After 4 months with my 200, an answer...

[Tom]

Excellent work man - that's a great bit of math and a great post! I'm sure this will be quoted and requoted for years to come!

Thanks for sharing.

 

[MarkCup]

Excellent work man - that's a great bit of math and a great post! I'm sure this will be quoted and requoted for years to come!

Thanks for sharing.

Thanks all!

With the opinions and contributions both on here and Cliosport, it turns out there's many more variables at play here. So whilst my findings are not absolute...they're a good steer in the right direction.

I'm going to carry on recording data and may switch over to 95 for a month every now and then to see if I see any noticeable decrease in MPG.

 

[Si200]

Excellent post!

When i tell people I only fill up with V-Power or occasionally Tesco 99 and have done for years most look at me like I'm mad!

"It's just more expensive, thats all" being the common response lol

 

[Adey]

Well done Mark! Great thread
Maybe now i'll switch back to the 'premium' fuels
FWIW i remember a while back some mag (i think) did a series of tests compairing
V-Power
BP Ultimate
Tesco 99
And the winner was? - Tesco 99!!!

 

[PB.200]

This is not evidence. That difference could be down to average temperature over the periods being tested.

 

[MarkCup]

This is not evidence. That difference could be down to average temperature over the periods being tested.

So in your opinion would colder temperature improve or worsen mpg?

Regardless, I'll keep this going for the foreseeable future so doubts like yours can be fully discounted.

 

[Paul4d]

i used to run my mini on just tesco 99 and everytime i took the spark plugs out they were pink :/ i think ill stick to shell in the clio.

 

[Womble]

Ok for the non believers it is simple. on 95 Octane the ignition is retarded to stop detonation, this in effect gives you less power, which means to attain the same speed you need to increase the throttle pressure, which means more fuel being used. On 99 the ignition again is optimised and you get more power, which means you need less throttle to attain the same speed as you would on 95.

As for fuel quality, try VPower against Tesco, and you will find Tesco, gives more mpg than Shell.

Most petrol comes from the same tank, you will see all the tankers queuing to fill, a Shell, a Texaco, Esso, Asda etc etc. The tanker driver adds the additives to make it Esso or which ever it is.

As of keeping records my Father has noted every gallon of fuel he has used for the last 50 years, and never missed writing down how much he has put in and how far it has gone. Will make a good reading.

 

[PB.200]

So in your opinion would colder temperature improve or worsen mpg?

Regardless, I'll keep this going for the foreseeable future so doubts like yours can be fully discounted.

Colder = worse.

Engine runs outside optimum temp longer as one example.

Im not saying its not true the vpower is more efficient but i would have expected mpg to rise anyway as the weather gets nicer.

I use super btw.

 

[MarkCup]

Colder = worse.

Engine runs outside optimum temp longer as one example.

Im not saying its not true the vpower is more efficient but i would have expected mpg to rise anyway as the weather gets nicer.

I use super btw.

Good point...does that offset the increase from denser fuel due to lower temperatures ?

I'm personally not fussed with the mpg I get, having owned my 172 Cup for so long I wish I'd done something like this, so when the 200 arrived it was alway going to happen.

I was certain I got better mpg and smoother cleaner running on higher octane in my Cup so ran the 200 for a few thousand miles on 95 first to see if I'd notice a change when switching to the 99.

The difference in running, low rev drivability and throttle response was more than noticeable, and I thought the extra cost would outweigh the extra mpg I thought I was getting.

So it was quite a surprise when I trawled through all my data to come to a conclusion that seemed so clear...hence my fancy graph LOL

 

[Foxspeed]

you will always get external variances UNLESS its run in a labrotory like the eu fuel test cycle

run over a long enough time frame and the effect of those variables will be less as the figures average out

i have tested many vehicles in real life situations over a set route and by swapping drivers to average out differences....the figures obtained were used to influence whole life costs for vehicle purchase tenders!

 

[ado]

Nice test mark.

However, I have found that my MPG has improved by 1-2 MPG since my service in sep. You should service the car before you change fuel next time to see how it responds.