Lean Burn for non-Civics? (custom???)

[cbaber]

You don't have to have a special cat. Lean burn cars come with one from the factory, but its not required for lean burn to work.

[cycleguy]

Okay, so it seems I would have to look at (and mask) the readings from the O2 sensor as well - that makes sense.

I see that there are suggestions of custom engine tuners that are capable of providing lean burn modes, which is cool but I just don't think I can justify the amount of money it will cost. I would really like to come up with a small, simple solution that costs me under $150. After all, I have a completely gutted 94 metro that I probably couldn't sell for more than $1000 on a good day. I like the idea of piggybacking on the stock ecm under the dash. For now, I could make a relatively simple data logger to compare manifold vacuum pressure, injector pulse width, and 02 sensor voltage.

The Megasquirt looks like a nice option for doing this, but it seems they start at about $250. I am afraid there will be a lot of additional costs with this method. Has anyone on here used one?

I don't expect this project to yield a super big fuel economy gain so I don't want to spend too much time/money working on it.

[iveyjh]

I have a 2000 Chevy Metro 1.0 3cyl. I use an Apexi Safc air fuel mixture adjuster that works with the map & TPS sensors. Google Safc/Vafc, I find mine on ebay or craigs list.
I get anywhere from 50 to 62 mpg according to how I drive. I get 52mpg at 60-65mph have got over 70 mpg on shorter legs.
You can adjust fuel ratio lean for only low load under 3000rpm or any range that you want.
I have been running this on 3 of my cars for 10 months, 2000 metro, 1998 hx 51-62mpg, 2002 Acura RSX 34-38 mpg. If you set it lean on low load it will not hurt the engine. It actually runs cooler.

[deathtrain]

I have heard of putting a pot on the o2 sensor can work but you will need to install a AFR gauge to monitor it.

[cycleguy]

I looked into the Apexi Safc a bit and think it would be a good option if I can get a used one cheap enough. For now, I think I might look at trying to get one of these units. Thanks

[E4ODnut]

Sorry to shock you into reality, but unless you are very knowledgeable in the art of engine tuning, and are prepared to spend a lot of time and not a small amount of money in the process, what you are seeking is not achievable.

The bottom line is that all the OEM manufacturers of factory EFI equipped vehicles have done a very good job of compromising power, economy, reliability and emissions concerns. Any gains you will get in one area will be hard won and will negatively affect the others.

I have considerable experience in tuning my engines for economy so I'd like to think that I know what I'm talking about. I also have a 91 Sprint and a 91 Miata in my stable. They work so well from factory that I wouldn't even consider modifying them. My Sprint is a $900 beater with almost 300,000 km on the clock. It averages 58 mpg Imperial in summer, 56 in winter. I don't know how I could improve on that.

[cbaber]

Originally Posted by E4ODnut

Sorry to shock you into reality, but unless you are very knowledgeable in the art of engine tuning, and are prepared to spend a lot of time and not a small amount of money in the process, what you are seeking is not achievable.

The bottom line is that all the OEM manufacturers of factory EFI equipped vehicles have done a very good job of compromising power, economy, reliability and emissions concerns. Any gains you will get in one area will be hard won and will negatively affect the others.

I have considerable experience in tuning my engines for economy so I'd like to think that I know what I'm talking about. I also have a 91 Sprint and a 91 Miata in my stable. They work so well from factory that I wouldn't even consider modifying them. My Sprint is a $900 beater with almost 300,000 km on the clock. It averages 58 mpg Imperial in summer, 56 in winter. I don't know how I could improve on that.

Why would lean burn not be achievable? Its been proven many times that leaning out the mixture at low loads at highway speeds results in a big jump in economy. Of course there are tons of variables and you would need a good base to start from, specifically something already designed for economy. But to say its not achievable based on only your experiences is a little harsh.

[cycleguy]

Originally Posted by E4ODnut

Sorry to shock you into reality, but unless you are very knowledgeable in the art of engine tuning, and are prepared to spend a lot of time and not a small amount of money in the process, what you are seeking is not achievable.

The bottom line is that all the OEM manufacturers of factory EFI equipped vehicles have done a very good job of compromising power, economy, reliability and emissions concerns. Any gains you will get in one area will be hard won and will negatively affect the others.

I have considerable experience in tuning my engines for economy so I'd like to think that I know what I'm talking about. I also have a 91 Sprint and a 91 Miata in my stable. They work so well from factory that I wouldn't even consider modifying them. My Sprint is a $900 beater with almost 300,000 km on the clock. It averages 58 mpg Imperial in summer, 56 in winter. I don't know how I could improve on that.

Well, I guess I better quit trying to Ecomod my Metro entirely. While I'm at it, I can quit all the forums and just rely on the auto manufacturers to meet my needs. Thanks for the support. Remember - never question anything and never strive to do better than others have done. Cheers.

[steffen707]

Originally Posted by cbaber

I need to do a bit more research on the tuning but if you could tune the ECU to run a lean mixture from certain loads and speeds that would be good. Running lean-burn in high load situations and at high rpm is not very effective. You need to be at low load at a steady speed at low RPM. I wish there were some tuners on here to ask if it was possible to set something like this up with emanage ultimate which seems to be the easiest option.

Since my engine already has lean burn I just want to control when it happens with my own settings, not with the stock ECU. With the stock ECU if will kick you out with intake air temp changes, TPS going over a certain amount, etc. I would love to have a more free running system for when I am driving on the highway.

I contacted hondata about this, and they said they don't bother with the vx and don't even have fuel/ignition maping for it. That ecu is a rare bird, and I expect tweaking with lean burn will be very difficult, and potentially catastrophic to the engine. I am however very interested if anybody does play around with making their d15z1 lean burn more without issues. Bring on the mpg!

[steffen707]

Originally Posted by cbaber

Why would lean burn not be achievable? Its been proven many times that leaning out the mixture at low loads at highway speeds results in a big jump in economy. Of course there are tons of variables and you would need a good base to start from, specifically something already designed for economy. But to say its not achievable based on only your experiences is a little harsh.

Also remember that the d15z1 and I think the HX motor as well have special swirl combustion. hey're designed to withstand the high heat that is created in lean burning.

Try taking a stock d16z6 si engine and just lean the fuel injectors out to 20:1 air fuel ratio and you're going to destroy the engine. The engine has to be designed to go to lean burn in the first place.

Sure leaning out the A/F ratio to like 14.7:1 from 13:1 will realize a gain, but from my limited tuning experienece, you don't want to mess with high AF ratios on a normal engine.

"VTEC-E is a variation of SOHC VTEC which was used to increase efficiency at low RPM. At low RPM, one of the two intake valves is only allowed to open a very small amount, increasing the fuel/air atomization in the cylinder and thus allowing a leaner mixture to be used. As the engine's speed increases, both valves are needed to supply sufficient mixture. A sliding pin, which is pressured by oil, as in the regular VTEC, is used to connect both valves together and allows the full opening of the second valve. The engine runs at normal performance using the second cam position that would typically be tuned for high-RPM performance in other two-stage VTEC designs."
Taken from http://en.wikipedia.org/wiki/VTEC#VTEC-E