Has anyone had any luck with any aftermarket products to improve gas mileage on the hemi? I am getting 10-11 mpg around town and it’s killing me. I was talking to a guy that said the k&n cold air intake has been known to give an extra 2 mpg. I also heard that switching to a more free flowing muffler has helped. Anyone have any other opinions on after market products?
Thanks.
I have a 2011 2500 HD Hemi, Gas is killing me as well. 10-11 mpg max!
I dont think a toyota camry is going to pull my boat though!
I’ve got a K&N on a 350 chevy suburban. i did get about a 2mpg jump on it and about a 25hp gain on the WOT. I”m happy wiht it and will put it on all my engines…
Are those cold air intakes difficult to install?
Dream’n
Quote:
Are those cold air intakes difficult to install?
Dream’n
No they are pretty simple I put one on every car I own. 
I second JS. I didn’t put mine on, but after looking at it, i’d do it before i’d skip it. Make sure you buy the model with the fittings for YOUR engine or get a REALLY good deal on CraigsList…
Do some research on hot air intakes, worked years back on my 98 dodge ram 3/4 ton with the 360 motor. had about +1 mpg with a cold air intake and about +3 to +4 with a hot air intake. In theory a cold air intake will give you a little better millage because it will make the air/fuel mixture denser creating more horse power but actually can decrease millage at the same rpms. generally the only reason you see a millage gain is with the added horse power it takes less throttle to achive the same speed. with a hot air intake it will lean your air/fuel mixture out which will cause less fuel consumption and creates less horse power. less horse power = less fuel usage but it can be a fine line of being under powered as well and going the wrong way.
That’s some pretty low mpg’s there…. I drive an 05 Ram 2500 5.7l Hemi, and get 14 when i’m pulling my boat… Maybe my gauge is wrong.
I have a Jeep GC Limited with a 5.7 Hemi. Around town it’s 15-16 and on the highway short runs 19 and longer trips 20-21, this is at 1800rpm = to 68mph. When I pull my Ranger bass boat it’s a steady 14mpg. I have a K/N filter and run synthetic oil and I check my tire pressure to make sure it is at max air pressure.
I’d be happy with a 2 mpg gain. It would pay for itself pretty quick.
Ive got a 5.7 hemi in my jeep grand cherokee ltd, cold air intake[K&N] and i changed to valvoline blend syn oil i went from 10 mpg to 12.8 mpg. Im towing a alumacraft dominator 175 W/ a merc 150 opti with all my gear. Also you dont change oil as often, i change every 4000 miles, so you save money there also.
I don’t know about a Hemi but the K&N in my Mercury Marquis and My Impala give me at least 2 MPG in the city. And as much as 3MPG on the highway.
Hint don’t clean a K&N to often it kills its effectivness
Might want to look into a K&N before you spend the money, they don’t always give the performance gains they advertise.
Or so it seems…
Hit a few of the auto/truck forums and you’ll get different opinions, some seat of the pants and I take them with a grain of salt, but some actually dyno’d the motors and the results might make you look elsewhere for mileage gains.
I just dropped my speed from 75 to 65 and drove a little less aggressively and gained almost 2 mpg according to my MPG thing on the dash.
Just a thought.
Al
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