EGR Modification for better gas mileage?
I was wondering if there is a way to modify the EGR valve tip, where you machine a portion away so EGR is always used by the engine, but still not throw a check engine light by making the EGR valve hang open.
I was reading an article where only 30% of fule is burned in the cylinder and 70% is pushed out. would this give improved gas mileage? 94 Civic VX is what I am driving. |
no cuz it acts like a massive vaccum leak. trust me when you have a bad egr valve it falls on its face and has absolutely no power. a bad or sticking egr valve made my mpg drop (95 s10)
the chevettes was blocked when i got the car i hooked it up idled fine reved fine, under a load hell no didnt wanna accept any gas pedal input haha BUT i dunno could try it but i wouldnt expect much so dont spend too much money hehe |
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EGR needs to be added only during certain times. It doesn't take much EGR to stall the car when at idle. Adding EGR under full throttle is bad for power. It needs to be phased in gradually as the throttle is opened more. I've played with the EGR tables in my ecu and didn't see much difference. I also didn't get too crazy with it since exhaust gasses tend to leave a dirty coating in the entire intake. |
Hi all,
I wanted to say that on my petrol engine (European Honda Civic 1,339cc) the EGR is not only put for environmental reasons (lower NOx) but my ECU also opens the EGR valve as countermeasure when knocking is detected by the knocksensor. This is a more efficient way to fight knock than retarding ignition. I'm telling this because it's possible for my engine that I can not win any MPG when changing something to the EGR valve. It was my plan to minimise the EGR opening and probably make some mpg gains, but with the anti-knock function of the EGR I'm not convinced. It's true that also on my engine there's no EGR opening at idle and low revs (till +/- 1600 rpm). My EGR is fully integrated in the cylinderhead. All canals are 100% in the cylinderhead (shortest possible distances) and the electromagnetic valve sticks out on top of it. Guess this is a very good solution to avoid condense and cludging in the system. |
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any internal combustion process that turns heat into mechanical energy has a theoretical maximum efficiency of 40%. that being said, because thats the absolute maximum you'll never see it. in general, you see about 1/3 of the energy go out the exhaust, 1/3 out your cooling system, and only 1/3 into powering the car. so if you were to say that you were only converting 30% of the energy in the gas to usable mechanical energy you'd be about right. |
At part throttle (where 90+% of driving happens) EGR improves fuel economy, as long as the EGR is low enough that the mixture still ignites readily. This is similar to WAI, because EGR reduces "pumping losses".
So, more EGR is better, so long as the engine doesn't misfire. |
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Reason: the exhaust gas slows down the flaming speed of the burning mixture and this has a negative influence on engine efficency=bad fuel economy. If there's misfires because of EGR, something's badly wrong. Emissions of NOx go down of course when increasing EGR (because lower temps), but once over 10% you will see CO and HC increasing. That's why 5 to 10% is a maximum on petrol cars as well for emissions as for fuel economy. |
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