[Frank Lee]

...driven nearly 60K miles up and down the eastern seaboard to photo shoots, averaging between 220 and 240 miles between fill-ups. At one point during a long stretch of highway driving, I ran it from full to empty (with a few gallons of reserve in the trunk) just to see what its true mileage was-281, or about 21.3 mpg, based on its 13.2-gallon capacity.

Why even put that in there? Without values for gallons/fill it's completely meaningless. Running it to empty once doesn't change a thing.

...our Integra had been rid of its faulty power steering, air conditioning and ABS systems to cut static mass...

That's all good!

...and given an Unorthodox Racing lightweight crank pulley to reduce rotational mass. Its engine had been upgraded with a custom intake and exhaust to decrease backpressure and increase aspiration, and Hybridynamics of Latrobe, PA, Crome-tuned air/fuel ratios and ignition timing to within safe limits, increasing power by maximizing combustion efficiency. All combined, the modifications gained us 24 whp and 23 lb-ft of torque over stock, and a mixed-driving average fuel efficiency of 31.7 mpg-an increase of nearly seven mpg over the revised EPA estimates, and more than 10 over our starting averages.

Commencing eye rolling in 3...2...1.... A 49% fe increase from that? Color me skeptical. Of course, if "stock" in this case means worn-out, shot, beat, and wildly out-of-tune, then...

I painted it green to celebrate.

I do like the green color.

The US EPA states that for every 10 percent of static mass eliminated from a vehicle, fuel economy improves by seven percent.

2685 > 2065 = 23% weight reduction; @ +7% fe/-10% lbs = +16.1% fe; 31.7 x 1.161 = 36.8... right? FWIW.

Last pic shows total weight of 2060...

Couldn't find any source saying 7%. Has anyone else? Found these:

Originally Posted by NHTSA

For example, the National Highway Traffic Safety Administration (NHTSA), which operates the federal fuel economy program (CAFE), long ago characterized weight reduction as the “most obvious method for improved fuel economy.” A decade later, its opinion had not changed; it characterized weight reduction as “probably the most powerful technique for improving fuel economy,” and it estimated that “each 10 percent reduction in weight improves the fuel economy of a new vehicle design by approximately 8 percent.” -NHTSA, Model Year 1989 Final Regulatory Impact Analysis at IV-15.

^Old, and not EPA...

Originally Posted by fueleconomydotgov

Avoid keeping unnecessary items in your vehicle, especially heavy ones. An extra 100 pounds in your vehicle could reduce your MPG by up to 2 percent. The reduction is based on the percentage of extra weight relative to the vehicle's weight and affects smaller vehicles more than larger ones.

Bah- don't feel like doing that math.

Originally Posted by ford

For every 10 percent reduction in weight, fuel consumption is estimated to improve by 3 percent. EPA: Ford leads industry in fuel-economy gains and CO2 reductions - egmCarTech

http://www.alcoa.com/car_truck/en/pd...vantage_cv.pdf

^This pdf has a graph that I didn't see how to grab and copy. It may be the best breakdown of this issue I've seen. It says a small car will see +4% fe with -10% weight. It says a small car with a resized engine could see +6.5% per -10% weight- an important distinction with "resized engine" being smaller displacement, optimized for the lighter weight. Between this and the Ford piece, I'd go with +3-4%/-10%. But that's certainly debatable.

An itemized list of the component weights and total weight loss sure would have been nice. Odd to use a published weight as a starting point and a measured weight as a finishing point.

Decreasing static and rotational mass, and decreasing drag (improving aerodynamics) increases downforce and braking performance, improves handling, elevates top speeds, decreases acceleration times, and increases power and torque output.

Yes and no. Decreasing drag doesn't automatically increase downforce, especially to the degree braking performance is affected. Torque output isn't affected either.

• The term "drag coefficient" is the classic standard of measurement used to identify a vehicle's wind resistance. In short, vehicles that are tall and boxy are the least aerodynamic, and are rated with higher numerical values, while shorter, narrower, longer vehicles with smooth transitions and less frontal area are more aerodynamic

Pretty mixed-up explanation re: Cd and CdA that is sure to mess up many readers... but at least we know what it all means.

One of a car's more significant areas of drag is the area between it and the driving surface. Lowering a car decreases the amount of air traveling underneath it that can cause drag with points like the wheels, control arms, exhaust, etc. According to Mercedes-Benz, "Lowering the ride height at speed results in a three-percent decrease in drag." Our Integra's aggressive BC Racing coilovers keep the car from bouncing over uneven surfaces, that would otherwise allow an influx of air under the car. Their decreased travel also limits changes in toe and camber over uneven surfaces, reducing rolling resistance slightly.

That's all good.

According to EPA estimates, a 14-percent savings in fuel efficiency can be seen per ten percent of rotational mass removed from a vehicle's driveline.

Source? Is this only for the city cycle? Is this for cars, or semis?

Tires are also significant contributors to rotational mass, as well as drag, and frictional energy loss known as "rolling resistance", which can rob more than 20 percent of an engine's output to the wheels

The tires alone??? Maybe if they're all flat! Or... 20% for the entire drivetrain. Tires don't rob anything from an engine's output to the wheels. Ahhh, that's what he's talking about. Which leaves the whole rolling resistance thing completely unexplained.

