hey guys new to the forum and new to the 24 valve cummins a previous 7.3 psd owner and was wondering currently in town i get about 15 mpg and freeway about 18 i was hoping either do injectors or a chip not sure which one will yield best mileage currently have a 4" turbo back straight exhaust and a s&b cold air intake with a airdog 100 lift pump the trans is the stock auto with 110k on the truck any pointers as to what will yield the best mpg for me? and not kill my trans

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oh ps any tips on what a good chip or injectors are would be great had a shop quote me $100 a piece to do injectors to 75hp and figures that will gain me about 2-3 mpg the truck is also a 2wd only diff is factory are 245 tires and its got 265's on it

 

Does that $100/ea include install? If not, that's STEEP! I had 65HP injectors before my 150's, and they were very nice. Everything about the engine changed in a positive way. Better mileage, better starting, more power, they really helped out. Unfortunately, even injectors of that size have the potential to take out a stock auto if your not careful. Same goes for chips. Even a 65hp chip/tuner can wreck the auto.

I would suggest a used Edge EZ, or a Smarty. The Smarty will hold it's value much better for resale down the road, or just keep it. The EZ's go cheap, as they don't add too much power. Both will help with mileage. The Smarty comes with a Mileage setting, and it works well.

 

x2. A mileage chip and injectors will wreck an Auto trans. TQ and valve body should be enough with a smarty and RV injectors. Also, to answer your question...50-75 injectors and a Smarty is my opinion for increased mileage. I saw an increase with 150's until my foot got heavy

 

I noticed a big gain when I went to DDP 50hp injectors and put on a 3 piece manifold. Also, if you havent done it in awhile, a valve adjustment is in order. With a stock auto, I wouldnt try to add to much before you put some money into that.

 

yes the $100 includes install and as far as driving goes i dont really drive aggressive i take my time where im going as im trying to get good fuel economy however i do tow equipment ranging from 6k-13k and that would be when id be driving it moderately to hard if im going over a mountain pass so i was also wondering if i did just injectors alone would that be best or a chip better which one would result in more of a mpg gain? maybe i'll only do one mod just trying to get my mileage to hopefully about 18 city and 22 hwy if possible i doubt that with mods i could get any better than that

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and also so RAWilliams you recommend just a smarty tuner by itself? any guess what i'll gain as far a mileage goes with a smarty? granted as long as you drive nicely

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and for those of you that recommend injectors should i have a shop change mine over to 75 hp or should i just go with DDP injectors are those the best? i see injectors that are like 4-6 hole guess the more holes the less fine your fuel atomization is?

 

The Smarty is probably the best turner you can get for the 24 valve, VP44 engine. The Mileage mode does work very well, but it's hard to say exactly how well. I'd say a gain of UP TO 4mpg could be had. You have 9 levels, each with many sub settings. The Mileage mode is easy driving, and good mileage. It has lots of timing though, so while towing heavy it is advised to switch to a different tune. Timing can make a huge difference in power, and economy. Injectors alone won't change timing, just how much fuel can be injected.

More holes is BETTER Atomization, as they are typically smaller holes.

 

ok so go with a smarty tuner first and do injectors after i do trans? i dont think if i did get a smarty id run anymore than 50 hp just run it on a mild tune if towing and mostly the mileage tune for everyday driving

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Well I found a smarty chip for sale guys asking $400 here's a link to it I'd appreciate your guys opinion on if it's a good buy or not Smarty Tuner for Cummins

 

$400 is a good deal on a Smarty. They hold their value well. You can always try to get him down a little, but $400 is a respectable price.

 

i got a smarty with 9 tunes i like it if you dont have a timing box they say to use odd numbers on the tune why is trhat?

 

Odd numbers add timing, even numbers don't. Too much timing can damage you engine.