Hey folks first let me give the back ground.
I have a 99 ram 1500 8" bed 2wd. 5.9 140K, plennum is fixed, 5 year old trans, rebuilt rear end, electric fans, 180* t-stat, CAI
I am getting a solid 17 mpg it does need a tune up as the plugs and wires are 80k old I have new tires ready as soon as the current tires go bald.

I have been reading about the varrious tb mods and was wondering if you get any mpg improvements and if so which would be the best for mpg. a 50 mm or a 52 mm. Would it be worth the trouble to do it myself or pay for one that is already done like a fast man model.

Thanks

 

How the hell are you getting 17 mpg?
Especially with worn out plugs and wires? New plugs and wires would net 2 mpg. So that would mean you could get 19 mpg.
WTF? You're doing something wrong. I am not just trying to be an ***, but my dad's truck which is newer, gets only 16 on the highway. And it is RATED for 19.

 

I was getting 8 when I bought it(bad plenum) I fixed that and applied cooler spark plugs and a 180* t-stat. I went up to 18 mpg As the tires went bad it droped down to 13mpg I took the camper shell off and it picked up to 15mpg. Then I did the electric fan and it went up to 17mpg. I do not know why the lack of the cap improved my mpg other than droping about 150-200 lbs off of my truck. I drive almost all high way at 60mph. It still needs tires.

 

There are throttle body mods I have seen & even those who sell pre-modded out TB on ebay. Better air flow in there & out through the exhaust is all good & will improve performance. It could improve MPG but the problem I have had with this, is that the better performance inspires my right foot to go down more leaving my tank empty faster than before the mods.

 

I modded my own throttle body and my mileage got a little worse.

It definetly improved airflow though. I think there was a significant improvement.

Since you have a CAI with better airflow it should be even more of a performance increase.

Just use your old one and mod, takes maybe an hour with the right tools, that includes removing it and putting everything back together.

How the hell are you getting 17MPG

I get 10.......

 

In my experience a standard cab truck has better mileage potential than any extended cab/quad cab setup; also an 8 foot box version is better than any 6.5 foot, even if a standard cab shortbox model. That could be part of it.

I tried very hard to buy a used standard cab/8' truck at the time I eventually bought the extended cab Ram I now have, but in the last 15 years such a truck is bordering on non-existant at least around here. I found exactly two for sale, a GMC with 300K and requiring extensive front end work (and who knows what else) and one Ram shortbox, same year and twice the price of the truck I bought. Versus hundreds of extended and quad cabs.

I get 10.9 long term MPG average; best tankful was 13.4, 80~100% city driving and basically all winter fuel. Will see how mileage changes in the next few tankfuls with real gasoline, not that winter gas with the high volatility formula for cold starts, which has a higher percentage of fuel that goes directly into the air via evaporation rather than through the engine making power.

 

I have a quad cab 8' bed 2wd 1500.......look at the above posts I think the bigest thing is 60 mph all interstate all the time.

The things that gave the largest improvement were electric fans then all at about the same time I did the plenum t-stat spark plugs and CAI.

I am surprised at some of the other mpg reports I read on hear leading me to think most folks dog their trucks or slap over size tires on them.

 

cooler stat hurts mileage, it doesn't help one iota.

 

I modded mine too with a dremel (easy to do and I posted pics in a thread about it you can search)
it wont help mpg but more air flow means more fuel so....
and the 180 stat hurts more than it helps especially in the 98+ years it seems... pcm is looking for 195 degrees and fattens the fuel flow a bit until its reached acording to folks like Drew here.... I swapped back to a 195 but had to many variables like generation 3 injectors which also played a part in my mpg improvements...
how are you calculating the mpg? not the overhead gauge I hope?
mant folks dont understand the tire size /gearing relationship and just dont realize what they are doing or convince themselves its not a factor...

 

I will say when I did the 180* t-stat it was the same time as plenum and tune up. It is such a PIA to get to. I like seeing my temp gauge leaning way over to the left.
As far as mpg. I drive 500 miles or so as my fuel gague does not work below 1/4 tank and fill my truck to the first time the pump clicks off. I then divide miles by gallons for mpg. Just like one should. My mpg is usually fairly consistant between 17 and 17.5 with an occasional 15-16 ish mpg when I am on vacation driving around town a bunch.

I will say through much reading almost all sights say between 190 and 205 will make the best mpg. If I ever take the bracket off the front of the motor again I would change the t-stat back to 195*as the hose and the t-stat are now about 5 years old.