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Discussion Starter #1 (Edited)
Despite the drop in temperature, I have had a significant 5+ MPG drop on V-Power. Down to 35 MPG from 40+ MPG. This is my first time on High Octane Petrol. The manual does say it can take more than 95 RON and oxygenated fuel (whatever that is).

What is everyone views after using V-Power Petrol or high Octane? Please don't post about the diesel that does appear to be effective in my experience.

I will be going back to 95 ron.
 

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i-Vtec
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I have always found the same,Costco Premium gives the most poke but the worst MPG. people will tell you it takes the ECU a few fills to adjust to the increase in Octane. No idea if its true, but also I find that I use the right foot more enjoying the extra poke you get with premium petrol.
 

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No idea if its true, but also I find that I use the right foot more enjoying the extra poke you get with premium petrol.

It sounds like that is the case:- I know E10 Gives a reduced MPG, But I found it to be far more than a ~10% decrease in MPG that most state - Mostly because it was noticeably more responsive, and fun to go whoosh.


I've used Costco 95 / 99 RON for a number of long runs, and I've never noticed a particular tendency either way when just cruising normally; any fluctuations are generally attributable to other factors, such as average cruising speed.
 

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Discussion Starter #4
Performance is not what I was aiming for. Those days are behind me. But I have to admit the i-vtec throttle response is incredibly fast when pottering around town. I have not had the car for a while, my other car is a Porsche... no correction its a Toyota T-Sport and the throttle response of the Civic is even faster.

Because my wife commutes in the Civic on a steady route (just checked out her trips on AA Car Genie device) they are consistent so I don't think it is a heavy foot or increased traffic, unless it was me but I don't think so. Perhaps the "i" in i-vtec is being too intelligent removing the economy programming on 99 even without a heavy foot.

I will try and fill up again on V-Power and see if the ECU adjusts otherwise I am waisting £8 every fill other than for the cleaning properties.
 

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Enjoying life
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Mine is the other way. 95 Ron I get 29mpg, premium gets me 32 mpg
 

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Adjustments performed by the ecu are fairly simple; afaik changes are to AFR based on intake, and more importantly when it comes to RON, ignition timings based on knock sensors.

Higher RON leads to advanced ignition times, yielding more power - the engine will knock forward the times until knocking occurs, and then wind the timing back.

Interestingly, as higher Ron fuel burns cooler, it has a lower calorific value meaning less chemical energy for a given volume than a lower Ron fuel - the knock resistance allows for compression and timing advances, though, which allow for more efficient mechanical exploitation of the fuel.

Sent from my SM-N950F using Tapatalk
 

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Discussion Starter #9
Haltmer, good post. Higher RON leads to advanced the ignition times, but I would say yielding only a tiny bit more power (confirmed by 5th gear testing)

As well as the V-Power in the Civic I have put BP Ultimate into the other car (Toyota T-Sport) and this too had a drop in MPG over 2 fills (80% of my tests are blind tests as my partner does the commuting while use the train)

BP Ultimate and Shell V-Power both go hard on the cleaning properties (V-Power is best at this) and I wonder if it is these cleaning properties that result in the drop in MPG (despite lubricating claims). This goes against a more scientific test by 5th gear that showed V-Power the best at max BHP (but did not test MPG or torque).

When the Toyota went back to standard 95ron it ran really well (cleaner engine?).

I am going to hypothesise that when the Civic goes to use Tesco 99ron I would get a massive 8 MPG better than V-Power. If not then back to 95ron with the once a year fill on V-Power for any cleaning benefits.
 

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Earth Dreams :)
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I just use V power...
Don't really give a crap about the mpg.. When it gets towards a 1/4 tank - refill..

Car seems happy with it, so I'll continue to use it..
 

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I am going to hypothesise that when the Civic goes to use Tesco 99ron I would get a massive 8 MPG better than V-Power. If not then back to 95ron with the once a year fill on V-Power for any cleaning benefits.
I usually fuel from Costco:- 95RON For usual use, coming in around 1.25/l at the moment (Very cheap).

If I'm planning on going for an enjoyment / long drive, I'll fill with 99 for around 1.31/l - I'll also do this every few weeks If I haven't recently:- This 99RON is the same as Tesco 99 RON.

Further to that, If I'm going on an extended motorway drive, I'll sometimes opt for 95RON and a shot of Redex for any cleaning benefits that may possess.

As far as changes in MPG Go, I've never noticed anything of statistical significance after a fill, be that changes in MPG or engine note / feel, other than European E10, which as aforementioned, felt more snappy with a big drop in MPG - Though this may be placebo.

I'm sure my fuel system is feeling very pampered :)
 

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Have u tried disconnecting the battery for 15 mins this way it resets the ecu also check your tyre pressures this affects your fuel economy.
Plus i got a diesel i had the transmission oil changed the differences is day and night smoother gear change silent and better fuel economy

Sent from my SM-G960F using Tapatalk
 

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Discussion Starter #13
Eagle I don't like to change the oil myself, :wink3: but will consider this for the next service based on your experiance in the other thread.

Still on the 2nd tank of V-Power. By the time I get onto Tesco 99 the outside temperature would have changed invalidating my testing but we shall see. Not only is V-Power result in £8 more inefficiency you have to consider the extra cost of the fuel itself. Also, note for distance travelled I am recording this via GPS connected to OBD2 port via The AA Gar Genie.
 

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Shell Vpower is now 99RON. I haven't noticed any drop or increase in MPG in my FN2 but it seems to enjoy the fuel. Getting expensive though at £1.38 to £1.45 per litre depending on which Shell outlet I visit.
 
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