I am not buying some of the "ad-speak" in this conversion. Right off the bat, they are talking about "air flow restriction" with photographs of "sharp edges" and whatnot. But . . . we are so far upstream of the Big Air Restrictor aka throttle plate, that no one can say that the air flow meter is restricting the engine's breathing. Hawgwash.SlowLane wrote:Than follow it up with this one: http://www.splitsec.com/technotes/AFM_t ... ersion.pdfsatchmo wrote:Did you read this: http://www.gowesty.com/library_article.php?id=805dingo wrote:I like the idea of using hot wire AMM instead..cant be that difficult...whats the out put signal look like? how is it different from the
flipper ?
And follow up with this: http://www.gowesty.com/library_article.php?id=1532
I think those should answer your questions.
Split Second are the makers of the AFM replacement GoWesty was/is offering.
In a nutshell, the MAF sensor doesn't have the range of output (0-5V) that our ancient AFMs do (0-9V-ish), not to mention a different response curve. The Split Second solution is a digital one, and while I'm all for microprocessors where they make sense, I think in this case an analog solution would give smoother results. I only wish I had the analog background to design the circuit.
Next, when I read of "be sure to keep your oiled mesh air filter clean" because it could "affect the sensor wire calibration", I have to ask, "why have an oil mesh air filter when the stock paper filter is a known superior filtration device?"
Then I read that the analog signal of the AFM seems to fill the blanks better than a digital trying to play catch-up with its own fill-in-the-blank programming yet the concluding paragraph just has to declare that it expects this digital hot wire system is going to improve driveability. No it isn't. It is going to luckily maybe match the original. Period.
The calibration table is where I am most out of my league. I never did find a "recipe" with all of my exhaustive testing of a non 0-2 fuel injection system. I had a tailpipe sensor, not a bung further up the exhaust stream. But I did replicate over and over the fact that a hot pissed-off air-cooled 2.0 preferred a richer mixture and offered better fuel economy. If I were to offer a hill-billy rationale, I could feel the responsiveness of the engine under my right foot. Any time that the accelerator did not translate in verifiable work (acceleration), I ran hotter. There is some beautiful little point where the mixture is converted into work more effectively, and this allowed lower CHTs. If I was too lean, all hell would break loose as I filled the cylinders more but less work was accomplished > heat heat heat. I will re-verify this spring when I do my much-anticipated EGR/CHT relationship test on my Florida itinerary with the BobD.
Currently, my best understanding of the mixture claims that 11.2 under full acceleration at 55 mph leaning to 11.6 or so by 70 mph with a sharp lean to 13.5 or so at steady cruise to a fuel shut-off 22 or so under high speed throttle-off, turning back on to 16 at lower rpms, seems to be the sweet spot.
Airkooledchris and I did some testing with his 0-2 sensored engine, and we had to conclude that there are secret moments where somehow the engine is happy? with stochiometric 14.7 ?? because it somehow knows that the (if installed) catalytic converter is the princess who must be kept happy, yet it would seem too lean for the head temps? Where are we at with that, Chris?
Colin
I was there when CDs promised "brilliance" in sound recording, but we all knew that "0"s and "1"s were taking away ambience that only analog could provide.