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Is there an easy way to add EGR to a carbed motor? I hear it increases gas mileage quite a bit and can cut down pinging. I remember my old 89 camaro would get 25mpg and had no egr with the Ebrock 750 and Performer RPM intake, but the cam had plenty of overlap so maybe that was a crude form of EGR in itself. Any easy way to add EGR to a mild combo? Thoughts?
 

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EGR tends to reduce economy but it does tend to reduce the tendancy for the engine to ping at part throttle with a lot of timing/vac advance. The reason for this is because it causes the engine to produce less cylinder pressure. The whole purpose of EGR was to reduce NO2 emissions and it works the same way as does reducing the compression ratio or retarding the cam timing(460 after about 1972)
 

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Greenbroncoguy said:
don't really know, but I do not see how adding HOT exhaust gas into the intake to be re-burned would HELP with pinging???

-Matt
EGR is introducing gases into the mixture that cannot add to combustion(they don't burn), which, as stated, causes it to reduce pinging by cooling the combustion. Keep in mind, as hot as the exhaust gases are, they are still cooler than the mixture in the combustion chamber after the mixture catches fire.
 

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EGR if done correctly can increase fuel economy by aiding to the vaporization of the fuel before it gets into the chamber. However, as stated above it adds nothing to the combustion process and usually ends up decreasing MPG and performance by cooling the burn (actually makes less fuel burn, so it burns cooler).

The key to good fuel efficiency is combustion efficiency. High compression with an efficient combustion chamber design, good fuel vaporization, and plenty of turbulence in the chamber (goes hand-and-hand with good cylinder head design) will make the burn quicker, dump less heat into the engine, give you more power and economy. Less ignition advance will be needed for peak horsepower.

If you're considering doing work to the engine to get better gas mileage, you may want to consider "edging" the chamber, and also installing "Singh Grooves" to the squish pads. These two modifications have been shown to greatly reduce detonation tendencies and therefore allow you to run higher compression on cheap fuel. The Singh Grooves increase chamber turbulence and help fuel efficiency by themselves. The smoothness of the chamber after edging also helps speed the burn, as there are no "speed bumps" to slow it down. Doing just these two even without raising the compression will help your thermal efficiency. They just happen to have the nice side effect of decreasing detonation and therefore allowing you to run higher compression than you normally would be able to. Compression is the key to thermal efficiency.

Edging Ahead
Groovy Heads

These two modifications are cheap (free if you do them yourself) and have been proven to work. They'll require a lot less experimenting and fabricating, as well, compared to building an efficient EGR system.
 
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