The "dyno" runs at low speed during the test and tends to load the engine as if the vehicle was climbing a steep hill in high gear.

Some of the performance cars I am working on (Porsche, Turbo Volvo, Jaguar) have a hard time passing the NOX emission standard.

If I add a small amount of alcohol while the engine is running under load can it reduce the combustion temperature and reduce the NOX output?

As I have also been toying with a water injection system to increase mileage, wouldn't this water injection system also reduce the NOX?

Any comments on my questions, or any other thoughts or experience with this problem are welcome.

I'm guessing that if the alcohol has a lower adiabatic flame temp, then yes it could lower the overall combustion temperature which in turn can lower your NOx. Should be some literature on this in any book on combustion. If you can, run the engine at a certain RPM (preferably high)on usual fuel whilst recording the temp until a stabilized or steady state temp is reached. Then do the same experiment but this time once you have reached the steady state temp, add small amounts of alcohol to see if there is any change in temp. If the temperature drops by say 100 degrees then you'll probably have a reduction in NOx.

The vehicle is a 1982 GMC s-15 pickup. The engine was r&r'd about 2 years ago, but has been driven alot since.
Combustion chambers were cleaned, first using water through carb while engine was running, followed by GM's "top engine cleaner" again through carb (its carburated w/fixed jetting and a mixture solenoid as a booster), then removed plugs and poured directly in cylinders- two bottles / applications. Then Techroline fuel additive was added to the fuel and run through. The Cat converter is a week old and was removed when the above cleaning was performed and reinstalled after a couple hours running time. O2 sensor is also new. The EGR valve(Needle Valves) is 2 weeks old and the passage was cleaned with various chemicals and is open... proof of that is that the engine stalls when you manually squeeze open the EGR valve at idle. All the emissions solenoids are working and the vaccume going to the EGR valve appears to be sufficient. Spark plugs, wires, cap and rotor are all new (a couple weeks ago). The truck runs fine, no error codes are stored on the computer, and all emissions measurements except NOX are good. Timing looks good, although I need to check to see if the harmonic balancer has slipped. Other than that, I don't see what more I can do to fix it. I'm at 2200 for NOX, and I need to get down to 1500 or so at most, and the smog guy's printout says around 550 is the average.

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