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unleaded 95 or super 98 octane?


chips

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Judging by the frequency with which the topic is raised on here, that's probably a conservative estimate...

very happy to be able to say that's not the case with me having covering those 2 cap and manual reading in the opening post :lol:

but i get the feeling a lot of responses didn't read the O.P. also.

anyway, on a more positive note, I managed to feed it some 97 on the weekend.

and the subjective (knowing of the change in fuel type gone in) immediate seat of pants feeling was that it was more lively and responsive.(faster revving, sharper response, larger range of power)

given that i've recently found out that the fuel sensor detects and adjusts maps that will protect the engine if needed and performance to suit that should be the case.

I'm sold on it!

now just to release the gag :shutup: to hear what's going on rather than just B) the action on the tacho!

Edited by chips
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So why 3-4 years back did cars coming out of Tesco have problems which were identified as being caused by the petrol ? Supplied by a company called Greenergy, a trader. As I said there are ways and means of meeting standards and there are plenty of traders out there who know how and are only interested in making a buck. Traders may not want to be known as Pikey Teds , they are substantially more sophisticated than that !

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Because no company is perfect, and mistakes happen. I think you'll find that every retailer, including the big boys, have had issues with their fuel at some point: It just doesn't get publicised as much.

 

I know for a fact that a couple of years back my local BP had to sort a few people out due to engine damage caused directly by iffy fuel. Doesn't stop me using them still.

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So why 3-4 years back did cars coming out of Tesco have problems which were identified as being caused by the petrol ? Supplied by a company called Greenergy, a trader. As I said there are ways and means of meeting standards and there are plenty of traders out there who know how and are only interested in making a buck. Traders may not want to be known as Pikey Teds , they are substantially more sophisticated than that !

 

Traders gain and lose reputations and when it is the latter and have been badly 'bitten' survival is likely to mean they will make doubly sure there is no repeat. Lancia is a good example where they ignored the rusting issues that then led to their demise in this country.......

 

I have never had any issues using Tesco Momentum in my ZEDs - it was either that or Shell Opitmax/V-Power, with only a couple of top-ups with 95 in the depths of Scotland and I had an uprev setting on the 370 for that RON.

 

Just cannot understand why owners should skimp a few pence on theur fuel..... but it does make you wonder if they then skimp of other running costs.... :shrug:

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ok, so refineries of majors might make a mistake but if you are trying to tell me that traders/supermarkets consistently supply fuels of as good a quality as the majors then, I think you are wrong. Cars nowadays usually pass the 80k mileage mark with the fuel purchase often unclear. Buy a car from new and run it on supermarket fuel only or a majors fuel only and the supermarket one would fail soonest.

If you are a PHD chemist and have had 30 years working for a major oil company and been involved in dealing with traders, then I will bow to your knowledge

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Guy at work is a real skin flint, and ran his 2.7 Diesel A6 Avant on supermarket stuff (Asda) for as long as he had it. It started to develop a real problem, and he must have spent £1000 taking it to garages, and getting things replaced. He was almost out of fuel one day, nowhere near Asda, so filled up with Shell standard stuff. The next day, the issue he had being trying to solve had gone. Was the fuel.

Also, in F1 ( i know we dont run F1 cars), some teams are finding serious performance from just changing fuel, as much as 50hp in some cases, its unreal. Just goes to show, fuel is not just fuel.

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My neighbour has a subaru wrx, doesn't look after it. The tyres he used were remoulds, and always the cheapest fuel. Needless to say hes got tiny metal shards in his oil. Only a matter of time!

 

Painful to see somone not look after their car like that, he bought it brand new for 24 grand in 1999. All he had to do was fill it with the right petrol, thinking on he never had it serviced either....... :scare:

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My neighbour has a subaru wrx, doesn't look after it. The tyres he used were remoulds, and always the cheapest fuel. Needless to say hes got tiny metal shards in his oil. Only a matter of time!

