Dano's Boost Tuning 101 + Cool Stuff
 

So we now have the ability to easily flip a toggle and switch our ECU from the OEM Load Targeting logic to Boost Targeting logic. One could have been doing this all along but you would have to modify all the Load tables to put the values out of reach so the ECU would be forced to use Boost Targeting logic. Cobb has turned all of this into a check box under Advanced Parameters in ATR.

What does this mean and why would we want to do it. Well let’s talk briefly about Load Tuning. To load tune effectively requires a lot of experience and or time spent logging and making adjustments. Since load is some ambiguous number the ECU generates from a number of variables it is near impossible to lay down a TRL table and end up with a smooth boost curve, without a lot of trial and error logging and making changes. We must also keep in mind how the ECU and motor responds to load and target load. If you don’t request load values that naturally follow the torque curve the motor puts out, the ECU will spend a lot of time oscillating boost to try and achieve those load targets. This is not good for making power at all and will take lots of time to get dialed in. Oh and once you have it just right, AMB temps will change and you may be back to square one. haha

Boost on the other hand is not an ambiguous number generated by numerous variables, it is a direct number taken off the MAP sensor. Well, with this in mind it is easy to see how much easier it would be to ask the ECU for say, 18PSI and with a little tweaking, actually get 18PSI and hold it. 18PSI is a number we can all relate to but who knows what 2.13 Load means?? Load is also a moving target whereas boost is not so it is much easier to hit a boost target than a load target…nuf said!

So I have been load tuning for a year or so now and can tell you from experience it would take me about 20 map revisions after a major hardware change [Turbo, IC, EM, etc] to get my map dialed back in. About two days ago I thought I’d try my hand at Boost Tuning and I have to say the experience has been pleasant. It took me 5, yes 5 map revisions to get my boost dialed in to exactly where I wanted it. Some of those revisions were to increase boost after I got the base map laid down so really just 2 or 3 revs to get WGDC and Boot Targets dialed in. Wow!!! Me likes!

So all I did was take my existing Load Tuning based map, set my WGDC values to 20, set my Boost Targets to a conservative 18PSI and flip the toggle in ATR. Oh and for good measure I copied in Christian’s WGDC IAT comp table he created for this to help combat possible load fluxuations caused by temp changes throughout the year. Time will tell how this table reacts.

So in the very first log I hit my early lower RPM boost targets but couldn’t quite reach target in the upper RPMs. Well all this was expected so I looked at my logged WGDC values and made map changes to match what was being logged. Some say the table value = 2x + 20 but in my experience it is more like 2x +10. Then you get the Boost Dynamics/Load Dynamics values multiplied in and the final result is reached. I am not 100% sure about this logic but it seems to work and I spent hours and hours on my Load Dynamics tables dialing in my GT28 and that is my conclusion.

Anyway the results came very easy and very fast and I have attached my current map and logs as examples of how to get started. My goal over the next few weeks will be to see if I can get the Boost Comp xGear tables to limit boost per gear. After looking at them I don’t quite understand how they would work but I’ll give it a go.

If anyone knows what the A & B are for I would love to know. I could assume A would be normal operation and B would be DSC active but who knows.

Stay tuned for updates!

for the MS6 guys. below are my BT and WGDC table values to match up with the logs. Again, the reason I started this thread was to try and illistrate how easy the new Boost Targeting logic is vs. the Load Targeting logic. Did I say 5 maps to completion?

http://mail.netsecurenow.com/img/boost-tune\bt-114e.jpg

http://mail.netsecurenow.com/img/boo...\WGDC-114e.jpg

Update: 5/11/11

After some extensive testing by many, it has been determined that setting up your ECU to follow Boost Targeting is a crap shoot. You may find that while attempting to set your ECU up to follow BT logic you may fall into one of 3 categories.

Looking back at all the posts, eliminating some of the earlier mistakes some have made, we still seem to have about 3 different overall categories that the ECUs fall into when switching to BT logic.

A) Everything works as designed [vast minority it would seem]
B) Adjusting TRL xgear tables to close to actual Calc load is required [Cobbs suggestion but why even switch to BT logic if you still have to tune TRL gear tables]
C) Adjusting TRL xgear tables to unachievable values and neutering the additive side of LD table values is required.

If you fall into cat B, I would just use load targeting. If you can tune your TRL xgear to within .05 of actual then you are already there with load targeting.

If you fall into cat C, that's fairly easy and the way Forzda and others did BT before Cobb came out with the magic toggle :) I wonder if the guys that fall into cat B would remove the boost toggle, if their ECU would move into cat C and behave better. It could be that Cobb's "logic" is mucking up the process.

