[Land-speed] A question for the list

[Chris R Harris]

Many thanks, an excellent piece of info.

We regularly hook up an O2 sensor and Innovate gauge to the exhaust of our 
various carbed rods both blown and NA to keep fuel nice and trim for light 
load highway cruise for best gas mileage where they honestly spend 99% of 
their time, right. We also checked the factory and aftermarket computer 
settings of a 2012 Shelby and 2013 Boss 302 and were amazed at how lean they 
run at around the 2,000 to 3,000 rpm with light load, supporting your info.
All good fun still playing hot rodding with both the old and new but 
important to understand what has become vastly different systems indeed.

Chris Harris..........NZed.

> Lean-of-Peak, Rich-of-Peak = (ROP and LOP)
>
> Since OEMs are in a never ending quest for emission reduction and gas
> mileage, those two goals drive much of the new technology. NOX production
> and detonation are both temperature related so lower EGTs are a good 
> thing.
> However, lower EGT could result in either increased efficiency (getting 
> the
> more work out of the BTUs available) or it could be very inefficient (LOP 
> or
> ROP) meaning the AFR is on either side of stoich. Stoich (14.7:1 for
> gasoline) results in the peak highest temperature of combustion. Stoich is 
> a
> poor environment for both detonation and NOX. To get efficiency, gas
> mileage, lower detonation tendency, and lower NOX, you would want to drive
> the equation to the highest LOP and still have a smooth running engine.
> Traditionally, smooth running with an AFR 15:1 or higher, was difficult to
> achieve. However, direct injection, VCT, COP, knock sensing, and EMU spark
> control, all come together with a high CR to extract as much useful work 
> as
> possible from a smooth running engine in a LOP environment that could not
> exist without all of them working together.
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