Thinking of Civic DX to HX Conversion (lean burn engine)

[euromodder]

Originally Posted by vskid3

Unfortunately, most of my city driving is done in an area with steep hills and/or a stop sign every couple hundred yards.

You could start asking the local government(s) to remove those stop-signs where they aren't absolutely necessary, and replace them by the yield sign :


Having to stop again and again with no crossing traffic is a totally unnecessary and huge waste of fuel.


Over here in Europe we give main roads priority, while the roads have to yield to the main road.

[California98Civic]

The WAI was as easy as you imagine--even easier maybe. The stock intake tube terminating at the front right lifts off the resonator quite easily. Then I took the filter housing cover off because the tube did not want to come off easily, so I wanted to investigate. Turns out the tube has little ridges on it so that when it is installed it becomes more difficult to disconnect. I cut down the ridges/teeth (there are two) with an exactoknife and then banged out the tube from the housing with a small hammer. Then I decided simply to let the filter housing draw the air from the top of the engine compartment as a first experiment. That seems to possible work, though I also reduced weight and further inflated my tires on that tank, so... results are confounded. Right now I have begun experimenting with building my own curved tube using PVC plumbing pipe, hoping to position the opening close or closer to the block for hotter air. Hope that helps!

[California98Civic]

Originally Posted by vskid3

There isn't really any weight reduction I could do. I have nowhere to put my tools besides in my car, but they only weigh about 30lbs. The back seat is usually being used by passengers, removing it would just lower my people moving efficiency.

I hear you. I have little in passenger demands, just my eight year old daughter. Spare tire? Jacks? Linings in the trunk? I have seen the eco-modder wiki calculations that suggest 0.5% per 100lbs, and I am just using that unscientific rule of thumb. I'm looking for 226lbs to remove (10% of the civic couple's curb weight). I took out more interior lining and today will remove the rear seat belt assembly. Total should be 25lbs. The air conditioner goes next (maybe 35-50lbs). Then I thought I would swap the battery because street racers use the 8lbs batteries, which would save probably 12lbs over the standard. From there the ideas get quite drastic, and I would rather not change much about the look and feel of sitting upfront, where I spend a lot of time, so maybe I will not make the 226lbs figure after all.

[PaleMelanesian]

You're missing a big part of the HX advantage - gear ratios. If you swap in an HX trans, you'll get a big highway boost. Even better is the 92-95 CX/VX transmission.

Aerodynamics will help a lot at those speeds.

Neutral coasting when you can will also help. Running the engine at 3000 rpm is a waste no matter what throttle setting you have. Idling at <1000 rpm is much better.

[vskid3]

I found a different route that lets me bypass that particular area with a lot of stop signs, so that should save a bit.

I removed the air tube to make a WAI, I didn't even need to hammer out the tube after cutting the tabs out (thanks for pointing them out). Haven't gone more than a few miles per trip since then, so I don't know how hot it really gets. The intake is noticeably louder at low rpms and moderate throttle, I kinda like it.

Are you sure the HX has different ratios? I've seen some things saying that, but it seems like most said they're the same as the DX. Could someone with an HX post their RPMs at a given speed in 5th gear?

For some reason my Ultragauge is giving me an average reading that is way too optimistic. I'll have to check if the gallons and miles readings are correct. Should I calibrate it with a highway tank or use several tanks of my typical driving? I think I'll calibrate it with a highway tank so I can at least get an accurate instant number at steady speeds.

I gassed up yesterday, $3.77 a gallon! This weekend is probably going to involve long hours at the hardware store and with my car. Anyone happen to know where to get coroplast/abs sheets in the Monterey/Salinas area of California?

[PaleMelanesian]

I'm running ~2500 rpm at 60 mph in my DX. Stock gears.

My daily commute only has one stretch as high as 55 mph, so the gear ratios are not a problem for my driving. When I do take it on the highway, the mpg falls flat on its face.

[California98Civic]

Originally Posted by vskid3

Anyone happen to know where to get coroplast/abs sheets in the Monterey/Salinas area of California?

I just located a supplier here in Orange County CA. It is a small quantity we need, by their standards, so I have found they're a little reluctant to supply. I made a deal. I recommend calling around and being really polite and accommodating.

Please report back how the WAI does for you, if you get the chance. I don't have a gauge, so it would be interesting to see your numbers since we have nearly identical cars and both live in California.

[Pendragon]

Originally Posted by California98Civic

I hear you. I have little in passenger demands, just my eight year old daughter. Spare tire? Jacks? Linings in the trunk? I have seen the eco-modder wiki calculations that suggest 0.5% per 100lbs, and I am just using that unscientific rule of thumb. I'm looking for 226lbs to remove (10% of the civic couple's curb weight). I took out more interior lining and today will remove the rear seat belt assembly. Total should be 25lbs. The air conditioner goes next (maybe 35-50lbs). Then I thought I would swap the battery because street racers use the 8lbs batteries, which would save probably 12lbs over the standard. From there the ideas get quite drastic, and I would rather not change much about the look and feel of sitting upfront, where I spend a lot of time, so maybe I will not make the 226lbs figure after all.

Leave the spare and jack in the car otherwise you will be stranded in a potentially dangerous circumstance if you have a flat tire. Work on some aero instead.

[vskid3]

Originally Posted by California98Civic

I just located a supplier here in Orange County CA. It is a small quantity we need, by their standards, so I have found they're a little reluctant to supply. I made a deal. I recommend calling around and being really polite and accommodating.

Please report back how the WAI does for you, if you get the chance. I don't have a gauge, so it would be interesting to see your numbers since we have nearly identical cars and both live in California.

I found a sign shop near me, I'll send them an email (the only time they're open is when I'm at work).
Unfortunately, my driving for each tank varies, so it'll be hard to see a change from the WAI. And I plan on doing a few more mods before the end of this tank, so like you I won't be able to tell what exactly helped. I will be able to see how hot the intake air is with the Ultragauge and see if it even makes the air warm. After I get my mods worked out and my Ultragauge calibrated correctly I'll probably do an A-B-A test with the normal vs WAI.

[rkcarguy]

I would have all kinds of recomendations, mainly involving your ECU......but I see Cali as your location.
This means no OBD-1 conversion or tuned ECU, wouldn't even be sure if the HX swap would pass with the stupidity going on down there, unless you plugged the factory ECU back in for test time.
Up here in WA I had a friend help me convert my 1996 DX to OBD-1 (92-95 ECU)and he also chipped it. In stock form it was lucky to see 30mpg. We were able to lean the cruise air/fuel ratio to around 16.5:1 before it started having any surging or pinging, and backed it down to 16:1 resulting in a 3mpg gain. 2nd, I lowered the car. With the air pressure high the tires will wear more on the insides, but mileage went up. If you have non-directional tires they can be flipped on the rims and their life doesn't suffer much over normal.
I installed a cheap short ram intake, new plugs and wires, and now we see 36mpg and a couple times over 40mpg. The car now has over 207K miles on it.

For the record, I am a big hater of the WAI. There is more energy to be realized in less of a cold air/fuel mixture vs. a warm mix. In a lean burn engine this can be doubly bad, as the detonation threshhold is one of the governing factors as to how lean the mixture can be made. A hot engine is going to ping earlier than one sucking in nice cold air, and the ECU will add more fuel and pull back timing to counter this.
A WAI is just a driver aid, like putting a stop on your throttle so it only opens 1/2 way.