95 vs 98 Octane - Fuel Economy Difference

[1TUFFUTE]

I tend to use 98 and weve never really checked kays tho. Occassionally go 95 if its really expensive but learnt a bad leason with terrible economy from half a tank of 91 once. We deff get at least .5l better economy around town with the new cai airbox tho. It even shows on some hills on the instant economy readings that I got. Took down some readings before the airbiox was fitted. Pretty cool if you ask me.

[Andy217]

I use united p100 fuel, gets me an extra 50kms to a tank and it is usually 6-10c a litre cheaper than 98! Only problem is trying to find a united servo in perth that sells it haha

[Rodge]

Originally Posted by flappist

My car was expensive.
It is very important to me as I use it daily and I rely on it.
I use the best fuel and oil I can buy.
I fit expensive performance tyres.
I have it maintained by professionals.

I am not interested in the slightest in risking compromising my transport in order to save enough money to buy a cup of coffee.......

SC FPV and F6 and designed to run perfectly on 95 Octane. Like you I have almost always used 98 but came across this report in an AA magazine and started to wonder.
1. Is it really worth driving out of my way to buy 98 Octane, closest bowser is 8 km's away and with the very short range of the SC car around the city it kind of defeats the purpose both in respect of time and money if you have to drive a return trip of 16 km's just to get it while to be fair I acknowledge from time to time I go that way anyway.

2. Is there really any point in the (apparent according to my bum-o-metre), very slight improvement in top end kick this fuel gives me over winter when about 7 days of of 10 I'm struggling for traction on wet roads.

As you can see, there's a little bit more to it than just a free cup of coffee.
And who says 98 Octane is better for your FPV or Ford car than 95...it wouldn't happen to be BP would it ???

Originally Posted by mike_nofx

So they only did the test once with each fuel type?
Over 170km there would be many variables which could sway one way or the other. 3 times minimum with each fuel type would be a better sample range.
That extra 1km that the 98 ran for, did the 98 run have the car stop on a slight slope leaning away from fuel pick up, for example?

Yeah they only did it once and I agree it would have been better if they tried it several times to get more accurate results. They did however start and complete the test journey at a reasonably flat racetrack (albeit driving in a normal way on the track), because of the danger of running out of fuel in traffic.

[flappist]

Originally Posted by Rodge

SC FPV and F6 and designed to run perfectly on 95 Octane. Like you I have almost always used 98 but came across this report in an AA magazine and started to wonder.
1. Is it really worth driving out of my way to buy 98 Octane, closest bowser is 8 km's away and with the very short range of the SC car around the city it kind of defeats the purpose both in respect of time and money if you have to drive a return trip of 16 km's just to get it while to be fair I acknowledge from time to time I go that way anyway.

2. Is there really any point in the (apparent according to my bum-o-metre), very slight improvement in top end kick this fuel gives me over winter when about 7 days of of 10 I'm struggling for traction on wet roads.

As you can see, there's a little bit more to it than just a free cup of coffee.
And who says 98 Octane is better for your FPV or Ford car than 95...it wouldn't happen to be BP would it ???




Yeah they only did it once and I agree it would have been better if they tried it several times to get more accurate results. They did however start and complete the test journey at a reasonably flat racetrack (albeit driving in a normal way on the track), because of the danger of running out of fuel in traffic.

Well three points:

First one is that petrol tends to age VERY quickly and 95 or 98 for that matter does not stay that way for more than a few weeks.

Second is that it is your choice what you use. The extra 8km comes down to money which as an accountant is something on which you focus.
When there was not a lot of 98 or even 95 in Australia I would always plan my trips to ensure availability and carry up to 60l of "spare" petrol when needed.

Third is that while all "domestic" cars are quoted at suitable for 95 as if they were not there are a whole heap of potential legal issues running them on the "wrong" fuel quite a number have quoted their "power" and "torque" with a disclaimer that these figures are on 98 not 95. I suspect there is a reason for this.

As far as who says it is better......

I have done almost 500,000km since 98 came out much of which was repeating the same 800km trips at the same times of day. I experimented with many different fuels and as I was using log books it was easy to go back over long periods to compare.

The core of what I found was:

BP Ultimate & Vortex 98 were the best and about the same.
Shell Optimax was next
Then all of the 95s

Fuel economy was better in cold weather and when keeping the revs about 2000, lower was actually worse.

Fuel economy was better when the tyres were at a higher pressure.

So on the road I run my cars on Ultimate or Vortex and keep the tyres at 36-38.

It may be different for you as you are in a different country so the petrol and climate might not be the same.

[Bill M]

I have experienced no difference between 91, 95 & 98 octane fuel when used in my AU XR6. I believe it was tuned for 91 so if it was not designed to run on it then I wouldn't expect to see any benefit. I primarily use 98 once every so often in the XR for it's detergent value based on a statement by someone with credibility in the fuel chemist profession.
Still I do feel a sense of empowerment when I do use it

[LTDHO]

I have made more power out of 95 (twice) than 98 ever did.

