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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

gas mileage

  • Thread starter Thread starter 93killerbee
  • Start date Start date Apr 14, 2004
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93killerbee

New Member
Oct 15, 2003
44
0
0
ohio
Apr 14, 2004
#1
  • Apr 14, 2004
  • #1
I need some help, i just installed a magnaflow 2 1/2 inch cat-back system with 3 inch tips, before the install i would get about 300 miles out of a full tank of gas now im getting about 200 miles out of a full tank? my mods are upper/lower typhoon intake mac 1 5/8 equals 2 1/2 inch h-pipe, cold air intake. im running 93 octane gas. any help would be good.
 

Bone Racing

New Member
Sep 7, 2003
1,075
0
0
Long Island, NY
Apr 14, 2004
#2
  • Apr 14, 2004
  • #2
a/f ratio?
maybe your open exhaust made the car breath heavier and its become very inefficent
 

ECU5.0

Banned
Jan 10, 2004
1,803
1
0
raleigh, nc
Apr 14, 2004
#3
  • Apr 14, 2004
  • #3
hmm....is it just because you like the power and are stomping on it all the time? could be a number of things....cant think of anything off the top of my head thouhg
 

MadMatt5oh

Member
Jan 10, 2003
441
0
16
St Paul, MN
Apr 14, 2004
#4
  • Apr 14, 2004
  • #4
I have the same problem, I have a lose connection on the dist. Old plugs and wires, etc. Cant fill the tank or it pisses out the gas. Ive only been able to drive it one weekend but 100 miles to a tank is absolutely unacceptable!
 

blkstangman88

New Member
Apr 6, 2004
646
0
0
Apr 14, 2004
#5
  • Apr 14, 2004
  • #5
Thats not to bad cuz my 88 gt only or still gets 230 thru 280 to the tank, depending on how heavy my foot feels.
 

ALMOSTFINISHED

Member
Jan 8, 2004
315
0
17
Westchester County NY
Apr 14, 2004
#6
  • Apr 14, 2004
  • #6
gas

u people are real lucky. i can only manage about 140 out of a full tank of 93. thats city driving. it sucks but what can u do when u have a mustang right?
 

blkstangman88

New Member
Apr 6, 2004
646
0
0
Apr 14, 2004
#7
  • Apr 14, 2004
  • #7
i think there somthing wrong with ur car......everyt think of a ignition set up? i got a complete msd ignition set up and i got a couple extra mpg.
 

blkstangman88

New Member
Apr 6, 2004
646
0
0
Apr 14, 2004
#8
  • Apr 14, 2004
  • #8
i think there somthing wrong with ur car......ever think of a ignition set up? i got a complete msd ignition set up and i got a couple extra mpg.
 

remat457

Founding Member
Aug 7, 2002
587
0
16
Seattle/Tacoma
Apr 14, 2004
#9
  • Apr 14, 2004
  • #9
My motor is stock but didn't lose gas mileage when I put the same catback and a 2.5" H pipe on...must be something else...
 

65ShelbyClone

Founding Member
Sep 9, 2000
4,675
38
119
Antelope Valley, SoCal
Apr 15, 2004
#10
  • Apr 15, 2004
  • #10
All the mods in my sig still get me 21mpg, which is about 260-280 useable miles before having to fill up. Thats only marginally worse than with a stock engine.

A cat back alone shouldnt cut your mileage down by 1/3. Like everyone else said, it could be a number of things. First make sure your right foot didnt get more agressive.
 
B

blk92stangg

New Member
Jan 30, 2004
583
0
0
Hawaii
Apr 15, 2004
#11
  • Apr 15, 2004
  • #11
65Shelby, do your drive highway miles or city? Since Honolulu is one big traffic jam all day, I am getting about 180-200 a tank...I would LOVE to get the mileage you do.
 

TenorPlayinGuy

Founding Member
Aug 3, 2001
1,208
0
36
Canyon Country, Ca
Apr 15, 2004
#12
  • Apr 15, 2004
  • #12
my car averages about 210 to 230 mpg ... but i have a 4cly tranny so im not reading actual mileage... im actually getting my 300 per tank... but i cant tell... my car only has headers, straight h, and flows and still gets good mileage... im going to a flex fan, and underdrive pullies with a k&n to get some more mileage though.
but like everyone said... a change like that tends to make your right foot more stompy and man can it make a difference on gas milieage... and in so cal this time of year bad mileage is a BAD thing... gas jumped to 2.45 for 93 here... im gonna need a second job JUST TO PAY for gas to get to my other job... lol

doh well cant live without the stang...
 
