The most I ever seen was 17-18 mpg on stock tuning and that was on long highway trips and that was also with the lastest reflash. Before that it was 14 mpg no matter what I did.

On 35's with spartan tuning I would see between 20-22 mpg @ 120 km/h.

I recently put 37's on and the engine actually seems "happier" at 120 km/h then it did with the 35's because of the drop in rpm. My mileage seems a bit better providing there is no wind. Even a slight head wind now will drop me below 20 though and with a strong head wind the mileage gets down right ugly. Those damn 37's are so hard to turn.

 

With 35 inch tires, doing 120, getting 20-22 mpg, thats just amazing!

If I could get a new truck that would for sure do that, I think i would just go out and get one!

 

I cant wait to do mine. Mike, I know the higher the hp of the tune, the better mileage. Because of my heavy foot I was thinking of stopping at 210 and maintain factory safeguards. what are your thoughts on this and the amount of less mileage I could expect?
Spartan or H&S???? Thats the question...

 

With 35's, which is what i believe your running, your should still see a significant mileage increase with the 210. I think at least some of the fuel economy gain does come with the transmission tuning though. The converter locks in high gear at 80 km/h which is really nice but i think it is only available on the race tunes (250 and above). With that said, i don't think you'll ever see 20mpg from what I've read on the forums with the 210.

H&S or Spartan? Tough question. I believe at this point spartan tunes are probably a little more refined but H&S will probably catch up. H&S does have better customer service from what i've read but I have noticed Spartan making an effort to improve theirs. I had problem with my monitor twice now, which is apparently unheard of, but still was very frustrating for me. In the end they did right and got me fixed up and even added a few goodies for my time. I guess I would say I am happy with my Spartan, but if you would have asked me a couple weeks ago I would have said go with H&S.

 

Another front hub issue - I had problems with the vacuum lines for engaging the front hubs and got that fixed. Now, one of the hubs is not disengaging. I tried quite a few times the other day, backing up, etc but to no avail. Had to drive it home in 4x4. Had it in the shop overnight and it disengaged. Monday is another warranty date!
On my 2003 I had one hub done on warranty and the other side just off warranty - not that great IMHO.
I saw a thread someplace about actually using the breather vent to shoot grease into them - anyone ever try this???

 

First front hub replaced at 38000 kms...

 

Is the hub vacuum operated?

 

Yes, they are vacuum operated with the manual option on the external dial. I did some reading on this on the Superduty forum by searching 'greasing front hubs' and there are quite a few guys who have all but eliminated the high premature failure rate by greasing them via the ABS sensor hole. They also go to say that there is another bearing that requires hub removal to get to but I would not bother with that (I dont think!).

 

Sounds pretty much the same as with the 05`s system.

 

My 2003 was the same too - first hub around 60000 kms and the other just after warranty expiration!

 

Yeah this system that ford uses, works good when it works, but it is problematic.

Too bad cause when it works good its really handy to have!

 

the v10 has something a 6.4 does not. the v10 sounds absolutely awesome with custom exhaust and a cold air intake. the 6.4's i've worked on have had some improvements in mileage with a DPF delete and program,but they still get very poor mileage. in reference to the boost concern at part throttle,dropping off when floored, i dont really think there is anything wrong with it. the 6.4 has a very dynamic boost control based on tons of inputs. if it wants 35 psi at part throttle,it gets it. if the engine light isn't on for boost response,there really isnt anything happening that needs to be worried about. the pressure will drop off when floored because the sudden increase in load demand yields more airflow.you are still getting the same power,but the boost(available air volume) is being traded off for flow(consumed air volume).if they had a flow meter on the dash right beside the boost guage,it would eliminate the very frequent customer concerns i used to hear every day about too much or too little boost. also,the noise you are hearing at high load throttle drop..does it sound like a loud fluttering noise? the 6.0 was terrible for it,and the 6.4 often produces the same noise. it is just boosted air flow having no where to go but back out the intake when the load demand drops off and the egr throttle plate slams shut.it is easy to identify by the passenger side wheel well,under wide open throttle in 4x4, foot planted o the brake,and when it makes max boost,drop the throttle. it will make a Shoosh-shoosh-shoosh sound. it can be monitored by scanning engine pid data and watching the EGR_TP pid dutycycle when the load is dropped.it will shoot up to high DC for a moment and then return to full open, 0% DC. that function is totally normal.hope that describes your concern!

 

i prefer removing the hub lock actuator and soaking it in penetrating fluid. the grease method turns to sticky goo in the cold and then they stick and dont work at all.