First off, I'd like to say hello, I've been lurking here for a long time, but haven't really posted yet.
Car setup - 2007 335i, manual trans, MMP1k turbos, FBO, PR stage 2.5 bucket lpfp, DI only
For the last couple of years I have been running a custom flex fuel tune from a known tuner in the community, but I won't mention any names. This tune was not very good, lots of overboosting, throttle closures, and maxxed out trims. I have experience tuning other platforms in the past, mainly Hondata, but I had a lot to learn about N54 tuning before I felt comfortable doing it myself.
I have recently begun working on fixing my tune myself, and I'm trying to learn all that I can. I began by taking my existing tune and converting it to the new MHD+ map switch base. I first worked on getting my fuel trims in line on both pump gas and e35 blend.
Once getting my trims looking better, I began working on boost control, and I was excited to try the MHD 3D boost ceiling. I turned on the feature and began working through my issues with throttle closures and overboost. I found my WGDC base table was never scaled properly, and after fixing the scaling, and working on the base tables a bit, my boost control seems to be working well. However, I am now noticing my boost target is inconsistent despite using the 3D ceiling.
My tune is flex fuel, set for full interpolation at E50, and I am currently running E35. My pump 3D ceiling is set to 18 psi and 180 load target, and flex 3D ceiling is set to 26 psi and 187 load target, so I believe both of those load targets should be high enough to not interfere. Most of the time, what I am seeing is the boost target will shoot up to about what I expect around 24.5 psi around 4000 rpm, but will slowly taper all the way to redline, being around 22.5 at 5000 rpm, and 20.5 by 6000 rpm.
Here is a log showing the taper.
Log with flat target until 5500 RPM
This log in this link was from just a few minutes prior, the same map revision, but in this one, boost target is flat as I would expect from 4000 to 5500, and then suddenly boost target drops by 2 psi and there is a small throttle closure.
I have some other logs that I won't include here because they are not very good due to wheel spin, but those logs show targets as low as 20 psi.
I'm just trying to understand, is this taper to be expected considering my load and ceilings are set flat? What can I do to adjust this behavior? Hopefully this post makes sense, as I have a tendency to ramble, but if I can provide an clarification or more detail, please let me know. I'd be happy to post my bin file if anyone cares to look over it.
Car setup - 2007 335i, manual trans, MMP1k turbos, FBO, PR stage 2.5 bucket lpfp, DI only
For the last couple of years I have been running a custom flex fuel tune from a known tuner in the community, but I won't mention any names. This tune was not very good, lots of overboosting, throttle closures, and maxxed out trims. I have experience tuning other platforms in the past, mainly Hondata, but I had a lot to learn about N54 tuning before I felt comfortable doing it myself.
I have recently begun working on fixing my tune myself, and I'm trying to learn all that I can. I began by taking my existing tune and converting it to the new MHD+ map switch base. I first worked on getting my fuel trims in line on both pump gas and e35 blend.
Once getting my trims looking better, I began working on boost control, and I was excited to try the MHD 3D boost ceiling. I turned on the feature and began working through my issues with throttle closures and overboost. I found my WGDC base table was never scaled properly, and after fixing the scaling, and working on the base tables a bit, my boost control seems to be working well. However, I am now noticing my boost target is inconsistent despite using the 3D ceiling.
My tune is flex fuel, set for full interpolation at E50, and I am currently running E35. My pump 3D ceiling is set to 18 psi and 180 load target, and flex 3D ceiling is set to 26 psi and 187 load target, so I believe both of those load targets should be high enough to not interfere. Most of the time, what I am seeing is the boost target will shoot up to about what I expect around 24.5 psi around 4000 rpm, but will slowly taper all the way to redline, being around 22.5 at 5000 rpm, and 20.5 by 6000 rpm.
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Here is a log showing the taper.
Log with flat target until 5500 RPM
This log in this link was from just a few minutes prior, the same map revision, but in this one, boost target is flat as I would expect from 4000 to 5500, and then suddenly boost target drops by 2 psi and there is a small throttle closure.
I have some other logs that I won't include here because they are not very good due to wheel spin, but those logs show targets as low as 20 psi.
I'm just trying to understand, is this taper to be expected considering my load and ceilings are set flat? What can I do to adjust this behavior? Hopefully this post makes sense, as I have a tendency to ramble, but if I can provide an clarification or more detail, please let me know. I'd be happy to post my bin file if anyone cares to look over it.