8

87'GTstang

New Member
Feb 16, 2004
1,025
0
0
Apr 15, 2004
#13
  • Apr 15, 2004
  • #13
21 mpg on a 267k miles original 5.0.

If your car is designed to run 87 octane, just run 87 octane. 93 shows no benefit except being down on power because your car's timing cannot take advantage of it. What kind of shape are your oxygen sensors in?
 

Pod

Member
Aug 17, 2003
71
0
6
Cambridge, UK
Apr 15, 2004
#14
  • Apr 15, 2004
  • #14
Hehe, you think gas/petrol is expensive there. You should try England.
79p per litre.
£2.98 per US gallon (3.78 litres per gallon)
$5.07 per US gallon (1.7 dollars per pound, roughly)

5 bucks!
and you think 2.45 is a lot!

As for mpg, I'm not really sure about mine, as the fuel gauge doesn't work. I get about 200 miles before the fuel light comes on which is when I fill it up. Completely stock except for an offroad h-pipe and no silencer. Mixture of city and highway and a bit of fun every now and again.
 

blkstangman88

New Member
Apr 6, 2004
646
0
0
Apr 15, 2004
#15
  • Apr 15, 2004
  • #15
running 87 gas in a 5.0 HO is the dumbest thing ive ever heard, every time i even thought of putting that crap in my 5.0, my car started pinging and backfiring. i dont care what ppl say, i only put 93 in my stang. with 93 gas i get way better response time, and mpg and with the 87, all it does is clog fuel injectors and filters.
 
1

1Slow5oh

New Member
Mar 24, 2004
92
0
0
Bartonville, IL
Apr 15, 2004
#16
  • Apr 15, 2004
  • #16
Wow you people should feel blessed...... my car gets around 160 per gallon...... and that was before the 4.10's im screwed now..... any suggestions on how to reduce this??? i might have junk o2 sensors would that be doing it????
 

ninety15.0

New Member
Mar 10, 2004
1,336
0
0
Apr 15, 2004
#17
  • Apr 15, 2004
  • #17
i think i had the same kinda problem when i did my full exhaust....but it went away really quick when i realized it was only cuz i wanted to hear that signature sound. Keep your foot out of the pedal and u will do a lot better....the other things is do a big tune up... i went from getting 20 mpg on the highway to ust over 27 just by doing a full tune up. good luck man
 
H

Highway High

New Member
Dec 31, 2002
86
0
0
Apr 15, 2004
#18
  • Apr 15, 2004
  • #18
What does a full tune up consist of? Im getting around 12 mpg every fill up Granted, I don't keep my foot out of it, but I really dont drive it too aggressively now, just the occassional romp. I drive a lot and freaking filling up like every other day is starting to get expensive.

Logan
 
8

87'GTstang

New Member
Feb 16, 2004
1,025
0
0
Apr 15, 2004
#19
  • Apr 15, 2004
  • #19
blkstangman88 said:
running 87 gas in a 5.0 HO is the dumbest thing ive ever heard, every time i even thought of putting that crap in my 5.0, my car started pinging and backfiring. i dont care what ppl say, i only put 93 in my stang. with 93 gas i get way better response time, and mpg and with the 87, all it does is clog fuel injectors and filters.
Click to expand...
Put it this way, your car came off of the assembly line designed to run 87, and at one point it ran perfectly - plain and simple. That my friend is called hiding a problem and trying to cover it up - until it catches back up with your engine. The only way it would run better with 93 and worse with 87 is if your ECU was reprogrammed and its MAP curves altered either digitally by a computer, ECU controller, or a computer chip. But if not, your car is running the way it does on 87 because of a problem/malfunction.
 

ALMOSTFINISHED

Member
Jan 8, 2004
315
0
17
Westchester County NY
Apr 15, 2004
#20
  • Apr 15, 2004
  • #20
I dont think anything is wrong with my car.. my friend has a 92 gt and gets just about the same mileage. i live in ny, maybe the gas is different or something. i have done a full tune up, fuel injector cleansing, and new o2's. i am also a master tech so i would know if something was wrong with my car.. any other suggestions please let me know.....thanks
 
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