 

Painful to see somone not look after their car like that, he bought it brand new for 24 grand in 1999. All he had to do was fill it with the right petrol, thinking on he never had it serviced either....... :scare:

that really doesn't sound like a petrol problem though

Edited by ioneabee
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If that is your background Jeff E, then I'm even more surprised you're not aware of the basics such as the BS numbers in use, and the testing procedures involved in obtaining one.

 

Is supermarket fuel the same quality as big brand fuels? Probably not, that's why it's cheaper. Is it of a sufficiently decent quality to use in every single car produced in the last 20 years, including performance ones? Of course it is, and to suggest otherwise is nonsense. If you want to needlessly spend the extra money then please do so, but don't try and skip the obvious basic details in an attempt to fool the members on here: They're not as daft as you think.

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Guy at work is a real skin flint, and ran his 2.7 Diesel A6 Avant on supermarket stuff (Asda) for as long as he had it. It started to develop a real problem, and he must have spent £1000 taking it to garages, and getting things replaced. He was almost out of fuel one day, nowhere near Asda, so filled up with Shell standard stuff. The next day, the issue he had being trying to solve had gone. Was the fuel.

Also, in F1 ( i know we dont run F1 cars), some teams are finding serious performance from just changing fuel, as much as 50hp in some cases, its unreal. Just goes to show, fuel is not just fuel.

 

So are you trying to tell us that everyone who used that Asda garage was having the same problem? Really? I can believe a bad batch once in a while but consistently bad fuel over a period of weeks or months is a bit difficult to accept, think how many people must have filled up over that time at all the Asdas in the country.

And comparing F1 cars and their fuel to 350Z's and what comes out the pump at Asda isnt really relevant, I could get another 50hp out of my 1 series with race fuel and a remap.

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I have no idea about other people, but all i know is, he had a 20minute trip to work for 5-6 years, always filled up with the same fuel, at the same station, and his car developed an issue that no garage could cure. He put a tank of Shell in his car, and after some driving the issue went away. That is what happened. Im not going to say anything else, other than they are the facts,i was sharing an experience.

I know comparing a F1 car to road cars is abit pointless, but was just making it obvious that fuel can make a huge difference to an engine, regardless of its application. Mark at Abbey found that when he disected a DE engine run on 95octane fuel that had blown up.

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I have no idea about other people, but all i know is, he had a 20minute trip to work for 5-6 years, always filled up with the same fuel, at the same station, and his car developed an issue that no garage could cure. He put a tank of Shell in his car, and after some driving the issue went away. That is what happened. Im not going to say anything else, other than they are the facts,i was sharing an experience.

I know comparing a F1 car to road cars is abit pointless, but was just making it obvious that fuel can make a huge difference to an engine, regardless of its application. Mark at Abbey found that when he disected a DE engine run on 95octane fuel that had blown up.

 

I am not an expert by any means but that is because the DE doesnt have the sensor to deal with lower grade fuel in a car set up for higher grade at high revs. The later engines do. Although I am not sure what that has to do with the quality of fuel across companies. Just because Shell might theoretically give better bhp than say Tesco I am not sure how that equates to Shell elongating the life of the engine?

 

I use random places for fuel, wherever I happen to be when I need it. Shell is just 30 seconds drive from me so I usually fill up there but would have no qualms with using Tesco, BP etc.

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I have no idea about other people, but all i know is, he had a 20minute trip to work for 5-6 years, always filled up with the same fuel, at the same station, and his car developed an issue that no garage could cure. He put a tank of Shell in his car, and after some driving the issue went away. That is what happened. Im not going to say anything else, other than they are the facts,i was sharing an experience.

I know comparing a F1 car to road cars is abit pointless, but was just making it obvious that fuel can make a huge difference to an engine, regardless of its application. Mark at Abbey found that when he disected a DE engine run on 95octane fuel that had blown up.

 

I am not an expert by any means but that is because the DE doesnt have the sensor to deal with lower grade fuel in a car set up for higher grade at high revs. The later engines do. Although I am not sure what that has to do with the quality of fuel across companies. Just because Shell might theoretically give better bhp than say Tesco I am not sure how that equates to Shell elongating the life of the engine?

