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BMW 3-Series (E90 E92) Forum
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PROcede Boost vs. RPM Curves
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03-06-2009, 11:35 AM | #67 |
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It makes sense to me to lower/raise boost based on the engine dynamics going on across the rev range to make a smooth power delivery (but it's way over my head).
I'd like more info on where the boost choppiness comes from. Is it the tune? Free flowing mods (DCI, DPs, etc.). Is it normal to see this? |
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03-06-2009, 12:13 PM | #68 |
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Keep in mind that an evo dyno isn't apples to apples.
It's a small engine spinning a large turbo, it takes time ( and a few thousand rpm ) just to reach full boost. You can't presume that the evo torque curve starts low because it's desired that way (I had one, it's NOT desired. The car is seriously _DEAD_ below 4k rpm, a CRX will haul out faster than an evo below 4k rpm...). The 335 can do full boost very early. That is a really awesome feature that there is no need to dismiss. EDIT : dadasracecar << I misunderstood your post, I thought you said the evo curves were not flat [because of the large ramp at the start]. But now I see that this post is OT to yours, you were actually saying that they *are flat*. Mods << feel free to delete this post. -scheherazade |
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03-06-2009, 01:19 PM | #70 |
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1) the spike is indeed a throttle related spike. It can be confirmed be it not being shown on a boost gauge.
2) for being so vehement about things, you seem to ignore the fact that the other two logs are of a stg 1 map set to 80% and a stg 0 map set to 90%. The relative boost curves are spot on. Is there anything else you would like to complain about? Shiv |
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03-06-2009, 01:32 PM | #71 |
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shiv <<
So, how about that idea with the separately user adjustable boost targets per rpm range? (like low, mid, high, and/or some in between (interpolated)). You considered it at all? -scheherazade |
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03-06-2009, 01:40 PM | #73 |
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I for one do not want flat boost all over the RPm range, seems to my ignorant self that it would be undue and uncessary load on the engine internals.. I would much rather have a flat torque curve and predictable and smooth acceleration...
And also I could not care less about tuning the car myself.. How many of us actually have the knowledge and expertise to do that?? Shiv, this guy has an agenda to push another tune, it's obvious just ignore him and go put together my V3 !!! |
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03-06-2009, 01:40 PM | #74 | |
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03-06-2009, 03:34 PM | #76 |
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Hey dadasracecar - why not go over to the other place and argue with Terry and his crowd. They live by the feud. Of course they'll bitch-slap you silly, track down and hack into your websites, post pictures of your home and business along with your addresses and phone numbers. If you ever had a nude photo taken with a goat, they'll post that too. If not, they'll photochop one. Did I mention that they'll ban you and incessantly disparage your character.
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03-06-2009, 07:31 PM | #80 | |
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03-06-2009, 10:19 PM | #82 | |
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Sometimes truth IS stranger than fiction....lol. Nice one Lawdude. |
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03-07-2009, 02:09 AM | #85 |
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The lines look pretty squiggly, even on map 0. Is that a tuning problem or a measuring problem? Also that 16psi boost spike seems pretty scary. What did you do to cause that? Is it something that will be fixed in future maps?
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03-07-2009, 02:13 AM | #86 | |
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As far as the pressure oscillation goes, remember that the air is moving across the sensor and the pressure will naturally vary due to the pressure waves, boundary layer, turbulence, and flow separation -- so it will never be a constant static pressure. You can also see the oscillation in the stock datalog. |
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03-07-2009, 08:20 AM | #87 | |
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There is definitely a throttle closure around 4000 rpm as evidenced by this BT datalog I did of actual boost versus target boost. You can see that when boost overshot the target, the throttle plate closed (look at the dip on the red line) momentarily to correct it. Also shows that the Procede does allow the ECU to intervene when necessary and did not compromise this safety feature. The boost values are in kilopascals, not psi, and full throttle has been scaled to show as 100%. |
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03-07-2009, 08:35 AM | #88 | |
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Slower sampling rate graphs will tend to look smoother since they miss caputuring as many data points and extrapolate linearly between them. The time stamps on my BT logs are about 0.03 seconds apart.....that's 3/100 of a second or about 33 samples per second if I am reading things correctly. Very fast. |
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boost, datalog, procede |
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