Post by: peteo48 on February 23, 2018, 05:20:49 PM
I'm thinking that this engine, more than the earlier cars, might benefit from premium fuel. Any views?
Post by: Downsizer on February 23, 2018, 06:11:02 PM
Post by: JazzandJag on February 23, 2018, 06:12:08 PM
Give it a go for a couple of tankfuls and then a tankful of 95 and see if you notice any difference.
Post by: culzean on February 23, 2018, 06:41:52 PM
The recommendation in the manual for the Mk3 is the same as for the other Jazzes - 95 Octane or higher but the compression ration has seen a sharp increase with the Mk3 - it's now 13.5:1 so really a pretty high CR.
I'm thinking that this engine, more than the earlier cars, might benefit from premium fuel. Any views?
Cars with CR as high as 13.5 are normally direct injection and avoid pinking by only injecting the fuel once the air in the cylinder is compressed, that way the fuel / air mixture cannot explode while it is being compressed. I don't know if new Jazz has direct injection but the only way to see if it is happier on 97 or 99 is to try it. Wait till tank is pretty low before changing fuel and give it a few miles to sort itself out, but try it on the steepest hills you can find to check for extra power and pinking (or lack of it).
I have seen a noticeable difference in 95 and 97 in both Jazz and Civic (both with 11:1 CR ) but its really up to you, I found that if you used the extra 'pep' you did not get more MPG, but you can notice that you need less throttle opening to achieve same speed on higher octane, may be more noticeable on CVT actauly than on a manual - check the revs needed for a certain speed under certain conditions (like up a certain hill or 70 on the motorway on comparable sections).
Post by: guest4871 on February 23, 2018, 09:45:25 PM
I use Shell V Power exclusively.
Not for any reason of performance or octane rating (which I think is probably a little "old hat" these days as explained above) but because of the quality of the additives.
I do a relatively low mileage so any difference in cost is relatively small and the additives work much better the older the car is.
Post by: mikebore on February 23, 2018, 09:46:20 PM
For years I believed that if it didn't pink there was no benefit in higher octane, BUT, as I understand it most modern engines automatically adjust the timing to just avoid pinking. If this is the case there is a technical reason why performance/economy might be better with higher octane, but I have not been able to detect it.
Post by: 123Drive! on February 23, 2018, 09:49:32 PM
Try it and see how it goes! Have fun.
Post by: Jocko on February 23, 2018, 10:31:47 PM
Post by: peteo48 on February 23, 2018, 10:47:12 PM
Post by: culzean on February 24, 2018, 07:38:07 AM
I switch between 95 and Super (97?....not seen 99 on a pump).
Tesco do 99 and I tried it once (we were passing the Tesco garage) when going to Wales with full load of passengers and luggage in the Civic, it just flew up those welsh mountains and even the steep and bendy road up to Harlech castle no bother, went up in a higher gear than I thought it would. There is actually less power 'contained' in higher octane because the additives to raise the octane either don't burn or are less powerful (ethanol) but by being able to advance the spark the engine can make much better use of the fuel. I tried high octane in one of my older motorbikes and it actually ran worse because with timing set for lower octane and no ECU / knock sensors it could not move the spark around. The closer the spark fires (retarded to stop knocking) to top dead centre of stroke the less time the charge has to burn properly and the more of its force is wasted. If spark fires too early (advanced) with lower octane the expansion of the igniting charge raises cylinder pressure and causes the lower octane around the edges to explode before it should, it then tries to push piston down the same way it just came up without passing TDC, the forces are large and that is why pinking / knocking can wreck your engine in very short order - by trying to reverse crankshaft every time a cylinder fires.
Post by: mikebore on February 24, 2018, 08:02:20 AM
Post by: peteo48 on February 24, 2018, 08:26:12 AM
I can't help feeling that if the benefit of 97/99 octane fuel was really as great as some people claim, then Honda would say something like "Recommended octane 97/99. Minimum octane 95", rather than let the vast majority of their customers drive around with a sub-optimal performance.
That's a very good point and some expensive cars often say premium recommended. The wording in Honda manuals (and also in Toyota) is "95 Octane or higher"
You can see why lawyers deal in semantics! What are they saying here? What does "or higher" mean? Anybody knows that you can put premium fuels in any car so why say "or higher?"
I don't think for one moment that 95 Octane from any supplier (like supermarkets) will do any harm but I wonder if there are benefits to be had. I bunged some Tesco Momentum in the car yesterday but it will be mixed in with whatever was left in by the dealer. Might go with, say, 3 tankfuls then go down to 95 and see if I notice anything.
