Post Your Average MPG (GTP's ONLY PLEASE)

[00GTP4ME]

That's what I thought. I remember hearing in auto shop that a car in CA will be around 15% more efficient than one in the rockies. Lame.

[tomgtp]

I have a '99 gtp,and I get 24-26 with 50-50 driving.Mods includeynomax cat back,k/n air filter and the big 3.My screen was missing on my tb when I bought the car.Other than that she's all stock.

[BNaylor]

Well so far it looks like none of our GTPs qualify for the "Cash for Clunkers" program.

[3100]

every 1000 feet above sea level you loose 3% of your total power.

[00GTP4ME]

Originally Posted by 3100

every 1000 feet above sea level you loose 3% of your total power.

Sucks to be me.

[3100]

1000------------------3%
4400------------------x%

13200=1000x
x=13.2

240HP----------------= 100 %
x HP----------------= 86.8 %

100X=20832
x=20832/100
x=208

in other words if you originaly have 240HP at 4400 ft you will loose 13.2% and your total HP will be 208

[Nbellomo]

22.8 in city I live in Orlando, fl. I put 93 in my car

[worktester]

1997 gtp 3.8 supercharged
i get between 20 to 24mpg around town
and 30 to 32mpg on the highway w/cruise control on

[CrazyHorst]

Generally, air density plays into horsepower because the denser the air in the cylinder and the more fuel you can match it with, the more power you can get from a single combustion event. (This is the basis for why turbo and super -charging increases power....because it increases the air density).

High altitude is generally harder from a power standpoint on NA engines. Charged engines make their "own atmosphere"....also why a lot of early gasoline aviation engines were -charged.

My thoughts are you can potentially get better fuel economy at higher altitude on level road cruising. But real-world high altitude generally encompasses a lot of hill climbing....which requires greater throttle openings due to above power problems....and I think in the end the overall, combined fuel economy is lower.

My GTP which does a lot of interstate cruising at 70-80mph gets around 25mpg regularly via the "book" of mileages and fuel pump figures*. I use 87 octane always.


* the way the tank is filled makes a profound difference on how book mileage is calculated. Personally, I always try to fill to the point where I'm about to get a splashback of fuel (several clicks of the hand-valve after it stops for the first time). I believe that all pumps behave differently on where they stop at the first shutoff event. Also important is watching a moving average since it damps out peaks that probably aren't accurate data due to one reason or another.

[grandprixgtx00]

Originally Posted by CrazyHorst

My GTP

I use 87 octane always.

2 words that should never be in one statement.

[CrazyHorst]

My quick calculations indicate a savings thus far of $670 at the pump over the car's life of 168k miles.

I don't believe it hurts the base engine. The ESC sensors won't let it get that far out of control.

Does it hurt peak performance? Absolutely, but slightly, in the grand scheme of things.

[BNaylor]

I use 87 octane always.

Originally Posted by grandprixgtx00

2 words that should never be in one statement.

87 octane? Poor choice or bad judgment and I wouldn't be bragging about it too much on this GP forum.

[grandprixgtx00]

yeah, for some reason i remember Crazyhorst posting in my subject about me doing a top swap on my GT. something about doing a top swap on a L36 and being a ticking time bomb?

some day you should tear the heads off your motor, and look at cylinder #6. bet it doesnt look too pretty

now lets talk about a ticking time bomb

[00GTP4ME]

Originally Posted by grandprixgtx00

some day you should tear the heads off your motor, and look at cylinder #6. bet it doesnt look too pretty

And please post pics!

[rkvons]

Originally Posted by grandprixgtx00

2 words that should never be in one statement.

Yeah, when I open my fuel door there's a little sticker on there that says, "Premium Unleaded Fuel Only". I think the manual has some things to say about using low octane fuels and basically saying damage could result. But this topic has been discussed so may times. The money saved from using lower octane fuels can be applied to the purchase of a new engine.