Okay I've searched the threads and didn't really find anything on this so here goes. Okay bought my new to me 04 Dodge Ram 1500 Hemi QC a few months back. I didn't expect awesome gas mileage but did expect that it could be improved with a little tweaking. In the old days opening the exhaust and air cleaner usually did it. Is this still true for these days? Mine is all stock and getting 15mpg mostly highway. I was thinking of exhaust but which route is better? True duals after the cats without the y-pipe? Bigger y-pipe and better exhaust from there on back? Air intake just drop a K&N air filter into the Hemi hat or a whole new CAI setup? Let me know whats worked for you. I'm not expecting much of a gain, 2-3 mpg would be nice. I'm looking for both more power and mpg. Thanks!

 

Proper tune up and going with full synthetic fluids plus proper tire inflation is still the best bet. But a little better flowing intake/exhaust setup will help. The stock cats flow pretty well, the two biggest restrictions are the "Hemi hat" over the throttle body and the **** poor factory "Y" pipe.
Best MPG bang for the buck IMO is to yank the parasitic clutch fan and go to an efan.

I have what is probably the heaviest non-Mega Cab 1500 on the site, weighing in at 7000 lbs and roll on 35" tires and average 12.5 in town, 16 highway which is pretty much average for a stock, 5500 lb. non-MDS equipped Hemi QC 4x4, so I'm not b*tching...

 

That's a good idea Hammer with the fan. I'll have to look into that. I've definately heard about the y-pipe. What about just removing it all together and having true duals? Better or no? The hat is coming off but not until after the exhaust has been sorted. Thanks for the input so far, good stuff. I always run full synthetic and check the vitals as I call it lol. Thanks again for the good info!

 

Mines all stock, at 69 MPH and 1800 rpms I'm getting 18-19 MPG on the interstate

 

I've never seen better than 15 highway either. I'll have to address the exhaust soon because it looks like the stock muffler may be having rust issues. That surprises me since I thought most modern vehicles came with stainless from the factory and this truck has never seen road salt.

 

I think the best I've ever done was 17.4 when mine was stock on a trip up to the farm and back. Best since the lift and tires was 17.1, but average is about 16.3, I tend to get impatient on those 360 mile trips and set the cruise on about 78, figuring smokey will spot you 10 mph over on the highway before writing you up. I'm sure I could do a smidge better if I would keep it under 70...

 

To add, make the truck run more efficiently than it does stock. Free up the restrictions in the hemi hat , Y pipe and muffler, free up some restriction by adding an electric fan instead of the clutch, tune it, solid tune up and you should be good for a few extra MPG. My truck sees 18 city and 20 highway IF I STAY OFF THE GAS (which doesn't happen to often). Normally all go and no slow equals around 16 or so mixed.

 

There's not a lot of hope for around town aside from driving like Grandma. I've found, through extensive cross-country highway trips, that keeping it under 70 mph and 2000 rpm yields the best highway mileage.

So, dumb question for you guys Re: Hemi hat... Basically, you are saying to just take off the black plastic aesthetic piece covering the engine? Easy as that?

 

Yep, it's basically a baffle and is pretty restrictive. Replace it with anything from about three bucks worth of PVC and a $4 boot up to a full commercial CAI kit...

 

here is the inside of my stock hemi hat, notice all the chambers.