Just filled up today and had 24.8mpg on the tank, highest I've gotten since I bought my 3.8l a few months ago. If I put 3.53 gears or higher in it, how much would it effect gas mileage? Anyone have specific numbers from when they changed um?

Thanks!

 

There will be minimal change in fuel economy. Some say they do better...all depends on how your drive.

 

ha...I'd kill for that mileage. best I usually see(with mostly interstate miles) is 18 mpg...and thats w/ stock gears!

 

If your gettin 18MPG Highway something is seriously wrong with your car. Either your putting your foot in the box WAY too much, or you are running really rich somewhere in your setup.

 

It's highway mixed with city. actual highway driving is only about 10 mile whereas 10 more miles is city. then there is city driving when i go to work. So in reality, most of it is city miles

 

So will it go up or down for city driving? Up or down for highway (55mph)? Up or down for interstate (70mph)?

That 24.8 was on the interstate for about half the tank, but usually I'm not on the interstate too much. I bought the car for good gas mileage (used to drive a truck that got 10/11mpg until gas hit $3) so I don't want to kill it too much, but I want more speed.

Also, will the speed limiter remain at 115 or will it drop?

 

limiter wont change with a a gear swap.

And normaly you will see better city MPG as the engine has to work less hard.
on the highway becuase of the extra rpms you noraly see a 1.5-2mpg loss doing around 80mph has been the case with most of the gear swaps i have seen 80mph.

also if your gonna do it do 3.73's they are a good choice for extra acceleration while not getting to high in the rpm rang which sounds like what your looking for.

 

yeah i was kinda wonderin what was goin on cuz i'm thinkin about doin something like that with 3.73's but every couple months i gotta make the drive from MD to FL and idk how thats guna hurt my highway driving long distance...usually i cruise at 2,500 RPM and i get a good 4 hrs on one tank...

 

i have 3.73 in my 99 v6 and i get 220 miles before the fuel light comes on

 

That doesn't say much, you have to divide the miles by the number of gallons you put in when you fill up. And I get 325-350 on 15 or so gallons.