Okay guys, don't flame me if I say something stupid or completely incorrect here. I'm fairly new to the turbo scene but I know a bit about engine theory. Anyways- here's the idea. The wastegate opens to relieve exhaust pressure and limit boost. When these exhaust gases are dumped, they are vented into the atmospere or into the exhaust system (essentially bypassing the turbocharger). With that being said, an EGR system recirculates exhaust gases back into the intake manifold and into the cylinder to reduce combustion chamber temperatures to reduce emissions. So- what if these vented exhaust gases coming from the wastegate are recirculated into the intake manifold (basically creating an EGR system) to lower cylinder temperatures, so that higher boost pressures can be achieved? Would there be too much exhaust pressure entering the intake manifold? Not sure if this has already been attempted by someone, I just happened to have a light bulb pop up over my head.

 

you'd be infringing on a patent for Direct Exhaust Injection... maybe if you set up manufacturing in china and brought kits in the form of parts, then assembled them here you'd make a lot of money.

jokes aside though, the EGR valve does what it does by reducing the amount of oxygen available to burn in the combustion chamber, and it's only purpose there is to reduce NOx emissions and improve fuel economy. its kind of like the vtec in the new base civic. it leaves the intake valve open for longer than necessary, so that some air gets pushed back out, whereas EGR simply replaces that air with CO2. EGR turns off under full throttle, because it obviously robs horsepower by not letting the cylinders get filled with air-fuel mixture all the way.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by grandtheftlunchbox &raquo;</TD></TR><TR><TD CLASS="quote"> an EGR system recirculates exhaust gases back into the intake manifold and into the cylinder to reduce combustion chamber temperatures to reduce emissions. </TD></TR></TABLE>

EGR recirculation, IIRC, most definitely does not reduce combustion chamber temperatures. Rather, I think the main purpose of EGR systems was to speed up the warmup of cars for emissions purposes, to aid the functioning of the cat converter.

Whenever I can, in whatever car I have, I eliminate the EGR system. Why would you want exhaust flowing back into the intake charge? You're reducting the amount of volume that fresh oxygen can take up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chimmike &raquo;</TD></TR><TR><TD CLASS="quote">

EGR recirculation, IIRC, most definitely does not reduce combustion chamber temperatures. .</TD></TR></TABLE>

NOPE.....high Nox is directly related to cyl temps.
the egr, introducing spent gas into the mixture, loweres the combustion temp, thus lowering Nox.

it wouldnt work, because, the car doesnt use it all the time, and the engine only needs egr at certain times, and for the guys running low boost, what of all that gas? would choke the engine.

 

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