Fuel mileage

D

dodgediesel59

New member
Joined
Sep 20, 2009
Messages
109
Well guys i have found the only problem with the swap and that is fuel mileage. I did a 200 mile run running 61 the whole way and babying it. I got 15.4. I Did a 340 mile run and was pissed about mileage and beat it hard and ran about 85-90 and got 14.8. What the hell can I do to get my mileage up on this pump?? With my Vp around 480 HP with the current injectors and the box on i was doing about 19.8 if i babied it. I have plate slid back all the way and have tightened up the afc some as well. The injectors i am running are jammer 4s which were 125s on a vp. I had them reset to 280 bar when swap was done. The D/Vs are 191s. My question is what can i do to get the mileage up on this truck? I was expecting it to drop a bit with the mechanical pump, but 4-5 mpg is alot these days. If i could even get back up to say 18 i would be happy.
 
I wouldn't complain. My milage is at best 13 babied. I have 18.5* timing, mach 1.5's, super b, 4k kit, ground plate, slide halfway, afc full foward, but I know I have some fine tuning to do. Do you run an ETH or ETC? If you drive everywhere in 6th gear, I'd try running in 5th and see if that helps. Also, do you run any fuel additives? Even though the label on most of them says it will improve your milage...you can't help to lube the pump and somewhat possibly increase the milage...Just throwing out some more ideas...

Also, I'm assuming your milage calcs are hand drawn, not comp figured...Im not trying to be rude, but help explain a few possible factors into the equation.
 
What gears do you have? Just wondering...I have 4.10s and I get 15.0 with my current set-up...maybe more if I babied it and drove slower.
 
Just gonna throw this out there, but is 22* a little too much timing? I am going to run somewhere around 16-18* just a thought that the engine might be having to work to hard against itself...???
 
what gears do you have in the rear axle? 4.10 or 3.55? manual or auto? also doing 85-90 mph your are pushing your rpms up to 2000-2500. best bet is to keep the rpms below 2000 more around 1600-1800 and keep your boost around 5psi or lower. you have to remember you have the aerodynamics of a brick and the faster you travel the more wind resistance you are going to receive. traveling 60-65 mph is the best speed to travel at.
 
looks at crabelle's truck he was getting 33mpg with his 2wd 12v it was 3.55 rear with a 5 speed with a gear vendors over drive unit behind it he could run highway speeds (75-80) at 1600-1700 rpm
 
My truck was converted 7 years ago. Depending on the setup I get anywhere from about 17.5 to 21mpg average. Injectors, dv's, and turbo's change the mileage. Small twins, 100-150hp injectors and 181's gave me the best at around 500hp. 300hp plus injectors, large twins, and .024's at over 900 hp are the worst. Driving like an idiot changes mileage too.
 
bump the timing to 20*, i dont have much experience with the vp but i would think the p-pump is going to push more fuel so be careful on your take off's. what are rpm are running on the highway? what size exhaust wheel is on that garret? my truck was setup for highway only. i lived 110 miles from work so i needed. also im guessing you did some "testing" after the swap. check all your boots for leaks, check fuel leaks, how long did the truck seat while you did the swap? are your brakes dragging, do your tires need air. small stuff like that adds up quick when your dealing for 8K lbs
 
I have set my timing to 22* via timing light (ended up being 7.36mm lift on a 180hp pump). I run stock injectors with delivery valves cut halfway and chamfered and I also have .093 coversion lines. 3.55 gears 6-speed 4x4.
I ran from Casper Wyoming to Denver Colorado, 300mi, and got 18.6 MPG at 80MPH and 70-75MPH I got 21.06 MPG with some wind and altitude ranging from 5000ft to 7300ft.

My old HRVP-44 with 50hp injectors would not dream of this mileage. Had a hard time squeezing 16MPG when electronic.
 
I got 17.5 on the tank before last. Kept boost under 10psi and cruise set at 70mph. This last tank I got 15.6. Made 4-5 70-110mph runs for fun. LOL Timing is pin timed at 24*, .020 dv, 100 plate 3/4 forward, AFC modded and half forward, 7x.012 injectors set at 250 or 280 bar (can't remember).
 
You must log in or register to reply here.
Back
Top