Super unleaded vs unleaded
- Thread starter cyborg
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The extra power/torque realised by the higher octane fuel can improve fuel efficiency a little. Although the mpg gains are negated by the extra price at the nozzle.
Anyway, if both UL and SUL were priced the same, clearly SUL would be the one to go for.
Anyway, if both UL and SUL were priced the same, clearly SUL would be the one to go for.
Unless you car is specifically mapped for higher RON fuels, it's generally not worth it. The only benefit you're getting is the extra cleansing agents which can be added by chucking a fuel additive in when you fill up.
One thing that needs remembering: Higher RON number != bigger bang.
Higher RON fuels are more resistant to detonation and that's about it. Unless you're running more boost on a turbo car, or have an ECU map for higher RON, save your money.
One thing that needs remembering: Higher RON number != bigger bang.
Higher RON fuels are more resistant to detonation and that's about it. Unless you're running more boost on a turbo car, or have an ECU map for higher RON, save your money.
I usually run my CTR on 95 RON. I've compared it to Optimax and the car didn't seem to run any better and I lost around 4 mpg. I'm in the process of running my 3rd tank of V-Power through now and again it doesn't seem to be any different and is looking like it's cost me 3 mpg. So, I expect I will be back to 95 RON soon.
Of course, this is different for each make of car and I've seen other CTR owners swear by V-Power so maybe engine to engine?
Of course, this is different for each make of car and I've seen other CTR owners swear by V-Power so maybe engine to engine?
merlin said:
No, I didn't. I've read conflicting things on how long it takes an ECU to remap but this is my third tank of fuel now (I'm planning to run four through it) so I would expect it would have remapped by now.
I expect it will generate more BHP but it doesn't seem to be enough to be noticable (to me anyhow).
I had this debate at work, and as they pay my fuel expenses I decided to test this. I ride a motorbike so perhaps not too appropriate but the results probably translate to cars easily enough.
I fill up at a shell garage once a day, so I switched from using their standard unleaded to their vpower (?) stuff for two weeks.
Normally I get about 52 MPG, and I travel on average about 98 miles per day (week days). The first thing I noticed was a slight and I mean slight increase in acceleration, but the MPG hardly changed at all, at best an extra 2 MPG.
So no major gains with the Super Unleaded at shell.
BUT... I started filling up at a garage just outside Bristol on the A38, some little petrol provider, but the fuel resulted in a pretty good increase in performance and similar MPG, next time I'm there I'll write down the name of oil company providing the fuel, it's pretty cheap too. (NB at this garage it was also their super unleaded stuff)
David
I fill up at a shell garage once a day, so I switched from using their standard unleaded to their vpower (?) stuff for two weeks.
Normally I get about 52 MPG, and I travel on average about 98 miles per day (week days). The first thing I noticed was a slight and I mean slight increase in acceleration, but the MPG hardly changed at all, at best an extra 2 MPG.
So no major gains with the Super Unleaded at shell.
BUT... I started filling up at a garage just outside Bristol on the A38, some little petrol provider, but the fuel resulted in a pretty good increase in performance and similar MPG, next time I'm there I'll write down the name of oil company providing the fuel, it's pretty cheap too. (NB at this garage it was also their super unleaded stuff)
David
Soldato
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Unless your mapped up for a fuel, or your cars timing adjusts its not worth it. although even before I mapped my bike on V-power it ran better on optimax, just a little smoother and percieved slightly better accelaration, but it was slight. Economy was near the same (I really dont care on the bike what economy I get). Now its mapped its a different kettle of fish all together though!
V-Power has been at every Shell station since July 2006 I am told, the branding actually changed later in the year but the depots were shipping only V-Power from July and not Optimax....
One of the guys at BM3W (who owns a tuning business) did some detailed tests on different fuel types and they were quite interesting reading. The car mapping is important and also the state of tune will have a big impact on any benefits which may be derived.
One of the guys at BM3W (who owns a tuning business) did some detailed tests on different fuel types and they were quite interesting reading. The car mapping is important and also the state of tune will have a big impact on any benefits which may be derived.
Higher octane fuel will do nothing for your cars performance or mpg UNLESS the ECU can take advantage of it...
Infact, with a lot of cars you may even suffer some loss of mpg or performance as the calorific value of the fuel is lower and it burns slower..
To get better performance from higher octane rated fuel, your car must either be retarding the ignition because 95 isnt sufficient, or be capable of allowing more advance until its knock sensor kicks in...
Some fuels may work better than others as they have more oxygenates in them or detergents that clean the engine... but you can have the same effect running 1 tank of optimax every month to keep the engine clean..
Remember, Octane rating is merely a measure of a fuels anti-knock ability, not its power... an engine must be able to take advantage of the fuel to make any use of it...
Infact, with a lot of cars you may even suffer some loss of mpg or performance as the calorific value of the fuel is lower and it burns slower..
To get better performance from higher octane rated fuel, your car must either be retarding the ignition because 95 isnt sufficient, or be capable of allowing more advance until its knock sensor kicks in...
Some fuels may work better than others as they have more oxygenates in them or detergents that clean the engine... but you can have the same effect running 1 tank of optimax every month to keep the engine clean..
Remember, Octane rating is merely a measure of a fuels anti-knock ability, not its power... an engine must be able to take advantage of the fuel to make any use of it...
Dimension said:My 2003 Impreza gets over 100 miles more to a tank of Vpower then normal 97 ron super unleaded.. it standad apart from back box and airfilter
I now get 350 miles to a tank.
That nicely proves my point as the scoob ecu will take advantage of the higher octane fuel...
My Forester will run happily on 95, but produces a lot more power and better economy on 100... sadly due to the price difference I stick to 98... a nice midrange fuel
If I run on anything other than V-Power, I notice it. I had no choice but to stick in a 1/4 tank of BP Ultimate the other day and the results weren't great. Noisier, less economical, less willing at high revs - not good all round. Switching back to V-Power and the car's happy again
I'm not sure how much effect the remap has on my car's fuel preference, but I was advised that a 98+ octane fuel would be preferable on all ocassions.
I'm not sure how much effect the remap has on my car's fuel preference, but I was advised that a 98+ octane fuel would be preferable on all ocassions.