Post by: mikebore on February 24, 2018, 08:29:07 AM
Post by: Jocko on February 24, 2018, 08:47:23 AM
Post by: Downsizer on February 24, 2018, 09:24:49 AM
Post by: Kenneve on February 24, 2018, 10:15:34 AM
However i did change over to 'branded fuel', and the 'odd' noises disappeared, not only that but the MPG improved as well, which covered the extra costs. So rightly or wrongly I've never used 'supermarket' fuel since.
However just to counteract that story, I've also heard that wherever you buy your fuel from, ie 'supermarket' or 'branded', the delivery tanker drivers, all fill up from the same tanks, at the fuel distribution centre, so is it all in the mind? :(
Post by: Jocko on February 24, 2018, 10:39:19 AM
Post by: guest1372 on February 24, 2018, 11:14:08 AM
I can say that there is little linking the brand names to the supply chains these days, Shell petrol won't be refined or drilled by Shell. The majority of forecourts are licensees, the operators may have many different brands in their group, but that doesn't mean everywhere sells the same thing, there are regional / seasonal differences that have greater variation than that between brands which have to comply with a fairly detailed standard.
Distribution is in the hands of just a couple of wholesalers now, the 'customer blend' is done at one stage before tanker fill to enable QC and standards to be monitored. UK petrol is now imported, our few remaining refineries mostly produce diesel based products and liquified petroleum gasses.
(My father spent most of his career with ExxonMobil special products division as a Chartered automotive engineer, he still gets quite a few trade magazines which I tend to browse)
--
TG
Post by: culzean on February 24, 2018, 12:10:44 PM
I can't help feeling that if the benefit of 97/99 octane fuel was really as great as some people claim, then Honda would say something like "Recommended octane 97/99. Minimum octane 95", rather than let the vast majority of their customers drive around with a sub-optimal performance.
Different areas / countries of the world have different grades of fuel available and car makers fettle their engines to run on what is expected to be available. This grade can probably affect performance and emissions so they have to be careful what they recommend - if they test their car on 97/99 and it is not likely to be available they will not recommend it , they will just state the minimum octane you should use that will not cause problems.
Post by: guest4871 on February 24, 2018, 01:08:10 PM
The additives part is all a bit mysterious, I compare it to Evian vs Volvic water, they're all fundamentally the same but one maybe tastes better? Or is it just marketing?
I can say that there is little linking the brand names to the supply chains these days, Shell petrol won't be refined or drilled by Shell. The majority of forecourts are licensees, the operators may have many different brands in their group, but that doesn't mean everywhere sells the same thing, there are regional / seasonal differences that have greater variation than that between brands which have to comply with a fairly detailed standard.
Distribution is in the hands of just a couple of wholesalers now, the 'customer blend' is done at one stage before tanker fill to enable QC and standards to be monitored. UK petrol is now imported, our few remaining refineries mostly produce diesel based products and liquified petroleum gasses.
(My father spent most of his career with ExxonMobil special products division as a Chartered automotive engineer, he still gets quite a few trade magazines which I tend to browse)
--
TG
A pretty accurate summary above of an extremely complicated subject.
Also remember that around the world the standard octane rating can be as low as 90.
Regular gasoline in Japan is 90RON, hence the indicator from Honda to use 95 RON or above.
What we get in UK is only either Premium at 95 and Super at 97/99 etc. Regular got dropped in the UK years ago.
Just to add to the fun, each brand's RON also varies by country!
And the brand formulation changes from summer to winter too.
For a broader insight see https://en.wikipedia.org/wiki/Octane_rating which covers the subject very completely.
The RON figure these days indicates the base product before additives. Try finding out what the additives are!
The higher octane ratings normaly have lower bio fuel (ethanol?) content.
Post by: peteo48 on February 24, 2018, 01:56:16 PM
It's clever marketing, especially to mildly OCD types like me but the Australian Motor pundit - John Cadogan (AutoExpert.com) calls it "weapons grade BS" - he did an item on BP Ultimate and made the point that by saying the top grade petrol was necessary to clean your engine they were effectively saying that their own regular fuel was rubbish!
Post by: Jocko on February 24, 2018, 02:50:38 PM
But it's up to you. You pay your money and take your choice.
