AutoVE nearly complete - observations and questions
11-01-2007, 07:12 AM
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AutoVE nearly complete - observations and questions Ok guys, I think I am nearly complete with my auto ve tuning. My last log had bens mostly in the 98-99 range, and a few cells with a bit more correction than that.
1. My main VE table is something on the order of 40% less in the idle region than stock, and my hot starts are not that great. For a hot/warm start I have to push the throttle to get it to start. If I compare the 800 rpm and 400 rpm cells of my main VE to the cranking VE table, the values differ significantly. I know I need to modify the table, but how it is usually done? If my 800 rpm column is off by say 40% approximately, do I scale the entire VE map by 40%, or do I use the 400,800,and 1200 rpm columns and scale each of the cranking VE map accordingly, and make the percentage scale linear between those three rpm points. For example, if on my main VE table if the values differ by 30% from stock a 400, and the values differ by 40% from stock at 800, and the values differ by 20% (I'm just throwing numbers out for an example). Then would I scale the cranking VE table at those rpms by those percentages, and then try to scale it linearly between, so between 400 and 800 it would get scaled by 35%, etc.
2. My next question is w/o usage of an eddy current dyno, and sitting at high rpm points and high load for extended periods of time, how do you map those cells? Thus far to get all the cells I have, I used a lot of brake pedal modulation to hold me in those rpm cells while I kept the throttle in one particular MAP cell. My brakes just arent' up to the task of holding back near WOT at high rpm areas.
3. When taking off from a stop, I often get some KR (up to 4 or 5 degrees sometimes). This occurs right after I let out the clutch, and start rolling. Once I hit ~1800-2000 rpms with the vehicle speed around 10-15 mph, it gets some KR. I've looked at the logs, and sometimes it looks lean compared to the command, and sometimes its not. I targeted those cells paricularly hard when I was doing my last round of auto VE, those were the cells that corresponded to BENs over 1.0. That range was between BENs of 1.03 and 1.07. I hope that takes care of it. If you'd like, take a look at my before and after tunes, and the logs that lead me to make those changes.
4. I often stall when the car comes down to idle, mostly when stationary, sometimes when coasting to a stop. When the car gets very close to a stop, then it wants to idle very rough, and sometimes it will save itself, sometimes not. I have played with the overspeed/underspeed timing corrections a bit, but not sure I have enough. Can someone with a trained eye take a look and see if maybe I'm just not going agressive enough. Also, I made some changes to the throttle cracker, based upon the idle tuning tutorial in the stickied in the tutorials section. I have not drove the car since those changes. I hope that helps.
5. There is a table in the Fuel->Mixture folder, B3609 called "PE Delay Counter Adjustment". Stock my table is all filled wiht ones. I looked at many of the modified tunes on holdencrazy and it looked like all the other tables were ones. Joecar suggested that I make that table all zeros. Does anyone else have experience with this? I'm unsure of how this table works with the single adjustment parameter B3608 called "Delay before Engering PE Mode"
6. There are areas in my main VE talbe that are over 100, sometimes up to hte 105 range. I know these number arne't truely a volumetric efficiency, but does this seem realistic?
I would very much appreciate any and all help on these questions and concerns.
I have attached several items. Two are tune files. The first one is the before tune, then I have several logs. One log is about an hour long and consists of highway driving at varying loads trying to be VERY smooth on the throttle as much as possible. Then there is a log where I wanted to target idle BENs, so I did that seperately. Then there is a log with a fewll WOT or near WOT pulls. I have also attached the tune file I applied changes to based upon those three logs.
My basic modifications are MS4 cam, dual 3.5" intake, LS6 manifold, 1 7/8" long tubes, dual 3" exhuast, M6 trans, in a 2800 lb FD RX-7.
I was unable to upload my hour long log for the VE tuning log. In case anyone wants to take a look I can email it to you. I'm near a computer 95% of the day, so I can email probalby within 5 minutes of you giving me your email address.
