Ecomodding an automatic '04 Civic Sedan

[California98Civic]

Originally Posted by mpg_numbers_guy

What about when approaching a stop and you've coasted to below 15 mph and the mpg readout is 30 or under? Is it okay to turn it off and coast the last few feet?

If RPM is still over the minimum threshold, usually about 1500/1600 in my experience but sometimes lower, then the computer should have cut off fuel entirely if your foot is totally off the throttle. That would be "infinite" gas mileage. Can you select gears at all? Is the a "L1" and L2" choice on your gear selector?

Originally Posted by mpg_numbers_guy

Wouldn't the gains from that be negligible with the air dam?

Maybe.

Originally Posted by mpg_numbers_guy

... wouldn't the reduced weight reduce coasting ability? Like, when going down even a slight downhill my MPGs jump to like 85...wouldn't the weight reduction require the generation of more momentum in cruising, thus cancelling out the benefit from the lighter weight?

It all depends on your driving conditions. For example, if you drive in traffic where both somewhat hard acceleration from a stop is frequently as unavoidable as friction brake stops, then weight reduction is a good idea. If you have lots of opportunities to coast off all or almost all of your speed, then weight reduction is probably not much of a benefit.

Originally Posted by mpg_numbers_guy

I generally take turns at 15-25 mph (when safe) to reduce acceleration, wouldn't this make that impossible due to the increased steering difficulty?

Above 5 or 10 mph, most people cannot tell much difference between PS and non-PS, in my experience. It's most useful in parking and such.

Originally Posted by mpg_numbers_guy

Aren't the batteries expensive, and isn't their lifespan short enough to where there is no ROI?

Yes, they are more expensive. My Odyssey 1200 with the metal jacket coast over $200 and it lasted 7 years. If you buy the right charger and plan not to draw down the charge very much, using the alt once you get down to 50% charge, then the battery will last ages. I think I killed mine prematurely because I started charging devices on it and not always remembering to plug in at night anymore. If I were doing it again, I would go for lithium batteries. More charge cycles. I jsut could not justify the outlay for a new charger when I have a great one for the Odyssey battery, so I bought another odyssey battery (lead acid). My alt delete is probably worth about 3 mpg. Maybe more. Impossible to measure. I have no idea if it is a great ROI measured directly. But if I think about how much I learned and how these mods and my fuel savings encourage me to keep the car, and then if I remember the cost of Prius in depreciation and insurance... well, every mod to "Black & Green" has pretty good ROI.

[Xist]

You can remove the power steering belt and do an A-B-A. I do not have any proof that removing my power steering improved my fuel economy, but it is only noticeable when I am stopped, and it does not bother me. I did not test it, I needed to move the power steering pump out of the way to replace my alternator, and I just removed it. I have not wanted to pull the power steering from my much-heavier Accord, but I might as well for an A-B-A, and perhaps I would decide to delete it.

Then again, I do not want to drive a car that has a roof that flexes over 50 MPH, so I am not sure what I am going to do with that car.

Air dams are considered to be most of the benefit of a belly pan with only a fraction of the work, but all of the cool kids have belly pans...

I am not now, nor have I ever been a cool kid...

[mpg_numbers_guy]

Originally Posted by California98Civic

If RPM is still over the minimum threshold, usually about 1500/1600 in my experience but sometimes lower, then the computer should have cut off fuel entirely if your foot is totally off the throttle. That would be "infinite" gas mileage. Can you select gears at all? Is the a "L1" and L2" choice on your gear selector?

Yea the auto lets you select third and second gear, but not first. So are you saying downshift when coming to a stop to keep the RPMs above 1600 instead of coasting to a stop in neutral from a distance?

Originally Posted by California98Civic

It all depends on your driving conditions. For example, if you drive in traffic where both somewhat hard acceleration from a stop is frequently as unavoidable as friction brake stops, then weight reduction is a good idea. If you have lots of opportunities to coast off all or almost all of your speed, then weight reduction is probably not much of a benefit.

There are stops on my routes, but my driving style rarely require stopping except for stop signs. Yet. This fall I will be going to college in Virginia, and most of my driving (if any) will be heavy traffic, so weight reduction would seem to be key then.

Originally Posted by California98Civic

Above 5 or 10 mph, most people cannot tell much difference between PS and non-PS, in my experience. It's most useful in parking and such.

The problem with that is that my dad wouldn't let me do that...and since I'm on their insurance until this fall I'm kinda stuck there.

Originally Posted by California98Civic

Yes, they are more expensive. My Odyssey 1200 with the metal jacket coast over $200 and it lasted 7 years. If you buy the right charger and plan not to draw down the charge very much, using the alt once you get down to 50% charge, then the battery will last ages. I think I killed mine prematurely because I started charging devices on it and not always remembering to plug in at night anymore. If I were doing it again, I would go for lithium batteries. More charge cycles. I jsut could not justify the outlay for a new charger when I have a great one for the Odyssey battery, so I bought another odyssey battery (lead acid). My alt delete is probably worth about 3 mpg. Maybe more. Impossible to measure. I have no idea if it is a great ROI measured directly. But if I think about how much I learned and how these mods and my fuel savings encourage me to keep the car, and then if I remember the cost of Prius in depreciation and insurance... well, every mod to "Black & Green" has pretty good ROI.

