Can I get 20 mpg with 4.10 gears?

What do you mean it won't happen... I'm doing it in my 3700lb car. Granted, I will never see that in the city, but on the highway cruising at ~70-75mph I manage 20-21mpg with my 4.10's and TKO 5 speed... that's with a 315-35-17 tire out back too.
 
94SC50 said:
I stand totally corrected on this issue. I hate my car, it gets nasty mileage and I envy all of you getting double the miles per gallon more than me.

I know you you feel JR Im not doing much better w/ mine. My MPG have sucked latley after the 3.55 gear install and Im not driving the hell out of the car either. It has brand new 02 as of last may, new fuel pump and filter, new spark plugs but I guess I just have one of those cars that like gas.
 
Depends on your driving. The best gas mileage I ever got was the tank after my 3.73 install and that was because I had to baby it around for a week to break them in. I got 22 mpg out of that tank and ever since have gotten a pretty consistant 18 mpg. So it has a whole lot to do with how you drive. My friend with a stock 4.6 liter was managing to get 13 mpg with his car when he first got it. But that because he was always flooring it and didnt like to use 5th so he kept it in 4th on the highway.
 
You guys with power adders getting over 16mpg better check your A/F ratios :lol:

Also, for some of you with gears and NOT the right correction speedo, remember if your speedometer is turning faster than your are "really" driving, it will appear that your mileage is better than it really is.

JR...Dont worry bro...Im around 13-14 mpg, and PROUD of it...I know Im running rich, but Im not taking any chances.
RC
 
i think i get close to 20 mpg with my car and thats with some city and highway ,but i dont check it that often and don't fill it everytime , there are times when i can watch the needle move under boost at 60psi fuel pressure :rlaugh:
 
I have the 3.73's with the 23 speedo tooth. So I am off 5% all the time. I just filled up & calculated my mileage again.

I went 254 miles on 12.2 gallons of gas. Now you take 95% of 254, and divide that by 12.2, and you get 19.77 MPG. That is what I got, and I have been driving like a maniac at least 50% of every stop light I leave. And we DO NOT have any highways here, so there is no crusing at 55mph anywhere.

If you car is out of tune, or you have a blower, you can only dream of 20mpg with ANY rear end gear. :rlaugh:
Scott
 
Mines a 5 speed with 3.73's, limited amount of bolt-ons, and wide tires and I NEVER get less than 20mpg, and usually get about 225-250 miles per tank. The 3.73's actually improved my mpg over the stock 3.08's, and I drive it very hard when in the city, but on the expressway I'll set the cruise at 75-80mph.
 
I get about 225 miles per tank, mixed city/highway driving, and I have a depleted uranium foot. :) Translates to about 19 mpg -- though I just made a tweak to my calibration that I hope will give me 3 or 4 more mpg. We'll see!

Dave
 
Killercanary said:
Mine is correct Rob as I have a 6 tooth inner and a 19 or 20 tooth outer, its been so long that I can't remember.

Is there anything you CANT do Paul?

1. Run under 12.5 in a Vert on Motor
2. Get your car in a magazine.
3. Get over 20mpg

:spot: :spot: :spot:

RC

BTW: Rims going on a couple of hours!
 
I know you have received a lot of replys, but I consistently get over 20 mpg on the highway when I am light on the pedal. I have 4:10 gears in my 97 cobra with several mods, and even running the air on a long trip recently, I had 22 mpg. Running the car a little hard in the city I can get as low as 14. That really sucks due to the Premium only that I have to use.
 
Killercanary said:
What do you mean it won't happen... I'm doing it in my 3700lb car. Granted, I will never see that in the city, but on the highway cruising at ~70-75mph I manage 20-21mpg with my 4.10's and TKO 5 speed... that's with a 315-35-17 tire out back too.


I was reffering to it not happening in the city. Now on the highway it's a totally different ball game. I have yet to see any GT get 20 mpg in the city. Now if they are out there than I have been sadly misinformed, and will stand corrected. But like I said I don't see it happening in the city. 315's out back and you still manage to get pretty good gas mileage, and you run 12's in your car. What is your secret?
 
SN95 weight loss plan...

Here's another stupid question... Aren't the aluminum driveshafts lighter than the standard ones? By my understanding, in general, efficiency is increased anytime rotating mass is reduced. So if I replaced my driveshaft with an aluminum one, could I gain a little bit in the mileage? I don't think I've heard of anyone doing the aluminum driveshafts for that purpose, but I was just wondering...

I'll put on my asbestos-lined, flame-retardent jacket now...
 
doesn't it also matter what octane gas you run??? I noticed that my stang 202 miles out of 12 gal w/ Shell Vpower 94 octane. I put shell 87 octane this time and it seems like I won't get to 202 this time. Well... my car also runs super ritch so i will have to look into cleaning some sensors and getting new O2 sensors as well, since someone said that that's the major A/F ratio problem.
 
lietuvis91 said:
aluminum driveshaft sounds expensive just for better mpg

You're absolutely right on that. But I expect that the guys who have done them are doing them for more than just better mpg. So, if its one of those where I get better mpg and a little more oomph, then it sounds like a reasonable thing to look into.
(even though I said earlier I didn't want to do drivetrain stuff)
 
A lighter driveshaft could help a little in that area, it couldn't hurt, that's for sure. Lighter wheels and brakes would also be an improvement. If you wanted to run around with some draglights, complete with skinnys, the weight reduction alone could net a nice mpg increase.