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11-01-2011, 09:42 AM | #26 |
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^^^^^About that post^^^^^
I took out the K&N last night and did a rough measuring (only had a tape measure) of the MAF housing and it gave me 2-5/8" (66.675mm). I also measured the stock airbox MAF housing and I got 2-7/8" (73.025mm), a ~7mm difference between the two with the stock being bigger. I used the intake calibration datasheet and applied the values to the map and the curve went down close to what we did during the live tuning yesterday, with the difference that my curve wasn't as perfect. I guess I'm on the right track. I still need to fix my curve, so I'll probably do some more live tuning and maybe start over so I can do things right this time. Here's my datalog: https://docs.google.com/spreadsheet/...hl=en_US#gid=0 Sorry about it being so long...
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11-01-2011, 10:27 AM | #27 | |
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The difference in the cross-sectional area of the two intakes is only one consideration. A different intake can flow differently at different MAFv due to its design. So, for example, two different aftermarket intakes that are 65mm are not going to have the same MAF calibration. So, the next step is to continue tweaking it until your fueling is good. Bill |
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11-01-2011, 10:55 AM | #28 | |
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My MAF wasn't reaching over 4.02 volts, so we will doing the tweaking there. I'll still use the datasheet calibration to start from there and see where that takes me. Is it possible for the ecu to have changed that calibration? I've been comparing the calibrations within the Cobb branded Stage 2 map, and the one we did the live tuning with, and there's a notable difference in the curve, with mine being higher. |
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11-01-2011, 03:40 PM | #29 | |
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Your log shows that you are running pretty rich and still have a good amount of MAF tuning to do (at least in closed loop - we can't tell from the log what is going on in open loop). When you get to certain points where you've improved the MAF calibration, reflash the map with those changes. That will reset the ECU (and therefore the long-term fuel trims). Bill |
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11-01-2011, 03:57 PM | #30 | |
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Something I just noticed today. I had loaded the Stage 2+, not the Stage 2 as I thought. I don't know what was it, maybe I read it wrong, or press the scroll button along with the OK and didn't even notice. I flashed the correct stage 2 map this morning and the difference from what I had is noticeable. I didn't have a wb today, but I'll do tomorrow. As for today, I got the P0244 code again at 4th gear at about 4500 rpm, but I was datalogging this time. What I can tell you is that I'm overboosting. I didn't have a problem in 1st, 2nd or 3rd, just 4th gear. Here's the datalog (and this time it's already set to public): https://docs.google.com/spreadsheet/...hl=en_US#gid=0 |
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11-01-2011, 06:05 PM | #31 | |
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What line does your overboost start? It is difficult to scroll through large logs on google docs. You can try the LWG map, but sometimes with catless exhaust you run into boost creep which cannot be tuned around. Bill |
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11-01-2011, 06:23 PM | #32 | |
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I don't see my boost going up with rpm. My boost gauge is off by about 1-2 psi, but it never goes up with revs. It goes up, stays there for a couple of seconds, then tapers down. Also, after I got the code, I did another pull in 4th without resetting the code, and it behaved normally. I'll take a look at my duty cycles tomorrow via live tracing. Do you have any pointers as in what to look for when tuning the duty cycles? Or should I just flash the LWG map to start with? |
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11-02-2011, 10:07 AM | #33 | |
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Bill |
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11-02-2011, 12:31 PM | #34 | |
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After we got the fueling where we wanted it, I started doing pulls in 4th gear under the same conditions as yesterday to check if the LWG map helped, and apparently it did. No more boost cut, no more P0244 code. I did several pulls on 4th from 2500 to 5000 rpm and there were no problems. The boost spiked at about 16.5, then tapered down as it is supposed to. I did some 5th gear pulls from 2500 rpm, but it was too much speed for the amount of traffic, so I could never get it past 4000 rpm. Still, no problems there. Now, another question... My friend, the guy who's doing the tuning, is asking me to ask you why the boost targets drop down so quick? As in, why doesn't the boost stay at its peak throughout a larger rpm range? I don't know if you understand what I'm asking... I told him that I thought it was because of the working range of the turbo, that it couldn't be pushed any longer because of how this particular turbo might behave. Can you shed any light on this? |
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11-03-2011, 10:12 AM | #35 | |
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Bill |
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11-03-2011, 11:13 PM | #36 |
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P0244 code again...
