What will adding a pair of headers to a diesel engine do for fuel mileage?

 

I'd post this in one of the diesel forums that your truck falls under.

 

If your diesel is worth a crap, it already has a turbo. So, headers won't do much. If it doesn't have a turbo, headers probably won't help it. Headers usually do their work at higher rpm, with some exceptions like the FE Ford motors with terrible exhaust manifolds. Unless your motor is spinning 4000 + rpm, spend the money elsewhere. Like on a turbo.

 

anything that increases flow on a diesel will help with a naturally aspirated motor. I cosider my diesel to be worth a crap, and there is no turbo. Open up the intake and exhaust and these IDI's shine.I did that and it really woke up my 6.9. There are some that really think the headers are great, but they are pricey, as there is only about one company making them, and they aren't exactly a high volume sales item. I changed my 2 1/2" exhaust to a 3" and that made a lot of difference. Make sure there is no big "bowl" on the bottom of the air cleaner lid, commonly referred to as the "soup bowl" it was intended to quiet the intake noise, but it managed to restrict airflow. If it never had the soup bowl, it may have a hole in the bottom of the air cleaner that is way too small. That's the way mine was. I cut out the hole to the same size as the intake and that also helped. Then there is the stok intake hose, if you do away with the plastic section the air cleaner hose attaches to, and pipe it to the front of the truck, it will make a big difference as well. By doing all this, i gained a lot of power and take off get up and go, as well as 2-5 mpg depending what I am doing, whether it be running down the road by itself or towing a load. It used to drop to 10 MPG before I did all this towing a heavy load, now it runs minimum 12, sometimes as good as 15 with no overdrive. I now have the kind of throttle response that you would expect from a gas engine.

 

http://www.bankspower.com/app.cfm?appid=AF04

 

Not having a turbo does not make my diesel not worth a crap! The IDI diesels made by Navistar are excellent engines, and I never plan on turboing mine.

 

Aren't they the ones in the right lane going 18mph blowing black smoke on every hill.....????

Really, oil burners need as much air as they can get and natural aspiration, especially the restricted type you describe just doesn't cut it, and imo makes the engine not worth a crap. If you're happy with your modified engine, then I think everyone will be happy for you. And if you had a turbo, you'd wonder how you lived without it....

 

With headers and an opened up exhaust system you may actually expierience LOWER gas mileage. This is because you will always have your foot in it so you can hear those pipes!

 

We had an IDI 7.3na in a 92 E250, and it had just as much power as our 351w did. And got better loaded mileage (17mpg 7.3, and ~15 351w)