Dano's Boost Tuning 101 + Cool Stuff

[Dano]

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?





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