|
Title: How hard should you push your k03? Post by: turdburglar44 on October 10, 2014, 11:27:10 AM I feel like this is a very common question and wanted to share how I decide how much boost is 'safe' on a me7.5 1.8t. Not only on the k03 but any turbo.
I found a k03 compressor map and graphed rpm across it. Assuming 90% volumetric efficiency across the board. (Haven't bothered to find real values) (http://s24.postimg.org/ott8csxn5/New_Doc_5_1.jpg) (http://postimg.org/image/ott8csxn5/) Note that after 5k rpm you are off of the compressor map. This means that the turbo is using the majority of its power to create heat rather than move air. From there I just input the values of the max pressure line into kfldhbn. The ecu then compensates about 10% under those 'max' values and limits load accordingly. You can log 'charge limit for turbo protection' to see this in effect. Things you would always want to log as you increase boost would be intake temperature (watch what happens after 5k rpm) and either maf voltage or mass airflow. Increase boost pressure until airflow stops increasing. More boost does not mean more airflow!!! More boost does not mean more power!!! Title: Re: How hard should you push your k03? Post by: nyet on October 10, 2014, 12:12:03 PM 15-16psi taper to 8-9psi IMO.
Title: Re: How hard should you push your k03? Post by: Lost on October 10, 2014, 12:53:26 PM I feel like this is a very common question and wanted to share how I decide how much boost is 'safe' on a me7.5 1.8t. Not only on the k03 but any turbo. I found a k03 compressor map and graphed rpm across it. Assuming 90% volumetric efficiency across the board. (Haven't bothered to find real values) (http://s24.postimg.org/ott8csxn5/New_Doc_5_1.jpg) (http://postimg.org/image/ott8csxn5/) Note that after 5k rpm you are off of the compressor map. This means that the turbo is using the majority of its power to create heat rather than move air. From there I just input the values of the max pressure line into kfldhbn. The ecu then compensates about 10% under those 'max' values and limits load accordingly. You can log 'charge limit for turbo protection' to see this in effect. Things you would always want to log as you increase boost would be intake temperature (watch what happens after 5k rpm) and either maf voltage or mass airflow. Increase boost pressure until airflow stops increasing. More boost does not mean more airflow!!! More boost does not mean more power!!! Would you plz explain how too read and understand a compressor map? Use yours as example with axis and mening. Thanx. Title: Re: Post by: turdburglar44 on October 10, 2014, 01:17:22 PM Y axis is pressure ratio ie; sea level is 14.7 psi so 2 pressure ratio at sea level would be 14.7 lbs of boost. x axis is compressor flow in cubic meters per second. The rings represent efficiency percentages. The inner most ring is the most efficient.
Title: Re: How hard should you push your k03? Post by: nyet on October 10, 2014, 01:46:54 PM ECUxPlot will plot calculated P/R vs volumetric flow
Unfortunately, the P/R calc is rough; it doesn't take into account the various pressure drops accurately yet, but it is in the ball park. Title: Re: Post by: turdburglar44 on October 10, 2014, 04:25:51 PM I've used that a few times. Pretty awesome.
Title: Re: How hard should you push your k03? Post by: buergi on October 10, 2014, 05:29:25 PM Hi,
are you sure this is the correct map ? I am pretty sure that 1.8t engines used 2072 compressors. There was an article published in MTZ about the 225hp engine in which the compressor maps of the standard K03 and the K04 were compared. See http://www.motor-talk.de/forum/aktion/Attachment.html?attachmentId=527706 (http://www.motor-talk.de/forum/aktion/Attachment.html?attachmentId=527706) buergi Title: Re: How hard should you push your k03? Post by: justindcady on October 10, 2014, 05:32:21 PM Now...what if one's goal is to maximize torque output between 2,500-4,500rpm? For purposes of SCCA Solo/Autocross, I'm under the impression that torque is FAR more valuable than horsepower, so a taper back down to 10psi by 6,500 doesn't break my heart. But, if I'm able to squeak out 20+psi between 3,000-4,500 with sufficient detonation control...what's the harm?
Title: Re: Re: Re: How hard should you push your k03? Post by: turdburglar44 on October 10, 2014, 06:55:10 PM Hi, No I'm not positive.are you sure this is the correct map ? I am pretty sure that 1.8t engines used 2072 compressors. There was an article published in MTZ about the 225hp engine in which the compressor maps of the standard K03 and the K04 were compared. See http://www.motor-talk.de/forum/aktion/Attachment.html?attachmentId=527706 (http://www.motor-talk.de/forum/aktion/Attachment.html?attachmentId=527706) buergi Title: Re: How hard should you push your k03? Post by: userpike on October 10, 2014, 11:23:03 PM with the use of an intercooler you can go "off the map" some. those maps are specific to each compressor wheel afaik not a turbo assembly using that compressor wheel with an intercooler/piping, attached exhaust system etc. just the compressor wheel specs.
Title: Re: Post by: turdburglar44 on October 11, 2014, 11:39:33 AM Yea if you have a better intercooler you can push a little harder. I don't like that approach though. Definitely you have to log and see what's happening with your whole setup together. Like I said. As long as air flow is increasing then you are fine.
|