Increasing the angle of a car's hood by propping it at the rear isn't always beneficial in and of itself, but decreasing the angle at which it meets the windshield, while covering the windshield wipers, helps cut drag.

Ummm... erm... source?

A tall wing, like the Type R unit or an aftermarket GT-style wing, will increase downforce, but create a large point of drag. We simply removed our small stock wing. Extending the lateral surface area of the trunk with a level, flush-mount wing would make it even more aerodynamic...

Righty-oh!

Getting really picky, side moldings are also another point of drag, albeit small ones. Removing them is aerodynamically sound and looks better.

Good luck quantifying that one...

Low-profile sideskirts, like the ones we obtained from Versus Motorsports, further limit the amount of airflow that can enter the underside of a vehicle, decreasing drag and increasing downforce.

Depends on what's going on up front. Might work here, might not; it wasn't evaluated at all.

One modification we left out when installing bolt-ons in the second part of "Ultimate Efficiency" was the addition of an aftermarket header. Here's why: they generally weigh a lot less than stock, cast steel units. Our two-piece DC Sports 4-2-1 unit shed nearly 15 pounds, and increases mid-range power to bump up fuel efficiency for the daily commute.

If it works at mid-range, great. I think most headers come into play at high revs tho'. Dyno chart shows more power from mid-on.

One area that could use work is the recessed headlights found in the '94-'97 cars, that might as well be thought of as tiny parachutes. Honda realized this, and designed the '98-'01 cars' headlights to mount flush with the bumper.

Info and logic I trust says headlight buckets don't act like parachutes at all, especially with the nice tight gaps "in the buckets" this car has. Honda didn't "realize that", especially for '98. They changed it for styling.

Other significant offenders of drag are a car's side mirrors. Our APR carbon fiber replacements' small, rounded bodies and minimal uprights were designed with reducing drag in mind. Thanks to some brainless NHTSA mandate, OEs in the U.S. aren't permitted to equip cars with convex mirrors from the factory; if they could, mirrors like our APRs might come standard.

Significant? Ehhh... I wouldn't make that a blanket statement tho'. It's possible the stockers are more aero in spite of the size penalty. If convex mirrors have been proven to increase accidents I wouldn't call their banishment "brainless". Admittedly, I haven't looked for supporting data for my opinion on that convex thing.

Decreasing turbulence at the rear of a vehicle is widely regarded as black science in automotive circles; what you might think would make a vehicle more aerodynamic often makes it less so. The general rule here is that air exiting all sides of the vehicle should merge at a significant distance behind the vehicle, and large points of drag, like the rear bumper, should be eliminated.

I think aerodynamicists have a grip on it. And the bumper statement? I don't think so. I like the "what you think often makes it less so" statement- especially since the pics show big vents cut into the rear bumper.

replace the glass with a polycarbonate alternative from Flex-a-lite, which weighs only a few pounds, is scratch-resistant enough to survive years of use, and offers the advantage of being able to be sanded/buffed back to a brand-new finish.

Now that I'd like to see!

As mentioned before, a one-piece bellypan spanning the entire underneath of a vehicle is one of the best ways to improve aerodynamics, and if it ends in a valence at the rear, will streamline airflow and decrease the huge drag point that is the rear bumper. Like with the headlights, Honda revised this area of the Integra in '98, adding a slight cut-out to help pent-up air escape easier. Short of a belypan and valnce, diffusers like these lighterFaster carbon fiber units are one of the best ways to alleviate drag. They're also lighter and more attractive than billet plates of years past.

I think this is more sales pitch than anything else. Pent-up air...

It's too bad, but bellypans haven't proven to be that great; certainly not one of the best drag reducers. Then in the pics we see the ridiculous fart can hanging down...

As aluminum and carbon fiber become more widely used among OEs, electronics simplify and ergonomics evolve, look for interiors to weigh less straight from the factory.

Electronics are simplifying? I thought the trend (and weight) of electronic content was still up, up, up.

Over 40 pounds of sound deadening material was removed, and total interior weight savings ran close to 100 pounds, not including the seats. Even more could be lost, breaking out the drill and angle grinder.

These are realistic numbers.

Honestly, what does a sunroof do besides allow magnified heat to beat down upon your dome? We fabbed up a dry carbon "plug" to replace ours, and lost 35 pounds of top-heavy weight in the process.

If the car no longer has functional heat/aircon/defrost, it may do a lot! But yeah, up top is a great place to lose weight!

Power and torque numbers were measured at our Integra's wheels before and after this round of modification, using MD Automotive's Dynojet dynamometer, and fuel consumption was measured by dividing the distance we traveled during road testing by the volume of fuel expended, calculated by subtracting the amount of fuel drained from our car's tank after road testing, from what was added to it before. Fuel was measured by weight and volume. More than 400 miles of mixed driving were logged to limit margin of error.

Why do rags never exploit dyno runs for fe testing? I need more info before I give street testing like this credibility- like fuel logs or scangauge readings over a statistically significant period of time. I'm interested in more details of their filling/draining/measuring procedures.

It is tough- no, make that virtually impossible- to identify any particular mod as having any particular effect when you throw multiple mods at the car simultaneously.

What can I say? It's raining out and I have no life.

Some of my statements will be edited/clarified/debated/corrected I'm sure. Good.