Specific fuel consumption

Honest John Back Room » Technical matters
Do you want the Road Tax system to change? Do you have thoughts on the potential changes to the Road Tax system? | No thanks
View Threaded
Tue 22 May 2007 23:04
Specific fuel consumption - nb857
I was watching Top Gear on Sunday and they had the Merc SLR on. JC said that it could empty it's 21 gallon tank in 19 minutes, that's 66.3 gallons/hr under full load for a 626 hp motor.

At work we have a machine with a 360 hp Cat C9 (8.8 litre) and it works at between 94-100% for 12 hours at a time and consumes about 10 gallons each hour at this loading. So it has just over half the power and uses a 6th of the fuel. What gives?

So why does the Merc SLR use so much fuel (assuming my maths is correct and JC's figure are accurate)?

What is the specific fuel consumption of a typical car? 210g/kw/hr ish?

How much does unleaded weigh?

Is it just heavey duty engine that are at peak effiency (sp) under full load/torque?

Reply | Report as offensive | Link
Tue 22 May 2007 23:26
Specific fuel consumption - Screwloose

That equates to roughly 3-4 mpg. Not unexpected for that much power fighting that much drag.

An industrial diesel is designed to minimise it's fuel consumption; 10g/ph is about right for a constant revs engine of that power.
Reply | Report as offensive | Link

Looking for a garage you can trust? Honest John's Good Garage Guide has thousands of reader recommended garages, plus how-to guides and tips on servicing.

The Good Garage Guide
 

Ask Honest John Right column

Value my car

Related posts