I have a 2012 dodge 1500 hemi 4x4 and am wondering what the best cold air intake and exhaust is to assist for MPG.... Any suggestions would help.... THANKS!

 

You're going in the wrong direction. Those mods are used to make more power. To make more power you need more fuel. If you want to get more air in and out, your truck is going to add more fuel to that more air.

If you want better MPG, drive it like and older person because nothing mechanical is going to get you better mileage

 

I gotta disagree with you, bro...

Making an engine more efficient and making more power are often the same thing- but folks don't take advantage of that.. instead they race around and complain about mileage.. a great big cam ain't gonna help things, especially if it is a bad match w/ the gears/weight/use.. but a cam (on these things) that lowers the torque curve matched to the transmission, gears, and expected use will help economy big time- but never so 'big' that is justifies the cost of doing so..

cheaply reducing parasitic loss of power is the best way to improve mileage WHILE improving performance, too.. rocker rollers instead of pivot rockers, efan, anything that allows the engine to produce power quicker- so you're no lugging about trying to build RPM's and get to the range required to do whatever job you're performing.. freer breathing intake and exhaust do that too- but not necessarily colder air.. colder air is MORE air, and needs more fuel, and even then you are limited by the mechanical relationship of overall gearing ratio's which is married to engine RPM's..

it's all about engine load in the range you most often find yourself, and eliminating parasitic loss the best you can.. little things like an efan, like rocker rollers, like better engine and drive line lubricants help- but, anything beyond that is going to take a long time to recover the cost from a few drops of gasoline..

 

Im sorry, Ive seen all kinds of ideas but never anything factual that outweighed the cost savings of fuel versus the amount spent actually trying to save.

 

I can agree with that ... I will say, however, something such as an electric fan IF you spend a lot of time in the city traffic actually will pay for itself

 

Hear, hear! The tiny fuel cost/mile gained by gears, programmers, etc., etc. will almost never break even, much less provide any real saving.

 

I'd reckon that depends on how much you use your truck, or how long you plan on keeping it?

I went to 4.56:1 gears, and saw a dramatic increase in mileage when towing- and towing was the purpose of having that rig.. pulling a 5500# trailer netted me around 6MPG w/ factory 3.92:1 ratio's on 34" tires.. dropping about $1k on gears, and another $3k in various parts and pieces brought that average to around 9MPG... driving anywhere from 400 to 1k miles a week over a period of three years, I'm thinking I made a smart move.. but there is more to it than just economy of fuel use-

gears make life easier on the transmission, and keeps the engine from lugging as much.. that extends the transmissions life tremendously.. I ran a 46RFE in that thing, and a rebuild costs somewhere in the neighborhood of $2k, and upwards of $3.5k..

any part that reduces parasitic loss of power increases mileage while at the same time reduces wear.. such as rocker rollers- that simple mechanical pivot being replaced with less friction (which equates to less force needed from the crank/cam relationship to actuate the valve train) lets free a few ponies, but also less wear.. anything that uses the crank that doesn't move you forward is loss of power, and causes wear that doesn't need to exist.... rocker rollers cost around $250 for the 5.9 V8.. I dunno what they run for the hemi.. within the life of an engine, say, 10 years for speaking terms, they will pay for themselves in economy, but pay even more with reduced wear on cams, bearings, lifters and push rods.. you won't see that savings unless you keep your rig a while, but I'd guess it to be the difference in rebuilding in ten years or rebuilding in twelve to fifteen... yup.. that much..

an efan is a no brainer.. I had about $150 in my rig and watched the fuel mileage drop around 2 whole points while driving in the city.. a dang efan, if you operate in the 60/40 highway to city driving range most of us do, will pay for itself in the first year..

at the point exhaust needs to be replaced, it's a no brainer to open it up to breathe better.. more efficient air-in-air-out allows the engine to operate cleaner and with less effort.. yeah, there is potentially more air and therefor fuel being introduced if you have a heavy foot- but if you don't, you can reach the RPM level needed to perform the function quicker and maintain it easier (keep that vacuum high!) to conserve fuel- it would likely take a couple years to pay for itself..


big cams built for high RPM usage, stupid high stall t/c's, boosting w/ bottles or high volume s/c's instead of smallish turbos or low volume s/c's, designer exhausts, fancy intakes/throttle bodies- these are a waste when it comes to chasing economy, OR longevity.. they sure are fun, though, huh?

fwiw, though, I got tired of twirling wrenches on that silly gasser to coax it into doing what I wanted.. I crunched the numbers and sold the hades out of it and went diesel.. I tug around 12K# now and stay in double digit fuel mileage (diesel costs the same as high octane I ran in the gasser) and I have a TON more power and torque..

quite frankly, I've determined a 1/2 ton truck is a waste of function.. if you need a truck, get one- don't get a p/u body wrapped around a performance car's engine (which is precisely what the hemi is- the torque curve is too high to make it useful as a truck is intended)... that said, for the time I used that 1/2 ton 5.9L V8 as a truck was intended, I have ZERO doubts most the mods I did to it paid for themselves over the long haul- and at least half of that figure was in fuel savings..

 

On the dyno my 06 Hemi had made all it's torque by 3900 rpm which is a very usable number. Maybe your 360 didn't make torque that low, but the Hemi will

 

that 360 made power right off idle.. It was pulling hard at around 1200RPM (with assistance from the t/c), and on up to around 2800RPM.. it was very rare I made more than 3kRPM in any condition, and I can count on one hand how many times that engine saw north of 4kRPM's..

it's my opinion, and likely not a popular one in a forum full of hemi owners, that anything with a curve north of 3kRPM's is a bad match for a p/u..

let there be NO doubt that 5.7 is more powerful than the 360 in dang near any form.. even if you build them out, the hemi has more potential... a 408 (4" stroke, .030 over) 360 is perfection for a truck engine, imHo, but one mother mopar never made.. on the track? the hemi is superior all the way around.. towing a 5k# trailer 500 miles @ a 60/40 cty to hwy ratio? Give me the 360.. no- give me the 408, actually, but I'll take the 360 over the hemi..

 

Maybe my '04 STL QC is special, it's an all around stock truck...20" wheels, no upgrades, still using conventional oil, 3.92 gears (I have the exhaust cut back to the cats). I get 418 miles per 26 gallon tank (drove from Dallas, Texas to Jackson, MS on one tank. Having to deal with construction in LA eats gas). Not quite sure of the octane rating on the gas, as it doesn't state one on the pump (100% Ethanol free gas). I've seen a lot of people complain about the gas mileage, so why does my truck still average around 17 in town and 20-21 on the highway?