This time I saw it peak at about 18.5psi, but it went back to 16 and started tapering down as normal. Got the code while the boost was tapering down. It was a peak at WOT. It didn't increase with revs up to 18.5, it just peaked there right when I punched the pedal, then back to 16 and tapering down as the revs increased. Should I look at my duty cycles? Modify them? How do I go about doing this? Is there a guide? Should I go Stage1 which has less boost and see if I get the same behavior? Or should I get an external EBCS to try and correct the boost peaking problem? Are the duty cycles different from stage1 to stage2 (noob question I guess)? Should I just remove the downpipe? I have a nameless/catless bellmouth design, but from what I've read this shouldn't make a difference. I see and read about many people running ok with just the downpipe and stock catback, so I don't see why I should, but I ask anyway. My fuel is ok, and I don't see boost creep behavior, so I don't know what else to do. It only happens at 4th gear, and only when my tuner is not present. Could it be that I was running too cold? I was coming home from work, it was about to start raining, but I let it get to normal operating temp before driving it. |
11-04-2011, 09:48 AM | #37 | |
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Bill |
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11-04-2011, 10:06 AM | #38 | |
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How do I verify it's not boost creep? Datalog? What will tell me it is actually boost creep? |
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11-04-2011, 10:12 AM | #39 | |
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Bill |
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11-04-2011, 10:40 AM | #40 | |
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11-04-2011, 11:10 AM | #41 | |
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As a test, try pulling 20% from one of the wategate comp. tables and see if you still end up overboosting. If you don't, then you know that you can at least tune around the issue. If you do, then you'll need to switch to a catted downpipe (or avoid going WOT in higher gears). Bill |
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11-04-2011, 11:58 AM | #42 | |
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My dp comes in 2 sections, so I can reinstall the second cat section of the pipe. Would you recommend I do that? The "not going WOT in high gears" was already in my mind. I did the pulls to confirm the issue was gone since it didn't happen when I tuned the last time. I did plenty of 4th and 5th gear pulls and it didn't happen. I got home, reflashed the tuned map as instructed earlier and the DAM was at 1.0 before I got the code. |
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11-04-2011, 01:02 PM | #43 | |
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Putting in the stock cat midpipe should introduce enough backpressure to avoid boost creep (if that is your issue). Bill |
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11-04-2011, 01:38 PM | #44 | |
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11-05-2011, 11:06 PM | #45 |
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Started doing some research on the P0244 code and found an interesting thread on which I believe you solved the problem I'm having: http://www.iwsti.com/forums/cobb-str...alculated.html
My friend, the tuner, went browsing through ATR (I gave him my copy) and found the "boost limit fuel cut table". Since he only had the base mapping, he told me to check the value I had on this table. The boost target for my map is 16psi, and my boost limit fuel cut was set at 17psi. My tuner told me that it was set too close, and my datalogs showed peaks of ~17.75 at the most. I increased this value to 18.75psi and flashed the ECU from the AP with the same map I already had, but with the increase on that value. The car started at the first crank, not like previous flashes where it took cranking it twice. The DAM reached 1.0 after 10 minutes of driving. I performed a pull from 3rd through 4th gear (scary), saw the boost gauge peak at about 17.5psi and didn't get the code. I also saw there's a counter for this code to come up, so I'll continue testing to confirm. |
11-06-2011, 08:00 AM | #46 | |
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Bill |
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11-06-2011, 11:11 AM | #47 | |
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I did some pulls with my tuner's MS3 this morning when we got off work and had no issues. I haven't seen it peak again, but since there's a counter for this code, I'll keep testing it to see where it takes me. |
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11-06-2011, 12:44 PM | #48 | |
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Bill |
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11-06-2011, 04:08 PM | #49 | |
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One of the pulls I did this morning was to 115mph this morning (the roads were empty since it was 6am sunday morning) and the boost control performed perfectly. I still need to try to force the condition, as in going WOT from 4500rpm to see if I still get the code. I'll let you know. |
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11-09-2011, 07:51 PM | #50 |
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No code yet since last time...
Did a datalog, and basically got the same results out of 3 4th gear pulls from low rpms, no boost peaks over 17.5 and no code either. I plotted everything against time so I could look at the rpms vs boost in an increasing manner. My tuner says I need to tweak the wgdc a little, but shouldn't be too much. |
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