my quest for more MPG's

[mugencivic4dr]

The reason for this thread is to show my progess (if any) on achieving more MPG's out of my 92 EX (auto). Hopefully if anyone else has the same interest in this subject maybe this thread would be of some help to them. This will probably be a slow progress and with every little thing done to improve my mpg's will be posted/documented in this thread.

First of i have a 92 EX (auto) and so far my average MPG is around 23, which consist of about 75-80% highway and 25-20% city and straight hwy i get almost 27 mpg (which is close to the goal i want to hit). My goal is to get as close to 30mpg as possible, but of course with city driving involved it'll be almost impossible, with the city & hwy i do i want to hit 25.

In order for me to reach this goal, there will be excessive coasting and driving like on old person lol. Later on the road I will be planning on body mods (front lip, side skirts, sunroof visor, and full under body diffuser) that will help out as well along with lowering the car. When each of these "mods" are installed I will post on why I personally feel it'll improve mpg's.

Second, the type of gas I'm using (company) is Shell (occasionally Chevron) Why Shell gas? Because from my experiance with different gas companies, Shell burns a bit slower. I'm not going to go into detailon that but all i can say is go try it for yourself.

Thirdly, there are a couple parts that need replacing that I feel may help me reach my goal. The fuel filter needs to be changed out and the transmission ecu needs changing as well. Hopefully with these 2 parts replaced, the car should drive smoother.

If this is in the wrong section, feel free to move it to the correct one

[GeoffM]

The fuel pump needs to be changed out and

From what you've described, this will not help you one bit.
When the fuel pump goes, it goes. It's not partially out.
High flow fuel pumps won't help you for power or MPGs.

I use mostly Speedway and occasionally Costco gas, and get about what you do.

[Losiracer2]

-put a cold air intake on (netted me 3mpg on my DD)

-add an H23 Plenum on your EX intake manifold. Since the plenum is 3x the size of the F22 one, you'll have more air in reserve and your engine won't have to work as hard which means it'll be slightly more efficient.

Those two mods alone should give you 4 mpg.

[wildBill83]

The bigger plenum seems to only be efficient if you can keep your foot off the throttle I did an H22 plenum and double stacked IABs (one gutted) and lost MPG. May have been because of my idle being a tad high from a vacuum leak as well.

I would think you would want to do mods to a F22A1 and put low rolling resistance eco tires on with eco smooth hubcaps.

[deevergote]

In most cases, more airflow = more fuel needed. Therefore, the more air you take in, the more fuel your ECU will dump. You can tune the ECU to lean it out a bit, which could result in an increase in MPG... but the stock ECU is programmed to react to the stock components, so when you alter those components, the ECU doesn't know what to do.

[cloudasc]

Here's my contribution to the thread..

1. Reduce unsprung weight, eg. find the lighests wheel and tire combo you can live with.
2. Change the nut behind the wheel, eg. driving habits, when driving pretend there are raw eggs glued to your pedals, and if you press too hard, they will explode all over your interior, as one example.

[deevergote]

To address the first post:

The added aero parts will also add weight... so the benefit may be negligible, or non-existent altogether.

Quality fuel is quality fuel. It really doesn't matter what brand, or what additives they use. Believe as you wish, but especially in old cars such as ours... it matters very little. (also, only use 87 octane... if you're using anything more, you're wasting money.)

The fuel pump either works or it doesn't. Changing a working fuel pump won't do a damn thing to help our MPG.

Is your transmission computer throwing error codes? If not, replacing it likely won't change a thing. Don't start replacing random parts because you simply assume they are bad.


Here's a list of things that actually might help:
Have your injectors cleaned and balanced by a reputable company.
Do a compression and leakdown test on your engine. Repair or replace the engine if the test shows a problem.
Use OEM ignition components... distributor cap, rotor, plugs, wires... and make sure they're in proper condition.
Clean and tighten all ground points. A fancy grounding kit is not necessary, but the factory connections should be functional.
Be sure all engine and transmission fluids are fresh, and the correct type (OEM here is always smart, ESPECIALLY in the transmission.)
Be sure your exhaust system is functioning properly... including the catalytic converter (if that is clogged, the engine must work harder to force exhaust through.)
Replace your oxygen sensor with a new Denso or NTK/NGK unit made specifically for your model (if the connector is wrong, send it back and get the correct one. Do not splice.)
Inspect and adjust your brakes. Sticking calipers, a sticking e-brake cable, warped rotors... those things will create mpg-killing drag. They'll also eat your brakes faster, and make your car unsafe. To really do it right, replace all brake components, and replace/rebuild your calipers.

