Best MPG stock 4.6L GT

[Bonestk87]

Ok what is the very best anyone has gotten out of their 4.6's??? Any mods/ tuning to get it there? Trying to decided whether to keep mine or sell it to get a commuter. I drive 60 miles one way to work and gas is not getting any cheaper. Its a 99 GT 5spd. Is 28mpg realistic?

Jeremy

[pr1042]

stock gears?

[DeddRekoning]

I get 22 with an auto, 3.73s and a few bolt ons with highway driving only

[JC316]

My numbers going with city, then average 70/30 highway, then pure highway:

96 NPI GT, 5 speed 3.27 gears -17-24-27
96 Mark VIII Swap GT, 5 speed 3.27 gears - 19-26-30
98 PI swap GT, bolt on, LT header, 3.73 5 speed - 15-20-23
99 GT Vert, auto, 2.73 gears, bullet mufflers - 16-22-25

[Bonestk87]

mpg

Well the gears is what I'm wondering about. If it takes 2.73 rear end gears to pull down 25+mpg then thats what I will do.

I was going to go stock longblock, typhoon intake, 75mm Accufab T.B, CAI, BBK full length headers and O/R x-pipe, spintechs and Magnaflow tailpipes with a tune of course. Stock 19 LB injectors. 18in wheels. I just want it to breathe better. I was thinking of a 3.23 rearend gear?


Just curious what y'all was getting. I have all the parts in hand. Decisions, decisions, decisions....

[351Coupe]

I had a highway trip in my 04 one time where I got 26 mpg, it was stock 5 speed with stock 3.27 gears.

I would say normally I drive 70% highway, and usually get around 22.

[sspstang]

I would think 22-24 would be about the max. 28 is really going to be pushing your luck.

[Steve]

Our Mach gets about 25-26mpg on the highway. The car is bone stock with exception of exhaust work.

[MGannaway]

Our Mach gets about 25-26mpg on the highway. The car is bone stock with exception of exhaust work.

lol my old Mach got 26 mpg with a Eaton on it Mach 1's FTW

[Downs]

08 GT/CS According to the car's computer over the last 1200 miles I've averaged 20MPG. I also did a highway and city reading and again according to the computer got 24mpg on a trip to the Wichita Mountains which was mostly highway and when I was doing city mileage I was pulling down about 17 or so going back and forth to work.

[pr1042]

Mach 1 - rai/x pipe/catback. I was set for tune and 4.10s but didn't want to kill my mpg

Best so far is 24, 40 mile round trip to work everyday which is about 50/50 city highway. I cruise at about 75-80 normally though

[HOOCBB]

I got 28 MPG ONCE in my 02 GT 5 spd w/ a head wind coming back from Oklahoma.

In my 09 GT 5 spd, I am currently showing 21.7 Avg on the computer, but I can only seem to muster 25 MPG max on the highway. To get that, I have to do no more than 65 MPH and baby it to speed. I have 3.55s too. At 70, I get 24 MPG. At 75, it really starts to drop...80 gets me aout 22.

Both cars had catbacks/axlebacks and K&N drop-in filters...the 02 was lowered.