89 cummins in a 99 Ford S.D. auto,F-350. This engine is all stock except I ran the turbo thru the Ford cooler. My question is what other turbo, and ,or injectors would give me the best fuel mileage, and performance. I use the truck to pull 5th wheel dump trailer. Thanks for your help.

 

with every thing i have done to my truck if i drive it right i can get 22 the thing i would say to do first is bumo the timing an 8th or a 16th of an inch that helps quite abit and then make yourself some sort of cold air intake and that should up you by about 2.5 mpg i know just the timing bump gave me 2 more mpg

 

intake , exhaust, frees up some milage , but the best thing to increase milage that ive noticed is agood converter to replace the factory pos

 

What I've been told is that running my turbo thru the cooler, it would produce lag because, that set up wasn't originally inner cooled. Is this right? and if so what should be changed? Should I put a turbo off of an earlier engine, say a 93 or 94? My engine is an 89 12v.

 

If your into fuel economy, my suggestion would be leave it stock. With the exception of an intake and exhaust system thats it. The other thing would be change you'r driving habits, drive more sensible. Gearing is another benefit. If your at 4:10 go to a 3:73, 3:55, or 3:07. Get rid of the Auto and put in a M/Transmission. Aerodynamics will play an excellent key in fuel economy. Lower resistant tires, or skinnier and taller tires help.

 

Does it have the ford or dodge transmission? If its the ford then you shouldn't have to worry about it, if its set up right it should have a lock up converter. What you were told about the intercooler is false. The cooler air makes it more efficient, it could cause some lag but I doubt it. This is what you need to start with.

Get the injectors cleaned and pop pressure reset.

4' exhaust, make sure it has a true 4" downpipe too.

60mm upgrade depending on the pump settings. I only went to 56mm on mine it it runs cooler than the 60mm. I get better mpg too. Also a better flowing intake horn wouldn't hurt.

Skinny tires. I run 235/85-16 on mine.

If you have 4.10's in the diffs then you won't get the awesome milage unless you drive slow. 3.73 is the highest you could get in a sd powerstroke I believe.

I did all the above to my '93 and get between 21-23mpg.

 

I have the Ford trans. 4R100 electronic controller, which I have been programming different ways to try to increase mpg,3:73 gears. White93, what do you mean by 60 or 56mm? exhaust is 4" all the way. Thanks everyone for your help.

 

A timing bump will do you wonders. Plus as others have said get your injectors freshened up.

 

They do have 3.55 for fords. And you can still tow just fine.

 

How much does your trailer weigh and what kind of mileage are you getting? Its possible that you could be getting good mileage as it is.