Thoughts on 3.08 diff ratio

They test these engines for millions of miles before they even sell them. It's like drivers of 30 years ago that were used to mechanical engines couldn't wrap their head around, "that's just not how you drive an electronic engine". Things have changed in the 30 years since. It's not gonna hurt these new engines at lower rpms like that.

 

Three things come into play, cam design, peak torque and volumetric efficiency. Mechanical injection systems have a peak torque plotted on a chart, this usually means the best fuel consumption. The electronic injection system flattened out the torque but has a peak torque rating and that’s what you gear the truck to. The larger engines >14 liter usually have that peak torque around 1200 rpm, the smaller ones <14 liter are a little higher, 1400 rpm.

 

Dress it up anyway you want.

The motor is still working harder at lower rpms.

 

I don't know Ridge. I looked at the torque curve on my 14L Series 60, and if I recall correctly, it said peak torque is 1500 rpm (maybe even higher). I Imagine this is in any given gear?

 

The fan speed on a new engine isn’t related to rpm’s if it’s spec’d with a variable speed hub. My fan is on all the time and speeds up and slows down depending on engine temp.

 

the 60 is a flat torque engine, pretty good one too. The peak torque rating is at 1100 rpm, the lowest fuel consumption is at 1150 rpm, the peak HP is at 1500 rpm.

 

The 3.08s should be good for those hills with your engine, especially if you're not hauling super heavy loads. You might notice a bit less oomph on steep inclines, but overall it will do great.

 

Lowest fuel consumption at 1150 rpm? There is no way I can run that engine at 1150 rpm. That would be lugging the heck out of it. Are you sure that is correct? Everywhere I've read says that the Series 60 likes to run with higher rpm.

 

They might recommend it but that’s doesn’t mean it’s good stop and think about it 1,100 rpm is just barely off of high idle there’s not much torque developing at that low a rpm

 

What benefit would there be to a manufacturer lying about their torque curve?