Now for modifications:
Reduce weight. A lighter car requires less energy to move... therefore, less fuel. First, take all your personal crap out of there. Anything that you don't need to take with you on a regular basis should stay home. If you have a bumpin' system, get rid of it. Full size spare? Ditch it. In fact, ditch the donut and jack, unless you're going on a long trip. Invest in a can of Fix-A-Flat (tire guys hate the stuff, but it'll get you out of a pinch), and a AAA Plus membership (good for 100 miles a year.) Don't have passengers very often? Yank the passenger and rear seats and put em in storage. Don't have a need for AC or Power Steering? Pull em. The full AC system, with all related components, has been reported to weigh nearly 100lbs!

Install lightweight wheels. 15" is good. I wouldn't go bigger than 16". Narrow is better as well, though many aftermarket wheels seem to start at 7" wide. Go for 6.5" if you can find it.
Use all season tires of a fairly hard compound. The good thing is, these tires will also be cheap, and have a fairly long lifespan. Harder tires provide less rolling resistance, and therefore require less energy to move. Keep them inflated to 32psi. Some people may even push that higher, but I've found that the risk outweighs the benefit.
Just keep in mind that these tires aren't going to glue you to the ground, so be cautious, and look ahead so you can avoid an accident.

Any airflow mods done to the engine MAY increase fuel economy... but be careful here. Mods will 1) inspire you to drive more enthusiastically, and 2) possibly require you to press the gas harder, as the powerband will be shifted up in the RPM range... meaning low-rpm torque will suffer.
If you modify the engine, consider tuning the ECU. Leaning out the fuel mixture will give you more power AND better fuel economy, if done right (if done wrong, you'll get a busted engine... so research before doing anything!) Remember that buying some random "chipped ECU" on ebay and actually TUNING an ECU are totally different. You're going to need to program the ECU for YOUR setup, not just go with some random program.

[oyajicool]

You may want to try some of these and let us know how well you do.

http://ecomodder.com/forum/fuel-econ...ifications.php

[PR CB7]

will increase plenum volume, but it'll decrease velocity, if anything, a full f22a1 should get better mpg's than any other engine for the accord

if you take a look at the 93 civic vx, which brought the z1 engine, it uses a pipi size throttle with an even smaller TB, the injectors are smaller than factory civics, it has an oil cooler and a wideband style o2

wifeys car has a rebuilt engine in it, im running it on a chipped p06, and its tuned as lean as possible

it averanges 340-360 a tank, nitrogen filled tires, (new tires) full exhaust, honda mtf, lighter ps pulley, injectors and intake has been cleaned, new fuel filter, it was a b1 block so i had to retrofit then oil cooler, and it has an external trans cooler

[oyajicool]

What MPG on that VX?

[wildBill83]

VX is also a lean burn motor right?

[Scolirk]

I'm no expert, but I definitely know that more air = worse performance. 2 months ago I was getting about 600km per tank, roughly 10.5L/100km. My buddy throws in a K&N air filter, suddenly I'm getting about 500km per tank. Maybe I'm doing more city driving than before, but I'm pretty sure that filter is responsible for my fuel economy.

I'm definitely going to check out the link above for mods. Looks like it's a pretty in-depth post!

[deevergote]

I was getting 21-25mpg from my H22A with the JDM P13. I had my P28 street tuned by a competent tuner (though it was a rush job, lacking some tools), and I now get 28-32mpg regularly. When the ECU is tuned properly, I think basic airflow mods can increase economy. Just not with a stock ECU, which will simply provide more fuel in response to sensing more airflow.


And yeah, the Civic VX is a BEAST when it comes to fuel economy! Personally, I think I'd prefer one of those over a hybrid. Way less expensive to fix when something breaks, and far fewer things to break!

Oscar, only 340-360 a tank? 10 gallon tank? My Fit does better than that! I'd expect the VX to do way better, especially if you've done work to it that should make it even more efficient!

[oyajicool]

That is why I asked my question.

[mugencivic4dr]

From what you've described, this will not help you one bit.
When the fuel pump goes, it goes. It's not partially out.
High flow fuel pumps won't help you for power or MPGs.

I use mostly Speedway and occasionally Costco gas, and get about what you do.

my bad, i meant to say fuel filter