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**infamous n55 torque dip**
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01-30-2011, 12:50 PM | #23 |
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i don't have the files... i'm going back to the shop tomorrow to get them and to have them printed with STD correction so we can compare to everyone around here. 14~14.4 PSI peak falling to 11~10 PSI at 6300 RPM, again , more on this later |
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01-30-2011, 01:27 PM | #24 |
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01-30-2011, 01:34 PM | #25 |
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Black e has a small dip but then corrects itself.
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01-30-2011, 02:06 PM | #26 |
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i'll tell you that the the dip IS created by the stock boost control, on the stock tune the car hits 10+ PSI (boost overshoot)then tries to correct it self over and over...more on this later (read tomorrow night)
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01-30-2011, 02:37 PM | #27 |
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That's too long
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01-31-2011, 08:55 PM | #29 |
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What's funny is that i had to drop low end boost a bit because my 7DCT was slipping under 4000rpm. As it is now, the car only runs 10-13psi under 3500rpm. Valvtronic is great.
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01-31-2011, 09:05 PM | #30 |
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Would the 6AT need the same boost drop?
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01-31-2011, 09:25 PM | #31 |
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01-31-2011, 09:45 PM | #32 |
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I have a feeling we can hit 450tq with race and meth. I need to order a meth kit...
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01-31-2011, 09:49 PM | #33 |
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01-31-2011, 10:02 PM | #34 |
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Let's do it! Lol
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02-01-2011, 09:12 AM | #35 |
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02-01-2011, 10:39 AM | #36 |
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thats a nice looking dyno!
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02-01-2011, 11:20 AM | #37 | |
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And if you look at the stock torque it does have the same dip. The dip seems to have been corrected in the tuned graph.
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02-01-2011, 11:23 AM | #38 |
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The dip is caused by boost control. It's an issue called "integral wind-up" that happens during a low rpm, high gear pull. During low engine speeds, the DME is unsuccessfully trying to reach the boost target. So the integral component of the pId system adds full positive correction. When boost target is finally achieved, the DME still has all this positive correction that it cant get rid of quickly enough. So boost overshoots for a moment. In the BMW, this causes a throttle closure and a big recovery dip. So nope, it has nothing to do with AFR, timing, etc,. Just boost control.
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02-01-2011, 11:26 AM | #39 | |
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I'm not saying you're wrong... it's just hard to believe... Are there any datalogs to support that? Edit: I'm sure you do. Can we see them? |
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02-01-2011, 11:29 AM | #40 |
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Integral (the "I" in PID) is the slowest moving correction of the 3. It's meant to make long-term offsetting changes to compensate for changes in operating conditions/hardware/etc,. It's not intended to catch spikes. That's the "D" or derivative gain. And yes, plenty of datalogs to show this.
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02-01-2011, 11:46 AM | #41 | |
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02-01-2011, 11:52 AM | #42 |
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02-01-2011, 11:56 AM | #43 |
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YOu said that sunday! lol
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02-01-2011, 01:28 PM | #44 | |
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If that is an obvious question/answer I apologize. Coming from my 2008 N54/MT 135 to the 2011 N55/DCT 135, I swear the new one feels faster stock...I think it may just be the way that the transmission shifts...
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