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Old 11-01-2011, 09:42 AM   #26
cianuro
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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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Old 11-01-2011, 10:27 AM   #27
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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...
The log permissions are not set to public, so I'm not able to view it.

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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Old 11-01-2011, 10:55 AM   #28
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The log permissions are not set to public, so I'm not able to view it.

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
Sorry about that. Try it now.

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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Old 11-01-2011, 03:40 PM   #29
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Sorry about that. Try it now.

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.
If you real-time tune a table and then you reflash a map, reset the ECU, or disconnect the car's battery, the real-time tables will be reset to whatever the values of those tables are in the reflashed map. Other than that, the MAF calibration is static (except for the application of the MAF comp and load comp tables).

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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Old 11-01-2011, 03:57 PM   #30
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If you real-time tune a table and then you reflash a map, reset the ECU, or disconnect the car's battery, the real-time tables will be reset to whatever the values of those tables are in the reflashed map. Other than that, the MAF calibration is static (except for the application of the MAF comp and load comp tables).

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
So flashing the changes, then resetting after the code brought my tables back to normal? I didn't quite get that until now. I thought that changes made in real time had to be flashed for the ECU to keep them. So, by this you're saying that I need to make the changes, save the map, transfer it to the AP via the manager, then reflash using the AP. Is that correct?

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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Old 11-01-2011, 06:05 PM   #31
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So flashing the changes, then resetting after the code brought my tables back to normal? I didn't quite get that until now. I thought that changes made in real time had to be flashed for the ECU to keep them. So, by this you're saying that I need to make the changes, save the map, transfer it to the AP via the manager, then reflash using the AP. Is that correct?

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
I'm just saying how the real-time table values can be reset to the reflashed map if you reset the ecu, reflash a map, or disconnect the car's battery. So, before any of those operations are completed, you want to save your real-time tune and reflash it to the ECU, otherwise you will lose them (if you never saved it to a map). Also, if you open another map while live connected to the ECU, those values in that map will be uploaded to real-time.

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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Old 11-01-2011, 06:23 PM   #32
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I'm just saying how the real-time table values can be reset to the reflashed map if you reset the ecu, reflash a map, or disconnect the car's battery. So, before any of those operations are completed, you want to save your real-time tune and reflash it to the ECU, otherwise you will lose them (if you never saved it to a map). Also, if you open another map while live connected to the ECU, those values in that map will be uploaded to real-time.

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
I'm seeing some boost spikes at lines 1638, 1668 and 1947 in the time column. They're just spikes that last for a fraction of a second, but one of those spikes happened when I got the code, I just don't know which one exactly.

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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Old 11-02-2011, 10:07 AM   #33
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I'm seeing some boost spikes at lines 1638, 1668 and 1947 in the time column. They're just spikes that last for a fraction of a second, but one of those spikes happened when I got the code, I just don't know which one exactly.

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?
Boost peaking and then tapering towards redline is the normal behavior. I would start with the LWG map.

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Old 11-02-2011, 12:31 PM   #34
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Boost peaking and then tapering towards redline is the normal behavior. I would start with the LWG map.

Bill
I did the MAF calibration from the datasheet to the LWG map. It turned out to be lean (13.2-12.8), so we played around with that until we got it reading from 11.6-11.4 at the wb. No more lagging and it feels steady throughout the whole rpm range, so fueling problem solved.

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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Old 11-03-2011, 10:12 AM   #35
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I did the MAF calibration from the datasheet to the LWG map. It turned out to be lean (13.2-12.8), so we played around with that until we got it reading from 11.6-11.4 at the wb. No more lagging and it feels steady throughout the whole rpm range, so fueling problem solved.

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?
Yes, even if you could run full boost to redline with this turbo/motor, you would be outside the turbo's efficient range. This why the boost target tapers to redline. Of course, if you are doing you are own tuning, you can attempt to run a little more boost to redline, as long as you have a means of monitoring power gains and make sure there's no knock as a result. It is going to become a case of diminishing returns past a certain point, however.

