I have been reading about gear ratios and engine RPMs and highway speeds on this forum. I have a question.
First, I will say that I have a CAT 1160 (V8 diesel precursor to 320
motor. The transmission is a 4 speed auto. I presume it is an Allison, though I do not know. A placard on the dash says the ratio is 6.8.
My question is: why can I go 67 MPH with pedal to the metal on the highway? My water temp never gets over 195. I do not have a tach. I sure would like to know how to hook one up.
It seems that the motor must be turning some high RPMs to go that fast.
Oh, one more thing, the bus does not go very fast up hills.
I am thinking that either the rear end has been changed or the motor is weak and may be dying.
I get 8 miles per gallon at 67 MPH. The tires are 11R 22.5
Please give me your theories. If possible, perhaps you can tell me how to hook up a tachometer.