Horrible fuel mileage w 07 Pete 379, NXS 625hp Cat

Must be the trk mfg.Mine is a 06 w9 with a mxs and it's 5" off turbo all way to Y and 5" out stacks.

 

02 6nz 475hp 1750ftlbs , 3 round trips took 450ltr fuel, wit fuel wire 400ltr fuel+more power, used to show 3,85mpg on display wit 3.73 rears, changed rears to 4.11, display read 4.10mpg, changed again to 4.30 display now reads 4.27mpg, mostly hilly hauling, 100000+net

 

The FLS and FTS numbers are fuel numbers changed in the ECM. They didn't change the fuel pressure at all from what I can guess. To shim the pump there is a hex plug or allen plug facing the drivers side frame rail on the fuel pump. Remove this plug, but becareful as there are a spring, short rod, and a "washer/shim" inside. Sometimes the washer/shim will be stuck in the bottom of the plug. Go to a local hardware store and they should have small copper washers that are just a tad bigger than the hole in the plug. Start with one shim and grind the edges down until it will drop into the plugs whole and then install the factory washer/shim along with the spring and rod back all back into the fuel pump. A fuel pressure gauge is really needed to set the correct fuel PSI for the best performance. Whatevery you do, don't go over about 110 PSI as you will push fuel past the injector o-rings. Also the fuel pressure return valve on the secondary filter housing goes bad about once a year. They are cheap and I carry a extra one in the truck.

The torque setting can make a big difference, but if I remember right you should have a 1850 setting already in the motor. To be honest I have never heard of the transmissions input shaft breaking behind a ACERT. This kinda puzzles me cause I know many guys that are running higher torque levels than you and we all lug down to 1050 (or sometimes lower). I'm almost wondering if your harmonic damper is bad or the motor may be out of balance a little...both will cause a broken input shaft.

As for the 4" turbo outlet...I have seen these and have no real idea whhy CAT or Pete went this route. The only thing I can guess is they are using it as a venturi type deal to speed up exhaust flow...but this close to a turbo I think it would cause more harm than good. Speaking of exhaust, if you haven't dumped your factory mufflers for high flow Donaldsons or a resonator...do it. The ACERTS move a ton of air and need the exhaust flow to be fast and smooth (if you already mentioned this, I apologize...I'm in a daze cause my 2 year old is sick and won't sleep)

 

A little off the mileage topic, When the input shaft broke, did you check the crankshaft end play? I had a customer with a broken input shaft last week , 1 inch twist break and found it pushed the crankshaft forword resulting in a damaged thrust bearing. The crank and block were ok but the thrust was missing about .025.

 

What fuel are you running?

 

670 HP? Never heard of that except on custom built engines in custom truck's. I may be wrong but the biggest I know of is the ISX 600. That Cat must have some after market parts.

 

I see the FASS as the best class 8 aftermarket filtration because of its filtration abiltites and pressurizing the fuel as it goes to the factory fuel pump. This way there is no restriction at all on the factory pump and the fuel is totally pure (no air). The next best would be a Davco. These filter good, but don't take out all the restriction in the fuel supply side.

Bully Dog does market their products more for fuel mileage cause thats what the majority of companies and o/o are looking for. They will do a custom tune for pretty much anything you want...all you have to do is ask them and give feedback if something needs changed. PDI seems to concentrate on the HP/TQ aspects, which isn't a bad thing. The tuned ECMs and downloader do much much more than the fuel and boost wires are capable of. The ACERTs need the 8* of timing put back into them in order to make them live longer and perform better. The only way this is possible is with a tuned ECM or downloader.

You can easily meet the 5.5 MPG goal. I know many guys that are getting 6.5+ running across PA on I-80 hauling 80,000+ all the time. All it takes is the proper parts and the right driving style to make this possible. As a added benefit you will out pull everyone on the grades and run cooler.