4.56 vs. 4.11 MPG

I finally made the switch from 4.11 to 4.56 and here is my findings...

I have a 3.4l 5spd 99 taco with a 6in lift, supercharged, flo master, K&N, intake. and run premium gas. Most importantly I run 33X12.50's which put me on the edge of 4.11 gearing or 4.56 gearing.. I pulled the trigger and made the switch and here is the mpg differance...

with 4.11 gearing I got:

Between 210-230 a tank
Between 13 - 14mpg

With 4.56 gearing I get:

Between 230 - 250 a tank
Between 14 - 15.5mpg

I've never seen anyone post a after gear change results thread , I mainly saw speculation of what you "should and probably will get" instead of numbers. so here are the acctual numbers that i got from my 4.56 cut over. Not a huge diffence but it is some improvement. Hopefully it helps in some people that are on the edge desiding

*Note. The speedo on my truck is off by +.05 per mile after the change to 4.56 and 33X12.50's. So in a 10mile block my odometer will read 10.5. So the gas mileage is even better the qouted. accounting for the difference I should get about 262 miles a tank and 16mpg. I just gave real numbers of my trucks current condition with out the variance of the speedo/ecu.

 

Wait... You got better fuel economy? I had always thought switching to 4.56 would give move your power lower at the expense of fuel.

 

good info

 

it's puts you back to factory specs, yes you'll be at a higher rpm but it is less strain on the motor....

 

Depends on your driving patterns and habits. Lower gears (higher number) make take-offs easier, bumps city/low speed mpg. While higher gears should help bump highway milage.

 

precisley

 

Nifty. Now I just wish i could throw 4.56 gearing into my truck and then have a super-high top gear. That would rule.

 

Yeah Better mileage, honestly i was shocked to. I figured higher RPMs would result in lower gas mileage, especially on the hwy only makes sense right... but no like they said, the way it worked out the motor is working less and i'm getting and brings you back to stock mpg. the result even with a mix of 80% hwy 20% street driving (roughly) I'm getting 1 - 1.5 Better gas mileage.

 

nice, good information. just curious to how much it costs for some 4.56 gears, i know i would definitly benefit from a set.

 

4wheel parts is having a sale right now on install

 

Hate to pop ya'll joy bubble there, but how does the ECU "know" that you've changed gears? Or tire size for that matter. The odometer is fly by wire, meaning there isn't a rotating cable any longer like the old days. IIRC the sensor that reports to the odometer is at the output shaft of the tranny. It reports driveshaft rotations. Far as the odo is concerned, your still running stock gears and stock tires, yet you are relying on what the odo is telling you.

 

^yeah wut he said....

 

If you look up on TTORA about Gearing and MPG. Most guys will tell you that going from 4.10 to 4.56 while running 33x12.5 will Improve you gas mileage.

 

Digiratus,

You are right my speedo/ECU is off I already tested it against the California highway patrol White Mile Dashes that are put on the road for air craft ticketing. The difference isn't much I think it was .95 in a 1 mile, I hit the mile marker on my speedo just before the pyshical marker. but that means my truck thinks I'm going further then i really am and that means i'm getting Better gas mileage then qouted not worse. I'll get real numbers today while i'm driving around and post them later.

 

i'm seriously considering it since you brought that to my attention at the meet

 

mine are 35's

 

did you account for the gear change in your mileage calcs? ie you mileage reported on your odometer isn't the same as it once was unless you recalibrated it.

for me, in my car, i went from 2.87 to 3.55 which is like 20% change, and i saw gas mileage drop about the same %

 

Definitely in a First Gen, Going up the Cajon Pass with 33's bed loaded with gear for the weekend is pretty tough for me.