Out of curiosity, how far can you go on a trip completely alternator-less without going below your 50% threshold?

Originally Posted by Xist

Air dams are considered to be most of the benefit of a belly pan with only a fraction of the work, but all of the cool kids have belly pans...

Since when does an ecomodder care about being cool?

Originally Posted by Xist

I am not now, nor have I ever been a cool kid...

Exactly!

[mpg_numbers_guy]

Decided to go out and get started on my side skirts mock-ups today.

I first measured and cut a piece of cardboard to size. Dimensions used were a semicircle with a 15" radius with two inches below it, as follows:



I then propped it up against the wheel well to get an idea worked in my head of how to go about building and attaching the skirts:



I then used metal plumbers tape to create brackets similar to what California98Civic and MetroMPG did with theirs. I bent the tape double to add rigidity to it. If it holds, great, if not I'll buy flat copper or aluminum bars to work with.

They actually held well on their own to the wheel well:




I bent the lower brackets outward slightly so the skirt wouldn't touch the wheel (currently it's about 1/16" away from touching...not sure if that's okay or not).

Here's the passenger wheel skirt mounted (zip ties were not tied at the time of the photo):

NOTE: this is only the test model the final version will be waterproofed with silver duct tape just like all my other ecomods.




Note on that last picture - my trunk lid isn't removed, it's just open.

Didn't test its durability today but will do so tomorrow. The brackets and skirts offer good mounting places for rear wheel spats, something I'll add when I install the final version of the skirts.

While I had my stuff out I decided to label my car:



I'll update it as my post-ecomodding FE changes tank by tank.

Planning on ordering an official Ecomodder sticker at some point...when I get around to it lol.

Also built a holder for my phone, for Torque fuel economy monitoring of course. Sometimes DIY goes too far:

[Xist]

Not normie cool, but Ecomodder cool.

I once saw some clickbait about some genius college kid that saved a huge amount of money by making his own laptop stand. I say clickbait because it was stupid. It was basically a modified pizza box.

If it is stupid and it works and all of that.

[California98Civic]

Nice work with the skirts, hey!

Yes, shift down to keep RPMs above 1600. You may even be able to feel when the car turns off the fuel injectors a second or two after you begin to coast in gear with a warmed-up engine you might feel a slight shudder or hesitation for an instant. That's it happening. But you don't always feel it.

As for battery, it depends on a few variables, such as day or night, music or now music, lots of stops where I have to key on. But in ideal conditions I can go the 25 miles round trip to work without using the alternator at all. Usually, I start using the alternator on DFCO as soon as the engine is warmed up.

[teoman]

While in dfco, it is ok to use the AC!

[California98Civic]

Originally Posted by teoman

While in dfco, it is ok to use the AC!

So true. I do this all the time in my wife's automatic trans Subaru. Full blast while the electricity is "free" !!

[teoman]

The ac feature really should be automatic or a button on the gear shifter.

While it is free use as much of it as possible!

Especially for those of us who live in dense areas and us the brakes a lot.

If i remember correctly my first set of brake pads lasted 67k km. The dealer was impressed. In some environments, no matter how hard you try it is unavoidable. Had the car been configured differently the brakes could have lasted a lot longer and i would have wasted less fuel on ac and various other accessories.

[Vman455]

Originally Posted by mpg_numbers_guy

I've thought of this, but wouldn't the reduced weight reduce coasting ability? Like, when going down even a slight downhill my MPGs jump to like 85...wouldn't the weight reduction require the generation of more momentum in cruising, thus cancelling out the benefit from the lighter weight?

I'm thinking back to my high school physics here, so someone jump in if I get something wrong--several factors would seem to be in play here:

-acceleration due to gravity: acts the same on bodies regardless of mass
-momentum: proportional to mass and velocity
-rolling resistance: proportional to the product of Crr (which increases with mass), velocity, vehicle mass, and gravity

Assuming identical drag area for two cars with different masses, the question is: does the heavier car benefit from its extra mass by the proportional increase in momentum?

The heavier car will be disadvantaged in requiring more force to accelerate to a given velocity and to maintain it (since a car, even at a steady speed, is acted on by acceleration--the twin forces of aerodynamic drag and rolling resistance are constantly acting on it opposite to the direction of travel, requiring acceleration to maintain a given velocity). The heavier car will also be disadvantaged by more losses to rolling resistance while it is coasting or cruising.

So, the question above becomes: Does the increased momentum of the heavier car outweigh the increased rolling resistance and the necessary increase in force (and power) to achieve a given velocity in the first place? My gut says no--you can't get more energy out of the system than you put into it, and you're suffering more losses (reduced efficiency) during the coast or cruise itself because of the increase in rolling resistance; so the increased coasting distance and increased momentum during cruise likely isn't going to offset the increased fuel required to get up to speed and maintain it compared to the lighter car. But, I suppose you'd have to sit down and actually use your vehicle mass, BSFC, etc. and get some real numbers. (If, for instance, the increased mass puts the throttle in a more open position and at a better BSFC to achieve the same acceleration, it might end up being more efficient).