I've been complaining for a while about my fuel mileage.* I even had my 300hp BD injection pump detuned almost back to stock.* At one point fully bombed I had the pump at 300 hp settings, and 40 hp BD injectors along with the super-b turbo, exhaust manifold, BD trany with billet torque converter & flywheel.* Not many cars could pull me off the line.* After candy-caned the drive shaft and only 16 mpg highway I decided to take a few steps back.* Fuel mileage never really came back,* I tried 3.73 gears to comp. for the 33" tires (stock were 30") and still not much change.* Over a year later I finally check the AFC housing cover - YAHTZEE! Turns out after all the diesel shops and work I had done myself the cover had not been slid all the way forward.* The #10 fuel plate I moved a smidge forward of the stock plate location and then tightened down the cover ALL the way forward.* Went to Branson, MO about 4 hrs away last weekend and hand calculated 18.9 MPG at 70-72 with the cruise set.* That is within 2 MPG of the best stock mileage I ever got.* YES I'm happy.* I still have power galore.* ANYONE who wants to know exactly how to set up their 12v for Power, Mileage, and towing can ask me.* Its all pretty much in my sig.* I would skip the fuel pump if I could do it over with just a 3k governer spring, #10 plate 2-3 mm forward of stock, bigger turbo, 40 hp injectors.* Of course you will need a real tranny, 4" turbo back exhuast, delete the cat., and ex. manifold.* EASY right?* Feel free to add to this if you want.* I guess my learning curve isn't as steep as some but I figured out what works for me.* Keep in mind the 300lb front cattle guard and 150lb matching rear bumper aren't great for aerodynamics. Nor are the 33" Goodyear Duratracs which kick *** by the way.* CHEERS!![roll][roll]

 

i think i will slide mine forward and see if this helps mine thanks

 

I don't mean to be a wet blanket, but how would adjusting the AFC forward help highway mileage, as it has nothing to do with steady state fueling.

 

Same here.. Tuning the AFC spring, position and zero boost stop are most of the hard parts to do.. Sliding it forward would seem to me the opposite.

After all the upgrades, my mileage hasn't changed since I bought it.

 

I hear ya guys - I don't know either but I can tell you the egt's avg 100* less and I don't hear the turbo as much - seems like avg 5-10lbs less boost on the highway. I figured the cover effected when the turbo/full fuel came on. I'm not an expert but everything works/sounds more like it is in harmony with itself. Let me know what you think... thanks guys!!!!

 

Something else changed if you have less boost and EGT, since the AFC going forward would add fuel, doing the exact opposite of what you see. But that would only go up if the AFC was actually limiting your rack travel on the highway, which is very unlikely.