Bill
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Old 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.
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Old 11-04-2011, 09:48 AM   #37
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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.
Boost control can be a pain to dial in, but your best bet is to verify that it is not boost creep. With boost creep, you will not be able to tune around it. If it appears to only occur when it is cold out, then you can use the wastegate compensation intake temp table to reduce the compensation at colder intake temps. This will be applied to both your initial and max wastegate tables. You could also use the table to reduce wgdc across the board at all temps, at least as a test to see if you can mitigate the overboost concern (and if you find it still occurs at warmer outside temps).

Bill
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Old 11-04-2011, 10:06 AM   #38
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Originally Posted by Cobb Tuning
Boost control can be a pain to dial in, but your best bet is to verify that it is not boost creep. With boost creep, you will not be able to tune around it. If it appears to only occur when it is cold out, then you can use the wastegate compensation intake temp table to reduce the compensation at colder intake temps. This will be applied to both your initial and max wastegate tables. You could also use the table to reduce wgdc across the board at all temps, at least as a test to see if you can mitigate the overboost concern (and if you find it still occurs at warmer outside temps).

Bill
What I meant by cold was that maybe the car wasn't at normal operating temp yet when I did the pull.

How do I verify it's not boost creep? Datalog? What will tell me it is actually boost creep?
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Old 11-04-2011, 10:12 AM   #39
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What I meant by cold was that maybe the car wasn't at normal operating temp yet when I did the pull.

How do I verify it's not boost creep? Datalog? What will tell me it is actually boost creep?
You'll now it's boost creep if a signficant reduction in wastegate duty does not prevent the overboost.

Bill
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Old 11-04-2011, 10:40 AM   #40
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You'll now it's boost creep if a signficant reduction in wastegate duty does not prevent the overboost.

Bill
What would be a significant reduction? Doesn't the LWG map already do that? Would I be reaching my boost targets still if I reduce the wgdc's?
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Old 11-04-2011, 11:10 AM   #41
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What would be a significant reduction? Doesn't the LWG map already do that? Would I be reaching my boost targets still if I reduce the wgdc's?
When it comes to boost control, there's a lot of car-to-car variation, which is why we have LWG, NWG, and HWG maps. So, really, it just depends on your car whether or not you'll be able to tune out the overboost with a catless exhaust.

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).

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Old 11-04-2011, 11:58 AM   #42
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When it comes to boost control, there's a lot of car-to-car variation, which is why we have LWG, NWG, and HWG maps. So, really, it just depends on your car whether or not you'll be able to tune out the overboost with a catless exhaust.

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
Which table, high or low wgdc?

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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Old 11-04-2011, 01:02 PM   #43
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Which table, high or low wgdc?

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.
The easiest way to do a temporary test would be to just do it via one of the wastegate comp tables (for example the coolant temp comp), which would be applied to both the low and high wgdc tables by the ECU. Otherwise, if trying to tune it out, you would start with the low and high wgdc tables and generally try to keep the same spread between the two. The low table is what the ECU starts out at for wgdc and the turbo dynamics integral and proportional corrections are added to that, but limited to the high wgdc values. The low and high wgdc values are the table values with the wg compensations applied.

Putting in the stock cat midpipe should introduce enough backpressure to avoid boost creep (if that is your issue).

Bill
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Old 11-04-2011, 01:38 PM   #44
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The easiest way to do a temporary test would be to just do it via one of the wastegate comp tables (for example the coolant temp comp), which would be applied to both the low and high wgdc tables by the ECU. Otherwise, if trying to tune it out, you would start with the low and high wgdc tables and generally try to keep the same spread between the two. The low table is what the ECU starts out at for wgdc and the turbo dynamics integral and proportional corrections are added to that, but limited to the high wgdc values. The low and high wgdc values are the table values with the wg compensations applied.

