The forgotten HX - Story of an '01 Civic
 

Lean burn.

The best thing since sliced bread and everyone wants it. You have your 5th gen Civic VX, 6th gen Civic HX, and your 1st gen Insight and then it was eliminated for emissions (?) reasons.

But wait, there's more! From 2001-2005 they continued making the HX. It has a 117hp 1.7L VTEC-E engine with lean burn. .gov currently rates it at 31/39mpg. And here is the one I own:
http://ecomodder.com/forum/member-da...civic-side.jpg

I bought it this summer and first fixed a bunch of the problems that made it quite cheap (like replacing the pass. door that the original owner's angry ex-boyfriend scribbled "B*tch" in). Started commuting in it and was getting 40mpg in warm summer temps and light traffic.

First mod, a grill block:
http://ecomodder.com/forum/member-da...rill-block.jpg

This is blocking too much air for summer, but I am leaving it during the winter months.

Next step: remove that spoiler. I have no conclusive proof that it helps or hurts, but I really don't like it. I posted an ad on CL to swap and found a kid that wanted my trunk lid. So, we swapped:
http://ecomodder.com/forum/member-da...no-spoiler.jpg

I also removed my squeaky power steering belt at this time and didn't bother replacing it.

Next step: air dam.

I saw on a Miata forum, that someone had used paver edging to build an air dam. It was about the right depth and is nice and rigid. I also looked at a garage door seal that is popular for doing the same thing, but I'm pretty sure it would deflect which would defeat the purpose.

I pulled off my bumper last night and got to work. Here you can see it attached, as well as an unmodified piece of the edging.
http://ecomodder.com/forum/member-da...ver-edging.jpg
There is also a new upper grill ($20 shipped off eBay) with a coroplast grill block. It's a very poor fit, but it will do. This is also new tonight. The edging is held in place with 1/4-20 screws/nuts with fender washers. Since it is so rigid, this only works because the bottom of the bumper is flat.

There is also a lot of damage to the underside of the bumper, and this helps reconnect a lot of the pieces and stiffen it all up.

And here it is on the car:
http://ecomodder.com/forum/member-da...ivic-front.jpg
http://ecomodder.com/forum/member-da...1-civic-22.jpg
http://ecomodder.com/forum/member-da...civic-side.jpg

Not bad for $30 total.

My only concern is that you've gone too far on blocking off the air. A $1,000 to $3,500 repair bill does not offset the .5mpg you might be saving by letting in a bit more air down low.

Another "Hot" tip, form a guy who's been there, Change Your Thermostat!!! Cheap and easy to do, crazy easy, and it could save you the $1,000 to $3,500 repair bill if it overheats. Mine went out on me in Atlanta last spring and made a leak in my head gasket which is almost certain to happen when it over heats. It was due for a new timing belt anyway so I combined the 2 repairs and got away for $1,200. But in the back of my mind I always wonder if a screw wasn't tightened just right and I'm left walkin.

But I digress.....

Excellent job otherwise in all respects on you great HX!!

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

The mods look good!

Yes, that is a concern, but the Ultragauge is keeping tabs on my temps. On my commute in this morning, it never got over 195°F but it's about 40°F outside. I'll open up the lower block when it gets closer to summer and temps warm up.

In spite of the cold temps and heavy rain/standing water, for the highway leg of my commute: 59.6mpg.
http://ecomodder.com/forum/member-da...31-59-6mpg.jpg

I won't be able to keep it up that high though, I reset after the car was mostly warmed up and I had driven through the portion of my commute with more stoplights and traffic.

Curious how you can tell if it has lean burn. My dad has an '01 sitting around with a bad rod bearing that he's too busy to fix. It has the 1.7, but im not sure of its vtec. 5spd

Well, all the US market Civics in '01 had one of three 1.7L engines. The DX and LX have a non-VTEC engine. The EX has VTEC, and the HX has VTEC-E (E for economy). The trim level should be displayed on the rear of the car, but the emblem could have been removed.

