4.10s and revs?

[99nightmare]

I know that many things come into play here such as rim/tire combo, but what rpms are you automatic guys seeing with 4.10s at highway speeds (55-65 or so). I think we are going to go with the 4.10 but I would like to be able to pull 24-27 mpg on highway driving. Do you think that is possible with the 5 speed automatic and 4.10 and a tune? We have the stock 18 inch polished rims for now and will probanly keep them for the neqr future. Thanks to everyone who responds.

 

[ct07gt]

I can't tell you what kind of mileage you might see, but I can help you with what RPM you will be running. Assuming you want to see the revs at 70 mph, you would take the RPM that you currently see, we will say 2000 rpm for example. If you have 3.31 gears now, you take 4.10/3.31 and you get about 1.24. Multiply 2000 x 1.24 and you get 2480 RPM which is the engine speed at 70 mph. I don't have an auto so you will have to change the 2000 RPM to whatever you want.

 

[bynumj]

Gear Chart

Do a search on my post. I have a gear chart posted on this site. It will let you plug in your info and tell you what you want to know.

 

[Five Oh Brian]

I know that many things come into play here such as rim/tire combo, but what rpms are you automatic guys seeing with 4.10s at highway speeds (55-65 or so). I think we are going to go with the 4.10 but I would like to be able to pull 24-27 mpg on highway driving. Do you think that is possible with the 5 speed automatic and 4.10 and a tune? We have the stock 18 inch polished rims for now and will probanly keep them for the neqr future. Thanks to everyone who responds.

I have your exact combo: 4.10's, automatic, and stock 18" wheels. This turns 2100 rpm's at 60 mph and 2800 rpm's at 80 mph. Before I added the supercharger, I got 26-27 mpg on the highway at 60 mph (cruise control) and about 23-24 mpg on the highway at 70-80 mph (no cruise control, going with the flow of traffic).