How do you build a fast truck?

I was heading east on I-80 in NV at about 65-70 when I was passed by a truck doing at least 80. I assume he was loaded coming out of CA with a reefer. This guy was gone in a couple hills he was 3 hills ahead! Nothin but tail lights.

So I'm mostly curious and asking for academic reasons, but....

What gear ratios/ tire combos are used in trucks like these?

What RPM is a truck like this doing at say75-80 MPH?

How much HP is required? Can't imagine a small engine would be able to maintain any reasonable speed up a hill fully loaded with a cruising speed that high.

OK, and no BS please. What kind of MPG?

Your thoughts?

 

The truck was probably speced with 3.25 or 3.36 rears or even faster, with the 3.36 gears 78mph is 1600rpm with a .73 overdrive transmission. Most likely a 550 or 600 horse engine, or maybe one with some custom programming.

Mileage really would come back to gearing.

 

I'm running a B model CAT that has had a little muscle put in it plus some pump and timing advance work, a double over trans .62 final ratio 3.55 rears and 11R24.5 tires at 1600 I'm right at 90 in the big hole. As far as fuel mileage last quarters IFTA shows 5.8 no I don't stroll too often or to long when I do.

 

So on a 6% grade, fully loaded, can you stay in high range and do you cruise one or two gears down most of the time?

 

Some where in all my Cat literature I read that a B is most efficient at 1475rpm course the E are lower but I try to stay at 1400 or so which is usually 10th and 11th gear on two lane blacktop, up against the dash on the interstates. Usually with the O.D button in direct you have to really want to step to run high gear.

 

"Wore out" I'm running the same set-up except for the rears, mine are 3.70's but yet our fuel milage is about the same. I never pull mine below 1500, and your right about flipping the button in that last hole. Coming out of California Cody's probably right, not many B's running out there anymore, I know I ain't.

 

Which trans has a .62 OD ?

 

The RTOO series transmissions have the .62 overdrive, there are only two or three models offered by fuller. The RTO12513 can be made into one, I'm hoping to do this to mine to offset the 4.11 rears in my w900a.

 

I have 3.90 rears and tall rubber and can hit 3 digits. Buy me some fuel and I'll prove it!

 

SmokinCat If I am not mistaken when you change your trans. into a double over you will will no longer have low gears to start out.