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-   -   Do Metros have lean-burn? (http://www.fuelly.com/forums/f10/do-metros-have-lean-burn-2438.html)

MetroMPG 07-02-2006 06:05 AM

(Note: decided to move the Metro related babble into this new thread, rather than continue to hijack Dan's Project KBA, KMA thread.)

Dan wrote:
Quote:

http://www.parcon.uci.edu/paper/Cons...on/areasof.htm

I didn't know that the Metro also had lean burn.....

Quote:

Lean burn technology is very effective and current production models like the Geo Metro and Honda Civic VX can successfully achieve 50 miles per gallon. By raising the air-fuel ratio by a factor of 1.67 above the stoichiometric value, a 10% increase in efficiency is gained....

Neither did I.

I haven't seen any information about lean burn at teamswift or in my factory service manual. I think the article you quoted is wrong there.

95metro 07-04-2006 06:44 AM

Quote:

Originally Posted by MetroMPG
Neither did I.

I haven't seen any information about lean burn at teamswift or in my factory service manual. I think the article you quoted is wrong there.

Only the Metro XFi had lean burn.

MetroMPG 07-04-2006 07:36 AM

Quote:

Originally Posted by 95metro
Only the Metro XFi had lean burn.

Are you sure about this?

I've seen several comparisons of the XFi drivetrain design vs. regular 3-cyl Metros, and have never seen lean-burn on the list. I think if it did have lean-burn, its numbers would be even higher than they are.

Would lean-burn require a 5-wire o2 sensor, for example? Both the XFi and non-XFi share the identical part there, and it's a 1-wire affair (for a '94 Metro, according to the rockauto.com catalogue).

I've raised the question at teamswift - maybe someone can answer definitively.

---

PS - anxiously watching this thread to hear about Dan's trip...

95metro 07-04-2006 07:57 AM

Quote:

Originally Posted by MetroMPG
Would lean-burn require a 5-wire o2 sensor, for example? Both the XFi and non-XFi share the identical part there, and it's a 1-wire affair (for a '94 Metro, according to the rockauto.com catalogue).

I don't know. I remember reading that the XFis were lean burn when I first started looking for a Metro (I didn't realize they were US-only at the time). As far as I know, the lean-burn was entirely controlled by the ECU (which is different for the XFis compared to the standard Metros).

I think the ECU may have looked for the lean-burn signal from the O2 sensor rather than lambda, but I don't know.

I actually remember reading that the NOx emissions were higher on the XFi due to the lean burn, but I'll have to find my source again.

MetroMPG 07-04-2006 11:11 AM

Heard back from a teamswift member, who intelligently pointed out that the sentence in the linked article doesn't explicitly say that the Metro has lean burn. Read it again...

Quote:

Lean burn technology is very effective and current production models like the Geo Metro and Honda Civic VX can successfully achieve 50 miles per gallon.
Teamswift guy's interpretation:

Quote:

Originally Posted by teamswift guy
Notice that the author really only says that the Metro can achieve 50 miles per gallon, although he strongly implys that it has lean burn by the way he mixes it in with his comments on lean burn and the Honda.

So it may just be a case of poor sentence construction leading to an incorrect implication. E.G...

Bank robbers often drive getaway cars, and Dan is driving his new VX from Chicago today.

SVOboy 07-04-2006 11:18 AM

I knew there was something odd about dan...

Anyway, why doesn't someone just hook a DMM up to their car and go for a little ride?

MetroMPG 07-04-2006 11:26 AM

Quote:

Originally Posted by SVOboy
I knew there was something odd about dan...

Anyway, why doesn't someone just hook a DMM up to their car and go for a little ride?

Yeah, all that money to spend on cars must be coming from somewhere....

I think I've already done the DMM lean burn test equivalent for my car when I did the speed vs. mpg chart. If there were a lean burn mode, I would think it would show up differently than the essentially smooth line I got. From the reading I've done of Insight drivers, the slip in & out of lean burn mode is blatantly obvious on the instant fuel consumption display.

However, if it's only an XFi feature, I can't test that. But... the owner of the XFi who pointed out the sentence structure issue was also unable to find any reference to lean burn in his service manual.

95metro 07-04-2006 11:55 AM

I have no clue where I got the idea it was. I actually wrote it in my log way back in September/October. Maybe I found a reference to NOx emissions and assumed the XFi was lean burn...:confused:

I'll just say it was due to my brain-cloud. :p


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