Originally Posted by Seattle Smitty
"Are you smarter than the Ford factory" is just one of two questions to ask, the other being, "If the Ford factory had built the engine for best efficiency in all regimes (incl. part-throttle cruise) WITHOUT having to meet any emissions requirements, would they have used EGR?" The answer to that is no. Mixing an inert gas (recirculated exhaust) with the intake charge makes the engine less efficient in any circumstance. There seems to be an idea that because EGR only works during part-throttle operation, it therefore can't hurt anything. That's wrong; if the factory had built the engine without EGR, without the inert gas, it would make a given level of part-throttle power with less fuel. If you want more efficiency than the factory built into the engine, you can make a number of non-factory modifictions, one of which would certainly be deleting the EGR. But as I keep saying to those who insist that EGR "doesn't hurt", if you think you can run better with inert gas in your intake charge, why not install a bottle of argon?
HOWEVER, repeat HOWEVER, if you do make engine changes, pretty much ANY engine changes, the question, "Are you smarter" then applies with a vengeance. The factory, having had to employ EGR, spent a lot of dyno and track time fine-tuning the engine FOR THAT CONFIGURATION. In deleting the EGR, or doing ANY OTHER ENGINE MODIFICATION, you put your engine outside of the factory's expert tuning program . . . your engine is OUT OF TUNE. This is why people here and elsewhere frequently report disappointment with mods that should have worked better than they did . A huge range of tuning knowledge and awareness exists in our little world, from clueless to expert. The fact that you can spin a wrench and remove or install something says nothing about your ability to tune your engine for the change(s) you make. I like to think I know something about this, but am fully aware that I could know an awful lot more.
Come to think of it, there is a part B to the, "Are you smarter" question, and that is, "If you ARE smart enough that you could re-tune your engine to take reasonably full advantage of its now-not-factory configuration, do you have the tools to do it?" Tachometer, vacuum guage, dial-back-to-zero timing light, a compression gauge and maybe a blowdown guage to make sure the engine is basically healthy, a set of jets and emulsion tubes and needles and powervalves and what-not, an adjustable vacuum advancer and sets of distributor springs and weights, even an air-fuel meter, I'm surely forgetting things here, . . . and then can you afford and get dyno-time (and do you know how to USE dyno time?), or do you at least have a long, straight, even, lightly-traveled uphill grade to use as a poor-man's dyno (and do you know how to use that?), or do you have a local dragstrip (and do you know how to use that?). And do you have time, T I M E, plenty of time, to tune?
Because if you can't say yes to most of that, then you can't really do a good job re-tuning the changes you make from factory, and thus the effectiveness of your changes will be a matter of luck.
I don't write this from any position of superiority. I am driving a car every day that I fully rebuilt and modified significantly (incl. EGR delete, for reasons not important here), and it is not getting nearly the mpg I intend for it, chiefly because I haven't had any time to go through a good tuning program. Maybe this summer, and I am looking forward to the tuning exercise, which I feel is not a chore but a fun intellectual challenge for any good amateur rodder. Until then, my car performs less well than a factory-stock car would, even though everything I did has the potential to be an improvement; the current state of tune is that far out, even though the car runs reasonably smoothly and without drama.