Fuel Octane ratings. Do they really matter?

Aug 3, 2011
1,357
1
Following on from the recent discussion about fuel quality on the corsa vxr/cupra thread. Rather than filling that thread with off topicness Ive decided to see what pepole think in a seperate thread.


When I first got my Cupra I put 95Oct in it for a while, I dabbled in the odd tank of Vpower but didnt feel much difference, though MPG did increase slightly(circa 15-25 more miles from a tank. I realise that the car need to "learn" what fuel is being used and therefore to feel a difference you should run a few tanks of the stuff through the car so It can adapt its various parameters.

I dont like paying more for less(or nothing) so using Vpower/Tesco99/BPUltimate for me was always a bit of a sore point, lol.

Anyway, I ended up having the car mapped, so its now "set up" to run better on 99Oct than 95. So I havnt had to put any 95Oct in the car yet, I got some 97 from an Esso and didnt notice much difference. I have no conclusive or otherwise evidence that says higher RON fuels are any better.

Thorney Motorsport(sponsored by Tesco btw) have done quiet a few large fuel tests, tesco usually comes out best, I think Shell Vpower came out best once or twice as well. While sponsorship of the race team *might* influence results, Im not sure the dyno's are aware of any sponsorship. They make interesting reading any way. Heres a few links.


http://www.thorneymotorsport.co.uk/tuning/Fuel_Test_Results.shtml
http://www.thorneymotorsport.co.uk/tuning/Fuel_Test_Results_Update.shtml
http://www.corsavxrracing.info/pdfs/fuelTest2008.pdf
http://www.thorneymotorsport.co.uk/media/magazine/Auto_Express_Fuel_Test_-_January_2010.shtml

I also read a which article that ran a few normal daily drivers on both 95 and Higher oct fuel. They concluded there was no real advantage compared to the price, but when you think about the cars they were using you can see why. Though they specifically mentioned the 1.4tsi (170ps) engine saying it took well to the higher octane fuels and Shell Vpower was the best. So our 1.4TSI's surley would like some too?


Can Open :whistle:


Also, Im sure this has been discussion on the forum's before but rather than cracking open a year old thread I figured a new one would be good for debate.

Jay
 
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G3K

3 points and counting...
Aug 14, 2010
451
0
Hatfield, Herts
I'm running standard setup.

Tried V power the last 4 times and no difference at all. First of all thought there was more torque lower down but that was me in V power mode! I didn't get any more mpg so for me I have reverted back to ASDA 95 ron. Save money, maybe it hasn't got as much cleaning properties as more expensive fuels but I'm not keeping the car long term.

I know most will stick with V power but I think its a good marketing tool myself, charge more for something that does the same job.

I would love to see a quarter mile drag, one standard Boc using 95 ron against another standard using V Power
 
Nov 23, 2010
873
0
Dunfermline, Fife
I would love to see a quarter mile drag, one standard Boc using 95 ron against another standard using V Power

That would be good.. I did use 99 on the 1/4 but its not very scientific as i'm not sure if the ecu had even learned the new fuel. I did run a full tank of it prior to a full tank for the day of the event. It would need to be one that had more or less always run on 99/v power, compared to one that had always run on 95. Then u also have to factor in the weights of both vehicles inc drivers etc.....:confused:
 

G3K

3 points and counting...
Aug 14, 2010
451
0
Hatfield, Herts
That would be good.. I did use 99 on the 1/4 but its not very scientific as i'm not sure if the ecu had even learned the new fuel. I did run a full tank of it prior to a full tank for the day of the event. It would need to be one that had more or less always run on 99/v power, compared to one that had always run on 95. Then u also have to factor in the weights of both vehicles inc drivers etc.....:confused:

Good point, drivers would make probably the most differance.

Maybe putting the same cars on the same dyno on the same day and see what the readings show would give a fairly conclusive result.

I'm sure if a car is mapped to run on V power then V power would work best but I'm looking at it for a standard point of view
 
Aug 3, 2011
1,357
1
One of the Thorney motorsport test put two Astra vixxers both standard and then both mapped every 3 tanks of petrol (95/99) on a DD Dyno.

Jay
 

Hurdy

Yorkshire - born and bred
Oct 7, 2008
710
7
South Yorkshire
Well my Polo gti 1.4 tsi definitely runs better on water methanol injection, which changes my 99 Ron v-power to 112 Ron race fuel!:D

Shell claim 28 miles extra on average for a full tank of v-power compared to the 95 Ron cooking oil. In a 10 gallon tank that equates roughly to 10% saving! And v-power isn't 10% more expensive than 95 Ron fuel. Also it gives better protection to the engine as there are more additives in v-power too. Finally and crucially for me.....more power with v-power;)

No brainer really:whistle:
 
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WJs

MeepMeep
Oct 26, 2006
497
0
Netherlands
My car misfires (or Engine knocking/pinging) on 95 and some of the weaker "vpower" thingies. (like that Esso crap). I need Vpower or 98..
 
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Nutkin

Pop-a-Keg ya?
Aug 24, 2006
2,581
0
Schnaitsee
get some aviation fuel a bit of Low Lead 140 will really kick things off, will need stand alone mapping and to remove the O2 sensors and a decat but it will run like a dream!
 
Sep 2, 2010
569
0
Leeds
The car manual states the engine will produce slightly less power on 95 Octane petrol. So if Seat themselves say that then the octane rating must matter surely. I only ever put 99 in mine, only a few quid more per tank and it helps keep the engine cleaner too :p
 

InFus1on

Sideways is Bestways
Mar 7, 2010
121
0
Cwmbran, South Wales
I can't see why you wouldn't use VPower or equivalent?

If you take pride in your car you should use the best stuff. It might not make a difference, but if your gonna buy a performance car, why skimp on something as regular as fuel? You save yourself maybe a few quid per tank.

I physically can't use anything but high octane fuel.
 

Octane2097

Naturally Aspirated
Jan 20, 2007
792
0
South Yorkshire
full tank of 95 ron at my local garage would be £62.95
full tank of 98 ron at my local garage would be £65.65

for the sake of £2.70 il use the expensive stuff.
i suppose work it out over the year its roughtly an extra £70 in fuel
but id rather pay the extra £70 a year and have no power loss.

as for mpg and power? i cant comment i never put 95ron in it.
 

yellonvi-R

Active Member
Sep 8, 2011
4,331
3
birmingham
Ive never used this high octane fuel superunleaded or the like and ive owned some right beasts. Never had it cause me an issue using normal unleaded in any of my cars and even before when ive tried the super stuf ive never noticed a change.

Even tried high octane stuff in my sti type r before its rr run once for 2 weeks before the run. Bhp was the same as when id ran it on normal crap.
 
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