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Honda Jazz Forums => Honda Jazz Mk1 2002-2008 => Topic started by: Jocko on July 02, 2019, 04:28:00 PM

Title: Giving 97 Octane a try.
Post by: Jocko on July 02, 2019, 04:28:00 PM
Giving 97 Octane a try. My local Morrisons has a couple of pumps that supply 97 Octane petrol so I filled up with that today. It was 6p/ litre dearer than their standard 95 Octane, so nothing like as dear as the Shell V-Power.
My top up today was for 475 miles and the yellow light just on. I was delighted to get a calculated figure of 61.9 mpg.
I'll try 97 Octane for a few tank fulls and report back on the results.
Title: Re: Giving 97 Octane a try.
Post by: dave12335 on July 02, 2019, 05:10:02 PM
I’ve been using it since I didn’t realise my spark plugs were playing up. Seems a bit perkier with it although it is more expensive.

Is it environmentally better or worse, does anyone know ?
Title: Re: Giving 97 Octane a try.
Post by: Jocko on July 02, 2019, 05:47:43 PM
Is it environmentally better or worse, does anyone know ?
As it releases the same amount of CO2, it is no better.

In fact, the extra chemicals added may make it worse. Unless of course it returns better fuel economy. It is only the same petrol with additives!
Title: Re: Giving 97 Octane a try.
Post by: VicW on July 02, 2019, 06:56:12 PM
Having used Tesco 99 Momentum exclusively for some time I am convinced that it doesn't do anything for the car's performance, additives or not, yet it gets good write-ups. My car runs and performs just as well on my most convenient alternative fuel which is BP 95.
I now alternate between Tesco 99 and BP 95 octane fuel so I am running more or less on 97 octane which is fine.

Vic.
Title: Re: Giving 97 Octane a try.
Post by: peteo48 on July 02, 2019, 10:27:01 PM
I keep coming back to this subject.

The supermarkets charge, typically, about 5 pence extra for their super fuels - ie above 95 RON. The majors - Shell, BP, etc - charge at least 10 pence extra.

Tesco claim to put extra additives in their 99 RON Momentum fuel. Sainsburys tell you absolutely nothing.

When you buy food, you usually get a list of ingredients including additives but, for some reason, fuel companies can just make generalised claims but you never get any detail.

So - is supermarket premium fuel just higher octane or does it have extra additives? What are the additives anyway? Is it just clever marketing?
Title: Re: Giving 97 Octane a try.
Post by: SuperCNJ on July 03, 2019, 11:49:43 AM
It usually takes a little while for your ECU to adjust and adapt to the new fuel, it won't happen straightaway. I certainly noticed a difference in performance in my old Civic Type-R and 135i. It's not a huge difference but the car does seem to be a bit more eager. We've never tried it in the Jazz but will be filling up with v-power every few tanks in our new MK3 Sport to help keep the engine clean. There are a few youtube videos showing how the cleaning and lubrication additives in these more expensive fuels actually work compared to conventional fuel, so I'm fairly convinced they do work.  I doubt they would give any noticeable performance increase in a small engine like the Jazz though. I can't comment on fuel economy as I never really measured it nor can it ever be accurate enough (if I did) to be meaningful.
Title: Re: Giving 97 Octane a try.
Post by: peteo48 on July 03, 2019, 12:05:28 PM
Just done a back of the envelope calculation. I'm working on the basis that the supermarket high octane fuels have the same additives as their 95 RON stuff. Tesco apart, they don't claim otherwise and even in tests done on Tesco Momentum they found that deposits actually increased in one car they tested.

So I'd use Esso as I have several Esso stations near my home. Their fancy stuff will cost me £1.37 per litre so a 14 pence per litre hike on the 1.23 per litre I pay at Sainsburys for their cooking petrol. Given an annual mileage of 3,000 (give or take) and an mpg of 43.5 I'll be paying an extra £3.62 per month extra.

I can afford that and the other factor in my thinking is the type of driving I do - lots of short stuff where the engine rarely gets up to full operating temperature - I tend to think my engine is more likely to get bunged up than if I was doing a decent trip every day.

The rationale would change if I still at work and doing 35 miles per week day - a lot of it on the motorway. I was doing about 11,000 miles a year then so the fancy stuff would add around £15 per month to my bill.

