Squeezing a few more mpg out of a mustang gt

[Superfuelgero]

I second what has been said. I wouldn't add a splitter. 3.08 (or taller) gears would help at 75 if you don't have them. A mirror delete would be easy (and reversible) if your state allows them.

[SlideWRX]

First off, what tire pressure are you running? It depends on your comfort level, but I'm guessing 40+ psi is your starting place. I could run 40 in South Carolina, but when I came back to Michigan I had to go down to 36 to keep from getting beat up on rough roads. Stiffer springs and lower profile tires will probably keep you from cranking up the psi too high.

I wouldn't put a grill blocker of any sort on in Texas until I could watch my coolant temp accurately. I've got the lower blocked off on my Mustang, but again this is Michigan.

Are you keeping engine rpm below 2000 rpm between shifts? 1500 rpm? My Mustang will pull in 5th (top) gear from idle (700 rpm). not quickly mind you, but for most driving it's fine. On the highway I am stuck running 2200-2500 rpm, but otherwise it's below 1500rpm. Well, except when I want to remind myself it's a Mustang...

[gk_ghig14]

Car has 3.15 gears, lowest numerical in the GT. Not sure on shifting rpm(it's an automatic). Cruising rpm are around 2000 if not a little more, tires are about 27.6" tall

Not sure on tire pressure either. I'll check after I get the car back from the shop however I'm gonna run as high as safely possible(probably around 40)

Edit: Max pressure for my tires is 51 psi

[Ecky]

For reference, my cruising MPG vs speed is approximately:

55MPH - 38MPG
60MPH - 37MPG
65MPH - 35MPG
70MPG - 32MPG
75MPH - 29MPG
80MPH - 26MPG

I would recommend getting some instrumentation and finding your sweetspot.

[gk_ghig14]

Well took one of the backroads the other night and accidentally reset my mpg at a stoplight. But from that point on my speed was mainly 55-60 mph and I saw a high of 31 mpg but when home and parked it was reading 24ish mpg. Route had 2 stop signs, a stop light, and then a few street changes with acceleration needed

However this was at midnight so my real world results next month will very greatly. But gives me hope I can hit 21 at least on my daily commute


Mpg will also get better around february as the car will be getting smaller brake rotors(12.4" instead of 13.2", less unsprung weight) while allowing me to get smaller lighter wheels(17" at less than 20 lbs each hopefully). However this is mainly for cost savings, a good set of tires will run me $1300+ whereas new wheels and tires will cost me less(along with improving mpg)

[mcrews]

Welcome !
I always get a kick out of " I HAVE to go 75... It's the speed limit"!
Had a poster claim he'd get run over in Dallas highway if he went 70!
Odd thing...I was I Dallas at the same time .... Never got run over or honked at!!!!
I drive sa to austin to Dallas to Tyler to abiene....Never had to go over 65...never.
1.)So....adjust the nut behind the wheel.
2.) get a gauge go where it's flat. Drive up and down at 50 55 60 65 70. Track your mpg at each now you KNOW what you mpg is at each speed
3.) raise psi to 42
4.) having duals doesn't stop u from having a pan see link in my post

I got 30+ mpg on a trip from Sacramento to Dallas in a 340hp, sub 6sec 0-60, 3890lb Q45 that can top out at 150mph. It was rated 22mpg highway. Avg 63mph and never went over 70mph.

You either want to get better mpg or you don't . 70% is how you drive.

[mcrews]

Also it looks tight but the thing that helped me some was a 5.6% increase in overall tire diameter. If you decrease tire diameter you're toast. You can't reduce enough weight.

[gk_ghig14]

Yeah no way I'm going bigger tires. These are already massive(28")

Why not smaller though? I know on your car you can't change the computer calibration(I think) but on mine I can change all that for different tires

Well other than higher rpm cruising due to different effective gear ratio

[mcrews]

Callerbration does nt change the rpm. Mpg is about lower rpm at cruise. Smaller diameter will increase rpm at cruise

[Arragonis]

Can you shift to N when the engine is running ? (check the towing instructions). If you can then P&G (Pulse and Glide) might be your newest friend depending on traffic. I'm using this just now on my first Auto and it has improved things a little - hopefully.