How to better mpg on Detroit 60Series?

Google fleet airfilters. check this out. 325.00 to your door. i have one in my 06 columbia. very happy with it. have 3 oil samples on this filter. silicon went down slightly from fleetguard paper.

 

See if your motor can be upgraded to the 485hp if they still have that program. A friend of mine had the 430/470 had this done and it improved his mpg and the truck pulled alot better.

When the 500's was first coming out guys were complaining of lack of hp and mpg so they derated the motor then put in the 485 program and it helped.

 

can you explain this in more detail? Thanks

 

Hi im new here. yea this trick isnt new but the way i do it is i take out the valve check return,(its behind the head on the right) only take it off (it opens in to 2 parts) be carefull when you take it out because it has a spring and a cone also a little rubber oring ,if its broken you need to change it.now you have the female part the one thats connected to the elbow and you will see a small little hole(thats a big restriction) you can use the drill bit to make it bigger(use the next bigger size). but before us do all this listen to your motor. after you finnish doing all that it shouldnt sound the same. So thats the trick. and the motor sounds more freely and stronger. i hope this helps. i did it on dd2-3-4 and it works on all of them.

 

PICHU, new here too, i am familiar with 90 degree restriction fitting on back of head in return line. ive drilled these out on dd3 from .80 stock to .109 or .112. but it has no moving parts. what are you refering to ? rereading your post, is the spring and check valve held in head by restriction fitting ?

 

PICHU, new here too, i am familiar with 90 degree restriction fitting , is the spring and check valve held in head by restriction fitting ?hi!!paul yes fit,90d,is restriction too, + check valve too, you can drill both is if you want

 

PICHU, did not know valve assembly was there. have drilled many restriction fittings on DD3. going from .80 to .109 dropped fuel pressure from 73 psi to 65 psi # 1800. 12 psi at idle. gained 1 gear in the hills and faster response. also .3 mpg improvment . sold that truck in 2002. run a C15 now but im a gearhead so this interests me. does drilling out valve lower fuel psi further ?

 

The check valve is there to keep fuel in the head when the engine is off. Without it the fuel will drain out of the head and will make the engine hard to start.

Drilling the restrictor out too much will cause too much fuel to flow through the head, and can starve the injectors for fuel, leading to scoring and early failure of the injectors.

The largest recommended size to drill out the restrictor is 90 thousants. I have seen engines running more than this, but I have also seen injector problems.

The power gain is the same at 90 as it is above 90. You will just have more fuel in the head at 90 to keep everything lubricated.

 

Stranger, good explanation, ive got it now. not aware of injector issuses going over .90. Inland DD in milwaukee, wi told me about this in late 90s. there was a run of DD2s with poor perf/mpg they found psi too high and fixed it by drilling out fitting. they also did testing on a DD3 on chassis dyno .power continued to increase all the way up to .115 however it would not idle. they said not to exceed . 109 . ive had friends go .112. one has over 1 mil on original injectors and still going. i am surprised how sensitive dd is to this mod. does this work on DD egr engines ?

 

Gotta agree with pullingtrucker on this - tires have a major influence on fuel mileage. Not only rolling resistance, but inflation pressure as well. Underinflated tires will kill your mileage. Worst time of year: early and late winter when you are going from someplace warm back into the cold. The cold can do a major job dropping your tire pressure.