tuning boost, just like any other part of the system. I prefer to tune my MAF by disabling the closed loop fueling system and directly observing the AFR error while logging, then applying that % error to whatever MAF cell is active at the time. Other people never disable closed loop, and instead USE the closed loop system to tell them what their error is at any given time (the closed loop system is adding 10% fuel to hit stoich, so I need to add 10% to my MAF at that spot), etc. Both approaches are valid and have their advantages and disadvantages.

My approach stems from my [limited] experience with designing closed loop control systems. Trying to tune the system while the entire thing is active can be a HORRIBLE pain in the butt, and will often leave you chasing your own tail, trying to correct issues at one time using values that were derived a second and a half earlier, etc. You can really only do that IF the system is at steady-state, which the boost control system never will be unless you're tuning on a dyno that has the ability to hold RPM constant while you sit there at WOT. For that reason, I always prefer to turn off the closed loop corrections, get it working properly in open loop first, then add the feedback system back in just to keep the system on target in the future. That's not the only way to do things though.
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Old 10-06-2011, 11:41 AM   #306
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Quote:
Originally Posted by AB-737 View Post
That helps in explaining my boost levels in different gears... But I can only assume that I would have to tune my WGDC max table higher if I'm not reaching target boost but hitting that max level right? Or the other way, overboosting and the WGDC is below that Max number.

Once again maybe It's terms I'm lost at again...

My map has

Initial WGDC
Max WGDC
MAX WGD Limit Post-Compensation
Initial/Max WGD Compensation IAT
Initial/Max WGD Compensation ECT
Initial/Max WGD Compensation Atm. Pressure

When you say Max WGDC shouldn't be tuned, which table from the above are you referring to? Your statment of that contradicts what Bad Noodle said about changing from 30-50 down to 25-45.

Both the Initial and Max WGDC tables say that wastegate compensation tables are applied to those values, so in my map I'm guessing MAX WGDC is not as high as it can go. But the Max WGD Limit table is the one that does that.
Both of the max tables are safety nets, Max WGDC and Max WGDC Limit Post-Compensation. Max WGDC is a lower level safety net that's directly tied to your initial table, and is modified by your compensations just like the initial table. Max WGDC Limit Post-Compensation is more of a "Thor's Hammer" global limit on WGDC, regardless of anything.

I find the "Max WGDC" table is more useful as your safety net, while "Max WGDC Limit Post-Compensation" is more useful as a tool to globally limit your WGDC for doing special tests. For example, if you wanted to check your boost with no boost control system, all you need to do is change the single value in Max WGDC Limit Post-Comp to 0, that's it. If you want to limit boost for some reason, but not necessarily drop all the way to spring pressure, you can just set your Post-Comp Limit to say 20, or 30. Say you change your MAF housing, and you want to re-tune your MAF scaling, but you don't want to jump straight into full boost in case your scaling is not perfect right off the bat. You don't have to re-tune your entire boost control system every step of the way, just set your Post-Comp Limit to 0 to hold you at wastegate spring pressure, tune your MAF, turn the Post-Comp Limit to 5, tune the MAF for the new cells you're hitting, etc. You can use the Post-Comp Limit to slowly step into full boost, without having to re-tune the entire boost control system each step.
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Old 10-06-2011, 11:49 AM   #307
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Ok then I'm apparently reading two different ways on how to do this and getting "You're not understanding how this works" when I quote the other person.

I agree with you in disabling the closed loop system to dial in the car and then to re-enable it to keep things under control, that makes 100% perfect sense to me since I was already trying to tune it with TD enabled and was doing exactly what you were talking about I was chasing my tail.

I guess what I need to know is whats a good split between the min and max tables? Bad Noodle quoted 20... If thats a good rule of thumb then I have something I can work with and I can build my own tables with that number. Without having that number then I have no idea what to set the max at. I also see no reason in worrying about having that range large enough for TD to work with, since TD is a compensation so according to whats written on the table the TD control system should be able to add above what's in the MAX WGDC table but as noted the Thor's hammer of the LIMIT is the stopping point.
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Old 10-06-2011, 12:47 PM   #308
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Quote:
Originally Posted by AB-737 View Post
Ok then I'm apparently reading two different ways on how to do this and getting "You're not understanding how this works" when I quote the other person.

I agree with you in disabling the closed loop system to dial in the car and then to re-enable it to keep things under control, that makes 100% perfect sense to me since I was already trying to tune it with TD enabled and was doing exactly what you were talking about I was chasing my tail.

I guess what I need to know is whats a good split between the min and max tables? Bad Noodle quoted 20... If thats a good rule of thumb then I have something I can work with and I can build my own tables with that number. Without having that number then I have no idea what to set the max at. I also see no reason in worrying about having that range large enough for TD to work with, since TD is a compensation so according to whats written on the table the TD control system should be able to add above what's in the MAX WGDC table but as noted the Thor's hammer of the LIMIT is the stopping point.
I believe Max WGDC includes all compensations except for TD (IE: IAT, atmospheric pressure, etc).

I'd say start with a separation of 20, see how it works. If you find your WGDC goes out of control sometimes (it shouldn't if you have your initial table tuned well), you can try lowering max to put a cap on things.
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Old 10-06-2011, 12:54 PM   #309
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My biggest problem is I've been fighting with these WGDC tables for someone else's application. I smartened up and just put the stock tables back in there with all of the stock compensations and such TD still disabled and I'll try to reach my target boost with those rather than trying to correct for overshooting. I just went for a ride and didn't hit my target at all so now I'm working with something I can better control and understand.

Thank you for bearing with me on this one since there are so many different paths you can take, and theories on which is best.
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Old 01-31-2012, 03:00 PM   #310
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I think my head is about to explode from all this reading! So much info to take in in one day lol... but hey great guide!!
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Old 02-28-2012, 10:10 AM   #311
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Default need my 02 wrx tuned in nyc anybody?

Does anybody know any tuners or someone to reflash my evil in New York city area ?
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Old 02-28-2012, 10:13 AM   #312
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Ooops I meant ecu ! Lol
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Old 11-24-2012, 08:05 AM   #313
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Great write up bad noodle, lot of great info!
I had a problem with the link on page 6 "Cobb Tuning Guide". I got a message saying "No thread specified". Is this information still available?
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Old 08-06-2013, 04:33 PM   #314
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Is this info still current?
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Old 01-08-2014, 10:24 PM   #315
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......
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Old 04-30-2014, 09:31 AM   #316
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On page 7 if the 1.0 PDF Tuning Guide, there is a link to Cobb forums so the reader can learn more about boost. The link is dead: There is a post saying that Cobb closed their forums on July 2013...
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Old 04-30-2014, 10:44 AM   #317
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Quote:
Originally Posted by some dude View Post
On page 7 if the 1.0 PDF Tuning Guide, there is a link to Cobb forums so the reader can learn more about boost. The link is dead: There is a post saying that Cobb closed their forums on July 2013...
Ask for the info in the Accessport section. Cobb likely has this documentation backed up
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Old 04-30-2014, 10:49 AM   #318
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I would read cobb's racetuner documentation. They're always updating their info. They're good like that...
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