Of course this might be b----cks but it's real b----cks!
Title: Re: Giving 97 Octane a try.
Post by: culzean on July 03, 2019, 12:16:28 PM
I used to travel an 80 mile round trip commute in all weathers and found 97 octane would either give you a bit more pep, or more MPG.  Problem if you use the extra pep your MPG did not change much but if you drove normally I did notice about an extra 10% better MPG. Modern ECU and knock sensor combination means that the ignition timing gets retarded (spark is fired later in compression stroke) if knocking is detected - this reduces power output of engine, but protects it from knocking ( when the exploding mixture tries to send piston back down without passing through top dead centre ). Knocking is hugely destructive and will wreck the engine.  Pinking is a milder version of knocking and although not desirable will not destroy engine.  The ECU always tries to trim the ignition to its most advanced position for maximum power, with higher octane it can run more advanced because the explosion of the mixture is fully under control of the spark and is not being ignited by heat of compression ( as the mixture starts to burn it increases pressure in combustion chamber and lower octane fuel can ignite in an uncontrolled manner as it gets squeezed harder, if the ECU fires the spark later during compression the piston is already past TDC and on its way down before this uncontrolled explosion gets going) .   Direct injection petrol engines can run higher CR because at lower speeds fuel is not injected until nearly TDC on compression stroke, at higher engine speed the fuel is injected in the normal way into into intake stroke.

The ECU actually reacts quickly to any knocking detected, it needs to to prevent damage, the take away message seems to be that Knock detectors allow engines to use lower octane fuel without damaging the engine ( by retarding spark / reducing  power) - the other side of the coin is that if the knock sensors are not picking up any vibs the ECU will advance spark.  Car makers  maybe still do ship cars to certain parts of the world with engine set up for lower octane,  but I assume knock detectors mean it may not be so important ( and the 95 octane or higher fuels more widely available now).
Title: Re: Giving 97 Octane a try.
Post by: Jocko on July 03, 2019, 02:17:38 PM
I bought an old Cavalier CDi with 90,000 miles on the clock and ran it for a further 92,000 miles before giving it to my nephew. God knows how many more miles he put on it in the two years before it finally went to the great scrapyard in the sky. It was run on supermarket fuel all the time I had it and never had any issues of getting "bunged up" or problems with emission testing. If it hadn't rusted away it would still be going now!

The last time I used 97 octane I found the car a little smoother pulling at low revs. MPG was marginally better, but easily lost in the "noise" of fill up figures. Mind you, as I said above I got 61.9 this tankful and 61.4 the tankful before, so I do get consistent figures if I do similar drives. However I will need to beat 64.5 next tankful to break even on price!
Title: Re: Giving 97 Octane a try.
Post by: Pine on July 03, 2019, 08:01:41 PM
I have read that Costo and Sainsburys 97 Octane have exactly the same additivies as their 95 Octane fuels.  Tesco Momentum 99 did claim to have a better additive package than their standard unleaded. This was stated on the Tesco Fuels web page but the web site seems to have been taken down recently.  Greenergy, who supply Tesco petrol (and also have the contract to distribute Esso fuels) have the Quality and Technical Product information on their web site.  The Greenergy web site is worth a look at, they claim to be the biggest supplier of road fuel in the UK.
Title: Re: Giving 97 Octane a try.
Post by: peteo48 on July 03, 2019, 09:13:23 PM
I have read that Costo and Sainsburys 97 Octane have exactly the same additivies as their 95 Octane fuels.  Tesco Momentum 99 did claim to have a better additive package than their standard unleaded. This was stated on the Tesco Fuels web page, but this seems to have been taken down recently. 

Interesting and would explain why they are only 5 pence per litre more expensive than their 95 RON. I wonder if we can assume that the 10 to 12p premium charged by Shell, Esso and the rest is because they have additional additives. This means that the concept of running a tank full of the good stuff every now and then for cleaning purposes will only work if you used a branded product?

Title: Re: Giving 97 Octane a try.
Post by: John A on July 04, 2019, 08:23:32 AM
I have read that Costo and Sainsburys 97 Octane have exactly the same additivies as their 95 Octane fuels.  Tesco Momentum 99 did claim to have a better additive package than their standard unleaded. This was stated on the Tesco Fuels web page, but this seems to have been taken down recently. 
. I wonder if we can assume that the 10 to 12p premium charged by Shell, Esso and the rest is because they have additional additives.

My guess is that the only safe assumption is that they think they can charge a premium for what might be considered a premium product. Or am I being overly cynical?
Title: Re: Giving 97 Octane a try.
Post by: trebor1652 on July 04, 2019, 06:03:10 PM
I remember trying Tesco momentum when I had my 1.4 mk1 and the mpg fell through the floor.

Sent from my moto g(6) using Tapatalk

Title: Re: Giving 97 Octane a try.
Post by: Jocko on July 04, 2019, 06:12:26 PM
Only done a few miles since filling up, but I genuinely do think that low speed pulling is even smoother than with 95 octane.
Title: Re: Giving 97 Octane a try.
Post by: bus_ter on July 06, 2019, 01:38:02 PM


The last time I used 97 octane I found the car a little smoother pulling at low revs. MPG was marginally better, but easily lost in the "noise" of fill up figures. Mind you, as I said above I got 61.9 this tankful and 61.4 the tankful before, so I do get consistent figures if I do similar drives. However I will need to beat 64.5 next tankful to break even on price!

