GAS MILEAGE WITH 4 10 GEARS?

[06GTWhiteHorse]

How badly does your gas milage go down when you install the 4 10 gears? I have a 06 gt manual, with jlt cai, 91 oct tune, and american thunder axleback exhaust. It seems like i run around 15 to 16 average miles per gal.. I know heavy foot. I want to get the 4 10 gears but am worried that I will wind up with crazy bad gas milage.. Any help would be great. Thanks in advance.

 

[chad9350]

improve city, bc can use 5th more, may loose 3ish hwy; keep foot out of it, mileage more of HOW you drive.

 

[#1stangFAN]

improve city, bc can use 5th more, may loose 3ish hwy; keep foot out of it, mileage more of HOW you drive.

chad just curious but what do you get with you 4.56's?

 

[Five Oh Brian]

City mileage stayed the same for me. Highway mileage dropped about 2 mpg. With 4.10's (plus big stall converter and supercharger) I get about 24 mpg at 60 mph on cruise control and about 20 mpg at 70 mph on cruise control.

 

[GreyDiesel]

chad just curious but what do you get with you 4.56's?

okay, clearly Chad is the one to answer this, but its important to note that he has the T6060 transmission (out of a GT500?), so he has 6 gears instead of our measly 5. That would be, I would guess, why he went with the 4.56s. The sixth gear is a bit taller in the 6060 than in our 5speeds (0.63 vs 0.675). And with the 4.56s, 4th gear tops out at 100mph. You could not reasonably run 4.56s, with our TR-3650 because you'd shift into 5th at 100mph. 5th is an overdrive gear, and you would not have enough lower rpm power to keep accelerating quickly. You can run 4.56s with the 6060 though, because it has, essentially, an extra gear between 4th and 5th. Plugging the 6060 ratio numbers into my handy ratio/RPM calculator, I come up with:

2500rpm @ 62 mph
3000rpm @ 75 mph

I am curious what kind of gas mileage that translates to.

I am at about 2100rpm @ 75mph with the 3.31s, and get about 27 mpg hwy. (it varies a lot, but seems to hover around 27 on a flat stretch of road at constant speed)

 

[#1stangFAN]

i just did the math today and i got 25.7 highway and that was going 65 with 4.10's

 

[chad9350]

Final ration in stock TR6060 'sameish' as 3650... that said, with stock TR6060 I could get 18-26 city, depending on how I drive, tune, etc, and about 25-28 highway 80ish.

Its not difficult to get 15mph w/ 355 if you keep your foot in it....

4.10's are Great gear for 3650, if you go to the track ALOT, 4.30-4.56.

 

[GreyDiesel]

Its not difficult to get 15mph w/ 355 if you keep your foot in it....

yes, all you have to do is put it in first, mash the pedal, and wait about one second. I have 3.31s and hit 15mph all the time. Even on public roads.

Sorry... I am being an ass.

I checked my mpg after a day at the road course, and I had managed 7mpg. So yes, its all in how you drive. I can get it up to 30mpg on flat interstate. But that does not really count. EPA hwy estimates take into account hills and slowing down/speeding up a bit for traffic jams. You cant get 30mpg in those conditions. Hell... I can hit 99mpg coming out of the Rocky Mountains. (its basically a 70 mile bobsled course)

point is. MPG varies A LOT. The only thing that your pocket book cares about is the combined cycle. i.e. the average from tank to tank. On that, I am getting 19.5, and I do a lot of hwy cruising, then lay on it from street light to street light in the city.