Actual vs. requested boost on new tune, questions

[dennej1985]

Finally got around to running a few logs on both the integrated engineering logger and vcds logger after installing my tune. I'm seeing about a 2-3 (calculated) psi difference between actual and requested boost pressure. For example at 6000 rpm it's requesting 19.5 psi and it's getting 17.6. I'm new to tuning and want to know how far off that really is and if it's out of range where I should start looking. Leaking or mis-adjusted wastegate? I have to wait until I get to work in a bit but I will try to graph and post at least the VCDS log in excel.

[red4life5]

I have the same exact thing on the tune. First is requesting 22 and I’m seeing 16-18 depending on the day and can’t figure it out


2010 A4 S-Line Prestige

[dennej1985]

Here is a chart and the actual log on google drive in a pdf.....anyone have suggestions? another item to log? I logged mass air and timing here but obviously the resolution on the chart is best just for the actual vs requested boost. I live at 7000 feet if that helps, ambient pressure was 79hpa. Could the requested vs. actual discrepancy be due to the atmospheric pressure?

https://drive.google.com/file/d/1YvT...ew?usp=sharing

https://drive.google.com/file/d/1Y3y...ew?usp=sharing

[Perry01]

You should log a wide open throttle pull in 3rd gear from 2000 RPM to redline and include engine speed (RPM) as one of the parameters. At sea level on my IE Stage 1 and Stage 2 tunes, I was exceeding requested boost in the midrange but not above 4500 RPM. The stock turbo just can’t push enough air up top.

This is and old Stage 2 log showing requested and actual boost in PSI at 3200 RPM:



And 4550 RPM:



And 6200 RPM:

[dennej1985]

Thanks for posting those. I will log again tomorrow if I can. The nearest highway is four hours away and the top of 3rd is pretty irresponsible on the roads I have available, thus the shortened runs posted. Is there a reason everyone logs in third and not in second? Also, how did you make your graphs? My method was kinda cumbersome. P


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[Perry01]

Thanks for posting those. I will log again tomorrow if I can. The nearest highway is four hours away and the top of 3rd is pretty irresponsible on the roads I have available, thus the shortened runs posted. Is there a reason everyone logs in third and not in second? Also, how did you make your graphs? My method was kinda cumbersome. P

I have an 8 speed auto so 3rd gear doesn’t go too fast. You need to put load on the engine to see boost build up. 2nd gear won’t do this.

Make the graphs in Excel. Highlight the columns you want and insert line chart.

[bhvrdr]

Finally got around to running a few logs on both the integrated engineering logger and vcds logger after installing my tune. I'm seeing about a 2-3 (calculated) psi difference between actual and requested boost pressure. For example at 6000 rpm it's requesting 19.5 psi and it's getting 17.6. I'm new to tuning and want to know how far off that really is and if it's out of range where I should start looking. Leaking or mis-adjusted wastegate? I have to wait until I get to work in a bit but I will try to graph and post at least the VCDS log in excel.

What turbo?

[dennej1985]

Yeah, with the six speed I’m at or over 100 at the top of 3rd with the raised limiter.

It’s a stock k03. Runs really well but this boost discrepancy explains the slightly sluggish feeling I notice from time to time. I have a few other logs where the issue is not so pronounced. I was reading up in some of the wastegate adjustment threads and higher mileage k03’s seem to commonly have this issue. I came across the helper spring mod and may try that and log over the weekend to see if it has any effect.


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[bb-tt]

I am having same issue with my car. Fixed some boost leaks and logs look closer to Perry's now. Was leaking on one of the charge pipe connections and at the map sensor at that time couldn't get over 16 psi now exceed demand initially then quickly fall below demand. Need to go do some more logging but next thing I think I need to check is wastegate. Also thinking about max's external spring mod ( https://forums.vwvortex.com/showthre...tor-Spring-Mod ) did that on tt and worked well but think it will be more difficult to do on the Avant. IE suggested looking for leaks, intake clogged, exhaust clogged, faulty manifold flaps, carbon cleaning, or bad turbo as possible causes for not meeting demand. I guess it is possible that I have a bad map sensor also. I would hope the turbo would not be bad at 66 k miles, and know my intake and exhaust are not clogged. thought I had it solved when I fixed the boost leaks but sadly no! I am open to any suggestions of other possible causes, not looking forward to dropping test pipe to check waste gate.

[dennej1985]

I will be checking for boost leaks when I install the ECS intercooler kit that’s in the mail. I wish I had done some logs before the tune so I could see if the car was meeting requested boost at lower pressure levels. I ordered some springs from amazon to try that as well. Will post results and logs when I get around to these items.


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[old guy]

I don't know what I can add to this discussion other than an observation on your MAF log. The highest flow I see that you recorded was 170 g/s. I routinely see 165 g/s with a completely stock engine. Would altitude make that much of a difference? Your are at 7,000 and I am at 540.