Post by: culzean on February 24, 2018, 03:06:51 PM
I have used supermarket petrol "for ever", and never had the least bit of bother. I bought one car, with 100,000 miles on the clock, and ran it for another 100,000 miles, all on supermarket petrol. Never had the least bit of bother.
But it's up to you. You pay your money and take your choice.
https://practicalmotoring.com.au/car-advice/dirt-busting-fuel-fact-or-fiction/
(and its not from the Daily Mail)
As for injector cleaner..
Post by: jazzway on February 24, 2018, 04:13:33 PM
Living near the Belgium and German borders, i am cheaper with the V-Power tanked in Belgium than the regular 95 in the Netherlands.
Btw, i also think (and hope) that the better additives in Shell maybe prevent future problems with the fuel filter.
Post by: Skyrider on February 24, 2018, 04:56:07 PM
Post by: Jocko on February 24, 2018, 05:09:26 PM
For me it is simple. I don’t like ethanol in petrol! The Shell V-Power (98) i fill the tank with contains no ethanol. I get a little more noticeable MPG, some more power, but most important: NO ethanol.All fuel sold in the UK must contain a minimum of 5% bio fuel (usually Ethanol), so we have no option.
Post by: Skyrider on February 24, 2018, 05:17:36 PM
For me it is simple. I don’t like ethanol in petrol! The Shell V-Power (98) i fill the tank with contains no ethanol. I get a little more noticeable MPG, some more power, but most important: NO ethanol.All fuel sold in the UK must contain a minimum of 5% bio fuel (usually Ethanol), so we have no option.
E10 (10% ethanol) is in use in many countries, no doubt it will arrive here in due course.
Post by: culzean on February 24, 2018, 05:25:52 PM
For me it is simple. I don’t like ethanol in petrol! The Shell V-Power (98) i fill the tank with contains no ethanol. I get a little more noticeable MPG, some more power, but most important: NO ethanol.All fuel sold in the UK must contain a minimum of 5% bio fuel (usually Ethanol), so we have no option.
E10 (10% ethanol) is in use in many countries, no doubt it will arrive here in due course.
yeah, lets burn down even more rainforest to plant sugar cane to use for vehicle fuel - another great great idea by clueless legislators / politicians - with thousands of square miles of rainforest on fire it makes a mockery of worrying about climate change.
Post by: peteo48 on February 24, 2018, 05:47:44 PM
For me it is simple. I don’t like ethanol in petrol! The Shell V-Power (98) i fill the tank with contains no ethanol. I get a little more noticeable MPG, some more power, but most important: NO ethanol.All fuel sold in the UK must contain a minimum of 5% bio fuel (usually Ethanol), so we have no option.
E10 (10% ethanol) is in use in many countries, no doubt it will arrive here in due course.
yeah, lets burn down even more rainforest to plant sugar cane to use for vehicle fuel - another great great idea by clueless legislators / politicians - with thousands of square miles of rainforest on fire it makes a mockery of worrying about climate change.
Whilst I don't always see eye to eye with you on climate change I think you make a very valid point here. Never seen the logic of using food in cars!
Post by: jazzway on February 24, 2018, 07:27:55 PM
All fuel sold in the UK must contain a minimum of 5% bio fuel (usually Ethanol), so we have no option.In the Netherlands too. But exceptions are special fuels like V-Power, BP Ultimate, Firezone Competition 102 and maybe others.
E10 (10% ethanol) is in use in many countries, no doubt it will arrive here in due course.In Belgium the minimum is 10%, again with exceptions for special fuels.
Post by: culzean on February 24, 2018, 07:31:33 PM
This is not the original website I saw, which had a list of 'safe fuels' but it is another twist on the problem.
http://armchairbiker.com/ethanol-in-petrol-what-classic-bikers-need-to-know/
Post by: jazzway on February 24, 2018, 07:38:12 PM
Owners of classic vehicles including motorbikes have to be very careful not to put fuel containing ethanol into their tanks as it can cause seal failure and corrosion in fuel system - I saw a classic motorbike website a while ago with a list of fuels that did not contain ethanol.Exactly! When Belgium started with the 10% ethanol last year, there was a letter hanging at every fuel pump at Shell to use V-Power for classic cars etc because that contains no ethanol.
Post by: Jocko on February 24, 2018, 09:07:50 PM
I saw a classic motorbike website a while ago with a list of fuels that did not contain ethanol.I've seen that too (it appears to be a reprint of info I've seen from several years earlier) It is not the case in Scotland. All fuel in Scotland is supplies from Grangemouth and I believe Ethanol is added as a matter of course.