Honda engine question

[diamondlarry]

Over at cleanmpg.com, this thread came up and I knew that somebody here could answer his question.

Hello, I am a new prius owner, but thats not why I'm here. I'm giving my Civic to my father so that he can drive it instead of his work truck when he isn't making deliveries and I wanted to see what I could do to drive that more efficiently so I can instruct him.

I drove it last weekend and used the scan gauge to monitor FE and I'm wondering if I drive the civic like the prius, except for throw it in neutral in the glide phase is that a good method? The rolling in neutral got ife higher and I had a decent run according to the scan gauge.

The civic has 118,000 miles, new tires, plus all recommended honda service completed.

One thing I'm curious about is that I heard that back in the days that the youngsters were moding the civic for street racing, they were able to tap the computer with a pda to change the valve settings to get more hp and integrate their other modifications. Since the civic models from that year all ran the same motor but got different MPG , were the differences in the valve settings and could the EX be set like one of the models that got better MPG via a similar procedure? If so, is this easy to do and how would I go about doing it?

Great site, thanks for any input.

[thisisntjared]

they are not the same motor. not at all. same series but not the same motor.

[mrmad]

You are describing "chipping" the ECU. Doing that sets the fuel injection and ignition advance tables. The valve setting you are describing is changing the VTEC engagement rpm. It does not increase hp to change the VTEC point unless the engine has been modified (cams, compression, intake manifold etc). In theory, you could chip the ECU for leaner conditions, but it's hard to say if you'd gain much in FE. There's an article linked somewhere on Gassavers that showed one of the import magazines doing this on an RSX and gained 2% mpg. Not sure if the gains would be better on an engine that isn't tuned for such high rpms as an RSX or not. If you want to learn ALOT more on this, check out pgfmi.org and start reading. It's amazing how much work people have done reverse engineering the Honda ECUs in efforts to modify it.

[trebuchet03]

Originally Posted by theclencher

"I'm giving my Civic to my father so that he can drive it instead of his work truck when he isn't making deliveries and I wanted to see what I could do to drive that more efficiently so I can instruct him."

He's your father, he's older and set in his ways. Forget it, he's gonna drive like he always drives.

Naw... My father is on the road a lot for his work... He'll take every bit of advice and applies most of it. Perhaps that's a special case considering he owns the business he's driving around for In fact, when I go home in a few days - he wants to test out my SG and it seems likely he'll be getting one shortly


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As for chipping... I really wish I had a little more know how - or someone to help/explain what I need to do to grab all the data off my ECU then interpret as many of the maps and constants as possible

[Matt Timion]

Originally Posted by thisisntjared

they are not the same motor. not at all. same series but not the same motor.

Ding ding ding... we have a winner.

Sometimes they are the same displacement (1.5L, etc.), but not the same motor.

[GasSavers_Randy]

This is on a '99 civic, so they're all 1.6L 16v SOHC D-blocks (except the Si). Pretty big differences, still: VTEC (EX), VTEC-E (HX), and normal (the others). The D16y8 has an on/off cam, not variable. Fuel and timing can do a lot, but they're already tuned for mileage (except when you floor it). Only improvement is if you forget about emissions. If you want to go that route, look into pgmfi.org, etc, otherwise just drive it carefully.

[thisisntjared]

Originally Posted by Matt Timion

Ding ding ding... we have a winner.

Sometimes they are the same displacement (1.5L, etc.), but not the same motor.

sometimes i feel like nobody listens to me