For the cat A guys, consider yourselves lucky :)

Ich habe eine kopfschmerzen

subbed for reference.

Is this feature gonna be included for the 2010 version of ATR? I assume so, but I'm such a noob I really haven't a clue.

You'll see me lurking in this forum a lot in the next few months.

take an asprin mang...I've had one for 6 months or more...hahahah

is this equally useful on stock turbo? I have a little bit of experience tweaking my load per gear in ATR, and I am wanting to try this out. Is the reason your WGDC values are so low is because you are running a bigger than stock turbo? Just wondering because i usually see 70% or above to run around ~18 psi on my maps using stock k04.

absolutely a good thing to do on any turbo...it is just an easier way to get your desired boost. The downside "can" be that if you tune for 20PSI in the summer you will run 20PSI in the winter but the load will be much higher and could lead to trouble if not monitored.

The WGDC IAT comp table is supposed to help out in this regard but we will need to see some temp changes to know for sure.

My DC is lower b/c I am using a EBC in interrupt mode so it is driven much less. Instead of bleeding boost away from the WGA, the EBC prevents it from seeing any boost until it is commanded to. This is much faster and efficient than the OEM method.

DANO2010 is your Boost Targets table right cause you've got 8.50 in the 2250 rpm range down low, and aren't you using the GS EBCS? so you left your 500 - 2250 cells stock

haha

caught me!

nah..it doesn't matter what's down that low as I never hammer the car down there so the 50DC isn't ever commanded and the Boost Targets table doesn't have much for boost that low either. As far as 8PSI at 2250, again it will never be reached as I don't go WOT that low and the GT28 would never get 8PSI that low anyway LOL. 2600 is about as low as I go WOT and only when logging.

if a guy was running a K04 and EBC in INT [why?] it may be a problem but I doubt it. Who is going to floor it at 1K to reach spool by 2K and at that you may hit 5-8PSI.

^ True dat, but I am all about consistency

subed for more info.

looks good! Keep it up.

I do have a question tho, I see that below 75% throttle, your boost targets are very low, with a huge jump up(6-7psi up to 20psi) once 75% throttle is hit.

Does the boost actually build like this or is this just how the table needs to be populated for smooth rizing boost pressure?

Thanks for the maps dano, I bet with a few tweaks this map could also be used with my Stg3 BNR....

Thats why I wanted to take a look at it.... appreciate it... Thanks

@ Caldazar

Actually 75% throttle in the BT table is 100% throttle. Logged TPS never goes above ~74 so IDK why the table goes to 100. Christian has mentioned this somewhere as well and that's why the OTS values start out at 75 TPS.

With that said, yes I could perform some smoothing of the BT table values but I think in reality, boost comes on so fast, it will make very little difference and you never "hang out" around that TPS value anyway.

I mean if you are anywhere near 75 TPS you are going all the way right? so the transition will not be noticed.

This map is not totally completed so I still have some tweaking to do. I am so used to it taking so long to get a load based logic map to give me the boost I want that I never get around to polishing the map off. LOL That and I changed hardware a few times.

it will be nice on this map to actually FINISH!!

@ DSIT

yes it would be very close. your WGA preload will make some difference in how you set your WGDC tables up and if you are going to run an EBC in int mode.

I still wish the Boost Dynamics table had higher resolution for fine tuning boost. If you look at LD and BD table axis you'll see what I mean. My boost is currently within +- .3-5 PSI of target but that's alot in my book...maybe I am just too pickey LOL

subbed

and quesiton about your WGDC....how did you come on 20 as a starting point? just out of experience?

as i understand it WGDC isthe % it is open...so what it is saying is that your WGDC is open 20% of the time....what is the effect of raising or lowering this value?

20 was from experience. GrimmSpeed suggests 15 to start out with on their EBC but in my last go around it was much too low so I started at 20.

WGDC% in the table ends up being the table value X2 + 10ish. So 20 in the table will come out to be 50ish logged. I think most guys have the formula at value X2 + 20 but I haven't seen it be that high. It doesn't matter too much anyway see below.

Its hard to tell because other tables come into play that alter the logged WGDC value like Boost Dynamics, WGDC IAT Comp etc.

it may be that the table value is multiplied by 2 only, and then the adder and multiplier table values are figured in IDK. It would be easy to tell by just zeroing out the comp tables and set WGDC and see what is logged.

