Quote:
Originally Posted by borderm3
Are you certain of this, if so can you please elaborate?
This was a consideration when I first looked at the system. I know very little about this, but from a few minutes of research I gathered the hot film system is conservative with respect to temperature and velocity. Thus the change in temperature is still proportional to the rate of mass entering the engine.
e.g. The amount temperature decreases on the hot wire as a result of the increase in velocity results in the correct change in mass/time.
I know nothing about how sensitive this is. If this is a problem it will be very easy to tell on the first data log.
Another option is to attempt adjust the geometry of the system such that it yields the same conditions that are at the stock HFM. If this can't be done, take data from the new setup and the old setup, curve fit, figure out a function that normalizes the new setup to the old and use that to program some electronics between the hfm and ecu.
I am just spit balling 100%, It will require experimentation, but I still see no reason why it is a real problem. It is just a question of motivation.
I hope I don't come off argumentative. I'm sure you can tell, I am the kind of person that want's to know why. Many times things aren't done because people don't understand the system and assume it can't be done. After all, I am posting here to see if there is still any interest in this project. If there isn't, I will go radio silent and just work myself. I am very motivated to play around and develop a path forward to aftermarket upgrades on this platform.
Chris
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No worries, not at all.
As you change the size of the pipe that the MAF sits in, you are affecting the speed of the air flowing through the pipe. For example, a larger pipe diameter would decrease the speed of the air across the MAF sensor. The DME takes the reading from the MAF and then uses the predetermined characteristics of the pipe it sits in to build it's load parameters.
To be completely honest, I doubt anyone here will be able to tell you exactly what affect changing this would have. Our DME is obviously very complex with 2 MAF sensors and 4 MAP sensors, so unless you worked on the code I doubt you could give a definitive answer on the specifics.
But the one thing we can be sure about is that changing the diameter of the housing that the MAF sits in will generate a signal that the DME is not expecting in relation to the actual air entering the engine. That's also why I mentioned the placement of the MAF as well, I'm sure with the complexity of our DMEs the location of the MAF will also play into this as well. If you could keep the distance from the turbo and diameter the same, the DME would be most "happy" as you could make it with a custom intake setup.