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4.10 Gears and Highway use?

9K views 10 replies 7 participants last post by  pjk 
#1 ·
I have been considering switching to a set of 4.10 gears, but i have a few questions. I use my car for my dd and sometimes i have to travel for work. Basically my question is with 4.10's how bad is the fuel economy driving 70 - 80? And i know there will be a increase in rmps can that be harmful to the engine for a long period of driving? I tried to look this up but couldnt find anything, If anybody could give me some info it would be very helpful!:bigthumbsup
 
#2 ·
I just got a set of 4.10s a couple weeks ago, my highway MPG dropped by 1-2. At 70, you'll be getting about 23-24 average. City MPG stays the same, if not higher from the engine bogging less.

At 70, you'll be at around 2500 RPMs, which is perfectly safe (3V opens at around 3250 RPMs) You're thinking VERY high RPMs, which will definitely put some wear into your engine. You'll never have that problem though driving 70-80, so no worries.:bigthumbsup
 
#5 ·
As mentioned, MPG will drop and RPMs will pick up at cruise...

I have 3.73s and first gear ramps up FAST with them, and starts from a stop will be more aggressive with 4.10s...
 
#7 ·
You should be able to set the rear axle gear ratio in your live wire with you existing tune.


Sent from my Autoguide iPad app
 
#8 ·
American Muscle does give free tunes, but as GTRob already said, you should be able to set the rear axle gear ratio on your tuner. I'd rather custom tuned over canned though, since I have no experience in tuning.

But American Muscle wont give you free tunes for the gears, only if you buy a tuner from them (which I'm sure you wouldnt want to do since you already have a live wire) or buy the "Bama Tune Files" which comes with 3 custom tunes and free tunes for life after that. It's about $150. Much better than buying another livewire.

Bama Tune Files (If You're Not a Free Tunes for Life Member) at AmericanMuscle.com - Free Shipping!
 
#9 ·
there is an option when you upload the tune to adjust your gear ratio. Are you stick or auto? i ask cause with the stick the 05 has 3.55's and the auto has 3.31's, i always say if you're on the fence or if you do high speed driving then go with 3.73's. the 4.10s are great if you do tons of city driving like i do, but on the highway, i do 70-75 and i am barely cresting 2,000's rpm's and enjoying good mpg. With 4.10's you will be much higher then my 2,000ish with the 3.31's
 
#10 ·
I have a auto and yeah i need to go ahead and get custom tunes. I do mostly city driving, but i go to the lake and to cincinnati both right around 100 miles i normally dont take my mustang to the lake though, its kind of hard to tow a 30 runabout with it :laugh:
 
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