2005 GT, spoiler delete, 5 spd manual, stock 17" Bullits/Pirellis, 3.55s, WMS Ram Air intake, SLP Loud Mouths, X-Cal II w/Bama 87 tune, Mobile 1 5-20w oil, Mobile 1 in trans and rear diff . . . 160 mi. round trip from 2550' to sea level and back . . . 421 miles per tank, computer says 28.3 mpg.

Coasting, skip shifting and every other trick in the book.

 

just to let you guys know... Thats the fuel itself IS the lubrication and cooling for the fuel pump. Running it dry shortens the life of the pump ...

 

Prob 75% highway.

I just did a trip 200 miles away. Reset the computer in the garage, left and had 27.1 MPG when I got there. That was going about 68 mph without the A/C on.

Then I did some city driving which dropped it down to 25.5 MPG. I used the A/C on the trip back and got home at 26.2 overall.

This was without drafting any semi's.

I did the 1-3-5 shift whenever possible. And when I went to fill up, it said 393 miles to E.

 

This thread showed that 3.55 over the 3.31 on the highway was only a .1 mpg sacrafice.

http://forums.bradbarnett.net/showth...highlight=3.73

I just ran these numbers:
Stock wheel size: 235mm 55% 17"
235mm / 25.4 inches/mm = 9.252"
Diameter = 9.252" * 55% * 2 + 17" = 27.177"
Distance traveled per revolution = 3.14159 * Diameter
= 3.14159 * 27.177 inches/rev / 12 inches/foot / 5,280 feet/mile = 0.0013475 miles/rev
Shift point at 6,000 rev/min * 60 min/hour = 360,000 Rev/hour
Best Cruise Speed is very roughly about 45% of peak torque speed for this engine/load, which is 4,500 rpm * 45% = 2,025 rpm
2,025 rev/min * 60 min/hour = 121,500 rev/hour
Speeds with 4.10:1 rear axle:
1st Gear: 360,000 rev/hour * 0.0013475 miles/rev / 4.10 / 3.38 = 35 MPH
2nd Gear: 360,000 rev/hour * 0.0013475 miles/rev / 4.10 / 2.00 = 59 MPH
3rd Gear: 360,000 rev/hour * 0.0013475 miles/rev / 4.10 / 1.32 = 90 MPH
4th Gear: 360,000 rev/hour * 0.0013475 miles/rev / 4.10 / 1.00 = 118 MPH
5th Gear: 360,000 rev/hour * 0.0013475 miles/rev / 4.10 / 0.675 = 175 MPH
Cruise speed @ 2,025 rpm = 121,500 rev/hour * 0.0013475 miles/rev / 4.10 / 0.675 = 59 MPH
Guess efficiency = 24.0 miles/gallon @ 60 MPH
Speeds with 3.73:1 rear axle:
1st Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.73 / 3.38 = 38 MPH
2nd Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.73 / 2.00 = 65 MPH
3rd Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.73 / 1.32 = 99 MPH
4th Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.73 / 1.00 = 130 MPH
5th Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.73 / 0.675 = 193 MPH
Cruise speed @ 2,025 rpm = 121,500 rev/hour * 0.0013475 miles/rev / 3.73 / 0.675 = 65 MPH
Guess efficiency = 24.5 miles/gallon @ 60 MPH
Speeds with 3.55:1 rear axle:
1st Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.55 / 3.38 = 40 MPH
2nd Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.55 / 2.00 = 68 MPH
3rd Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.55 / 1.32 = 104 MPH
4th Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.55 / 1.00 = 137 MPH
5th Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.55 / 0.675 = 202 MPH
Cruise speed @ 2,025 rpm = 121,500 rev/hour * 0.0013475 miles/rev / 3.55 / 0.675 = 68 MPH
Guess efficiency = 24.9 miles/gallon @ 60 MPH
Speeds with 3.31:1 rear axle:
1st Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.31 / 3.38 = 43 MPH
2nd Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.31 / 2.00 = 73 MPH
3rd Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.31 / 1.32 = 111 MPH
4th Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.31 / 1.00 = 147 MPH
5th Gear: 360,000 rev/hour * 0.0013475 miles/rev / 3.31 / 0.675 = 217 MPH
Cruise speed @ 2,025 rpm = 121,500 rev/hour * 0.0013475 miles/rev / 3.31 / 0.675 = 73 MPH
Guess efficiency = 25.0 miles/gallon @ 60 MPH
Specs on the Transmission Ratios are found here, on page 8:
http://www.fileden.com/files/2008/3/...ng%20Specs.pdf

 

As of right now I get 350-375 per tank with a v8 five speed. She has 35k on her and I run a JLT cai w/bama 93 tune, SLP Loudmouth axle backs and Royal Purple XPR 5W20 motor oil. When I first got her I took it to visit a friend in Conn several times and got 33 mpg all the time. When I bought it new in 04 was getting about 14 mpg my first 2 years with her because I only lived 7 miles from work and beat the **** out of it every mile. I still work for the same company but at another location farther from home. My driving now is mostly highway at 55-65 mph with every SUV, Pickup, hybrid you name it passing me like i'm driving in wet cement. Only have to fill up my tank once a week which sets me back about $55.

 

I know it's not accurate, but when cruising on the freeway at 70mph, the computer says I get 31-32 avg mpg.

3.31's 5M

 

In town, with my daily commute, I have been averaging 19.1 mpg over the last two years.

On road trips, the best I have done was a bit over 360 miles and just under 28 mpg. I could have gone 400 miles on that tank (before hitting reserves), but I was heading home and I definitely didn't want to see if I could make it to the next town (70 miles away!) before I was walking.

 

Well with combined city/highway the most I have seen is 340 miles or 550 kilometers. We are also 3400' above SL here and that is on 87 octane, K&N intake/diablo tune.

cheers

 

I've managed 26.5 mpg over the course of 360 miles or so. I might have been able to make it another 40 miles with the reserve in the tank but I still had another 80 miles or so on my trip so I stopped to fill back up. Computer told me I had 370 miles till empty when I filled back up. That was bone stock. Its very difficult to see that milage with CR's agressive throttle mapping

 

I daily drive my car approximately 400 - 450 miles a week. I can get around 320 - 340 miles on a tank of gas. (I fill up when the low gas light turns on)

 

You have the interior upgrade package? I do and it starts b*tching at me at 50 miles to E and every 8 or 9 miles thereafter. I give in and fill it up before it gets to that point.

 

FYI - just noticed this a few months ago, but I noticed the reminder comes on exactly every 10 minutes.

 

I did the run from South Florida (Kendall) to Universal Studios on one tank of gas and got there with just under 1/4 left. That was about 250 miles I think.

 

I find its very hard to get the tank filled up to exactly the same level that I had the last time. Every station has a different pump handle and it will shut off at different times. Even if you play with it and fill it up till it spills on the ground I guess that is the best measure but I dont recommend this. I trust the computer and it is usually right on within about a half a mile per gallon when I do the math at the pump.