Petrol

[Dangerous Dave]

As the owner of a Mondeo 2.2 TDCi and having done 21k since I got the car, using only supermarket fuel & the occasional bottle of diesel cleaner (Redex etc) I can tell you that my EGR is almost clean too as I changed all my boost pipes for silicone ones recently. EGRs clean themselves provided you drive the car right meaning it gets hot enough to burn the crap off of itself. Blasting down the motorway for about 20mins @ 70mph will do just that.

It will be the redex cleaner that is helping your's, they certainly don't keep themselves clean even if driven fairly hard I've helped swap a few and they are normally a mess inside.

I've thought about trying a bottle of additives instead of the odd few tanks of BP Ultimate or V Power diesel but don't want to risk the warranty on the car when it says add no additives on the filler cap.

 

[mccarf]

That CSL is a remapped car. Running it on 95 Ron will make less power than a standard car running 95ron as the ecu will be retarding the ignition.

Never let the truth get in the way of a good story.

Fair, I did miss that bit which explains the enormous increase. The other car is a standard MR2 with 175bhp and it did have 8bhp gains which is still pretty decent for spending very slightly more on fuel.

 

[Alibaba99]

Depends how high the engine's compression ratio will go as to whether the ECU will actually make use of the extra RON. Most engines (as standard) probably won't go high enough to see a benefit. Usually you find high reving NA engines need it.

Why do you constantly insist on spouting this rubbish? Turbo charged cars will benefit from higher octane fuel as they will reach det before MBT. Increasing the resistance to det will allow more torque for a given boost level due to advancing the timing or allow boost to be reduced.

 

[theone8181]

I got a 10% increase in mpg going from regular to vpower (20 upto 22) on my 996 turbo. I run my M3 on vpower too, just go with whats on the cap as thats whats its optimised for, i suspect if it says 95 on there, premium will make no difference (happy to be proved wrong on this however).

 

[TheVoice]

I don't notice a difference in my Mazda 6 2.0 and I vary between Asda, Tesco and "Applegreen" standard petrols with almost no consecutive tanks being the same stuff.

What year? Mine was a 2007, no idea how the engines vary but it was noticeable. If I used regular fuel from any other place it was fine.

 

[Skillmister]

What year? Mine was a 2007, no idea how the engines vary but it was noticeable. If I used regular fuel from any other place it was fine.

2008

 

[adam cool dude]

My Saab 9-5 Aero asks for the good stuff as the Trionic ECU can adjust for it. Google "Saab Thinners" to see the improvement of increased octane.

My little Suzuki Ignis Sport with its paltry 120 BHP also states to use 98 Ron. Can't say I notice a difference but it helps considering it runs a 11:1 compression ratio.

 

[Mercenary Keyboard Warrior]

My Saab 9-5 Aero asks for the good stuff as the Trionic ECU can adjust for it. Google "Saab Thinners" to see the improvement of increased octane.

My little Suzuki Ignis Sport with its paltry 120 BHP also states to use 98 Ron. Can't say I notice a difference but it helps considering it runs a 11:1 compression ratio.

Isn't the Jap lower grade petrol something like 91, and their premium like 98-101 (iirc)

So only really untuned engines should run on the normal stuff and anything like a turbo engine etc will want their premium grade, to help reduce knock?

I seem to recall that the old WRX said 98RON was well, but when people cracked the code in the ECU they found the WRX imports had exactly the same software as the UK models, its just the UK ones would retard back based on 95RON (as would the WRX).

 

[Frozennova]

Isn't the Jap lower grade petrol something like 91, and their premium like 98-101 (iirc)

So only really untuned engines should run on the normal stuff and anything like a turbo engine etc will want their premium grade, to help reduce knock?

I seem to recall that the old WRX said 98RON was well, but when people cracked the code in the ECU they found the WRX imports had exactly the same software as the UK models, its just the UK ones would retard back based on 95RON (as would the WRX).

The Subaru ECUs have two ignition tables, after an ECU reset they have an ignition multiplier that starts at 1 then as the car is driven between certain RPM and load sites the IAM will increase unless feedback knock correction logs knock.

It wont switch over to the High KCA ignition table until an IAM of 8 is reached IIRC. If there is logged FBKC at an IAM of 1 then it drops to 0 and electronic boost control is disabled.
Some of my specifics might be a little bit off, but that's the rough workings of subaru knock control

 

[Mercenary Keyboard Warrior]

The Subaru ECUs have two ignition tables, after an ECU reset they have an ignition multiplier that starts at 1 then as the car is driven between certain RPM and load sites the IAM will increase unless feedback knock correction logs knock.

It wont switch over to the High KCA ignition table until an IAM of 8 is reached IIRC. If there is logged FBKC at an IAM of 1 then it drops to 0 and electronic boost control is disabled.
Some of my specifics might be a little bit off, but that's the rough workings of subaru knock control

Cheers, long time since i was up to date with that (like 15 years lol)

I do remember the old battery disconnect, then it would go better trick.

 

[NickXX]

All beers are the same water until they add additives. Its a National UK fuel pool too

No debate on long term use

I don't understand this - what additives would Shell/BP add over the fuel that they supply to Tesco/Sainsbury's. Also why would they go to the effort of adding it? I don't know what they would have to gain from it, as 99% of consumers do not care.

