posted on May, 20 2010 @ 09:10 PM
I'm replying to several posts in this one. First to PplVSNWO I think the 403 olds would be a decent CNG platform. Secondly environmental conditions
can, and are pretty much accounted for in good tuning algorithms enough so that only the most extreme condtions affect perfomance overly much. Which
leads into comparing America, and Germany as far as climate is concerned what works over there should logically work over here. We have the same
partial pressures of atmospheric gas planet wide last I checked. It is a cultural issue as was mentioned.
Next to Unlimiteddisaster, I think you're a little rusty on your tuning nomenclature too. Open loop condition only happens at cold start for a
minute or two, and at close to WOT. It also only takes the lambda (O2) calc. out of it's algorithms. As far as my presumtions being based on not
enough extensive knowledge of how to properly tune. Well... that is most certainly not the case. As mentioned I have set up stand alone management
systems. We're not talking modifying an existing OBD system. We're talking soldered the PCB board up, loaded a custom written OS, and then started
tuning from scratch, nothing to start with. Based all the tables on how the engine performed per 5 gas analyzer, and dyno output from idle to 6000
RPM. As far as an OBD I, II, or CAN system not targeting 14.7:1 all the time that is untrue. If it is in closed loop 14.7:1 is target AFR so much so
it even has it's own special term, Lambda, greek for change, specifying the amount the initial calcs need to change to hit target 14.7:1. If the
engine is operating in open loop it does target a little richer than lambda1 and is expressed in % of lambda1 so it's easier to program. As far as
richer burn being protective. It is in WOT conditions, not part throttle. At part throttle leaner conditions are just as safe yet more efficient, I
have hundreds of thousands of combine engine miles to prove it. Mechanics in my area can tell an engine I have tuned when they pull it down for
maintenance because the guts are clean, clean, clean.
Lastly even though our car's computers are left overs from the 60s, and 70s as far as language, and are maybe 80s to early 90s cold cuts for
processors. They still have a fast enough processor speed, and our newest sensors are sensitive enough to demonstrate VERY tight control of engine
parameters. Sure it's not 100% perfect all the time, and it never will be, but it's a darn lot more accurate than they would have you believe. Take
for example a wideband O2 sensor. It can sense and report the varying AFR of an engine under acceleration so accurately that I could tell you with a
very narrow margin of error what the exact AFR was every 10 RPM step. That's during accel when the AFR is the hardest to manage. Managing an engine
with an ultra lean burn heuristic takes more time thinking on the part of the tuner, and you have to think differently owing to which side of the AFR
curve you are on. On the rich side, leaner produces a hotter EGT, but after about 18:1 you flip to the other side of the bell curve, and it's exactly
bacwards, and you can quench combustion temps with air abundance, and thus protect the engine. Yes if you go just a tiny, tiny bit too far you get a
flame out, but it dosn't hurt the engine, and adds an almost insignificant amount to the emissions as it rarely happens if tuned well. The lean side
of the curve is very, very steep, and precise control is a must, but off the shelf modern components are already capable of pulling it off. The car's
PCM is already fast enough to make the changes in time. It's just not the auto industries paradigm of thought. Except in the case of European extreme
low emissions vehicles. Guess what?! Their tuning method is exactly what I am describing, exactly what Ford, and Chrysler discovered, but were too
chicken s#1t to implement, and exactly what I have been doing for over 5 years, and my engineer buddies have been doing for nearly 15 years. Spit out
the Detroit petrol flavored cool aid, and think a new thought. The way we aren't doing it is not only just not the best way, it isn't even a very
good way. It was OK 10-15 years ago today it's just stupid. If small time engineers with limited resources, and shallow pockets can build stuff with
what's available on the internet, at the parts store, and what we can fabricate with a decent CNC machine, and we can blow what the mainstream auto
industry spits out by a large margin (chasm would be a better term). What could Detroit, or Tokyo do with tens of millions if they WANTED to. They
don't WANT to, that's the point. Do I think they are dumb, and I just figured out what the big boys couldn't, no. They know better, they just
can't let it get out that they know better. Then there would be certain expectations of them that doesn't fit their business model.