Healthy enough for tuning?

[pwerwagn]

Originally Posted by bighorn466e

The next trip was quite long (FL->DE) and there were significant ambient temp changes. I noticed that on the cooler days I was getting about a MPG better and didn't feel like I was losing any power on the top of long grades. This was a bit of an eureka moment as I was losing ~12% mpg and 12% of 250 is 30hp which happens to be about the power consumed by my mechanical fan according to some engineering spec sheets.

I noticed a similar phenomenon with my VT365. It felt way stronger when cold, and even tho the fan sounded like it was pulling as much when cold as hot it wasnt. I replaced it with a horton EC450 elec fan clutch, and in ambient temps below ~72 or so, it never comes on. My IAT runs a little hotter due to less flow thru the CAC, but it doesnt seem so affect anything other than peak egt when I'm above ~2600rpm WOT.

The power increase with the fan on vs off is huge. On long hills I have left it on, and turned it off after speed stabilized and it will typically gain 5-7mph. I know kitmasters has a fan that is like ~20% on at all times, and then 100% on when called for. I think that would be the real ticket. OR perhaps a big electric pusher fan, and then bring in the mechanical when necessary.

What year is your truck? I have been heavily considering swapping out my VT365/A2500 for a ~03-05 ish DT466/A3000. I assume loaded with the 5th wheel you are in the ~22klb range? How does it pull tuned at that weight?

--Jeff