Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Thinking of Civic DX to HX Conversion (lean burn engine)

rkcarguy · 03-10-2011, 07:36 PM

I would have all kinds of recomendations, mainly involving your ECU......but I see Cali as your location.
This means no OBD-1 conversion or tuned ECU, wouldn't even be sure if the HX swap would pass with the stupidity going on down there, unless you plugged the factory ECU back in for test time.
Up here in WA I had a friend help me convert my 1996 DX to OBD-1 (92-95 ECU)and he also chipped it. In stock form it was lucky to see 30mpg. We were able to lean the cruise air/fuel ratio to around 16.5:1 before it started having any surging or pinging, and backed it down to 16:1 resulting in a 3mpg gain. 2nd, I lowered the car. With the air pressure high the tires will wear more on the insides, but mileage went up. If you have non-directional tires they can be flipped on the rims and their life doesn't suffer much over normal.
I installed a cheap short ram intake, new plugs and wires, and now we see 36mpg and a couple times over 40mpg. The car now has over 207K miles on it.

For the record, I am a big hater of the WAI. There is more energy to be realized in less of a cold air/fuel mixture vs. a warm mix. In a lean burn engine this can be doubly bad, as the detonation threshhold is one of the governing factors as to how lean the mixture can be made. A hot engine is going to ping earlier than one sucking in nice cold air, and the ECU will add more fuel and pull back timing to counter this.
A WAI is just a driver aid, like putting a stop on your throttle so it only opens 1/2 way.

03-10-2011, 07:36 PM	#20 (permalink)
rkcarguy EcoModding Apprentice Join Date: Mar 2009 Location: West Posts: 145 Thanks: 1 Thanked 5 Times in 5 Posts	I would have all kinds of recomendations, mainly involving your ECU......but I see Cali as your location. This means no OBD-1 conversion or tuned ECU, wouldn't even be sure if the HX swap would pass with the stupidity going on down there, unless you plugged the factory ECU back in for test time. Up here in WA I had a friend help me convert my 1996 DX to OBD-1 (92-95 ECU)and he also chipped it. In stock form it was lucky to see 30mpg. We were able to lean the cruise air/fuel ratio to around 16.5:1 before it started having any surging or pinging, and backed it down to 16:1 resulting in a 3mpg gain. 2nd, I lowered the car. With the air pressure high the tires will wear more on the insides, but mileage went up. If you have non-directional tires they can be flipped on the rims and their life doesn't suffer much over normal. I installed a cheap short ram intake, new plugs and wires, and now we see 36mpg and a couple times over 40mpg. The car now has over 207K miles on it. For the record, I am a big hater of the WAI. There is more energy to be realized in less of a cold air/fuel mixture vs. a warm mix. In a lean burn engine this can be doubly bad, as the detonation threshhold is one of the governing factors as to how lean the mixture can be made. A hot engine is going to ping earlier than one sucking in nice cold air, and the ECU will add more fuel and pull back timing to counter this. A WAI is just a driver aid, like putting a stop on your throttle so it only opens 1/2 way.