Putting in the stock cat midpipe should introduce enough backpressure to avoid boost creep (if that is your issue).

Bill
Ok. I'll start with the tables. It'll be a couple more days before I can test again, so I'll report back soon.
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Old 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.
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Old 11-06-2011, 08:00 AM   #46
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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.
That table is there to prevent a dangerous overboost condition by enabling a fuel cut when boost exceeds a specific threshold. It is what causes the P0244 code to be set, but it is there to protect you, not as a problem in and of itself. Our stage 2 maps have the max boost limit for your car set to 17.6 psig and the max boost target is 16 psig. 18.75 psig is almost 3 psi above your boost target. You can play with the boost limit a little, but I wouldn't raise it so high just to overcome the CEL being set - I would try to work on the problem that is causing that overboost. You may just want to swap in the catted mid pipe as a test and see what happens.

Bill
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Old 11-06-2011, 11:11 AM   #47
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Vehicle:
2008 WRX
Silver

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Quote:
Originally Posted by Cobb Tuning
That table is there to prevent a dangerous overboost condition by enabling a fuel cut when boost exceeds a specific threshold. It is what causes the P0244 code to be set, but it is there to protect you, not as a problem in and of itself. Our stage 2 maps have the max boost limit for your car set to 17.6 psig and the max boost target is 16 psig. 18.75 psig is almost 3 psi above your boost target. You can play with the boost limit a little, but I wouldn't raise it so high just to overcome the CEL being set - I would try to work on the problem that is causing that overboost. You may just want to swap in the catted mid pipe as a test and see what happens.

Bill
The stock mapping shows a 4 psi treshold for this code to be triggered. Since my peaks are only about 0.15 psi over the OTS map treshold, I don't think a 1 psi difference in this table will break my engine. I know from the logs I'm not even reaching 18 psi, and Puerto Rico doesn't have that much of a change when it comes to weather or altitude. Like I said, I'll continue testing. I know I'm not boost creeping, just overboosting at a peak.

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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Old 11-06-2011, 12:44 PM   #48
Cobb Tuning
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Originally Posted by cianuro View Post
The stock mapping shows a 4 psi treshold for this code to be triggered. Since my peaks are only about 0.15 psi over the OTS map treshold, I don't think a 1 psi difference in this table will break my engine. I know from the logs I'm not even reaching 18 psi, and Puerto Rico doesn't have that much of a change when it comes to weather or altitude. Like I said, I'll continue testing. I know I'm not boost creeping, just overboosting at a peak.

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.
I don't see a problem with tweaking it upwards a little from the OTS maps, but you had mentioned before that you hit 18.75 psig at one point. Just trying to make it clear that I wouldn't use raise the boost limit table to eliminate fuel cut because of a 3+ psi overboost. Maybe you aren't seeing that any more, so it might not apply. But, ideally, you would try to determine the cause of that overboost and fix it.

Bill
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Old 11-06-2011, 04:08 PM   #49
cianuro
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Member#: 235475
Join Date: Jan 2010
Chapter/Region: PRSIC
Location: Puerto Rico
Vehicle:
2008 WRX
Silver

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Quote:
Originally Posted by Cobb Tuning
I don't see a problem with tweaking it upwards a little from the OTS maps, but you had mentioned before that you hit 18.75 psig at one point. Just trying to make it clear that I wouldn't use raise the boost limit table to eliminate fuel cut because of a 3+ psi overboost. Maybe you aren't seeing that any more, so it might not apply. But, ideally, you would try to determine the cause of that overboost and fix it.

Bill
Yeah, sorry about that... That 18.5 was at the gauge which is about 1-2 psi off from what the AP live data monitor reads. I decided to trust the AP and I'll be ordering a new gauge sensor this week.

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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Old 11-09-2011, 07:51 PM   #50
cianuro
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Chapter/Region: PRSIC
Location: Puerto Rico
Vehicle:
2008 WRX
Silver

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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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