Quote: Originally Posted by Humph (original)
Very interesting Dan. I do about 400-500 miles a week in my Oct 06
Cooper works. My commute can be broken into sections. On the way to work 15 mins of urban driving, 30 minutes of crawling on the M60, then open motorway (M62, M6) for 20 minutes, and finally 10 minutes of national speed limit A roads (hard accelerating from lights here
). On the way home it is reversed but without the crawl on the ring road. I run a comprehensive excel spread sheet for my fuel consumption and cost per mile (work requirement) because the OBC is unreliable to say the least. I too have found that V power offers very little in the way of extra MPG on the motorway, but does last longer on the urban cycle. My fuel alternates between V Power and Total Excelium. Currently my car delivers the same MPG (Average 33.4) on both fuel types but the Vpower is more expensive. I do honestly believe the car pulls better on Vpower but this may be me trying to justify the extra 3p per litre.
Results from my sheet for those interested are.
Total Miles Travelled To Date 13816 Miles
Average Distance Travelled Between Fill Ups 288 Miles
Total Amount Of Fuel Used 415 Gallons
Average MPG 33.4 Miles/Gallon
(MY OBC Says 35.4) Total Cost Of Fuel Bought To Date 1742 Pounds
Average Price Per Litre 92.2 Pence
Average Cost Per Mile 12.6 Pence/Mile I also use the M60
Your spreadsheet looks really useful by the way!
Seems as if you have definitely found the same as I have then. I think my best option would be to use V-Power at weekends as I do more urban driving, but use a lower octane fuel for my daily commute!
Do you know anything about how the ECU adjusts to suit different fuels?
Quote: Originally Posted by ARCrawford (original)
Thanks Dan!
As for the Shell V-Power, higher octane fuels are not strictly more explosive than lower octane fuels, it's that they have been stabilized to avoid early detonation during higher compression. I've read that many high performance engines are designed to run best at the highest octane rating they can get because they adjust the compression to suit the fuel they're using - while sticking high octane fuel in a car like a Robin Reliant will actually slow it down instead of making it faster.
When an engine runs at higher revs, presumably the pistons will compress air/fuel mixtures more quickly prior to ignition. Is it possible that the Shell V-Power is only really efficient when running at these higher compressions and you're not getting the full benefit when cruising at high speed and low revs?
All the best,
Andrew.
I was hoping for a detailed reply like this Chemistry Man
I understand what you mean, I was under the impression of them being "more explosive" as you put it
Quote: Originally Posted by Humph (original)
Shell sell V-Power as a fuel developed with the Ferrari race team. To this end perhaps it does perform better when the engine is being driven in a 'race' style i.e. high revs, lots of gear changes, and acceleration.
Perhaps this is the case! Now I have read Andrews information on the fuel itself this explanation seems to fit the bill
V-Power definitely seems the best bet for Runs then!
