Mods To Avoid To Keep Gas Mileage?

[GT Drifter]

Going to get rid of my current 89 notch later this year and getting a different Stang.
I'm going to do a few mods to it because I can't leave well enough alone but since I have to drive like 45min to an hour to school. So I need to keep my gas mileage reasonable.
I'm thinking about doing a fender well intake, maf, intake manifold, long tube, catted x-pipe, cat back, 140* thermostat, maybe some 24lbs injectors and a chip. Would any of these mods harm my gas mileage much?
What about a set of heads if I can spare the cash?

Thankfully school is only 2yrs then I can have some real fun

 

[Spyderd68]

140* thermostat? What temp do you really mean?

Dave

 

[Matts89LX5.0]

bigger injectors and bigger fuel pump will definitely hurt gas mileage.

Matt

 

[90_Red_LX]

Put some gears in it, give you a lot better performance, and it's not too hard on you gas mileage.

 

[GT Drifter]

140* thermostat? What temp do you really mean?

Dave

Not 100% sure, I always hear to use a 140* thremostat.

I wouldn't think that 24lbs injectors hurt, they aren't too much bigger then stock or are they?

 

[GT Drifter]

I was thinking 3.73 gears.

 

[Matts89LX5.0]

well 19# injectors flow 19# of gas per hour and 24 # injectors do 24# of gas per hour--someone correct me if i'm wrong.

Matt

 

[GT Drifter]

I believe that's right, not sure.

What size are stock injectors anyhow?

 

[90_Red_LX]

Pretty sure 19#s.

 

[331 cobra]

well 19# injectors flow 19# of gas per hour and 24 # injectors do 24# of gas per hour--someone correct me if i'm wrong.

Matt

The injectors are not on all of the time, or else, driving 60 miles at 60 miles per hour would burn 152 lbs of fuel (19 lb/hr * 8 injectors * 1 hour).

You burn fuel at a rate that is roughly proportional to the ammount of air that goes in to your engine. So more air = more fuel.

If you want great gas mileage, you can do one of two things: Get a puny cam and a T56 with double overdrive, or get a commuter car. For the price of a t56, you can get a very thrifty commuter car and you might even pay less insurance for two cars than just a mustang (like me). You also have a parts getter for when you tackle the bigger projects and if you get a four seater, that is an instant excuse for a rear seat delete.

 

[GT Drifter]

I don't normally have more then one passenger in my car because I'm not a taxi.

I doubt I could afford insurance on 2 cars.

 

[Spyderd68]

331 Cobra is right about the fuel injectors. Your car's computer will adjust the injector pulse width according to O2 and other sensors input to maintain a constant air/fuel ratio (i believe 12.5:1) Putting bigger injectors in mainly concerns wide open throttle and applications that require more fuel through out the range. Correct me if i am wrong. I believe, putting 30psi injectors in and calibrating your mass air correctly will give you the same mpg as 19psi injectors with a correctly calibrated mass air meter, assuming all motor parts are constant.

Dave

 

[Michael Yount]

There's no reason for you to change your injector size - your engine won't be putting out enough power to have any need for larger injectors; so leave 'em alone. Your engine will probably get better mileage with a 180F or 192/5F t'stat than it will a 160 (I think that's what you mean when you say 140). There's no reason to run cooler than a 180F t'stat.

 

[TheUser]

superchargers increase mpg

 

[GT Drifter]

Would 3.90 gears harm fuel mileage much?

 

[Ranchero5.0]

3.55's and a A trim... Heck, my '93 get's 20+ MPG cruising at 80+ at 2700rpm and it's over 400hp to the rear wheels now. What more could you want?

My dad stopped driving his new F250 because it's a gas hog (15mpg). His commuter car? A 300hp Edel headed '89 GT with an E cam and 3.73's.

Jamie

 

[88mustangGT]

back to the topic, i am curriouse to what mods hurt and what ones help gas mileage

 

[blk92stangg]

You panty-assed lily-livered organic chicken eating whiners should go and buy a Geo Metro 3-banger and leave the gas guzzlin torque monster Mustangs to us red-meat eating, weight-lifting, testosterone brimmed he-men!!!!


J/K !!!

I think everyone is forgetting the greatest variable to gas mileage..your right foot. It will amaze you to see how much better your milage will be if you take it easy on the gas.

Truthfully, if you are worried that much about mileage anything that makes your car faster will kill it. I would just keep timing down so you can run 89 or lower gas to save money.

 

[88mustangGT]

well like was said a supercharger does give you 15-20% better gas mileage, i would assume having a good ballanced setup could get better gas mileage and more power than stock. ???????? im just curiouse if certen heads will give better milleage than others. and what would be the determinig factors.

 

[NKau]

There's no reason for you to change your injector size - your engine won't be putting out enough power to have any need for larger injectors; so leave 'em alone. Your engine will probably get better mileage with a 180F or 192/5F t'stat than it will a 160 (I think that's what you mean when you say 140). There's no reason to run cooler than a 180F t'stat.

THANK YOU. With that being said, if you want to have a fun car and keep the gas mileage reasonable, install 3.73's, have a good tune up done, and be done with it. You could modify headers/exhaust as you see fit, and as far as performance modifications, you may want to look into an intake; a Cobra intake would work alright with a stock headed motor, but your money might be best spent on a ported stock lower such as those offered by tmoss. With a good tune, no reason you shouldn't be getting 22+ mpg.