Can I get 20 mpg with 4.10 gears?

[lparsons]

Hey everyone

This will probably sound stupid, but I believe my 95 gt has the 4.10 gears in it. I bought it used, and the person I bought it from said that non-stock gears were installed. I haven't taken the time to open it up to look at them myself yet ... BUT ... I notice my speedometer reads about 20% higher than actual speed, and I can do 2nd gear burnouts on my new tires without much work.

Unfortunately, as we all know, gas prices suck. I drive this car quite a bit, and I'd like to get better gas mileage - I'm getting ~16 or 17 mpg right now. I have a five speed transmission, is it possible to get me up to around 20 or better? I just did plugs, wires, cap, rotor, and air filter.

I couldn't get the autolite copper spark plugs at the time, and ended up doing autolite platinums. I know everyone recommends the coppers, but they weren't available at the autozone near me at the time.

What could I do to improve my mileage? Other than re-gearing or doing anything else dramatic?

Previous owner also did about 3" cat-back custom side ported exhaust, no mufflers (we are only required to have cats in MN, as long as we don't exceed a certain noise level).

 

[94TURBO5 O]

Just keep your foot off of the accelerator pedal.

If you are changing gears every 2 feet then you prob have 4:10's. Seriuosly though it would be hard to tell you IMO cuz the which ever speedo gear you have in the car determines how much you are off not the ring and pinion.

 

[94GTLaserRC]

You will NOT get 20mpg!
RC

 

[94TURBO5 O]

Oh yeah I have 3:73's with the mods below and RC is right....... it just won't happen.

BTW I get 110 miles sometimes to a full tank and that's considered good.

 

[super302]

Lets put it this way...i got 19.8mpg with 3.08's (all city tho)(never 'got on it' to see what i could get)
With 4.10's(what i'm getting soon) plan on 17ish.

Just my theory

 

[iluv95stangs]

Your MPG now is probably off also due to the fact that your odometer is reading incorrectly. I have 3.55's and still only get around 15 mpg in the city.

 

[GTJake]

Previous owner also did about 3" cat-back custom side ported exhaust, no mufflers (we are only required to have cats in MN, as long as we don't exceed a certain noise level).

I have no cats in Minnesota..

Oh, and Paul gets 21mpg in his heavy very with 4.10s on the freeway.

Jake

 

[Mrgreen94gt]

I regularly get 20-25 mpg on the highway. I only manage about 12-13 city, though.

 

[lparsons]

Your MPG now is probably off also due to the fact that your odometer is reading incorrectly. I have 3.55's and still only get around 15 mpg in the city.

I should have pointed out my approximation of my mileage is based on taking my calculated mileage from the trip meter and multiplying by 5/6. In other words, by the trip meter, I am getting ~20 mpg consistently. But of course, that is logging miles 20% faster than reality, so my milease is 5/6 of that, or about 17.

As for cats in MN, on my last car, which was single exhaust, I eventually hollowed out the cat because it was deteriorating anways, and then reinstalled it without anything inside of it (just the shell). That is another thing you can usually get away with here, since we don't do emissions tests anymore.

 

[mo_dingo]

19mpg here with city driving only. I was at 17 before the gears.

If your gas mileage is that bad, you may have some problems. Clean the MAF/IAT, check your fuel pressure, hook up a vacuum gauge, etc. All of the usual stuff.

Unfortunately, you may need to replace your O2 Sensors. They may not be the problem, but they are the main source of a/f ratio problems when under part throttle, normal cruise. Check/perform the stuff above first.

Scott

 

[1Slick5.0]

16mpg with 3.55's in the city. I highly doubt you will get 20mpg on the highway with 4.10's. Maybe if its down hill and you coast in neutral!

 

[GTJake]

26 mpg on the freeway with 3.73's and a T-5 here.

Jake

 

[95snoozer]

i get 22-23 with mixed driving

and 25+ on the highway with my 3.73s. My car also weighs 32XX with me in it

I think i oculd manag eeasily 20+ with 4.10s.

in fact I may or may not trade my friend for them to maximize my car as an all motor car for the time being.

 

[94TURBO5 O]

Man some of you are getting great gas mileage.

 

[5.0stangette]

i get about 17 average...mostly highway/country roads(no stoplights) and i'm completely stock...you guys are making me VERY upset

 

[lparsons]

i get 22-23 with mixed driving

and 25+ on the highway with my 3.73s. My car also weighs 32XX with me in it

I think i oculd manag eeasily 20+ with 4.10s.

in fact I may or may not trade my friend for them to maximize my car as an all motor car for the time being.

What did you do to lose weight on the car? I hear people complain that SN95's are too heavy ... I'm not in favor of a rear seat delete, but I could be talked into other ways to cut the fat. Being as I am considered underweight myself, I'm not going to try to lose any of my own body mass for the sake of better mileage

 

[Venom351R]

Im lucky if I can squeeze out 175-200 miles out of a tank now I just recently went from stock 2.73's to 3.55's and it did make a big dent in my MPG, even when I drive the car easy for awhile.

 

[GTJake]

What did you do to lose weight on the car? I hear people complain that SN95's are too heavy ... I'm not in favor of a rear seat delete, but I could be talked into other ways to cut the fat. Being as I am considered underweight myself, I'm not going to try to lose any of my own body mass for the sake of better mileage

My car is 3325 with me in it, 3155 w/o me. Purty light. Weight reduction: aluminum heads, aluminum pulleys, no smog, no egr, catless mid pipe, no front sway bar, no dogbone, rear seat delete (~50lbs), no spare/jack, gutted trunk. I also have leather, power everything (power seat), and MACH 460 sound. Hopefully I can get a little lighter in the next few years with lighter suspension components.

Jake

 

[Jdubyu]

If you keep your engine below 3000 with 4.10's (just shift a little more often) you shouldn't have any trouble getting 20 mpg city. Remember that steeper gears actually make it easier for the engine to move the car. So if you just watch your revs, you should get 20 no prob. I also know a few people who are getting close to their stock mpg with 4.10, even on the highway.

 

[Silver95Stint]

It just won't happen bro. My advice is enjoy the higher gears and don't worry about gas mileage. You might also want to look at some octane booster or any other similiar product to save gas.