All highway, and the modifications I did was in my sig. The rims and tyres I had were turbo blades with some sort of tires with great tread. Tyre pressure at 38ish, was lowered due to the high temperature compensation.

The trip home from Sydney, going from (M)Yass with a full tank of 98RON petrol...managed to get back to Melbourne with a little under the second notch on the petrol gauge. According to my odometer (it is slightly out as I found out via those 5km odometer checking things that you get on the highway...odometer on my car is slower by probably a couple of meters for every km) I managed a nice 575.5km. Topped up just before at my nearest petrol station...and bowser read 42.42L. Take away about 3km from the 575.5km and that is the distance I travelled from Yass to my front door.

(42.42L/575.5km) x 100 = 7.34L/100km...

Those are the figures I got from the car and the bowser, unless both are wrong, I will stand by my 7 - 7.5L/100km on highway travels.

In saying that, my metro economy is close to 15L/100km

phong =P~

i sort of understand this, but when i suck my hand in the tank last week, i swear the fuel was about 60c so i dont really see how it can really keep it cool?

Dude I average 6.5 on a trip to the gold coast from my place, bout 250kms. Instantaneous reading would sit between 5-7 on the highway.
I also managed over 900kms to a tank, an average of just over 7L/100kms.
This was pre-cam and pre 3.45LSD, however, on that same trip to the goldie I average 7.0 now.

In my XG which has an EL block & head i was getting 11L/100km at a steady 100km/h over hills, and the same consumption at a steady 110 to 115 on the flat.

In my EBII with AU motor and free flowing inlet and exhaust i was getting 9.5L at a steady 100km/h over hills with a bit of weight on board and some minor town driving. Got a best of 8.5 and a worst of 10.5. I thought this was good.

My EL is looking to be in between the two, about 0.5 to 1.0L more than the EBII, but more mods may improve it slightly.

If i do a number of full throttle overtakes during a tank of fuel, consumption over that tank can increase by about 1.0L/100km.

Your cars are thirsty.... I was sitting on 110-130 on the freeway, and 2-4th gear full throttle across the range behind ballina...

Your car seems a bit thirsty on the freeways . might want to check out some sensors to make sure everything is running good.

phong =P~

the work ute uses bout 12-14 L/100 on the highway
its a 07 bf trayback with toolboxes in every spot known to man
it does round 16-20 round town tho ....its quite thirsty

Well, i just checked today and on a flat road my EL gave an instantaneous reading around 5 to 7 at 100km/h. So maybe the low averages mentioned are understandable when no town driving or full throttle overtaking or regular hill climbing is done.

People in my area say my averages are good for a falcon (i reckon about 40% of cars around here are falcons, and 40% are toyota 4wd's, 20% miscellaneous). Where i live is actually quite mountainous.