The forgotten HX - Story of an '01 Civic

[MetroMPG]

Originally Posted by darcane

I assume the ULEV rating is during standardized tests that may not hit the very specific requirements to engage lean burn. I haven't seen any testing, but I have to assume NOx emissions are high when it's engaged and this a likely reason it was killed.

However, these are only assumptions.

Lean burn was active during testing for the Insight to get the highway ratings it got.

It has a secondary catalytic converter (expensive) that specifically traps NOx gasses, and then catalyzes them into inert gasses at regular intervals. (Insight drivers will tell you about the 'lean burn purge'.) That's why it got the ULEV rating - even with lean burn, it emits less NOx than average.

Honda wouldn't have gone through the expense of adding this system if lean burn didn't register on the EPA tests.

[wungun]

I keep hearing about this Honda lean burn...
I call foul...
I think it's simply just ad copy to help sell cars, a nifty catch phrase.

We all know that an internal combustion four stroke gas engine needs a relatively specific fuel air ratio...
Runs it too lean and bad things happen....very bad things!

[2000neon]

Really? There is no denying that running an engine lean can cause problems, while under heavy load. This is due to detonation which can cause serious problems. However, at light loads, detonation is not an issue, and much leaner mixtures can be run.

It is certainly more than just a nifty catch phrase to sell cars.

Look up greasemonkey's thread "Getting the most out of leanburn", he even has a video which shows his air/ fuel ratio gauge go lean as he enters lean burn. A lot of driver's can actually feel the car the enter or leave lean burn while driving. Honda didn't spend extra money on the cars by installing a wideband O2 sensor just to be able to say it's there.

[KamperBob]

I'm agree with Neon. Anecdote: my motorcycle (Yamaha XT225) comes lean tuned from the factory for (ostensibly) low emissions. The head pipe can glow dull red in the dark. Many fans of the small dual-sport bike tweak the air-fuel mixture for a little more power. They gain a little torque but invariably lose FE in the trade. They're happy with 70mpg but bone stock yields 90 which I prefer.

Lean works. Hyper milers with helium feet are easy on engines by nature so it's good. So overheat is less of a risk. Hot rodders are a different breed...

[darcane]

Originally Posted by Daox

Yeah, just keep an eye on the coolant temp and make sure the e-fan isn't running too much.

It's been cold and rainy, so I've been keeping the heat on high to keep the windows clear and I've run into a "problem" I wasn't expecting. It now takes me nearly 20 miles of my commute to get the engine warm. I guess I'm burning so little fuel that the heater core is all the radiator my engine needs.

The thermostat appears to be working fine, since the temps (slowly) increase to 180°F ± 3°F and then stay there until I got to work.

[turbovr41991]

Originally Posted by darcane

The thermostat appears to be working fine, since the temps (slowly) increase to 180°F ± 3°F and then stay there until I got to work.

I found my Thermostat was stuck open. It would take my car 7-10 miles to get warmed up. After I swapped the it I was warm in about 1/2 the time.

I also try to minimize heat usage. If I need to defrost or blow cold air on the windshield with the AC on breifly. It takes the moisture out of the air very quickly.

[aerohead]

Originally Posted by wungun

I keep hearing about this Honda lean burn...
I call foul...
I think it's simply just ad copy to help sell cars, a nifty catch phrase.

We all know that an internal combustion four stroke gas engine needs a relatively specific fuel air ratio...
Runs it too lean and bad things happen....very bad things!

One context with respect to 'lean burn' is that you're hard-pressed to initiate combustion.
HONDA's CVCC engine,with 3-valve head pre-combustion chambers allowed the spark plugs to light off a relative rich,but small local mixture,with the flame front propagating outward into the leaner,non-stoiciometric mixture.
With the V-TEC engines,HONDA is pulling off the same trick without the expensive castings and mechanicals.I believe that air-fuel ratios as lean as 21-1 can be achieved.Heat is an issue,so the otherwise 'inert' Nitrogen is reacting in to NOX,but the catalysts keep these emissions in check.

[iveyjh]

Originally Posted by aerohead

One context with respect to 'lean burn' is that you're hard-pressed to initiate combustion.
HONDA's CVCC engine,with 3-valve head pre-combustion chambers allowed the spark plugs to light off a relative rich,but small local mixture,with the flame front propagating outward into the leaner,non-stoiciometric mixture.
With the V-TEC engines,HONDA is pulling off the same trick without the expensive castings and mechanicals.I believe that air-fuel ratios as lean as 21-1 can be achieved.Heat is an issue,so the otherwise 'inert' Nitrogen is reacting in to NOX,but the catalysts keep these emissions in check.

I run an AFR of 18-22 to 1 at cruise and never have an exhaust temp over 500*C measured 2" from the exhaust port. Under boost at that ratio I am never over 650*C. The only ratio under load I have to be concerned about is in the neighborhood of 15.6 to 1. Above 16 and under 15-1 I have no problems.

[darcane]

For Christmas, my wife and I agreed to buy ourselves presents and say they were from each other so we could focus on the kids. I picked out some snap on Moon discs and finally got them on:




With the cold temps and having to scrape/melt ice off the car every morning, it's really hard to compar mileage before and after. But, they look cool and can't hurt.

You can also see the air dam a little better here.

[CigaR007]

Very nice look !

Been wanting to buy some but there are no vendors near me and shipping costs to Canada are not worth it.