Exaust + Intake= >MPG?

[RPC]

Hey all, I'll try to keep THIS thread a little more civil!

I had a highly recommended muffler shop in Sacramento replace my stock muffler with an 18" Magnaflow and had the fella order me an AFE (apparently a spin-off of a K&N founder) air filter. He spoke very optimistically about a increase in MPG but I haven't done a lot of driving since the muffler swap and the AFE filter is on back order, due in tomorrow though.

Has anyone made these kinds of changes and had success (other than that great new sound!)? Any other mild changes one can make to get more bang for the buck at the gas station?

 

[etom]

i haven't noticed a difference in gas mileage

 

[Will816]

Anything one can do to allow the engine to perform less work while still doing its job will increase mileage. A decent portion of the fuel burnt goes towards running the engine itself. Making the intake and exhaust freer flowing allows less fuel to be burnt to perform its main goal: moving the car forward.

Other things you can do, if you can stand it, is to drive with the windows up and never use the AC. The AC drags on the engine, so it needs more fuel to maintain RPM. Windows down makes the vehicle much less aerodynamic, so again, more fuel to maintain RPM.

Gradual acceleration is also a key factor. The best way to drive like this is to either imagine there is an egg between your foot and the accelerator and you don't want to break it, or imagine a cup in your cup holder almost filled to the brim with water and it has no lid and you don't want it to spill.

I've also noticed a huge difference in my 4Runner when I drive at speeds over 60mph. At 60, I get about 23 mpg. At 70, I get about 17.5. These figures are according to the mpg computer, so I don't know if the numbers themselves are accurate, but the difference in the numbers is substantial.

Pointless story to go along with the topic:

One time in college a friend of mine decided we could make his diesel Ford Excursion get over 30mpg at 60mph. We bought something like 14 rolls of duct tape and painters tape and basically used that to completely cover the undercarriage, bumper to bumper. It was a little less than beautifully done so that the solid axles could articulate a little bit. Then we taped up all the openings in the grille (it was winter in Idaho, diesels are actually recommended to have the radiator covered when its cold) and front bumper and then removed the mirrors and replaced them with little tiny ones that we (you guessed it) taped on.

The next morning we got in and went for a nice road trip to Eugene OR to visit some friends. When we got back, we did a mileage check at the gas station and found that we had averaged 29.3 mpg in a 7,300 lb monster of an SUV. Not 30, but pretty darn good

 

[RPC]

Interesting experience, Will! I know of the correlation between a vehicle's aerodynamics (specifically windows up/closed) and fuel economy but man I like driving with that rear window down and the sunroof open! Doing that on the freeway and I might as well affix a sail to the roof!

I also try to show sense when getting the beast in motion, but this has been difficult lately with the new tone coming out of the rear! I could certainly do more though to adhere a little closer with the 65MPH speed limit...decrease the probability of a speeding ticking while increasing the probability of a favorable MPG! A win-win!

 

[KB084RUNNER]

If you switch your entire driveline to synthetic oils you will notice a 0.8 to 1.2 increase in mpg on average. Definitely worth it in the long run.

 

[RPC]

KB08- does that include transfer case fluids? I was told by the muffler fellow about changing the transfer case oil to a synthetic but he said something about putting 10 or 15K mile on it first. Mentioned allowing the gears to wear slightly will allow the gear oil to stick better.

Does that make sense enough to wait?

 

[CJ3Flyr]

Will816; that Excersion story is cool. I love it, duct tape, WD40 and a hammer will take care of anything, even drag

rpcowan, I don't know about waiting a full 10-15k. The idea of allowing for break-in 1st is sound. I wouldn't swap the fluids earlier than 5k and I'd definately change all 3 by 30k.

That's my 2cents.
:cheers:

 

[rjyhdc4]

Anything one can do to allow the engine to perform less work while still doing its job will increase mileage. A decent portion of the fuel burnt goes towards running the engine itself. Making the intake and exhaust freer flowing allows less fuel to be burnt to perform its main goal: moving the car forward.

Other things you can do, if you can stand it, is to drive with the windows up and never use the AC. The AC drags on the engine, so it needs more fuel to maintain RPM. Windows down makes the vehicle much less aerodynamic, so again, more fuel to maintain RPM.

Gradual acceleration is also a key factor. The best way to drive like this is to either imagine there is an egg between your foot and the accelerator and you don't want to break it, or imagine a cup in your cup holder almost filled to the brim with water and it has no lid and you don't want it to spill.

I've also noticed a huge difference in my 4Runner when I drive at speeds over 60mph. At 60, I get about 23 mpg. At 70, I get about 17.5. These figures are according to the mpg computer, so I don't know if the numbers themselves are accurate, but the difference in the numbers is substantial.

Pointless story to go along with the topic:

One time in college a friend of mine decided we could make his diesel Ford Excursion get over 30mpg at 60mph. We bought something like 14 rolls of duct tape and painters tape and basically used that to completely cover the undercarriage, bumper to bumper. It was a little less than beautifully done so that the solid axles could articulate a little bit. Then we taped up all the openings in the grille (it was winter in Idaho, diesels are actually recommended to have the radiator covered when its cold) and front bumper and then removed the mirrors and replaced them with little tiny ones that we (you guessed it) taped on.

The next morning we got in and went for a nice road trip to Eugene OR to visit some friends. When we got back, we did a mileage check at the gas station and found that we had averaged 29.3 mpg in a 7,300 lb monster of an SUV. Not 30, but pretty darn good

Nice. I think the change in gas mileage depends alot on the vehicle though.