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      08-25-2017, 10:45 AM   #54

Drives: 2011 135i
Join Date: Sep 2013
Location: Milwaukee

iTrader: (2)

Originally Posted by bNks334 View Post
You just said it yourself, the table for High +KFT mode is different, and the only way to kick the water pump into that table is to stay at WOT or be over 108f (stock settings). It 100% appears as if the pump is driven harder in HIGH and HIGH + KFT mode. I get what you're saying though... the pump should be at 100% as soon as the car goes over target of 223 (normal mode). However, you can't assume their is enough gain when the car is in that mode to ever hit 100% duty cycle. Unfortunately, we don't have the pid to log water pump duty cycle with MHD. I can check "torque" or "carly" to see if they have the pid. I know Torque allows you to log the radiators fan speed.

The cooling systems capacity is still exceeded with track driving or even a 4th gear pull even when you force the car into high+kft mode at all times. What's the benefit of coding the tables then? The cars stays in high+kft mode at part throttle, or even off throttle, which allows the car to continue to shed heat down to coolant temps of as low as 180f. When you get back on throttle you now have a much higher ceiling before you get back into that danger zone of 230f+
If you look at fe1rx's data you will find there are quite a few laps where the minimum value he logged is still over the set point (normal set point is 106). I do understand where you are coming from though, as under the off throttle sections *if* the DME is using the "normal" mode setpoint of 106 and you begin to approach that the P and D terms will soften and it will likely command something under 100%. It would be better to simply go full bore to try to build up a little extra buffer in the off/partial throttle sections. The reality is we really don't know how the DME switches between those tables and unfortunately we can't log either the coolant setpoint nor the commanded pump duty cycle (at least without bring out a scope and doing some tapping of wires).

So in terms of data we really would have to just rely on real world coolant temp data. Ideally we would try to control the variables so the only difference was the coolant tables. I.e. Same track, same day, same conditions, same driver, same tune except coolant tables. Kind of hard to do.

Your data is the closest thing we have to this, albeit not perfect. I download the CSVs threw them in excel and then trimmed them to the point where coolant and oil temps stabilized. Here is the data:

There does appear to be an improvement, but its not very big. On average roughly 3*F for coolant and oil temp. Interestingly the maximums are very close between the runs. Also it looks like the IATs were actually hotter with the COBB tune. Not sure the state of the modifications on the car, but that tends to suggest the ambient temps were actually hotter when you ran with the stock tables... Which makes the small improvement even less believable.

Last edited by WhatsADSM; 08-25-2017 at 10:55 AM..