How do you get these figures? Very impressive from an older petrol car. Is it the slightly smaller 1.2 engine that's making the difference?

When driving intentionally economically I can see 55MPG on the car (about 52MPG when I do the calculations). So you're getting 10MPG more!
Title: Re: Giving 97 Octane a try.
Post by: Jocko on July 06, 2019, 02:28:57 PM
Basically I try to avoid using the brakes as much as possible. Anticipation and lifting off early make a huge difference. I also make great use of Deceleration Fuel Cut off. The more use you can make of DFCO the better. It is like coasting in neutral, with the engine off, except you are in full control of the car.
The Mk 1 doesn't have an Instantaneous so I fitted a ScanGauge E which displays the Instantaneous and average mpg for a trip.

(https://i.imgur.com/qV2N6DN.jpg?1)

Today I started out with a trip to the local supermarket, then on to The Western General in the centre of Edinburgh. From there I went down through Granton, Newhaven, Leith and Seafield, then on to Danderhall. I came home via the A720 City Bypass, M8, M9, M90, Cueensferry Crossing, A92 then back through Auchtertool. According to the ScanGauge I covered 73.7 miles in 2 hours 20 minutes driving, max speed 63 mph, average speed 32 mph, and average of 64.6 mpg. I intentionally drive for fuel economy so I am disappointed when the big numbers don't materialise!
Title: Re: Giving 97 Octane a try.
Post by: Jocko on July 18, 2019, 09:31:41 AM
First top up after changing to 97 octane. 61.3 mpg, calculated. No better than 95 octane so far but we will see how it goes. 97 octane up to £1.327/litre hereabouts.
Title: Re: Giving 97 Octane a try.
Post by: peteo48 on July 18, 2019, 09:51:00 AM
I put some Irish petrol in again last week (Apple Green) and decided to use their 97 Octane. It is 9 pence per litre dearer than the 95 RON so a similar price differential to the big brands. Supermarkets only charge 5 pence per litre extra.

I think I'm getting the placebo effect. The car seems to have slightly more pep!
Title: Re: Giving 97 Octane a try.
Post by: Jocko on July 18, 2019, 01:01:27 PM
I think I'm getting the placebo effect. The car seems to have slightly more pep!
I am going to run a few tankfuls of 97 before changing back to 95. See if I feel the opposite effect. I felt it had more pep too, but now it just feels ordinary.
Title: Re: Giving 97 Octane a try.
Post by: peteo48 on July 18, 2019, 09:12:31 PM
Yes - think I'll do the same. My small mileage means that, cost wise, it's an affordable experiment. As you suggest the real test will be if you feel a pronounced dip after going back on 95.

What might work would be a blind "tasting" where you didn't know what was in your tank and had to identify the cooking petrol from the posh stuff.
Title: Re: Giving 97 Octane a try.
Post by: Jocko on August 26, 2019, 04:30:42 PM
I am still running 97 octane fuel. It is just from my local supermarket so no super additives.
That is seven tankfuls now (my mother-in-law is buying the petrol since we are visiting most days - 80 plus miles round trip), and I am getting great mpg. Mind you, the weather and traffic patterns are helping.
Today's top up took my Fuelly average, for the last 10 tankfuls, to over 60 mpg. I'll run for 10 tanks of 97 octane, and see what my 10 top up average works out at, before returning to 95 octane.

(https://i.imgur.com/2gT2lvY.jpg)
Title: Re: Giving 97 Octane a try.
Post by: VicW on August 26, 2019, 07:23:31 PM
How much extra are you paying for your 97 fuel, is it cost effective?

Vic.
Title: Re: Giving 97 Octane a try.
Post by: Jocko on August 26, 2019, 07:33:02 PM
is it cost effective?
Unfortunately not. I have to average about 64 mpg to break even.
Title: Re: Giving 97 Octane a try.
Post by: peteo48 on August 26, 2019, 07:35:56 PM
Think Jocko is using Morrisons 97. I've been using Sainsburys 97 and the price premium is 5 pence per litre. On the additives thing, only Tesco claim that their 99 Momentum has additional additives.

