The weight certificate on mine (CAT scale) showed 6,170 lbs unloaded.

With MDS enabled I got 13.8-15.5 mpg. With MDS disabled (Predator 87 tune) I am getting 15.0 -15.4 mpg. No more rpm surge and better throttle and trans shifts.

 

Has to be...my truck is one of the lighter rams and even it's a little over 5k lbs.

 

dont forget mine is a rcsb 2wd where are you getting the weights of these trucks from? mine on a scale is a little over 4200 okay thats not quite 4000 give me a break. also dont for a minute think mds motors arent as fast as non mds motors I out run titans , tundras 6.o chevy vortech maxx on the street and strip

 

I just bought an 08 ram about a month ago and the dry weight on the dealership registered 5400. As far as gas mileage I've been paying really close attention to both the calculations at the pump and the onboard console that tracks the mileage. Problem is I reset it when I'm on the freeway to see what it's getting. If I'm doing 68 mph and the truck has been running for what seems to be 20 minutes it'll hold a steady 20 - 21 mpg. Granted, the minute I start it up the next morning and drive it in this Ohio 17 degrees it doesn't matter how long I let it run or how great my gas was day prior - overall sinks like a rock. Yesterday I got 19ish the whole way out to Columbus and back (120 miles) and yet my tank still registered below 14 mpg when I threw in city driving. Either the onboard computer is wrong or it's what I expect - any amount of city driving in the cold is just brutal on it.

I bought the whole K+N system about four hours ago - should be here next week. I fully intend to see some gas mileage improvement because we have on all our dodges. I'm also going with a set of x-pipes with 3 inch tips. I love Flowmaster's but their rap for gas mileage is too much - I'll be hitting up Magnaflow most likely. I'll also be doing either superchip or predator. I hear a ton of guys complaining about MDS but if my Ram didn't come with MDS I wouldn'tve touched it. Yeah, I bought a truck knowing the gas mileage wouldn't be what it was on my old Eagle Talon but I want every mile I can get. I bought the Ram 4 weeks ago as of last Friday and I already have just under 2900 miles on it. I amended 3 year 36k warranty to a 1 year 36k lol.

Question for those interested - mine is a quad cab with 20's with the 3.92 rear axle ratio. I thought about having the gear ratio reduced - again, to gain more mileage. However, I do tow about 5200 pounds occassionally. Very occassionally. Am I going to notice a huge towing ability reduction due to lower ratio? I'm thinking I could make up for that in mods - K+N, exhaust pipes, programmers, the like. I'll have no reason to reduce the ratio if I start seeing better overall mileage after my upgrades. If not I might consider it. Mileage is hard to tell when it's this cold outside - it's gonna suck no matter what I do.

 

You've got 20 inch rims, which probably means a 33 inch diameter tire. Dropping the 3.92s will actually cost you in-city mileage, just because the engine will have to work harder to turn the large wheels. 3.53s will improve your highway mileage though. No, it will not affect your tow capacity, again, you will just work the engine harder to do it. Since it's only 5200 lbs and it's occasional, I don't foresee you having any trouble with 3.53s instead of the 3.92s.

Also, don't trust the overhead. It lies. Always work it out on paper, Miles Traveled divided by Gallons used when you fill up. I recently drove 650 miles to visit family, my overhead said I was averaging 15.4mpg, but actually I averaged 16.6mpg.

 

Okay, good to hear...I'll see what happens as it pans out...the one draw back I didn't mention I'm a little scared of is the drop in acceleration as a result of going a lower ratio.