The HX was only a coupe, so if you have a sedan, it's not an HX. The O2 sensor in the exhaust manifld should have 5 wires.

You could also run the VIN through this to determine if it is an HX:
Home : Free VIN Decoder - Vehicle Identification Number Check

That's a good question, about why they don't offer lean burn anymore.

The 5-speed Insight had an ULEV rating, even with lean burn: ULEV = "emits 50% less polluting emissions than the average for new cars released in that model year."

So I have to wonder if it was eliminated more for driveability/consumer acceptance reasons.

I think you made the right decision - that style is more likely to hurt MPG.

For comparison, Honda did put this drag-reducing spoiler on its 2001 Civic sedan. Most OEM drag-reducing spoilers on high-MPG cars are flush mounted, and fairly subtle, like this one is:

http://www.coches.com/fotos_historic...2001-03_r4.jpg

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.

Subtle indeed. I don't think I've ever noticed one on an actual car.

I figure there is a chance that the spoiler could be near the right height to reattach airflow, but I doubt it. No chance for any thorough testing, but I won't miss it either way. It was kinda ugly, and I much prefer the clean look it has now.

Upcoming plans: lowering it an inch or so and full moon discs.

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.

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!

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.

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...

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.

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.

ratio
 

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.

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:
http://ecomodder.com/forum/member-da...fullmoon02.jpg
http://ecomodder.com/forum/member-da...fullmoon03.jpg
http://ecomodder.com/forum/member-da...fullmoon01.jpg

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.

Very nice look !

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

Very cool! Which brand did you wind up getting and how do they mount?

They are authetic Moon Eyes discs:
Mooneyes Online Store - Specialty Equipment Manufacturer, Speed and Custom Parts for Motorcycles and Automobiles

They just snap in. I say "just", it's a REALLY tight fit. They aren't going anywhere.

Very nice discs.

Yes, I'm also seeing difficulty getting heat from an under-utilized engine. We had two 15 degree F mornings here this past week! I already insulated the valve cover and have a belly pan. Thinking about insulating the hood but its pretty cold out for that kind of work.

Ah hell! This morning another driver veered into my lane to avoid getting in an accident. I swerved to avoid him and we all managed to not hit anything...

Or so I thought. I got real close to the curb and when I checked the car out I found I just caught the curb with my new moon discs! Argh! Only had then on a week!

No dent in them, just some scuffing on about 1/3 of both passenger side discs.

<sigh>

Ouch. That stinks. Glad you and the rest of the car are alright.

They'll get scuffed up and smudged really easily. My policy is just to ignore it. You'll probably lose some of them in future, too, as they loosen over time (I've lost two so far, both on long road trips).

Yeah, it's just frustrating it happened in the first week of having them on.

On the plus side, after I filled up this morning (and it was therefore mostly warmed up) I headed in to work and averaged 61mpg:
http://ecomodder.com/forum/member-da...4568-61mpg.jpg
Never did that well before, and temps were only in the high 20's this morning. It's not scientific, but I'm sure some is attributable to the moon caps.

VMan, do you notice any squeaking with yours? I really only notice when the windows are rolled down, but there is definately a rhythmic squeak that corresponds to wheel speed.

Yes! I never drive with the windows down, though, and I can't really hear it at speed. So it only bothers me when pulling into my parking space where I have to drive between two buildings--you can really hear it then, reflected off the flat surfaces.

BTW, is that an Ultragauge?

Yep, that is my Ultragauge. Never leave home without it!

There are three panels of 6 gauges, that is the one I leave it on most of the time. The new Ultragauge looks a little different, but it mostly the same.

One thing to note in that picture is that it also shows my odometer. Because I key-off to kill the engine, I actually drove 25.3 miles not the 24.2 that it shows...

Kill switch - Engaged!
 

Well, I got the kill switch sorted out.

