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Super unleaded vs normal


Vicki350

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What Veilside said ^^

 

Iv been keeping all my fuel receipts which il happily pass to the next owner (which isn't going to happen anytime soon)! I feel I haven't bonded with any of my other cars like the zed. It's unique. Id much rather garage it and buy another car than sell it.

 

I kinda wish I'd kept my first car which I px'd for £200 just for those memories lol kept it under a sheet for a rainy day :p

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Problem is having bought a second hand Z service history or not, we don't know if the car has been run on Super Uleaded ever since new. :wacko: :wacko: :wacko:

 

So might as well use 95 ron?

 

That statement is true but still best use super juicy petrol from now on.

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AFAIK not being an expert but running lower RON on older Zeds will cause longer term damage via knock/detonation but newer Zeds have knock control and can retard the timing - Mark at Abbey once showed me a destroyed zed engine that ran for too long on 95 - ultimately though you will not get the best performance or MPG out of the car mapped to higher RON and running it on 95, you wont save all the difference at the pump as your mpg will likely reduce.

 

I always find scrimping on fuel confusing, buying a heavy car with a V6 mapped to 97 RON means a sizable outlay in fuel, the mindset should be that you are putting in 97 at the pump.

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It's not all doom and gloom.

If I remember correctly the damage only occurs higher up the rev range around 4k.

So if it was occasionally run on normal but not driven hard there would be less chance of damage than if redlined frequently on normal unleaded.

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Its not the cost/difference between normal and super that's the issue, its the regularity that you visit (in our cars.. a lot) so doesn't actually matter money wise that much what you put in, just depends how often you drive it (possibly how you drive it too). So you may aswell stick the recommended stuff in

If you've spent a good few thousands on a car and it says and you see with research to use the super... would you risk buggering the engine?... I know I wouldn't lol

 

In terms of buying 2nd hand it is a risk but just check its running ok and start firing the good stuff in. I bought mine with less than 16K so no idea what was getting put in...I've some hope as whomever it was knew some stuff... they took the crap stock tyres off and put all 4 on FK452's.

 

I do sometimes wonder why they got rid of this car after only 15K odds though (clutch and akward traffic driving maybe :lol: )

Edited by AMT
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Problem is having bought a second hand Z service history or not, we don't know if the car has been run on Super Uleaded ever since new. :wacko: :wacko: :wacko:

 

In general, most first owners will use the recommended fuel, there will be of course some that don't. The problem gets more serious when the residual value of the cars drop and new owners who underestimate running costs will start taking shortcuts to save money. You could buy a Zed with a complete set of fuel receipts but there's no guarantee that the owner before him/her has run on 97 RON. With a few exceptions,maybe as many as 20 in 9 years when our local garage has run out of 97 RON mine has been run on the good stuff from new but I've never kept receipts, I'm not that well organised :lol: .

 

Pete

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Problem is having bought a second hand Z service history or not, we don't know if the car has been run on Super Uleaded ever since new. :wacko: :wacko: :wacko:

 

Make sure to pay the extra and purchase a low mileage car to limit risk then. Its not an on/off scenario it build up over time afterall ;)

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As someone said - it's printed on the inside of the fuel flap. The idea of "not knowing" a cars previous means you'll not bother "incase" is ridiculous.

 

If you're going to use "normal" to save a few pennies here and there after buying a Z with its high tax, insurance, and maintenance costs - then saving pennies on fuel is, frankly, nuts. You bought the wrong car for your budget.

 

Buy a cheap-to-run and maintain daily instead. So I'd definitely recommend using super and enjoy the point of owning the car :)

Edited by Mike
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AFAIK not being an expert but running lower RON on older Zeds will cause longer term damage via knock/detonation but newer Zeds have knock control and can retard the timing - Mark at Abbey once showed me a destroyed zed engine that ran for too long on 95 - ultimately though you will not get the best performance or MPG out of the car mapped to higher RON and running it on 95, you wont save all the difference at the pump as your mpg will likely reduce.

 

I always find scrimping on fuel confusing, buying a heavy car with a V6 mapped to 97 RON means a sizable outlay in fuel, the mindset should be that you are putting in 97 at the pump.

As I remember Docwa said to me that you always need to remember there are knock sensors and knock sensors.

 

Remember as well that for a knock sensor to work the engine is already experiencing knock.

 

Knocks not great for the engine but the bigger issue is preignition can be caused by long term knock due to improper fuel use.

 

Knock - abnormal combustion outside of the combustion front in the combustion phase of the cycle (I.E the upper part of combustion stroke/start of exhaust stroke).......so abnormal but piston still travelling away from the combustion front

 

Pre ignition - ignition of fuel and air on the upstroke of the piston before the spark plug fires causing a combustion front headed downwards towards an upstroking piston.......kabooooooom engine dead.

 

RON of the fuel determines it's compression tolerance if you like. Lower octane is tolerant to less compression.

 

Use lower octane in a zed and when lashing it and the compression/temperatures rise....fuel puts up less of a fight before blowing it's load.

 

Knock (can be less serious if not severe knock) can cause damage to piston and combustion chamber giving sharp edges, irregular surface, and damage to the cylinder boundary layer of gas. Then you're into danger of preignition

 

A knock sensor won't do jack for a pre - igniting cylinder as far as im aware.

 

Prob not 100% accurate but thst should sort of get you there in layman's terms!

 

Sent from my SM-G900F using Tapatalk

Edited by Ricey@revolveautomotive
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Pre ignition - ignition of fuel and air on the upstroke of the piston before the spark plug fires causing a combustion front headed downwards towards an upstroking piston.......kabooooooom engine dead.

 

 

Otherwise known as 'Pinking'.

 

Some kind person in Pistonheads describes it well:

 

'Pinking' or Pre-ignition is when the temperature/compression combination within the cylinder is high enough to cause ignition of the fuel/air mixture, without the use of a spark plug.

The main issue is that pinking tends to be uneven in its combustion with little micro-explosions. If this explosion occurs close to a surface it causes pitting, too much and it can cause the holes in pistons mentioned above.

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See I think that's a bit of a muddled explanation but someone with more nouse might be able to clarify.

 

Pinking is knocking......not pre - ignition.

 

Knock (pinking) occurs on the down stroke once the sparky has fired but the combustion is abnormal (hence you get pressure spikes which cause a knock or pinging sound). This in small doses is not usually catastrophic and knock sensor reports back to the engine which adjusts the timing. Cumulative effect can cause what the chappy above has said, some symptoms of which can lead to preignition

 

Pre ignition occurs before the sparky fires on the upstroke which is why is far more catastrophic. The air fuel mixture doesn't just abnormally combust it combust when it shouldn't and therefore sends a combustion front hurtling full pelt towards and upstroking piston

 

 

 

Sent from my SM-G900F using Tapatalk

 

 

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