 

I use random places for fuel, wherever I happen to be when I need it. Shell is just 30 seconds drive from me so I usually fill up there but would have no qualms with using Tesco, BP etc.

I think you mean the knock sensor and unless I'm mistaken practically all modern cars have them.

 

The issue with 95 Ron in the DE is that it's tuned to run on the higher octane. Ignition timing, compression all that jazz. There's only so much the knock sensor can do to alter the timing to stop this from happening.

 

The ron of the fuel simply means that it can withstand higher temperatures. Ie if you put 95 Ron in a car which is set up to use 98 then you risk detonation in the chamber (abnormal combustion outside of the flame front) which can damage the piston, cylinder, sparks etc.

 

Detonation (which is always post combustion) can lead to preignition (pre combustion......ie piston on the upstroke) but it's far more catastrophic because the piston is then heading up towards combusting fuel/air.

 

 

I stand to be corrected by a more learned creature but I've spent hours reading about this recently and it's bloody complicated!

 

 

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Probably should mention that the knock (det) occurs then the unburned fuel and air th st is outside of the expanding flame front is met with hot gases and compression and therefore ignites abnormally causing an uneven combustion and pressure spikes.

 

Higher Ron will withstand the heat created by the compression and hot gases better.

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I think you mean the knock sensor and unless I'm mistaken practically all modern cars have them.

 

I stand to be corrected by a more learned creature but I've spent hours reading about this recently and it's bloody complicated!

 

Yep, although not all knock sensors are created equal - the old 200SX one didnt work at all, the DE one is crap but the HR one seems to be decent. They work by retarding the ignition if it senses knock, if this doesnt happen then you run the risk of serious piston/valve/chamber/big end damage.

 

The guy I bought my 135 from (mapped for V Power) said he was forced to use 95 RON for a week or so, after the 3rd tank the car just refused to rev past 6K at all - thats a PROPER knock sensor.

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I think you mean the knock sensor and unless I'm mistaken practically all modern cars have them.

 

I stand to be corrected by a more learned creature but I've spent hours reading about this recently and it's bloody complicated!

 

Yep, although not all knock sensors are created equal - the old 200SX one didnt work at all, the DE one is crap but the HR one seems to be decent. They work by retarding the ignition if it senses knock, if this doesnt happen then you run the risk of serious piston/valve/chamber/big end damage.

 

The guy I bought my 135 from (mapped for V Power) said he was forced to use 95 RON for a week or so, after the 3rd tank the car just refused to rev past 6K at all - thats a PROPER knock sensor.

So it's retarded meaning the spark happens later in the compression stroke meaning there's less time for hot gases to collect and the air/fuel is under less pressure for less time meaning less heat from both sources, therefore less chance of abnormally detonating?

 

For me to write nearly 4 paragraphs about det and for Doc to give the nod of approval this is a good day all round!

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For many of us the Zed is not a high mileage transport so 6000 miles a year may not be uncommon. Using official combined mileage consumption for a Zed ,24 mpg, this means you would buy 250 gallons per year (1136 l ) of petrol. So for every 1 p/l you pay for a majors fuel vs a supermarket fuel costs you £11.36 per year. So Ekona I am prepared "to needlessly spend " that amount of money to be assured of a quality product. You contradict yourself, post 18/1/15 quote " why would I not give a performance car the best " ?

Mercedes Benz, VW, Ford , Renault, Fiat etc have never, ever asked me about, or even mentioned, a BS standard in discussions with them. Have you read BS 228.2012 and BS 780.2006 ?

I am not trying to fool anybody nor trying to imply, as you insultingly suggest, that they might be "daft". Major oil companies fuels and oils are worth the extra cost. It may not be evident to you unless you are the unfortunate, down the ownership line, when it goes prematurely wrong.

I'm happily spending my £11.36 per year on my local Shell vs Tesco.

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Mercedes Benz, VW, Ford , Renault, Fiat etc have never, ever asked me about, or even mentioned, a BS standard in discussions with them.

 

Purely out of interest, care to expand on this? What "discussions" have you had with them and in what context?

 

It's just that in the current context, that is meaningless; they've never mentioned it to me either....

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