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09-23-2011, 10:30 PM | #1 |
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Cobb datalog and timing question
How do you interpret these timing drops? , and does everything in the log look ok or should i switch to a more conservative map?
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09-24-2011, 07:52 PM | #5 |
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Let me guess, an auto and you just peg the throttle and go. It's probably pulling timing during shifts to assist in the shift.
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2009 BMW 135i 6MT Sport, AFE intake, Cobb AP, Apex 18x8.5+9.5, 255/275 PSS
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09-24-2011, 08:29 PM | #6 |
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09-24-2011, 08:57 PM | #7 |
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Your not talking about the giant drops are you? Those look life shifts, RPM is helpful to have on the X axis for these.
I see 2 small corrections after the first shift. What map is this?
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08' 135i MT || Cobb Stage 1 'Aggressive' 4.01 Map | BMS DCI | Berk Mid Pipes | Maddad Eurosport Axleback | E93 FSB | M-Sport Black on Black | CDV Delete ||
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09-24-2011, 09:14 PM | #8 |
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Stg 1 91 v202 and I'm at about 5200 ft above sea level, if that makes a difference
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09-24-2011, 09:28 PM | #9 |
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Altitude def. has a large impact on the car, I'd really start by updating to 3.01 Sport map and log that and see if it changes before doing anything else.
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08' 135i MT || Cobb Stage 1 'Aggressive' 4.01 Map | BMS DCI | Berk Mid Pipes | Maddad Eurosport Axleback | E93 FSB | M-Sport Black on Black | CDV Delete ||
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09-24-2011, 09:43 PM | #10 |
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09-30-2011, 01:17 PM | #11 |
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If it froze during update you need to force abort the update, clear the rom off your AP and then force the update again. The same thing happened to me. There are detailed instructions on how to do that on the Cobb 3.01 beta thread
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09-30-2011, 05:03 PM | #13 |
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Well, throttle is probably staying open for the most part during shifts on an auto trans... That's what most auto cars do during shifts, gank timing. In DBW cars they could choose to close the throttle (like a human would with a manual trans). Looking at boost and TPS, I think they are not closing the throttle during shifts much and are instead yanking timing. You did not log both throttle and accelerator angle so its hard to tell, but you can see your TPS only dips slightly and very briefly on the shift. I can't tell if that was the human or the computer without seeing the throttle and accelerator both.
In a manual you don't just keep your foot to the floor when you press in the clutch to shift. Well, you can, but its rough on the car. You bounce off the rev limiter then burn the clutch, then the car gets pissed because the rear end tries to get loose shifting too hard. But I digress... I do see what are probably minor timing corrections in the middle of a gear there, two small dips on both graphs from about 4-5 degrees to 2-3 degrees, maybe 5500rpm? That is probably knock. The huge dips to -15 are just shifts. Knock is going to happen even on a conservative tune. It is not completely unavoidable. The ECU is doing its job and correcting. If it keeps happening you should eventually just see the ECU run less timing to begin with. I'd be very surprised to find out there wasn't a stored knock learning table in the ECU's memory. I'd only be concerned if it happens every time, or most of the time at that same spot, ~5500rpm at full throttle. If it does I'd try another brand of gas and maybe forward your logs onto Cobb. The other timing dip before the two knock corrections looks like traction control. I see the TPS drop from 100% to ~35%, timing drops very briefly from about 3 to -1, and there is a slight waver in boost. Again, hard to tell since you only show TPS and not also accelerator pedal position. Maybe you let off the gas... Even my 6MT with TCS completely off seems to cut power if I shift too hard at the drag strip into 4th gear. I went from 104.5mpg to 107.77mph between two runs on the same night by just not dumping the clutch so hard, so that's why I think that first event is E-diff or TCS or other interference.
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2009 BMW 135i 6MT Sport, AFE intake, Cobb AP, Apex 18x8.5+9.5, 255/275 PSS
Last edited by Freon; 09-30-2011 at 05:19 PM.. |
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