EcoModding for Beginners: Getting great gas mileage.

[Frankenstipe]

It's simple really, accelerate slowly and cruise around 50 - 60 MPH. That right there should easily save anywhere from 5 - 10 MPG or more depending on how you drove before.

Beyond that is probably a little too much to ask of most people, hell even asking that is like asking someone to loan you a billion dollars, just not going to happen.

[i_am_socket]

My girlfriend was complaining this weekend that I was driving "like a little old lady" doing just that in her car.

"So you don't want me to save you gas and money?"
"No, I want to get there."
"We'd get there in just about the same time with traffic and lights."
"I don't care, you're driving me crazy."

Yeah.

[trikkonceptz]

Originally Posted by i_am_socket

My girlfriend was complaining this weekend that I was driving "like a little old lady" doing just that in her car.

Well the simple question is ... do you pay for her gas?

If you do, then drive the way you want. If you don't drive the way she wants, and save money when you drive your car ...

[timgray]

I'm a hotrodder from way back. I have 30 engine swaps under my belt as well as 15 complete engine rebuilds and 5 custom intakes designed and welded by me.

1 - bigger air intake makes ZERO difference for anything but WOT at high rpm's. In other words unless you are looking for higher HP at high RPM Wide Open throttle (I.E. BAD gas mileage) this change will do absolutely nothing for getting better gas mileage. Also do NOT waste money on those "high flow" air filters. they will do nothing for your car.

2 - Exhaust headers. Bad idea. Again only good for high rpm WOT horsepower. Exhaust manifold logs with a restriction increase low rpm torque and actually increase gas mileage.

3 - Remove ALTernator belt... Get better gains by adding underdrive pullies to your car. This gives you a greater torque gain by slowing down ALL accessories and giving you a bigger boost than the ALT will.

4 - The electric "superchargers", spiral intake inserts, and other crap that claims increases in gas mileage all are 100% fake. dont buy them. I have a guy locally that has the stupid gas magnets, the gas "catalyst", the spiral intake, a cold air intake, and the electric bilge pump fan "booster" all on his car and he still cant understand why he sees no difference in Gas mileage.

5 - dont screw with the ECM unless you know what you are doing. One guy locally leaned out his car and got great gas mileage until he burned all his valves and popped a hole in a cylinder.

I have only 15 years of experience building cars and engines from parts on up, so take my advice with whatever value you want.

[timgray]

Originally Posted by JohnnyGrey

An ECU in closed loop mode will maintain a 14.7:1 ratio regardless of how clogged the air filter is (short of total blockage). Whether your throttle plate or a dirty filter is providing manifold vacuum, your engine does not care, and is burning at 14.7:1 regardless.

Incorrect. The car will ATTEMPT to get to the ratio desired in the AF table for that set of conditions. MOST of the time it is running rich except for cruise plateaus on the AF table.

Very rarely does your car run at 14.7:1.. at least from the 30 or so ECM's I have been in are set for. But then I only program GM cars. It may be different for imports. But even then I cant see how they could ever keeep the AF near that all the time. you always are running rich on acceleration.

[spyderbite9001]

Originally Posted by PA32R

Though it doesn't change your point, air resistance doesn't increase exponentially with speed: r=ce^(ks), it increases as a power of speed: r=ks^2. Here, r is resistance, c and k constants, s is speed.

Misuse of "exponentially" is a pet peeve of mine, sorry.

Sorry to burst ur bubble man, but your looking at the wrong equation. For air resistance yes, it is a function of the square of your velocity (v^2) however, when we talk about gas mileage we should be more concerned with the power req'd to gain/maintain the objective velocity. To calculate the req'd force or power we look at the equation

Power = Force Drag * V supposing that
Force Drag = (1/2)*density fluid*(v^3)*area*drag coefficient

and therefore the growth in power needed, which directly translates to gas mileage, is in fact, exponential.

Reference: Drag (physics) - Wikipedia, the free encyclopedia

[aerohead]

Hello all.I'm very late getting to the general discussion sticky on ecomodding.SVO and others have thrown out some great stuff and of great value to anyone considering mods.I have some tid-bits to add,and I thought I'd add them individually.-------------------------------- Transmissions have a tremendous effect on an engine's ability to transfer power most economically down the powertrain to the drive- wheel(s).I'm not saying that you can just run down to the corner parts store and get a different tranny to shove in your car,but it's important that everyone understands the significance the transmission plays in mpg.------------------------------------- So far,a 12-speed transmission has demonstated the best gain (15%).They exist only in the lab.----------------------------- The Continuously-Variable-Transmission(CVT) is a form of trans thought to promise a 15% improvement in mpg.The Subaru Justy has used this transmission for a few years,and it delivers worse mpg than other cars in it's class.-------------------------------- Presently,Mercedes offers a 7-speed trans,and Lexus just introduced an 8-speed. We'll have to wait to see how they stack up.------------------------------------- The premise for all the gears,is to let the engine remain close to it's "sweet-spot",where it achieves it's highest Brake-Specific-Fuel-Consumption(BSFC),the point of load and rpm,where the least fuel per horsepower/hour or kW/hour are produced.

[aerohead]

This material is from George Wallace,one of Chrysler Corporation's computer whiz-kid's research, that helped them win them the Mobil Economy Run competition, more than once.Wallace recognized from pre-competition tests conducted at the Proving-Grounds,that small-engined cars were"fussy" about hill-climbing,and cooked up the following strategy to deal with road grades during the competition.------------------------------- On level roads,or grades up to 1% they'd drive 55-mph(88km/h).----------------------------- On a 2% grade,they'd fall back to 50-mph(80km/h).------------------------------------- At 4% grade,they'd drop to 40-mph(65km/h).------------------------------------ At 6%,30-mph(48km/h).-------------------------------------------------- The US,EPA claims that maintaining the speed limit up a 3% grade can cost you 32% in mpg.--------------------------------------- Driving the posted speed limit up a 7% grade can cost you 55% in mileage.

[aerohead]

All the show cars and concept cars that get great mpg have special,low-rolling-resistance(LLR) tires.These particular tires are not in production and are not for sale,however,for the tires that are available to the general public,there is a "range" of coefficient of friction(Fr) for the tires available.------------------------------------------A 10% reduction in rolling resistance will net about 3.8% improvement in mpg,for comboned city/hwy driving.------------------------------------ Neglecting your tires,and letting the cold inflation pressure drop 25%,will cost you 1 mpg.-------------------------------- overinflating your tires 25% will net you a 1% improvement,but could destoy the tire,throw you out of control,and kill you,your passengers,and anyone else around you.------------------------------------ Tire manufacturers recommend that you never exceed the maximum pressure embossed on the tire sidewall.--------------------------.Also,it takes about 5-miles (8 km ) of continuous driving to get your tires up to their equilibrium temperature and highest economy.If your car is OBD-2,and should choose to monitor your mods with a Scan-Gauge,bear in mind,that any testing done without a 22-mile (35 km ) warm-up drive,will yield erroneous data,compared to a fully-warmed-up vehicle.In addition to the 5-miles necessary for the tires,all your lubricants will be below their equilibrium temps(and best performance) without at least 22-miles(35 km ) of warm-up.

[aerohead]

75-degrees F is considered"ideal" for testing,according to EPA.------------------------------ At 50-degrees F,you can expect to lose 5% mpg.----------------------------------- At 20-degrees F,you can expect to lose 11% mpg.