what is the point? Is it good for performance or just emissions? I got a carb intake for my TBI that has a exaust path under the intake that goes from the center from each head. It looks like it could easily be made to be functional, if I figure out the plumbing of a EGR intake.

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-Tas
'89 Formula WS.6

Got Beach?

 

It reduces NOx emmisions, and saves fuel by mixing inert gas with the regular a/f mix, therefore making the motor smaller in displacement (Only at part throttle)

It also reduces cumbustion temps, therefore curbing detonation. There is only a small amount of power lost because of heating the intake, but the advantages outweigh the small loss in power IMO.

 

EGR - Exhaust, Gas, Recirculation.

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There won't be any intake heating because your cylinder heads will not have the requisite crossover passages. Your engine already has egr on it anyway.

 

It does heat the intake: there's exhaust in the intake passages.

It costs fuel because it makes the engine run less efficiently, but since it only is active at light loads, the ability to advance the timing further without detonation may offset the loss of efficiency. A properly working system usually seems to have little ot no overall gas mileage effect. The older systems before computer control usually EGR'ed too much of the time, and made cars run noticeably worse.

It has no effect on HCs or CO emissions, only NOx as Joel pointed out. But since those are such a major contributor to certain types of smog, that system gets major regulatory attention. Newer cars use a solenoid to activate it under control of the computer; some (some TPIs included) have a temp sensor that actually has to get hot from the exhaust as feedback to the computer so that it knows the system is working, otherwise it will set a code. Some other computer systems look for a vacuum drop during their startup sequence, and will set a code if they call for EGR but the vacuum doesn't go down.

Nearly all stock carb intakes have had that exhaust passage for a long time, decades before the introduction of EGR in the 70s. It helps fuel vaporization, which improves driveability (sometimes dramatically), at the expense of WOT performance. If your intake doesn't have the boss on it to bolt an EGR valve and the passages to serve it, then it's not going to be practical to retrofit one to it even though the exhaust itself is already close by.

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"So many Mustangs, so little time..."
ICON Motorsports

 

There's a tech article on the EGR on this site, and at The Best Damn Garage on the Internet site.


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1991 Camaro Z28
5.7L 5-Speed (originally 305)
317 RWHP, 418 RWTQ
13.23 @ 107.62 MPH
Southern California
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