Thanks,
Kevin
1. My main VE table is something on the order of 40% less in the idle region than stock, and my hot starts are not that great. For a hot/warm start I have to push the throttle to get it to start. If I compare the 800 rpm and 400 rpm cells of my main VE to the cranking VE table, the values differ significantly. I know I need to modify the table, but how it is usually done? If my 800 rpm column is off by say 40% approximately, do I scale the entire VE map by 40%, or do I use the 400,800,and 1200 rpm columns and scale each of the cranking VE map accordingly, and make the percentage scale linear between those three rpm points. For example, if on my main VE table if the values differ by 30% from stock a 400, and the values differ by 40% from stock at 800, and the values differ by 20% (I'm just throwing numbers out for an example). Then would I scale the cranking VE table at those rpms by those percentages, and then try to scale it linearly between, so between 400 and 800 it would get scaled by 35%, etc.
2. My next question is w/o usage of an eddy current dyno, and sitting at high rpm points and high load for extended periods of time, how do you map those cells? Thus far to get all the cells I have, I used a lot of brake pedal modulation to hold me in those rpm cells while I kept the throttle in one particular MAP cell. My brakes just arent' up to the task of holding back near WOT at high rpm areas.
3. When taking off from a stop, I often get some KR (up to 4 or 5 degrees sometimes). This occurs right after I let out the clutch, and start rolling. Once I hit ~1800-2000 rpms with the vehicle speed around 10-15 mph, it gets some KR. I've looked at the logs, and sometimes it looks lean compared to the command, and sometimes its not. I targeted those cells paricularly hard when I was doing my last round of auto VE, those were the cells that corresponded to BENs over 1.0. That range was between BENs of 1.03 and 1.07. I hope that takes care of it. If you'd like, take a look at my before and after tunes, and the logs that lead me to make those changes.
4. I often stall when the car comes down to idle, mostly when stationary, sometimes when coasting to a stop. When the car gets very close to a stop, then it wants to idle very rough, and sometimes it will save itself, sometimes not. I have played with the overspeed/underspeed timing corrections a bit, but not sure I have enough. Can someone with a trained eye take a look and see if maybe I'm just not going agressive enough. Also, I made some changes to the throttle cracker, based upon the idle tuning tutorial in the stickied in the tutorials section. I have not drove the car since those changes. I hope that helps.
5. There is a table in the Fuel->Mixture folder, B3609 called "PE Delay Counter Adjustment". Stock my table is all filled wiht ones. I looked at many of the modified tunes on holdencrazy and it looked like all the other tables were ones. Joecar suggested that I make that table all zeros. Does anyone else have experience with this? I'm unsure of how this table works with the single adjustment parameter B3608 called "Delay before Engering PE Mode"
6. There are areas in my main VE talbe that are over 100, sometimes up to hte 105 range. I know these number arne't truely a volumetric efficiency, but does this seem realistic?
I would very much appreciate any and all help on these questions and concerns.
I have attached several items. Two are tune files. The first one is the before tune, then I have several logs. One log is about an hour long and consists of highway driving at varying loads trying to be VERY smooth on the throttle as much as possible. Then there is a log where I wanted to target idle BENs, so I did that seperately. Then there is a log with a fewll WOT or near WOT pulls. I have also attached the tune file I applied changes to based upon those three logs.
My basic modifications are MS4 cam, dual 3.5" intake, LS6 manifold, 1 7/8" long tubes, dual 3" exhuast, M6 trans, in a 2800 lb FD RX-7.
I was unable to upload my hour long log for the VE tuning log. In case anyone wants to take a look I can email it to you. I'm near a computer 95% of the day, so I can email probalby within 5 minutes of you giving me your email address.
Thanks,
Kevin
11-01-2007, 09:44 AM
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Another thing I noticed when looking at log_0053. At the beginning, right when I begin to move, it appears as if it enters PE mode, since the commanded AFR goes from 14.68 down into the 12-13s. I looked at the tune, and I don't understand. The MAP enable is set to 15 kPa, so thats alwasy met, but during that part of the log, the TPS is not above the threshold to enter PE mode. Why is it entering PE mode there. I want to have a better understanding of what is going on.
