Ford 8.8

[thomas]

I have 8.8 Explorer rear end with a 3.73 ring and pinion. I also have two other sets of ring and pinion's. A 3.08 and a 2.73. Any suggestions on which one to use.

thomas

 

[GT63]

I have 8.8 Explorer rear end with a 3.73 ring and pinion. I also have two other sets of ring and pinion's. A 3.08 and a 2.73. Any suggestions on which one to use.

thomas

Before you can determine that, there are other factors to consider; Rear tire Diameter, engine torque, stall speed , transmission gearing, etc. IMO I'd stick with the 3.73.

 

[RPM]

I'd probably go with the 3.73 also, unless you want a high speed cruiser.

 

[thomas]

I'd probably go with the 3.73 also, unless you want a high speed cruiser.

I'm running a C4 trans with 29.5 dia. tires. With the 3.73 rear end I'm turning 2000 rpm's at 40 mph. Temp. stays constant 180 degrees. Temp. starts to increase up to 230-240 degrees at 3000 rpm's. Thought by changing ring and pinion to 3.08 or 2.73, I could keep the temp. down and increase the fuel milage.

thomas

 

[gfigms]

I'm running a C4 trans with 29.5 dia. tires. With the 3.73 rear end I'm turning 2000 rpm's at 40 mph. Temp. stays constant 180 degrees. Temp. starts to increase up to 230-240 degrees at 3000 rpm's. Thought by changing ring and pinion to 3.08 or 2.73, I could keep the temp. down and increase the fuel milage.

thomas

I am running Ford 302 \ C4 trans \ 31x16.50R15 rear tires and 3.25 rearend ratio ... at 2000 rpm I am runing about 60mph ... if you can trust the speedometer.

 

[thomas]

I am running Ford 302 \ C4 trans \ 31x16.50R15 rear tires and 3.25 rearend ratio ... at 2000 rpm I am runing about 60mph ... if you can trust the speedometer.

So how high is the temp. at 60mph? Formula for your speedometer reading is: 20168 divided by tire dia. times trans. output shaft times rear end ratio divided by 1001.

C4's have three different output shaft's. 9 tooth, 8 tooth or 7 tooth.

I have a 8 tooth. Example for speedometer gear in my case. 20168 divided by 29.5 = 683.661 X 8 = 5469.288 X 3.73 = 20400.444 divided by 1001 = 20.38 tooth gear. Round up to 21 tooth, speedometer will read faster than you are going. Round down to 20 tooth, speedometer will read slower than you are going. Ticket.

thomas

 

[gfigms]

So how high is the temp. at 60mph? Formula for your speedometer reading is: 20168 divided by tire dia. times trans. output shaft times rear end ratio divided by 1001.

C4's have three different output shaft's. 9 tooth, 8 tooth or 7 tooth.

I have a 8 tooth. Example for speedometer gear in my case. 20168 divided by 29.5 = 683.661 X 8 = 5469.288 X 3.73 = 20400.444 divided by 1001 = 20.38 tooth gear. Round up to 21 tooth, speedometer will read faster than you are going. Round down to 20 tooth, speedometer will read slower than you are going. Ticket.

thomas

Temp holds steady at 175 to 180 ... running 160 degree themostat. Electric fan comes on with ignition ... I turn it off when up to speed.