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Woodsy · 01-08-2010, 01:28 PM

Ishoot...

You are way off..... Unless your a landscaper or someone like that who is CONSTANTLY towing a large trailer aound town you dont want 4.11s! In normal everyday (non towing/no plowing) use that truck will GUZZLE fuel.... your mileage would be horrendous.

Most modern engines are designed to run most effeciently right around 2000 RPM, give or take a few hundred RPM. Once you start climbing past that magic number, your mileage drops off appreciably.

Without getting into semantics like transmission ratios etc, just like everything else... a gear ratio is a compromise! Given the same final ratio in the transmission, a high gear ratio such as 3.08 will give better gas mileage because the engine turns at a lower rpm (lower HP & Torque) and the car travels farther... the trade off is that your engine will have to downshift while climbing hills occassionally, especially while towing.

A low ratio such as 4.11 you will have your engine in a much higher rpm thus making more HP & torque..... so less downshifting is required. But running at a higher rpm constantly burns alot more fuel. You dont want to run a truck with 4.11's up a highway.... you can pass everything but a gas station.

The trade off is a mid range ratio like 3.43 or 3.73.... it offers fairly decent gas mileage yet is able tow acceptably. This is ratio range most commonly seen...

Woodsy

01-08-2010, 01:28 PM	#10
Woodsy Senior Member Join Date: May 2004 Location: Weirs Beach Posts: 1,968 Thanks: 80 Thanked 980 Times in 440 Posts	Ishoot... You are way off..... Unless your a landscaper or someone like that who is CONSTANTLY towing a large trailer aound town you dont want 4.11s! In normal everyday (non towing/no plowing) use that truck will GUZZLE fuel.... your mileage would be horrendous. Most modern engines are designed to run most effeciently right around 2000 RPM, give or take a few hundred RPM. Once you start climbing past that magic number, your mileage drops off appreciably. Without getting into semantics like transmission ratios etc, just like everything else... a gear ratio is a compromise! Given the same final ratio in the transmission, a high gear ratio such as 3.08 will give better gas mileage because the engine turns at a lower rpm (lower HP & Torque) and the car travels farther... the trade off is that your engine will have to downshift while climbing hills occassionally, especially while towing. A low ratio such as 4.11 you will have your engine in a much higher rpm thus making more HP & torque..... so less downshifting is required. But running at a higher rpm constantly burns alot more fuel. You dont want to run a truck with 4.11's up a highway.... you can pass everything but a gas station. The trade off is a mid range ratio like 3.43 or 3.73.... it offers fairly decent gas mileage yet is able tow acceptably. This is ratio range most commonly seen... Woodsy __________________ The only way to eliminate ignorant behavior is through education. You can't fix stupid.