quote:
Originally posted by Terry:
JMH, FP60 does but as I indicated in the other thread this engine is not running in top form.
Not necessarily... As mentioned in the other thread, these older engines that do not have EGR may in fact be doing just what theyre designed to do...
Looking at some other results on a popular BMW forum, NOx readings at 15-25 MPH for the 91 318i (and a few from other e30 engines were:
983, 1034, 1080, 1549 (from an 84 318i - different engine, lower power), 1677, 1071 (engine unknown on last 2, but an e30 BMW).
This tells me that it may be more of a function of the fact that these engines are tuned a certain way, rather than the fact that these engines are ALL out of tune. It was surely fine for federal standards in 1991, but not for NJ standards in 2005 - so we have a problem
Just a thought, not trying to be argumentative.
All the same, if the FP is effecting the thermodynamics of the process in a beneficial manner, this should be seen even if said process has deviated from its optimum parameters. Not saying that the benefit will be substantial, but it ought to be measurable all the same. Assuming that the engine is the same degree 'out of tune' from last time to this time, the use of FP ought to have done something, right? It should have cleaned the combustion chamber, improved fuel characteristics, and effected thermodynamics of the oxidation to be more favorable to power and economy, right?
Come to think of it, if FP does improve power and economy, then it ought to be creating more useful heat from the process, to be converted to work. This useful heat would then have the side effect of driving the thermodynamics / eqm of the nitrogen oxidation, due to temperature.
Maybe Im way off, but I cant see how FP can increase combustion, improve power, and at the same time cause a cooler burn that would make lower NOx.
Only way I can see it is if FP has a higher LHV than gasoline, but a higher delta H of vaporization as well. So it in effect lowers combustion chamber temps, yet at the same time produces more energy from its combustion. Seems something would be off there though.
OK, enough rambling. point is, other cars exhibit similar results. many states dont measure NOx. So it could be combustion inefficiences, it could be that I have a dinan chip that advances timing (though they assured me that it is 49 state legal and does not advance at idle or at light throttle as much as it would at WOT), lean burn, or bad ignition. its most likely not the cat, based upon the results, not the o2 sensor, and since MPG has been consistent as ever, beating EPA numbers, I dont see how it is that much out of tune, unless my excellent MPG is due to a leaner burn, causing less fuel at the expense of other things.
OK, really enough rambling
sorry.
JMH