Adding EGR and EVAP function to megasquirt?

[douchermann]

Hey guys, new here. I was wondering how hard it would be to set up the megasquirt to control both EGR and EVAP? EGR is more important, so I'm primarily concerned with that. As some of you may know, the EGR's purpose is to re-route some of the exhaust gasses back into the combustion chamber to reduce NOx emissions. This also lowers the temperature of combustion, and with this, the car can hike up the timing, thereby increasing fuel efficiency at typical highway speeds. I know this for a fact, since my mileage has suffered horribly ever since the EGR valve stopped working.

I wouldn't find the megasquirt advantageous if I couldn't also control timing with it, which is why I'm trying to figure out if the megasquirt could control EGR. If the stock ECM is no longer controlling timing or fuel, the benefit could be lost (unless spending painstaking hours of trying to get the timing just high enough at typical cruising speeds without tripping the knock sensor).

As mentioned before, EVAP control would also be quite beneficial. If the evap system is removed, and vented cap installed (as necessary to prevent excess vapor build up), about half a gallon of gas can be lost on a hot summer day. Bad gas mileage is one thing, but using up gas when the car isn't even running is nonsense. At the peak of my engines life, it could get 24mpg on mostly highway/some city driving. I always used to love rubbing this in my buddies faces, who all drove turbo hondas that would get similar gas mileage and were slower than my almost stock beast. Ironically, it was soon after this that all components seemed to fail at the same time (EGR valve, oxygen sensor, 2 of the 8 injectors don't always fire), reducing my mileage to around 8-10.

I'm sure I'm not the only person who has thought of this idea, so what are your suggestions? This is what will ultimately sell me on the megasquirt; otherwise I will just buy chip burning equipment and tune my stock computer. Thanks in advance.

[Matt Cramer]

Hey guys, new here. I was wondering how hard it would be to set up the megasquirt to control both EGR and EVAP? EGR is more important, so I'm primarily concerned with that. As some of you may know, the EGR's purpose is to re-route some of the exhaust gasses back into the combustion chamber to reduce NOx emissions. This also lowers the temperature of combustion, and with this, the car can hike up the timing, thereby increasing fuel efficiency at typical highway speeds. I know this for a fact, since my mileage has suffered horribly ever since the EGR valve stopped working.

What sort of signal does the factory ECU on your car use to control the EGR valve? Is it on/off or PWM?

I wouldn't find the megasquirt advantageous if I couldn't also control timing with it, which is why I'm trying to figure out if the megasquirt could control EGR. If the stock ECM is no longer controlling timing or fuel, the benefit could be lost (unless spending painstaking hours of trying to get the timing just high enough at typical cruising speeds without tripping the knock sensor).

That's a very poor way to tune the spark map. You run the risk of engine damage from bouncing it off the detonation limit, and while you end up with a map that doesn't ping, there is no guaranty it's actually the most efficient spark map. The best way to get an optimum spark map would be on a steady state dyno.

As mentioned before, EVAP control would also be quite beneficial. If the evap system is removed, and vented cap installed (as necessary to prevent excess vapor build up), about half a gallon of gas can be lost on a hot summer day. Bad gas mileage is one thing, but using up gas when the car isn't even running is nonsense. At the peak of my engines life, it could get 24mpg on mostly highway/some city driving. I always used to love rubbing this in my buddies faces, who all drove turbo hondas that would get similar gas mileage and were slower than my almost stock beast. Ironically, it was soon after this that all components seemed to fail at the same time (EGR valve, oxygen sensor, 2 of the 8 injectors don't always fire), reducing my mileage to around 8-10.

I'm sure I'm not the only person who has thought of this idea, so what are your suggestions? This is what will ultimately sell me on the megasquirt; otherwise I will just buy chip burning equipment and tune my stock computer. Thanks in advance.

Evap should be an on/off signal, though finding the best point to turn it on or off may take some experimenting.