Is It Time For Super ?

[VamboMan]

With petrol prices dropping faster than the Russian Rouble, is it worth revisiting the use of Super Unleaded in our glorious V8 ?

I didn't buy my F for its economy so I'm not too bothered whether Super UL affects the MPG negatively however does it make for a better drive ? The answer could be just a personal opinion but I'm interested to hear what my fellow members say and what experiences they have running on Super.

[stevet]

Been thinking the same but annoyed that the prices aren't displayed on the front sign. Harder to compare prices. Just filled up today with regular at £111.9 the super was £121.9 so still 10% more

[noby76]

running at a high compression ratio of almost 12.0:1 i will say its worth it. heck my 10.5:1 compression IS300 runs sluggish and never responsive when running on standard 95 RON even in M sport mode. i chuck some Esso 97, BP ultimate or Shell V power in the thing and the difference is clear. you wont notice it right away but after a few fill ups i can tell the engine loosens up and revs more freely.. i know forums debates has been had with others claiming they cant tell no difference in N/A engines. i can tell the difference when mine is running on 95 shell fuel save vs V power Nitro. thing just takes long to hit redline in most gears on 95 but loosens up once on 97-99. not sure how many knock sensors are in the IS-F but i beleive the IS200-300 runs 3 knock sensors which proves the engines where designed to advance timing if higher RON fuel is used and retard timing once knock is detected from lower RON fuel. retardation of timing will casue the engine to do less work = less power/responsiveness. advanced timing does the opposite..

[Stuno1]

A higher octane fuel will return better mpg and a few more ponies. Is it worth it??? Not shure but I don't feed mine anything but the best. Pretty sure mpg wise it makes no difference if you factor in fuel price but it somehow makes sense to me!

[sofasurfer]

Always used V Power in mine. Would be rude not to.

[MNMJ]

V Power only for me, though I did stick 10 litres of the cheapo stuff in once in Lincolnshire when the only local Shell station was closed. That is not a county to run out of petrol in when its getting dark...

I don't know what its like on 95RON, but since I'm budgeting £500 a month for depreciation, an extra £15 a month on nice fuel is a pittance.

[stevet]

I know its not exactly the same engine but the RC-F engine guru was at Ascari last week and he said the engine is designed to perform exactly the same on any fuel (no increase in power or mpg) but the only reason to ever use super fuel is when running the engine at max revs (e.g. Track) for long periods as it will run cooler.

[Stuno1]

I know its not exactly the same engine but the RC-F engine guru was at Ascari last week and he said the engine is designed to perform exactly the same on any fuel (no increase in power or mpg) but the only reason to ever use super fuel is when running the engine at max revs (e.g. Track) for long periods as it will run cooler.

That makes no sense. He is basically saying use any Ron but preferably higher Ron for track but it makes no difference. It does make a difference. You definitely get more miles from higher Ron fuel and a VERY negligible power increase. This is the case with any car. Not having a pop at you but would like to hear his reasoning.

Stu

[stevet]

Have not got a clue about his reasoning, I know nothing about engines. He said something to do with the ECU will compensate for any fuel. Wish I knew more but he's the expert.

[Stuno1]

Indeed. I know most modern engines can run on lower Ron fuels not like the past when some had to be Ron on X ron.

[noby76]

this is a copy from the US IS-F's owners manual and as it says 96 RON or More.. so the standard 95RON is even underspec'd for this engine. it will still run fine on 95RON but not at its full capability since the knock sensors will cause the ECU to retard ignition timing and maybe engine mapping. by retarding ignition timing and mapping will result in the engine not running at its optimum.

thing most forget is the fuel is not what makes the power the higher ron fuel just takes a bit longer to ignite when compared to a lower RON fuel. by the fuel holding off a bit longer causes the piston to give maximum compression without knocking which results in engine delivery its full potential when its put under load/stress in other words at higher rpm. but not any engine benefits from this a 1.2 fiesta will not since its not a tuned/performance engine but most tuned/performance engine do mainly high compression/turbo charges ones.