Anyway where was I, oh when you adjust the value up or down you will get higher or lower DC which will yield higher or lower boost. Of course the Boost Dyn table is there to adjust and try to meet your target boost as well.

Lastly, The way the Boost Control system is setup will make a big difference on how the WGDC table is setup. In OEM form, the WG solenoid bleeds air away from the WGA so more DC is necessary to achieve XX amount of boost.

My EBC is setup in interrupt [ or 3 port mode] mode which keeps any pressure from acting on the WGA until it is commanded to. This allows for faster reaction time, faster turbo spool and less DC on the solenoid.

3 port is even better when you run an EWG as you can actually pressurize the chamber to force the WG to remain closed even though exhaust gas pressure is trying to open it.

My DC values would be much lower than the values in an OEM setup. IIRC my K04 values were in the mid 40s for example.

be careful because if you up your throttle DC tables to 100% from 80, the TPS goes to like 76.XX so u wanna make sure you cover the whole possible range. i always change all my tables from 68% and above to compensate for any possible inconsistencies.

ok so i plan on using the stock boost control system...so i would set my target boost values (lets say 17) in the boost target tables...then i would set the WGDC (to like 20 as you say) and log to see if i achieved the 17...if i didnt...i would up WGDC...if i did however...would their be any benefit in turning down the WGDC value (i.e. looking for the exact value that achieves the 17)...or would i just leave it and forget it?

now....we are dealing only with the boost tables.....so we really arent changing other things (like timing and fuel tables) correct?......would it be safest to leave those valus alone (ie in the stock form) or would i need to optimize these as well?

also how does your WGDC affect your air flow (you mentioned gaining more g/s)

also how did you determine your step up of boost? again experience?

also also you still need to calibrate your maf when doing this type of tunning right?

sorry if im asking too many questions

^no that 20% wga duty cycle is for his grimm ebc in interrupt..

.

ok lets assume that i achieve 17 psi at 20 WGDC.....would anything be gained by raising the WGDC even higher? Even though I am already achieve 17 psi? Would it cause me to over boost?

WGDC is there to allow the ECU to reach boost targets set in the Boost Targets table. Raising DC will do nothing except for allow the motor to spike between shifts possibly if it is raised at a shift RPM.

that is why finding the correct point is important and not just setting it really really high...got it

Man my car loves to make too much boost. I have the boost target table set to 18.5psi and my WGDC (stock boost control) down around 30% and I'm still spiking to 21psi.

^I thought the value that you set was actually lower than the wgdc you see in datalogs?

So wouldn't 30% on the wgdc table be closer to 70% (going off of dano's 2x+10 figure)?

Or you're saying that you have it at 30% in the datalogs? Which would be ~ 10% in the appropriate tables in ATR?

sounds like you just need to lower WGDC some more in the RPM range where you spike.

you want as little WGDC as possible and still achieve boost targets. If your WGDC is too low then the ECU will use the Boost Dynamics table to add DC and try and achieve target. So you want to keep the table values as low as possibe.

So this basically gets rid of gear based tuning for those who try to limit boost in the lower gears?

Yes, but I am working on a way around that.

You can use the APP translation tables to limit throttle position in the lower gears. :)

Still working on that but I have 3rd gear down.


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question...

you have low boost targets in your sub 3k columns and 50 in your WGDC...why the high WGDC value? as i understand it more WGDC easier to achieve boost...

does it have something to do with our boost target in that area is close to mechanical boost levels?

actually i was looking at some logs of mine and im going to attempt to reason this out here...

so i noticed WGDC is higher when boost levels are low...i reason this as we are very far from our boost target (in the upper range) so we wish the turbo to build boost quickly (hence the high WGDC) and then it tapers of to all more WG action as we achieve our high rpm boost levels

No, sorry, my values in ATR are 30% up to 6000rpm where I backed it down to 28% I haven't had a chance to get a clean log yet. I guess I'll just really drive them down and start from the beginning

I getcha, I was just thinking if you had roughly 40% values in ATR with your K04 that I'd start with 30 but it appears that wasn't low enough still.

Well unless you are in Australia [don't think there are any Moose there LOL] it is winter and WGDC values will be lower now than if you were tuning in the summer. Once you get them correct for now you may want to try and add like 2 or 3 to the values so there is room for growth as temps rise.

This however, may induce boost spikes post shift though if you raise them around a shift point. if you do then put them back and just know as temps rise you may need to increase them.

Setting them just right for now may work if the Boost Dynamics table has enough room to add to them when temps rise.

Thanks mang, I'll just start them all off lower and work them up slowly. Oh and yeah... I'm in MN so today we're looking at 11 degrees.

