Swamp2,
Quote:
Originally Posted by swamp2
Very nice stuff exdos. I am thrilled to see another pro-science, pro-experimentation, pro-do it yourselfer kind of fellow posting here on the forum. We need more like you!
The spikes you refer to (that you smooth over in some plots) are simply the drops in rpm during shifts, correct?
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Thanks for your kind words. My M Coupe(MC) is full of DIY tweaks to the OEM, including my own aerodynamic mods, which have all been developed after reading loads of information from stuff on the internet.
The spikes that I'm referring to are these. Take a look at the very first graph I posted, entitled: "
Volumetric Efficiency of M Coupe with EXDOS Ramcharger during acceleration in 1-2-3 gears", and in the plot of "Volumetric Efficiency in percentage" (the yellow line) you will see at the start of each acceleration in all three gears, that the VE produces an upward "spike" at the start of each acceleration phase, where the VE recorded is higher than the subsequent recording whilst under acceleration. I attribute the spikes in 2nd and 3rd gear, when the car is moving, down to the fact that there is a build up of static pressure within the air intake system, due to the ram effect, from lifting off the throttle whilst changing gear. In the case of the first gear acceleration from vehicle standstill, the drop in VE after the initial start is due to there being no ram effect at the outset and the NA engine is actually creating negative pressure within the air intake system, but once the vehicle gets to around 20mph, the ram effect really starts to contribute to filling the cylinders, as shown by an increase in volumetric efficiency. In the case of my car, the VE now gets to 100% at around 60mph with my latest mod, whereas before, the car needed to be at 80mph to achieve 100%VE, and before that previous mod it was 90mph. I have done an awful lot of study and experimentation on air-intakes over the past three years with the goal of attempting to make ram-effect a useful source of free energy at ordinary road speeds. I think I'm slowly getting there.
Quote:
Originally Posted by swamp2
Just wanted to add that I think you might be missing something when referring to the 335 intake system as being similar to the M3. The M3 looks like this, which I have never seen anything quite like on a BMW.
Cheers and welcome to the forum. |
I realise that there is a significant physical difference between the M3 and 335 intakes, as there is between my Z3 MC and both M3 and 335, but when I look at all these vehicles I am seeing "function" and not the physical manifestation. As I see them, all three intakes share the same features of function. As far as I am aware, the ram air-intake system now seen on some BMW's was first seen on the Z3 M Coupe/Roadster in 1998 and BMW has developed and refined this air-intake system through the E46 M3 and its later performance models. It definitely works!