I am aware some hot hatches like the golf GTI ,Honda Type R's/ S2000 states 98RON doesnt mean they wont run on 95 but they wont run at thier full potential.whilst sometimes even worser fuel economy due to the engine not running at its optimum.

this is a copy and paste from wiki based on the AUDI RS4

"On 98 RON (93 AKI) Super-Unleaded petrol it produces 309 kilowatts (420 PS; 414 bhp) at 7,800 rpm ^[5] giving it a specific power output of 74.2 kW (100.9 PS; 99.5 bhp) per litre.^[6] Based on a kerb weight of 1,680 kilograms (3,704 lb), this results in a power-to-weight ratio of 184 watts per kilogram. This engine also produces 430 newton metres (317 lbf·ft) of torque at 5,500 rpm,^[5][6] 90 percent of the total torque being available between 2,250 and 7,600 rpm.^[6] (Using lower 95 RON (91 AKI) standard unleaded fuel slightly reduces engine output, and therefore performance,^[5] and slightly worsens fuel economy)"

[Stuno1]

As always a good and informative post fella.

[Peter P18]

Always run the best fuel in my cars. The price per fill is negligible guys!

How many of you have had those money off a litre vouchers from the supermarkets?

10p a litre off, or even 20p. So you fill up with say £65 of fuel, go in and smugly hand over your voucher.

If you're lucky enough for them to accept it, they inform you it's now £63.12 or something like that! ;)

Wow! A whole £1.88 off! Lol.

Hardly seems worth it.

I've seen better MPG, acceleration, and smoother running from using the higher RON fuels. No denying you'd gain more if we could re-map the ECU to run on the higher RON fuels, but you do get more for your money. Peace of mind that your injectors will run cleaner, and your risk of any detonation is reduced.

Not criticising anyone, but seems odd to me that youngsters in their £2-3K 200SX's will fork out for V Power, yet guys with £20K+ ISF's use cheap stuff? You wouldn't run economy tires, so why use cheap fuel??

Just my thoughts.

[stevet]

"you wouldn't run economy tyres, so why use cheap fuel"

That's an easy one.

Economy tyres : Dangerous, noisy, car handles badly, car worth less

Cheaper fuel : It's cheaper

[Peter P18]

"you wouldn't run economy tyres, so why use cheap fuel"That's an easy one.Economy tyres : Dangerous, noisy, car handles badly, car worth lessCheaper fuel : It's cheaper

I hear you Steve. Maybe not the best comparison.

What I'm saying is for the sake of say £2-3 a fill up, is it not worth using the higher RON?

Think V Power was 1.28 or so when I got some petrol this morning?

Shell spent literally millions getting their V Power to be the best possible fuel it can be.

For the sake of a pint of beer, I'd rather use the good stuff! ;)

[stevet]

At 1.28 that's about £10 difference per tank but....

It's weird, the ISF I always used v power. The GS (same value) I use the cheapest I can find. Both never miss a beat but with the ISF you just treat them differently. It really is a special car.

[VamboMan]

Thought it was time for an update on this one.

Done 1197 miles in the last month, mixture of rural, B roads, A roads and motorways but no city, snail-pace driving. Achieved 26.995 MPG using Shell V Power Nitro +. To be honest that's about par for my normal summer MPG using standard unleaded so still not sure about 99RON. Let's see what the next 1000 miles brings.

[Keith_W]

Just spent a couple of weeks in the US and was shocked to see their Shell V Power was 93 Ron! There were three petrol options With the entry level being just under 84 Ron!! Had to concentrate when filling up as the diesel pumps were green and the petrol pumps were black. Glad it was a hire car.

[stevet]

Had a look back at my previous posts and noticed I paid £111.9 on the 17/12/14, yesterday filled up at 98p! Is this making anyone drive faster :)

[VamboMan]

After 2,476 miles on Super U/L my conclusions are that there's no significant difference in MPG compared with standard U/L.

Having previously driven 23,000 miles using standard U/L, my trip computer read 27.8 MPG however I've found out that the Tank Average is almost 1 MPG optimistic during my Super tests so let's assume I used to achieve 26.8. My more expensive Super U/L returned 26.94 MPG so the minute increase in MPG is not worth the extra 8p per litre for me.

If it increased the responsiveness of the engine or improved the smoothness of acceleration then it wasn't noticeable so I'll be reverting back to standard U/L at the next fill up.

Probably not the most scientific of tests but it's good enough for me.

[Stuno1]

Interesting but totally unsurprising. Thanks for updating :)

[stevet]

About the same results as I found. Only used the v power for the cleaning additives

[Grey One]

At the end of the day "you pays your money and takes your choice" - for me, owning a performance car like the ISF, it has to be V-Nitro and for my other cars too. In the end it may all be marketing smoke and mirrors, but I reckon over the long-term this is what performance cars needs and I definitely notice the difference in terms of responsiveness and performance...