When I run my piggyback module (Neuspeed) at the +8 setting I typically see 210 g/s. In colder weather up to 219 g/s.

[dennej1985]

I don't know what I can add to this discussion other than an observation on your MAF log. The highest flow I see that you recorded was 170 g/s. I routinely see 165 g/s with a completely stock engine. Would altitude make that much of a difference? Your are at 7,000 and I am at 540.

When I run my piggyback module (Neuspeed) at the +8 setting I typically see 210 g/s. In colder weather up to 219 g/s.

This is something I’m wondering about. With how linear the actual vs requested boost curves are on the graph I feel like maybe nothing is wrong here, I’m just compressing thin, high altitude air and that poor little k03 just can’t meet requested numbers. I haven’t been able to find much specific or accurate info on this. Altitude’s effect on turbocharged engine output is not as well sorted as that of n/a engines. I have seen a 1% power loss per 1000ft of elevation number a few places but it would be helpful to know exactly how that’s calculated. I mean the turbo is trying to compress less oxygen with the same flow so certainly there will be reduced efficiency involved. I will also run a mass air to engine speed log separately once the intercooler and charge pipes are installed.


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[Perry01]

Yes,

Higher altitude = lower MAF values. At sea level I see in excess of 300 g/s

[JLAllroad]

Would be nice to see what the N75 duty cycle is


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[A4x]

Stage 2 MAF values are around 220 g/s on 93 octane.

K04 should be 280-300 g/s.

[JWebb_C7_Comp]

Not to hijack....... but, what do you all use to log?

I thought about getting the VCDS Hex device and using a Samsung tablet to log. But the device does not have data(Bluetooth and WiFi only).




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[dennej1985]

I have a VCDS cable and log on vag com just because there are so many options for logging. The integrated engineering program you run with their flash cable also has a log function that I like but it’s not customizable so not as versatile.


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[JWebb_C7_Comp]

I have a VCDS cable and log on vag com just because there are so many options for logging. The integrated engineering program you run with their flash cable also has a log function that I like but it’s not customizable so not as versatile.


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Thanks. So, you use VCDS cable and Windows PC (or Mac w/windows)..




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[dennej1985]

Yeah. Windows pc. I saved the vcds log, which is a csv file as an excel xls file, selected the info and graphed it in excel.


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[JWebb_C7_Comp]

Yeah. Windows pc. I saved the vcds log, which is a csv file as an excel xls file, selected the info and graphed it in excel.


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Thanks for the reply; I truly appreciate your experience!


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[old guy]

VCDS is good for logging, but I find it a bit cumbersome since I have to use my laptop while driving. If you just want a quick reading on a particular parameter, TorquePro also works really well. For example, you can monitor your MAF g/s in real time and set the monitor to record the highest reading. You can also it to log specific parameters. Incredible amount of info for a $5 app.

[dennej1985]

VCDS is good for logging, but I find it a bit cumbersome since I have to use my laptop while driving. If you just want a quick reading on a particular parameter, TorquePro also works really well. For example, you can monitor your MAF g/s in real time and set the monitor to record the highest reading. You can also it to log specific parameters. Incredible amount of info for a $5 app.

I’m getting that for sure. Thanks.


Check that....android only


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[JWebb_C7_Comp]

VCDS is good for logging, but I find it a bit cumbersome since I have to use my laptop while driving. If you just want a quick reading on a particular parameter, TorquePro also works really well. For example, you can monitor your MAF g/s in real time and set the monitor to record the highest reading. You can also it to log specific parameters. Incredible amount of info for a $5 app.

I ordered the Carista Bluetooth adapter and I plan to try Torque, OBD Fusion and/or Dash Command for logging.. I may also try some customization..




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[dennej1985]

I have the dash command app. I wasn’t aware one could log with it. Do you need a certain adaptor? I have a cheap one that works via Bluetooth I bought on amazon.


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[JWebb_C7_Comp]

I have the dash command app. I wasn’t aware one could log with it. Do you need a certain adaptor? I have a cheap one that works via Bluetooth I bought on amazon.


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I don’t know; don’t have my adaptor or the application yet, the website for DashCommand says:

“Data logging is also supported in DashCommand. You can record logs from a dashboard or a data grid view and then playback your logs in either view for simple analysis tasks. The logs can also be viewed in ScanXL from more thorough analysis.”


Check out the manual at Palmerperformance.com.. it looks like you start by going into the Data Grid.



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[dennej1985]

What is the name of the N75 in the VCDS menu for logging? In searches it's always "block 144 or 118" but what is it called in the check box VCDS list?

[old guy]

Does this help? Clicky click®

[dennej1985]

No, their list is just number addresses. If i type the number it's supposed to be (114-4) into the advanced measuring blocks search bar it doesn't bring up anything close. 114 has 3 options: Tank leak: status-Test, Result of o2 sensor aging test and air conditioner fan activation. And 118 brings up nothing.