My experiment stymied last week. Had a 10 pence per litre discount at Sainsburys but pulled up at wrong pump and the petrol station was busy so put 95 in.
Title: Re: Giving 97 Octane a try.
Post by: Jocko on August 26, 2019, 08:11:55 PM
Morrisons 97 Octane is currently £1.337, here in Kirkcaldy. I think 95 octane is £1.267 or £1.277, but I cannot be sure. I'll check tomorrow.
Title: Re: Giving 97 Octane a try.
Post by: Jocko on August 28, 2019, 08:22:37 PM
Petrol is £1.337/litre for 97 octane and £1.277/litre for 95 octane, at my local Morrisons.
If I take my average over the 6 tankfuls of 97 octane (61.9 mpg) and compare it to the 6 tankfuls of 95 octane immediately prior to the change (57.5 mpg) then it does make 97 octane economically viable. However, I am not sufficiently convinced that the slight advantage is not just down to type of miles/length of journeys/weather.
Title: Re: Giving 97 Octane a try.
Post by: 123Drive! on August 28, 2019, 09:11:47 PM
As mentioned before, I use Shell V-Power and always finds it more powerful on my 09 i-shift. Due to geographic reasons, I haven't been using V-POWER on my manual Seat Ibiza but last week filled up £60, yes I know-expensive, to the top. Wow! The car suddenly changed and was alot faster. As driving school cars, it's hard to see if I get the extra mpg but on the Ibiza, you could feel the pupils going a lot faster when using V-POWER. The only problem now is that the new Shell points card is not as competitive as it was so I wouldn't go out of my way to fill V-POWER.
Title: Re: Giving 97 Octane a try.
Post by: sparky Paul on August 28, 2019, 09:34:44 PM
As driving school cars, it's hard to see if I get the extra mpg but on the Ibiza, you could feel the pupils going a lot faster when using V-POWER.

Is that a good thing?  ;)
Title: Re: Giving 97 Octane a try.
Post by: 123Drive! on August 29, 2019, 11:43:14 PM
As driving school cars, it's hard to see if I get the extra mpg but on the Ibiza, you could feel the pupils going a lot faster when using V-POWER.

Is that a good thing?  ;)

Lol! At least the petrol is being tested by a 3rd party, so not bias!

Not a good thing when the car seems to go faster but at least it shows V-POWER does work.
Title: Re: Giving 97 Octane a try.
Post by: madasafish on August 30, 2019, 12:52:07 PM
I keep exact records (Fuelly) and over a decade plus, seen no change in mpg using 97 or 95 Octance od VPower.

I read tales of improvement and look for teh consumption numbers. If none are quoted, then my opinion is no facts =bull excrement..

My long trem Mark 3 averages 43mpg over a year (or slightly less)..and has fone for s8x years.. whatever petrol I use..The journeys are the same, teh driver is teh same and teh results are the same.
Title: Giving 97 Octane a try.
Post by: jazzway on August 30, 2019, 01:41:26 PM
As mentioned before, I use Shell V-Power and always finds it more powerful on my 09 i-shift. ....
Here the same with our i-shift — that is, more power or more mpg.;)

As we live in the south east of the Netherlands i fill the tank in Belgium with Shell V-Power (98) or in Germany with Aral SuperPlus (98) = BP.
Both these fuels are €0.10/€0.15 per liter cheaper than the normal Euro95 fuel in the Netherlands.
Title: Re: Giving 97 Octane a try.
Post by: Jocko on October 08, 2019, 04:45:04 PM
Well that is 10 tankfuls of 97 octane used up so I decided to revert back to 95 octane.
For the 10 tankfuls I averaged 61.4 mpg as my Fuelly page shows.

(https://i.imgur.com/HcNIj6m.jpg)

I did not notice any deterioration in performance today, though the ScanGauge was showing slightly poorer mpg, however, that may have been more to do with the slightly damp start to my journey and the gale force winds (Forth Road Bridge closed to double deckers).
I know that the mpg is going to drop over the next few tankfuls irrespective of whether I put 95 or 97 in. It has already started to drop over the last two tanks, with the onset of the colder, autumnal weather.
I will certainly update this thread as I go on.
Title: Re: Giving 97 Octane a try.
Post by: Jocko on October 11, 2019, 08:34:29 AM
Worked out my cost per mile for my last tank of 97 octane refilled with 97 octane, and it equated to 9.84p/mile. Once I do my second top up I will see what it costs using 95 octane.
Hopefully I will be able to work out the ratio and compare that to the ratio in price per litre.
Title: Re: Giving 97 Octane a try.
Post by: Jocko on October 20, 2019, 02:13:18 PM
Did my first top up after a tankful of 95 octane and the cost worked out at 9.38p/mile, so not a lot in it. Over 12,000 miles it is only about £55 difference from using supermarket 97 octane, the 95 octane working out cheaper.
The jury is still out over whether I have noticed a drop in performance since reverting back to 95 octane. I would say yes, but there is a marked drop in the temperature since changing back and whereas I was normally running two up I am now carrying a second passenger, and another body in a 1.2 litre car does make a difference.
So 97 octane or 95 octane? I would say you pays your money and takes your choice.