petrol usage differences

[s class]

Flutes, that's on a long trip.  Around town, one is more likely to see 20L/100km with a 6.9. 

[WGB]

Wow - that's an impressive run.

I assumed that 6.9s would be thirstier on the fuel than that - perhaps I should upgrade!

The 450 is thirsty for a small V8 while the 6.9 is not bad for a big V8.

Really there is not much in it - especially when cruising at 100km/hr.

In the old figures a 450 should do 15/16 mpg (imperial) around town and 18 on a leisurely trip.

A 6.9 14/15 mpg around town and up to 17/18 on a leisurely trip - my 6.9 regularly gets 20l/100km around town.

I have seen a 280SE return 26mpg on a leisurely trip but hammered around town it is not much better than the V8's.

These figures are for 8.8:1 Euro's - not sure what the 8:1 brigade get.

Bill

[motec6.9]

Just for another perspective when my 6.9 was on striat gas i used to fill up every 300km after driving around Canberra which worked out to be 23.25l per 100km fuel consumption interestingly i used the same on the highway on stait gas car was fitted with 80 usable litre gas tank and impco 300 mixer Ps if anybody wants gas kit sitting at John reese Mechanical in Queanbayan N.S.W. after converting to Haltech F10 fuel only computer 18lt per 100km around town and averaged 15.5lt per 100km on the highway did manage 14lt per 100km accross the nulabour in 2003. after converting to Motec M48Pro system in 2003 averaged around 16.5lt per 100km around perth did not do any highway trips before incident with NOS interested what it will be when new motor is completed with increased capacity and higher compression.

[goldacre]

Just back from another trip to Busselton and this is what happened:

Filled up on 50 liters of 91 Octane fuel at BP in Stratton, Perth picked up the wrong pump, bugger. Drove to Busselton with a boot load of luggage and kids in the back seat with AC on and did a fair bit of suburban driving when down there and got 17.4 liters per 100 

Filled up on Caltex vortex 98 octane in Busselton and drove to Margaret river and back along Caves road then back to Stratton in Perth and filled up on BP Ultimate and got the following 14.05 liters per 100klm      and this is with the AC on and sitting on mostly 110 KPH

I think the main contributor to this was when i checked the tyre pressures in Busselton, they were all down to 24 PSI  must have been that spate of hot weather which caused the Federal tyres to gasp a bit. Pumped them up to 35 PSI and all sweet.

Overall very happy with the 14 liters figure and looking forward to see what happens when the Timing chain is replaced along with the injectors, seals and fuel pump.

G

[flutes]

So this leads logically into a discussion around tyre pressure, since you brought it up G.

I run at 31psi on the front at 32/33 at the back and this gets me my 16/17ish L/100kms.  I find much higher pressure, especially at the front, and the car starts to feel a little floaty.  This is with crappy tyres I might add....

G - 14.05 with AC and at 110 is excellent

[Bandolero]

I run 40lbs in the front tyres of the 6.9 and 35 in the rear.
If I run lower preasure in the front, the car understeers more.

(The 280 has 36 in the front and 34 in the rear.)

If I run higher preasure in the rear, it wears the centre of the tyre slightly. At 35lbs, it doesn't.
Running 40 at the front, the tyres still wear evenly but the ride is slightly harsher. It's worth it though for the better roadholding.

[goldacre]

Quality of tyres would play a part unfortunately the 14inch rims have a woeful tyre range and all i could get at a reasonable price were the Federal tyres from China  Have now discovered that they dissipate pressure when run over a long distance in extream heat (i had pumped them up to 34psi 4 weeks earlier) i guess that is the compromise with cheapies but aside from pressure drops in extream heat/distance they have been pretty good.

I just put up with the under steer as such which is easy when driving in the wheatbelt as you can steer into the bends a bit more 

I would like to get 15 inch alloy rims and splash out on Michelins but i so love those color coded hub caps (and always have since i was a child) and cannot bear to put them aside.

Wish list for 2010: 15 inch alloy rims which replicate the 14inch hubcaps with option to color code the centers, where is a genie when you want one 

G