I have since dropped comp but will keep the boost the same. Until it's tuned I run the LTD on 98. I suppose it could be safer? Dunno. Myth maybe? Dunno.

The tune will be set up (hopefully) for response and not top end kw's.

[Rodge]

Originally Posted by flappist

Well three points:

First one is that petrol tends to age VERY quickly and 95 or 98 for that matter does not stay that way for more than a few weeks.Not a concern for me as the GT-P chews it away fairly quickly. Just out of curiosity do you know how long does diesel takes to go off ?

Second is that it is your choice what you use. The extra 8km comes down to money which as an accountant is something on which you focus.Its more about the inconvienience but yeah if there's no material difference one has to wonder
When there was not a lot of 98 or even 95 in Australia I would always plan my trips to ensure availability and carry up to 60l of "spare" petrol when needed.A lot of dicking around that whilst it might be something that's appropriate in the wide open expanses of Australia, I doubt anyone in N.Z. would bother doing this

Third is that while all "domestic" cars are quoted at suitable for 95 as if they were not there are a whole heap of potential legal issues running them on the "wrong" fuel quite a number have quoted their "power" and "torque" with a disclaimer that these figures are on 98 not 95. I suspect there is a reason for this.Fair point and it would be interesting to know what the difference is. Torque seems to be more impacted than power from anecdotal stuff I've heard

As far as who says it is better......

I have done almost 500,000km since 98 came out much of which was repeating the same 800km trips at the same times of day. I experimented with many different fuels and as I was using log books it was easy to go back over long periods to compare.

The core of what I found was:

BP Ultimate & Vortex 98 were the best and about the same.
Shell Optimax was next
Then all of the 95s

Fuel economy was better in cold weather and when keeping the revs about 2000, lower was actually worse.

Fuel economy was better when the tyres were at a higher pressure.

So on the road I run my cars on Ultimate or Vortex and keep the tyres at 36-38.Some good feedback there, thanks, yeap I'm into 38 all round on all the cars.

It may be different for you as you are in a different country so the petrol and climate might not be the same.Possibly is due to lower prevailing temperatures and more hilly terrain

When I've filled up with BP 98 Ultimate i've typically got 420-430 distance to empty showing on the trip computer after a complete fill, (that's 90% around the city motoring). I'll keep an eye on this over winter running Shell 95, known as "Z" here now and see if there's any meaningful change.

[dmat2391]

http://www.youtube.com/watch?v=WuCUGcqO5SE
great explanation of why we should care about octane ratings for our motors. My opinion....as my wife keeps telling me R.T.F.M.......for my NA XR6 BA it says 91 is fine but you'll have benefits from 95. For the FG XR6T want to have fun use 98. if your desperate use 91 but it will run like crap.
It's up to the ECU maps as to the full usage and really it's the type of driving that will dictate the amount of fuel used.
I'd also back what Flappist has said look up his threads good stuff to learn

[bublik]

Trying to be as consisted and possible, I get about another 80km -130km per tank extra for using 98 Octane

[Franco Cozzo]

I was running Shell 98 in my Falcon before it was tuned, but my tuner filled it up with BP98 and said its much better than the rest of the other 98s and tuned my car to run on that.

He showed me some dyno graphs across multiple cars and he could get higher figures out of BP98 than the other 98 blends.

So I ran it on BP98 for a while, but this tank I filled up with United 100, to see any difference, so far my idle seems to be a touch less rough, its more expensive though.

I got 590km out of 67L on BP 98, average speed 54km/h, average indicated use 11.5L/100km.

I'm going to give Caltex E85 a shot soon, one of my workmates run his modified EL on 50/50 98/E85.

Our Fiestas say you can run them on 91, but come into the small car section and ask anyone here who has tried it, they idle like crap and stall when cold on our early year WS Fiestas, mine has only ever been run on 98.

Also seeing the difference on Hondas when I was working at the dealership, cars which have always run on 98, vs the people who don't want to spend the extra 10 cents for the good stuff, you can tell the difference when you look at fuel delivery components, and things like fuel regs which rusted over etc.

[T4ME]

Don't use 98 and Caltex mixed use United 100 and E85....much better blend.

If your car is tuned for a certain gasoline then don't go adding ethanol based fuels to it even at the low number of 10%...it will run leaner than the number settled on when on the rollers.

Caltex E85 is only low 70% ethanol so not as high as United's 85% min all year round.

Your tuner should have seen the same results from United P100 over BP 98...P100 is a better fuel at making torque/power.

[Franco Cozzo]

Unfortunately I can't get United 100 at my closest united, only their 100.

I'll keep that in mind about the 100 with the ethanol.

[zilo]

Any modern car that uses a knock sensor will automatically adjust for fuel types.

91.95,98,100 the ecu will simply advance until it pings then back it off a bit.

Using 98 with forced induction and high compression will yield the best high end performance....but normally aspirated? waste of money.

[T4ME]

Id rather use the correct fuel than rely on a sensor to save my motor somewhat.

Zilo....100 from United will give better results than any 98 from the bowser.