4.56 Re-gear First Impression

god forget that. id be trying to find a friend who knows what they are doin or something haha! thats just a ton of cash

x2 seems like a waste. should have gone to 4.88s and you would be set for 35s if you ever went that big

 

I am seriously thinking of doing this. I can't stand that my RPM is at 1200 at 75mph and a slight hill and I downshift and then over compensate and the truck applies the brakes.

My old 1990 Toyota Pickup could hold 70mph with 35's and stock gears no problem.

 

How is your RPMs at 1200 @ 75mph???

 

Do it, you will not be disappointed. Another benefit is that Im able to stop faster than before. When I let off the gas the engine helps slow the truck down.

RJM

 

So much wrong with that logic, but if that is what you want, great.

 

Overdrive in the Automatic, It is extremely low so that it gets the stated MPG.

 

* 500 mile update with pics, post #1.

 

sub'd.... I want to see some mpg info

 

Ok, guys here is an update with the mpg's:

-Gallons Miles MPG
12.327 184.5 14.96715
16.716 251.9 15.06939
15.112 235.4 15.57702
15.987 236.2 14.7745
15.897 221.3 13.92087

This mileage is all city driving with heavy footed acceleration which is how I normally drive. The last entry included towing my dirtbike trailer with 3 full size bikes.

As you can see the gas mileage is pretty much what it was before the gears. I honestly thought it would improve with the gears but I guess not.

I'm suspecting the stock ECU is compensating for the changes and that's what is giving me the crappy mileage. I might install a URD FTC unit to mess around with closed loop fuel ratios.

Overall I'm still happy with the performance gains and it was much cheaper than a supercharger with fuel mods.

RJM

 

Hey OP the price you paid $2183 for parts and labor, that seems like a pretty good price.

How long did they have your truck for?

 

I don't follow the logic of thinking that more aggressive gears would return better mileage. The reason Ford runs a 2.7 on the Mustang is because it allows them to claim 31mpg highway. When you get sporting gears, the mileage comes down quickly.

 

The reason I am regearing is with 35" tires, I need a more aggressive gear to return me to the proper RPM at speed and brings it back to a stock feel. Plus it's easier on the trans because it has trouble choosing a gear at HWY Speeds.

 

I have 4.56's and 32.5" tires (GY Duratrac 285/70/17). The theory is that with lower gearing you use less gas pedal to get up to speed when you are driving around town. I agree with that, it feels like a V8. So if you are conservative, you can get about the same mileage around town as a stock truck. But you are still spinning heavier tires and wheels, and depending on how much heavier, mileage will suffer.

However, on the highway, RPMs will be up and mileage will suffer. I get about the same on the highway as around town, and about the same mpg as the OP. I would love a really tall overdrive.

 

Hmmm

 

Update: I have a wide band gauge and piggy back ECU coming my way. I'm going to be running tests on the closed loop fuel profile. My thought is to tweak the closed loop system for better fuel economy and then tune the open loop for my URD exhaust.


Stay tuned.......


RJM

 

Why do j00 have a picture of a Nissan pathfinder in your sig and you on TW?

 

Can I get an update on gas mileage please?

 

I keep a mpg log in my build thread, I think there's a link in my sig

 

Thanks, very informative.