Looking for a fuel efficient solution. I've got a few ideas.

[trebuchet03]

Originally Posted by Duffman

I totally disagree for a couple of reasons.

That's fine - but, SAE disagrees with you I couldn't care about marketing - it's the E in SAE I like (but, I am biased )

[RH77]

Originally Posted by Big Dave

If you are willing to trash your car, you might squeeze 1-2 MPG out of it, but don't kid yourself you can make the engine run any better than the factory engineers can.

Vehicles we buy have one big compromise: Mass Production.

To that end, consistency for the average driver and cost reduction measures are generally utilized to pull a profit and ease the manufacturing process (plus extra horsepower we don't need).

EcoModders take this compromise and fill the gap. We can specialize our vehicles for how we intend on using them. So on the opposite end, to squeeze a few more seconds out of the quarter mile, people kid themselves that they can make the engine run better?

RH77

[Duffman]

Originally Posted by trebuchet03

That's fine - but, SAE disagrees with you I couldn't care about marketing - it's the E in SAE I like (but, I am biased )

Oh, your going to need to do a little better than that (links please ) as I have a little e in me as well.

[njlou]

Originally Posted by Big Dave

The guys/gals with the most success pound away on three areas: driving, aerodynamics, and gearing.

If you are willing to trash your car, you might squeeze 1-2 MPG out of it, but don't kid yourself you can make the engine run any better than the factory engineers can.

Look at the folks who have the goods and imitate what they do.

How true!!
You have to start with a high miler to get high MPG.
The mods you originally responded to will only yield a few MPG at the most.
You can do the obvious ie: tire pressure, air filter, plugs/wires, lighter oil, cut baggage and carry-ons, vacuum gauge, MPG guage, some light aeros, etc. Gutting the interior and other radical removals will yield minimal results. Slow driving will yield the most. The loss of (any ) value to the car will be more than any "savings" in gas.

[1.5Ldave]

Keeping the car washed and waxed as stated above will keep the car looking nice, but wont help with FE. The boundary layer is far thicker than the fraction of a millimeter that dust is.

Also be careful switching to synthetic oil, it has smaller molecules than conventional oil and will make any leaks worse. This is especially true for high mileage motors. Even if you dont see any leaks, switching to the synthetic might cause some that werent bad enough to let the conventional out, but will let the synthetic out.

[BlackDeuceCoupe]

Originally Posted by CuriousOne

Misc. Exhaust Modifications - Most exhaust components are made of cast iron (which is much heavier than steel, stainless steel, etc.), and some are crush bent and just overall very restrictive which creates backpressure. Backpressure in an exhaust system is never needed...

Any other ideas...?

This a popular misconception!

Almost all motors have valve overlap (intake & exhaust valves open at the same time). Exhaust backpressure keeps unburned gases in check during valve overlap!

Actually, this is one of the best things about direct gasoline injection - valve overlap doesn't affect FE - but that's a different discussion...

Anyway, what you *need* is negative overlap, if anything, e.g. exhaust gas retention, if you want to get the best mileage, NOT a free flowing exhaust system that sucks unburned fuel out your tailpipe.

Many, many ppl don't believe I get 40+ MPG with a high-performance B16A2 engine - been called a liar several times!

One of the ways I do this is by using an OEM airbox, OEM cast iron header, OEM midpipe, OEM cat, OEM resonator. The only aftermarket stuff I use in my intake/exhaust system is a K&N air filter, and Tenzo R muff - that's it. And, that's the biggest reason I get great FE!

Anyway, that's my recommendation - don't free-up your exhaust if you're looking for better FE...

[BlackDeuceCoupe]

Originally Posted by DifferentPointofView

WOAH WOAH WOAH!!! wait a minute. in order for best efficiency or best power, a balance of back pressure vs. exhaust flow is needed.

Oops!

I should have kept reading... Nice write-up!

Anyway, I can confirm everything YOU said...

My ride is living proof-of-concept!

[BlackDeuceCoupe]

Originally Posted by RH77

Consider the stock exhaust on the Civic VX -- very restrictive, yet very efficient -- hmmm...

RH77

Thank you!!!

[BlackDeuceCoupe]

Originally Posted by 8307c4

Increase Tire Pressure - Don't go past max.psi sidewall, you'll only wear the tires down the center, but max.psi sidewall is the best psi.

Originally Posted by trebuchet03

Prove it...

Using my ride as an example - I just ran outside and took some unmolested snappys.

• Pirelli P3000 tires: bought on 17-Sep-2004 (been on two different HX CiViCs)
• Rotated once on 11-Nov-2007, when I had a flat (picked up a sheetmetal screw).
• 60,000+ miles @ 45-50 psi (I only check them once a month, give or take)

Some feathering can be seen on the rear tire (left-side center blocks). This was the ONLY tire that had screwy wear, and it happened on my other HX, not this one. Probably an anomaly, defect, alignment problem, or because I've only rotated them once in 60K miles.

Sorry for the dirt and rocks, but we had severe thunderstorms here last night!

[NeilBlanchard]

Hi,

On my Focus ZX-5, the 205 16/50's were quite sensitive to inflation levels. Too much would wear them in the middle.