Re: Mechanical Supercharger
Sean, not at all, to some "lambda" is a life's persuit.
In a standard gas engine there is a perfect mix of air and gas, that ratio is most efficient at what is called "lambda". lambda is achieved when 14.7 lbs. of air is mixed with one pound fuel. The target, constantly being adjusted for engine load and other engine and driving conditions in the lambda is just that, 14.7. For those of us that want to see if in closed loop our cars are operating at lambda, we can. We do this by using the oxygen sensor that samples at a much higher rate then those found in stock Vipers. Stock Viper's Oxygen sensors are narrow band sensors, guys/gals that want to more accurate view their engine's ability to achieve lambda in closed loop operations rely on gauges driven by wideband sensors. As load changes, so does the require A/F (Air Fuel) mix. It would be incorrect to assume that simply having a wideband sensor and wideband gauging your car is going to allow one to properly address all issues surrounding closed loop operations. We also need a high-quality software interface (program) to the ODB2 found in our GEN2 vipers. I have one, it plugs into the drivers left hand knee location of the OBD2 fitting under the dash. I can directly look into the PCM's operations, especially the adaptives and make sure they fall within a specified range of the stock PCM operating throughout closed loop. In open loop, well that is where the fun starts and that is where two more computers kick in. There is of course more on this subject, lots more, but there you have a very simplified begining.
Prior to about 1986, big assed supercharged rigs were tuned for their high rev performance profiles. When you coasted to a light or drove slowly, your rig would sound like crap. That sound was the lugging sounds some of us remember growing up with. Now, throughout the whole rpm range we acheive a perfect balance. I actually cut 60% larger injectors back to stock levels when driving around normally. When I get on it, those same 60% larger injectors deliver more gas than would ever be possible with stock injectors. 15 years ago, that would have been magic.
Here for your enjoyment is a 1,000hp supercharged rig without computerized tuning. Set up to run well at high rpms, you can hear the surging and lugging at idle and low rpm. The young man you will see at the end of this video (brown jacket) is the kid that grew up to build this Viper engine. He knew more at 16 about engines that most men know at 50. If it goes....he knows. No, that is not me, that is one of the greats of the big rig makers, Big Al, 9,236 supercharged engines and counting.
http://www.youtube.com/watch?v=La0Fqb5uzFA&feature=related
Now, before somebody screams we are off rifles here. You would be surprised at the number of excellent rifle makers that come from the skill set and tolerance sensitivity found in racing engines. Everyone at Nemesis did, in fact David Ives first built IC circuits (computer chips, astonishing tolerances) before being dragged into the heavy duty race world.
