Quote:
Originally Posted by old jupiter
The Wikipedia article (Mr. Taylor's link, above) cites two effects as gains, that are actually net losses. "Reduced Throttling Losses," comes because the throttle must be opened a little more to make up for lost power. Put your foot to the floor and you can REALLY reduce throttling losses, but are you saving fuel? And "Reduced Heat Rejection," again should have been noted as a measure of the fact that your heat engine has a cooler fire inside it with EGR. What we'd like to do is make the MOST heat, and get the most out of that heat, with the smallest amount of fuel, emissions aside.
Mechanic, I'm not picking on anyone, and anyone reading Mr. Webb's posts can see he's a smart guy.
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Well, you seem to believe what many people did in the 60s and 70s when EGR first came on the scene. Get rid of it an your car will run better. It didn't work then and today with the much more sophisticated systems it won't work now.
One point you completely missed was compression ratios. The statement about WOT not increasing efficiency is not what we are discussing. The early egr systems were atrocious. I know how hard it was to start a 1973 Chevrolet, worked for a dealership when they were new. The only way the car was even drivable was to let it run for a few minutes. If you started it and put it in gear it died, over an over.
Compression ratios were as low as 8 to 1 in the era. No matter what you did with the EGR the compression ratio was the problem. EGR allowed advanced timing which helped some but with a compression ratio barely better than my 37 Ford Flatheads 7to1 power was not an option.
EGR is a principle component of emission controls. Applied properly EGR allows much higher compression ratios. Today Mazda's SKYACTIV engines are running 14 to1 on regular gas, impossible to do on any non EGR equipped engine in current production, and very close to diesel CRs.
Disabling any EGR system is also illegal, and recent legislation allows for prosecution of individuals who are responsible for disabling their emission controls on cars, the fine is $2500 per offense.
It used to be that they went after businesses that disabled systems.
In the early 1990s when 3 way cats and oxygen sensors became the norm, manufacturers were able to raise compression ratios and increase power, even on cheap gas and with fully functional emission systems. Fuel injection was a principle component of this advancement, with precise delivery of fuel.
Today after two decades of refinement you see power levels than have never been reached by production vehicles before. The Honda S2000 produces 245 horsepower from 122 cubic inches without supercharging. These levels of power have no historical context prior to 1975.
Modern systems also allow for ignition timing control with spark advance to the best point for ignition regardless of the fuel quality. Put cheap gas in and the system retards the timing, put premium is and the system advances the timing. The engine will run better with premium as long as it was designed to run better with premium. If not it's a waste of money.
In all of this progress engines became cleaner. The average engine in the 60s was tired at 100k. Today engines can easily pass 200k with regular maintenance. Oil in my Maxima stays clean and the level does not fall, even though it has 140k on the odometer. I just had the EGR cleaned to restore function.
I would seriously consider trying to understand the emission systems before you do the same thing people did 40 years ago, removing or disabling those systems will not make your car run better AS LONG AS THE SYSTEMS ARE WORKING PROPERLY. Individual re engineering of those same systems can cost you dearly, if enforcement every decides to enforce current laws.
To many people decide they are better engineers than the ones that originally built your car. They even start to re engineer before they even know whether the existing systems are functioning properly.
regards
Mech