How much? and Where?

 

Inflate tires to max sidewall pressure? That is a VERY bad idea...

 

I had seen in an ealier post in this topic that you should turn off your ac to save on gas. That is half true and I would like to point this out for everyone's benefit. on a hot day you are either gonna roll the window down or turn on your A/C... especially you guys down south. Now rolling down the window helps while you are moving and not while you are waiting at the stop sign or red light. I read (and it has been proven, I just don't know where) that keeping your windows open up to 40 MPH is more efficient when trying to save gas. After 40 MPH you should use your A/C cause at that point the drag faced from moving becomes more of a gas user then using the A/C.... Sorry I don't have a reference to prove this statement. But I hope this help a few of us out.

 

I too have read that ^.

I read 2 or 3 articles a while back that said under 50mph windows down is more efficient. Over 50mph, turn on the air.

I wish I'd have kept those articles bookmarked!!!!

 

mythbusters

 

Yeah those guys are amazing.... I loved it when they blew up the dump truck, and the otehr time when they tried to create the "brown noise"

 

Cheapest way to improve fuel economy is weight reduction. Start stripping out the fluff.

Um...what?

 

Checkout gassavers.org, and cleanmpg.com. They have some interesting ways to help mpg. And most have been tested to great extent.

 

Drive down hill

 

Intake, full exhaust... make sure your tires are inflated properly, dont carry a lot of **** in your car. Lowering the car for less drag.

 

on a drive home from seaside i averaged 46.3 mpg on the highway. no cruise control, avg 60 mph. all i have is intake, eibach sportlines, and 205/40/17 nitto's

 

so basically the lowest RPM in 5th gear.
With a Vector tune + intake, I get an average of 8L/100km (~30MPG) when doing about 85% city + 15% highway

One more tip:

Use your cruise control as much as possible, the ECM leans out the A/F ratio a bit

I saw tests that have been performed on this. If you are swetting and need some fresh air:

Under 60 km/h (~35 mph), put your windows down
Over 60 km/h (~35 mph), turn the AC on

You will maximize your efficiency that way. Of course the best is to sweat your ass off and drive with your windows up and AC off

 

i need help to get better mpg for my car ? any performance parts that can help? igot a 2008 cobalt ls coupe red

 

That's what I always do.

I usually inflate each tire to 35. Should I inflate them to 33 instead since the psi goes up like 2 when you start driving from cold tires?

QFT! I've seen a great difference in MPG between using CC and not using it.

Read this thread. They were stated many times.

 

Take a dump before getting in the car...

Seriously though, get the Trifecta tuning.
People are getting serious gains in fuel mileage.

It is $300 for the tune, but with gas still being $3 a gallon and knowing after the election it will dart back up, it is definitely worth it.

 

I hope you read your tire size wrong. 205/40/17 are less about 23.5" tall. TINY....small rolling dimater = High rpms!! My TC tires are 25" tall and I wish they would have put something that was 25.5" or so

If you have a SC it seems like people are getiing better mileage with the stage 2.

 

Without a wind tunnel you won't know if lowering the car will help or not.

Plus it depends on your average driving speed.

If 80% of your driving is city, it probably won't help.

If it's 80% highway, it might help.

When you lower the car you decrease the amount of air that flows under the car. That, i.e., puts more down force on the car. This increases the theoretical "weight" of the car.

If you were to lift the car, the increase in air flow under the car decreases the "weight" of the car by lifting it off the ground.

This is what it means when drivers will tell the crew chief the car feels loose or tight.
It's not as easy as blindly saying lowering the car increases MPG.

 

Take advantage of the direct fuel cutoff feature and coast whenever possible to slow down.

 

Lowering a vehicle does NOT produce downforce. It increases aerodynamics by reducing the vehicles total swept area. You don't need a wind tunnel to prove this, although that will help determine the *actual* benefit, as it will vary by car. Either way, it's not really significant. If you were to lower your car just to save gas, you'd probably never save enough to even pay for the springs. But obviously there are other benefits.

 

If you dont have a problem with the ride quality, feel free to keep the tires at 35 cold. Just be aware that at that pressure depending on tire width/design youre likely to wear out the center of the tire before the shoulders unless you drive4 aggressively.

OMFG, can we seriously get off the DFCO kick??? PLEASE? Its been around since like the beginning of time on GM efi and I never used to hear it get mentioned until recently, and mostly on this site. Also its : DECELERATION fuel cut off. And as far as coast to slowdown....well thats what your supposed to do

Oh, and even if you dont have DFCO, coasting to a stop/slow down saves fuel anyway. I am gonna pop a cap in the @ss of the next perswon who whips out DFCO like its some new technology or new invention here to save us from high fuel costs

Think of it this way, every time you use your brakes you waste fuel.

If you use your brakes that means your taking your cars kinetic energy(motion) and turning it into heat with the brakes. You had to burn gas to create heat and motion in the engine to get the car going though....
If you coast, youll lose speed lower, which means your fuel moved you farther....isnt that the definition of fuel mileage??

 

Fuel economy... it's mostly in the tuning.
GM tunes for extreme safety of the motor with the average driver, in the average climate, and the average elevation... Remember.. they have to warranty these cars.

 

Ugh, don't remind me!

 

I used to put my car in neutral and coast to a stop but I just read in Car and Driver "10 best myths about fuel econmy" or something like that and they say to keep the car in gear (automatics) and that will give you better fuel economy according to GM and Toyota engineers.

 

its more like around 50 i took a physics class with a crazy prof. and we were watching wind resistance and after 45 and before 50 roll 'em up!!

 

Go to any Tire Manufacturers web site for information on the pressure and weight data that is on the sidewall of a tire. It IS NOT the recommended pressure setting that the tire is to be inflated to. Tires should be inflated to the recommended pressure that the vehicle manufacturer has posted on the label, usually near the drivers door or in the Owners Manual. This is the COLD tire pressure.