I cut the yellow/black wire flagged with tape here:
http://ecomodder.com/forum/member-da...6-19wiring.png
(Actually the same wire, but on the backside of that connector)

More details here:
http://ecomodder.com/forum/showthrea...ons-22602.html




And if anyone else is wiring one up, a friendly reminder to change your cabin air filter. They shouldn't be left in there for 160k miles...:eek:
http://ecomodder.com/forum/member-da...nairfilter.png

The filters sit in little trays, so don't be freaked out like I was when you open the box with new filters and you only have these wimpy looking filters with no thick plastic, they're just inserts. Pop em out and pop the new ones in, Bada Bing.

And Darcane....ewww, gross, does your car work in a coal mine er sumthin?

Yeah, you can see in the picture that the new filters aren't in the trays, the old filters still are.

No coal mine, just lots of time. I believe those are the original, OEM filters I pulled out of the car. 13 years, 160k miles. If I took a close-up pic, you could tell it is mostly seeds, pine needles, bits of leaves and that sort of thing, and, of course, lots of dust.

Pic of kill switch installed:
http://ecomodder.com/forum/member-da...llswitch-s.jpg

Works great. In spite of bad conditions on this last tank (awful traffic, record heat, record rainfall/flooding, return of random miss that put engine in limp mode with 1500rpm idle) I got 47.1mpg.

You know your a hypermiler if... You get a dorky smile and stare when you spot a Civic HX or VX!

Maybe when I decide to upgrade Civics I will find a nice 7th gen HX. Lean-burn is just awesome for highway driving. I miss it (mine isn't working due to EGR valve).

Well, there seems to be something missing in my car...



http://ecomodder.com/forum/member-da...ng-missing.jpg


I'm doing a pretty major overhaul right now:
New (well, rebuilt) transmission
New clutch
New timing belt, water pump, etc.
New/reinforced motor mounts.


Going through the suspension too:
http://ecomodder.com/forum/member-da...leaked-out.jpg

Struts are completely shot and have leaked out all the shock oil.

It's getting:
New shocks and struts
Ground Control coilovers
New LCA bushings
New ball joints
New sway bar end links.

I think that's everything. Anything else I ought to do while I'm in there?

Well, didn't exactly go smoothly (last guy that did the timing belt tensioner overtorqued it and the threads came out with the bolt, yikes!, also medical issues) but it's done. Which is good, since I was really getting tired of driving the wife's playtoy ('01 Mustang vert).

http://ecomodder.com/forum/member-da...ntrol-rear.jpg
http://ecomodder.com/forum/member-da...trol-front.jpg
New Koni STR.T shocks and struts and Groundcontrol coilovers. Anyone know if there are supposed to be covers on the side of the engine compartment? For both the steering rack and where the compliance bushings are? I have none on either side. You can also see my polyurethane bushings on the control arms and engine mounts here.

http://ecomodder.com/forum/member-da...gine-going.jpg
It rained buckets and had a tremendous thunderstorm while I installed the engine. probably not the best time to be under a steel engine hoist...

Still needs a little tweaking of the coilovers and an alignment, but it is back to being my commuter.

And a couple pics as she sits now:
http://ecomodder.com/forum/member-da...2013-10-04.jpg
http://ecomodder.com/forum/member-da...4-civic-02.jpg

Lookin good!

Small change:
http://ecomodder.com/forum/member-da...ew-battery.jpg

New Optima Yellow top battery to replace my failing battery. In our recent cold weather, it wouldn't start reliably and prevented me from leaving the engine off at stoplights. Plus, every time it got too low, the ECU would get reset and would have to relearn the idle wasting even more fuel.

a bit o honey
 

Im just joking those snap in caps loosen up over time.
I lost one b4 I learned a trick use a dab of clear silicone sealant on 4 tabs b4 snapping into place.
Recap tube and toss leftovers into spare tire location should remain usable for about 1 year.
If they start squeeking again on bumps and such its time topeel off old stuff and reapply.
Be assertive when popping caps on also or it will turn or pitch smearing your blobs of sealant everywhere. "no workee"