APP translation tables...of course! Forgot all about those. That'd work. And if I had read through your whole original post more carefully, i would have read about the boost comp/gear tables, which will also work.

I took a stab at this today and I gotta say, after one map, boost is pretty much dead on what I have set in the tables. Works great. Fine tuning to come.

Ok, here's a map and 4th gear log today. This is my first map using boost tuning. I've been fine tuning another one tonight. Seems as though I start losing boost between 5,000-6,000 RPM and I'm not sure why because I'm targeting 19psi and it looks like I have plenty of WGDC left. I just installed a Corksport downpipe and the car feels stronger than it did, but if I could hold that extra .5-1.0psi till 6,000, I'd feel alot better. I think I should be pushing 300 g/s with my setup, but I'm in the high 280's.

I've been tapering AFR towards rich nearing redline, but I kicked it up a few notches leaner.

right on!

Interesting thought on WGDC

I had a theory that actual WGDC was table value x2 +10 then Boost Dynamics/Load Dynamics values were added if necessary. Tonight while working on this I experimented with the left hand side of BD table values and zeroed them out. This should effectively make the ECU run only the table values and not add anything. I lowered my values back down to 15 and captured a few logs.

The results seem to support my theory. My logged DC was 39.xx for all three logs taken back to back. So 15 WGDC value x2 + 10 would be 40 and I was in the mid 39 range.

FF it may be that you don’t have enough DC left, the BD table values don’t allow enough added to the WGDC table value or your turbo is out of breath or perhaps there is too much back pressure in the exhaust.

Well, I don't think I'm out of DC and at 18-19psi, the turbo shouldn't be out of breath just yet. As far as my exhaust setup, I've got a CS dp and the rest is stock. I just noticed my Boost Dynamics was 0.00 for -1.00 boost, so I changed it to 0.01 and we'll see what that does for me.

post back up if the BD table change makes a difference but you have enough raw WGDC to still make that boost anyway so I doubt it will help but you never know.

Its been awhile but IIRC right around 5-5.5k is where the K04 starts to give up right?

I looked at your map and you do have plenty of DC, the Comp tables look ok and your BT doesn't drop until 6k so IDK what else could be doing it.

Just wanted to follow up my WGDC theory with some evidence and my methodology to determine what WGDC values should be.

in the attached logs the map's Boost Dynamics table is zeroed out on the left hand side which means it doesn't alter commanded DC from the WGDC table to increase DC. I have the right side set as per Christian's EBC 3port table to allow for overrun prevention.

It looks like actual WGDC = table value X2+9

Then BD values are either added or multiplied to that sum to achieve target boost from the Boost Targets table.

Attached are two different logs with differing WGDC values as I am working my way up to what is needed to reach target boost without any intervention from the Boost Dynamics table. This seems a good way to determine what you actually need in WGDC table to start out with. In my first post here, things just seemed to fall into place very quickly but when I started to fine tune my boost curve BD table was over compensating and causing all kinds of trouble on my GT28 setup.

After I get WGDC table values very close to what is needed to achieve boost targets, I will then use Christian's BD table value [setup for EBC 3 port], which are very restrictive on the ECU, so DC can be altered as temps change.

Here is his suggested BD table values. Keep in mind that the OEM/OTS values allow the ECU almost total authority to alter DC on both sides. If you use the below table values, your WGDC tables will need to be much more refined than any OTS table and again these are for the faster reacting EBC in 3 port mode.


datalog1 has a commanded DC value of 15 from 2.5K to RL
datalog2 has a commanded DC value of 20 from 2.5K to RL

you can see in the logs that actual DC in both is 2x+9 of table value.

a note of interest is that around 5.4K DC begins to drop for some unknown reason. FF this could be what is helping to prevent your boost from staying at 19PSI.

Something to think about if you want is DBW. Boost and load tables are throttle/pedal sensitive.

Anecdotal example - after changing to the boost toggle, I had a softer pedal, like you, and liked it at first. Then I decided to pump up the pedal to where it was feel wise. On original DBW (which I had been running for a year or more) I did half a dozen logs and saw only one small shift spike - all others it ramped up beautifully after a shift. After DBW mod for peppier response (and it felt just like the original pedal with load tune) I immediately got a big shift spike.

Would not having your CL Max Throttle set to 100 prevent any of this pedal input trouble you describe or am I not understanding what you are saying LOL

Since setting all my CL Max Throttle to 100 and CL Max Load to 1.25 I havent' seen any post shift spikes.