[JLAllroad]

No, their list is just number addresses. If i type the number it's supposed to be (114-4) into the advanced measuring blocks search bar it doesn't bring up anything close. 114 has 3 options: Tank leak: status-Test, Result of o2 sensor aging test and air conditioner fan activation. And 118 brings up nothing.

Here are some of the parameters I started with. , not all at once. Note, ignition was on but engine was not running. In this state the charge pressure actual gives you barometric pressure, this will correlate with the grid.

1 hPa = 0.0145037738 psi
1 psi = 68.9475729318 hPa

In this version of VAGCOM I believe the second from the last parameter is the N75 duty cycle.


IMG_5769.JPG Image1534531454.247308.jpg



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[dennej1985]

I think I may have found it based on description and values after logging. Does charge spec cntrl spec value sound right? it's IDE 01900 in the log parameters search box. This was a percentage cycling between 1.6% and 92.6% during a couple of quick logs.

[dennej1985]

Thanks for posting I was out logging that parameter when you replied. After going through the whole list I figured it's gotta be that one.

[JLAllroad]

Thanks for posting I was out logging that parameter when you replied. After going through the whole list I figured it's gotta be that one.

I’ve been logging and sorting through the same as you. I’m APR stg2, 034 HFC, ECS intercooler and hardpipes, Bosch coils, NGK BKR8EIX # 2668, AFE dry filter, and ECS tip.

At 5k ft in Denver on 91oct, 300-800 hPa off spec with N75 duty at 77% at 6000rpm. Would think the duty cycle would be higher when not hitting spec.


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[Perry01]

What is the name of the N75 in the VCDS menu for logging? In searches it's always "block 144 or 118" but what is it called in the check box VCDS list?

On the B8.5 it is labeled:

Charge press. ctrl.: spec. value

[Perry01]

Here are some of the parameters I started with. , not all at once. Note, ignition was on but engine was not running. In this state the charge pressure actual gives you barometric pressure, this will correlate with the grid.

1 hPa = 0.0145037738 psi
1 psi = 68.9475729318 hPa

I convert boost pressure from hPa to PSI by dividing boost in hPa by 68.95 then subtract barometric pressure (14.7 at seal level).

[dennej1985]

New log with graph. This is only a couple of WOT first and second gear pulls, couldn't get out to the other roads today. This is after the intercooler install and upgrade from IE stage 1 to IE stage 2. This looks very different to me, huge requested spikes not being met at first. Is this all due to not testing load properly? Logged the n75 as well. The second file didn't upload totally right but the numbers are there if you want to look, the first file is the graph.

https://drive.google.com/open?id=1_9...3D5IVNDhMtjNfo

https://drive.google.com/open?id=1ms...1hIiR7JrCcihfP

[Perry01]

You need to allow your turbo spool up. Logging data in 1st or 2nd gear is not worth the time. Start off in 3rd gear at 1,500 RPM. Click the start tab and give it wide open throttle. Let off the throttle at or above 6,000 RPM and end the log. Create a chart and post the results.

I’ve been to Wyoming. You don’t have to travel far to find a nice stretch of open road :-)

[dennej1985]

You need to allow your turbo spool up. Logging data in 1st or 2nd gear is not worth the time. Start off in 3rd gear at 1,500 RPM. Click the start tab and give it wide open throttle. Let off the throttle at or above 6,000 RPM and end the log. Create a chart and post the results.

I’ve been to Wyoming. You don’t have to travel far to find a nice stretch of open road :-)

Lol. There are plenty of open roads but I am actually more than an hour away from any road over 55. I live in grand teton Park. I was just excited to pop the new parts on and test and didnt have time to get outside the park before work. I should be able to at least get out and do a log after my early shift tomorrow.


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[bb-tt]

So took the down pipe off today and confirmed what a few other posts have said, bad waste gate. Funny cause didn't have any play in the actuator arm but once i could actually grab waste gate it was loose and not seating properly. Had i figured it out in April could have got the replaced under the extended turbo warranty 7 years 70k miles, may go talk to dealer and see if they will play ball since they did engine rebuild for oil consumption earlier this year. If not i am going ko4 just have to decide jhm, cts, or other.

[Nano909]

So took the down pipe off today and confirmed what a few other posts have said, bad waste gate. Funny cause didn't have any play in the actuator arm but once i could actually grab waste gate it was loose and seating properly. Had i figured it out in April could have got the replaced under the extended turbo warranty 7 years 70k miles, may go talk to dealer and see if they will play ball since they did engine rebuild for oil consumption earlier this year. If not i am going ko4 just have to decide jhm, cts, or other.

You have to go in with the CEL on with the code P0299. They won't bother to check and will send you home and tell you to come back when the CEL with the code is on.

[A4x]

You have to go in with the CEL on with the code P0299. They won't bother to check and will send you home and tell you to come back when the CEL with the code is on.

I didn't have a CEL and they replaced my turbo under the extended warranty. All I had was a loud wastegate and that was enough. The Service Adviser was like "yup, we know all about that problem. Here's your new turbo..."