Since my 2010 GT is my daily driver and gas is going up, I'd like to direct my limited mods budget toward things that will increase both fuel economy and performance.

I'm thinking:

- underdrive pulleys

- tuner with "87 street" as well as 93 performance and race tunes

- swap my Roush CAI for a "better" one? I'm not sure if that would really make any difference, but the Roush CAI does not require a tune and uses the stock intake tube so I'm guessing it does not do much compared to the others that use a larger tube and require a tune

- axle-back exhaust -- I know this won't do much for MPG or performance, it is for sound, actually it may hurt MPG because I will want to get into the throttle more to hear it

- good synthetic 5W-20 motor oil (now using Mobil 1) + Z-Max additive

- stay away from wider tires (those GT500 take-offs sure are tempting)

- keep my 3.31 gears

- do those aftermarket spark plugs (like E3) actually do anything? I tend to doubt it but you never know.

Comments on above or other suggestions?

thanks in advance

 

Full exhaust will help a little. Axle back will not help.

A better CAI will probably not help. The whole point is to remove restriction, which any CAI will do. The reason that other intakes require tunes is that the air tube changes diameter, and the MAF sensor will not adjust the fuel correctly if the air is not measured correctly.

Plugs do little to none now adays, unless the current ones are very old and due for replacement.

I was able to squeeze about 6% more mpg out of my last ride with an intake and catback, but it was only a 4 banger.

 

Besides making the engine breathe easier, making it more efficient, it's mostly the usual rules that still apply...
-Be easy and smooth on the gas and the brakes.
-Plan ahead both with your route you take and with stopping early and easy (don't tailgate).
-Minimize idling.
-Check your tire pressures! I've found some vehicles/tires are very sensitive to low tire pressures. If you normally run 32 psi., try 35-40 psi. *Check the Max. Pressure Rating on the side of the tire and don't exceed that. Compare the "feel" of the ride and handling with the pressures. If it gets too bumpy and "light on it's feet", lower the pressure 2 psi. until you find the best balance of handling and mileage. I've seen +-5 psi make a difference of 3-8 mpg, although I think lower-profile tires are less susceptible to pressure changes than taller tires.
-Also try different brands of gas and octane levels.

Mobil1 is a good oil, I'd say keep using it.

You can also try drafting a Prius.

 

My underdrive pulleys gave me a 1-1.2mpg improvement. Definitely worth it as it's an extra 8-10 free hp too

 

Gas savers forum might be a good place to start....they are pretty ingenious about squeezing every last mile out of a tank

 

Driver mod is the best mod for fuel economy.

Slow down and short shift, get it in high gear sooner.

 

http://www.shadetreemechanic.com/tornado_air.htm

 

an alum. drive shaft but $$$. I gained back what i lost with the 3:73 along with the UDP's.

 

This is the only significant way to increase gas mileage.
I have gotten an honest 27mpg crusin' the back roads of MA doing this.
And I have 3.55 gears on my 4.6.

 

10% ethanol has hurt my mileage by about 10%.

So I would say target the corn lobby. Except I don't think I'm supposed to say that any more.

 

Absolutely, ethanol is a scam.

Don't get me started.

 

Weight reduction will help especially if its rotating mass. eg, driveshaft, rims, flywheels.

 

The money spent on all of that wouldn't be offset by the cost of the gas used.

 

I remember seeing this on eBay some years ago. Looked like a scam then, and it still does. I especially like the way they're using real physics principles to justify totally bogus science. If anything, this should hurt performance and economy, as it's a significant airflow obstruction...

 

Keep the rpm at 2000 or less. That alone has saved me $.and increased mpg.

 

Plus 1

 

Don't get a new 5.0 or gt500 if you want good gas mileage!! Especially if you start doing performance mods!! It is way to hard to keep the Rpms down all I wanna do in mine is unleash the power and hear that v8 roar!! These cars are meant and deserve to be driven above 2000 rpm! Especially when my city is filled with camaros and challengers and chargers that all think they can beat me....but I love the natural high you get from destroying a new camaro that costs 20,000 more here in Canada!! :-)

 

Thanks everyone for the tips so far, as always there is "no free lunch."

Except for that Tornado, gotta git me one of them for sure!

Of course the stang was never intended to be a Prius, you have to let that pony run every now and then . . . but I was thinking that I should stick to mods that improve both fuel efficiency AND performance, looks like we've got those pretty well covered.

I wasn't aware of the aluminum driveshaft, I haven't looked into the cost on that but imagine the pay-back is slow, but that is the case with most of the other mods too. The underdrive pulleys are definitely on the short list, and I'll get a tune (actually 3 tunes) to go with them.

Air is still free! Or pretty close . . . for now at least, until they find a way to tax it . . . I generally run my tires around 34-36 psi but will try it a little higher in the spring when the Pirellis go back on.

So the larger diameter inlet tube is a big deal to the MAF sensor (larger area, lower velocity for the same flow) but not such a big deal for total air flow / restriction, I get it now.

Unfortunately here in the Communistwealth of Massachusetts pure gas is illegal, we always get 10% ethanol . . . though it seems the ethanol level is even higher in the winter, lately I can smell the alcohol in the exhaust and it seems my mileage is a little lower than in the summer. That might be partly due to more idling to let the car warm up a little.

The driver is pretty good, understands the physics of all this . . . brakes are "energy dumps", coasting is good . . . of course I do have some fun with the car every now and then, otherwise I should have bought that Prius, but on a normal commute I regularly see 27+ door-to-door; I have even seen a little over thirty on the computer (this is for an end-to-end commute, not cheating by pressing the reset while cruising on the highway)

Luckily around here there are not many ricer, camaro, or challenger challenges to increase my fuel consumption.

. . . . haven't checked out that gas savers forum yet . . .

 

I believe my alum drive shaft helped with mpg's and will pay for itself in about a year. I think I gained around 1mpg or just a tad less. Underdrive pullies should help and pay for themselves rather quickly. Intake and tunes don't seem to help all that much. I break about even but I am using 93 instead of the stock 87 oct. Its alot more fun to drive for sure. I think if you start running to much air in the tires you will start losing some of the good handling/safety. 35 is probably pretty good.
I believe my catback did help some with mpg's also. They do free up some restriction.

 

there's tons of info out there- fuel efficient tires. Some think it's worth while others say there isn't much of a difference.

http://www.autoblog.com/2009/04/16/s...rance-fuelmax/