 

[Nasher]

I don't understand this - what additives would Shell/BP add over the fuel that they supply to Tesco/Sainsbury's. Also why would they go to the effort of adding it? I don't know what they would have to gain from it, as 99% of consumers do not care.

It's really hard to find any solid information on it. Probably because it's all the same with slightly varying RON levels.

 

[Mercenary Keyboard Warrior]

Well number 1 is marketing. If you can convince people of an added value then you have a start in justifying a price premium.
So these fuels being "better" is mainly that, because the majority of what the fuel must and must not be is covered by legislation, things like sulfur content

But that being said bad fuel will cause you problems.

Its things like the cleaners being added benefit. I remember years ago when these were not added, was a massive industry trying to convince people that a little bottle would miraculously fix their car, these still exists but i think struggle with the main fuel companies now mainly promoting this as a benefit.

There are things that can be added to fuel, look to why F1 banned this, that changes the way it works, so its completely possible to affect the way it burns within reason.
Things like being clean will keep things like spray patterns correct, but if they are clean they are clean, at that point the added cleaners are doing nothing. If you get some bad fuel then when you next fill up one with added cleaners is likely to be beneficial.

 

[jpaul]

I don't understand this - what additives would Shell/BP add over the fuel that they supply to Tesco/Sainsbury'sr

... see links in petrol thread from last month https://forums.overclockers.co.uk/threads/keeping-a-direct-injection-engine-healthy.18826815/

 

[Iamzod]

As the owner of a Mondeo 2.2 TDCi and having done 21k since I got the car, using only supermarket fuel & the occasional bottle of diesel cleaner (Redex etc) I can tell you that my EGR is almost clean too as I changed all my boost pipes for silicone ones recently. EGRs clean themselves provided you drive the car right meaning it gets hot enough to burn the crap off of itself. Blasting down the motorway for about 20mins @ 70mph will do just that.

I think my old car may have been the one referred to in the post you replied to. It used to smoke far less on V-Power when flooring it than it did on the odd time i got caught short nowhere near a Shell or BP station.

I can't remember the exact mileage as it's been over a year since i stripped it for parts after the DMF started to die but it would still return 65mpg on a run, pretty sure it was on 268k.

My ST220 likes to throw up the EML when running on 95 fuels, it either complains about a misfire or dodgy O2 sensor readings.

 

[Psycho Sonny]

This makes no sense. The engine oil is largely irrelevant to many fuel cleanliness issues

What do people mean by premuium too? In a bog standard car I’d much rather a 95 ron decent brand fuel than supermarket high octane. And there is no way I’m touching super market diesel.

This isn’t even about what you notice short term as a driver. This is about maintaining performance and keeping the engine running as it should.

yes i know that.

premium fuel is for premium cars or tuned cars, etc.

rather than wasting money on premium fuel for a "standard or average" car in order to get more life out of it. probably best to spend that money on more regular servicing with better fluids. like premium engine oil

 

[Nasher]

Another thing is if it actually does keep the engine cleaner, you need to keep using it. Just doing a tank of premium once in a while won't help. Once buildup is there, it's unlikely to shift it on it's own.

 

[Resident]

I think my old car may have been the one referred to in the post you replied to. It used to smoke far less on V-Power when flooring it than it did on the odd time i got caught short nowhere near a Shell or BP station.

I can't remember the exact mileage as it's been over a year since i stripped it for parts after the DMF started to die but it would still return 65mpg on a run, pretty sure it was on 268k.

My ST220 likes to throw up the EML when running on 95 fuels, it either complains about a misfire or dodgy O2 sensor readings.

My 2.2 has just hit 125k. I replaced the DMF at the same time as the clutch at 121k.

Mine doesn't smoke at all that I can notice and I drive it pretty hard

The only supermarket fuel I've had issue with was Tescos. Felt severely underpowered as though it was in limp mode.

 

[Simon]

It's really hard to find any solid information on it. Probably because it's all the same with slightly varying RON levels.

Wrong. Some oil companies have bespoke additives. Oxygenates are also used to control RON. The base fuel can vary depending on refinery output. Also winter fuels differ to summer grades

Another thing is if it actually does keep the engine cleaner, you need to keep using it. Just doing a tank of premium once in a while won't help. Once buildup is there, it's unlikely to shift it on it's own.

Clean up of existing deposits is possible with good detergent systems.

yes i know that.

premium fuel is for premium cars or tuned cars, etc.

rather than wasting money on premium fuel for a "standard or average" car in order to get more life out of it. probably best to spend that money on more regular servicing with better fluids. like premium engine oil

When you say premium what do you mean. You imply premium is high octane. But I’d rather a 95 ron branded than high octane one. The impact on efficiency is one thing but on direct injection engines the use of crappy fuels causes massive increase in PM10 emissions. My view is the government should be going after this rather than worrying about brand new vehicle emissions.

Saving money in fuel also helps you pay for a window cleaner on your house too. It’s about as relevant to the fuel system as engine oil.

A well known tier one supplier of diesel injectors banned their employees from using supermarket fuels in test cars due to the potential for injector failures.

 

[Psycho Sonny]

Wrong. Some oil companies have bespoke additives. Oxygenates are also used to control RON. The base fuel can vary depending on refinery output. Also winter fuels differ to summer grades


Clean up of existing deposits is possible with good detergent systems.



When you say premium what do you mean. You imply premium is high octane. But I’d rather a 95 ron branded than high octane one. The impact on efficiency is one thing but on direct injection engines the use of crappy fuels causes massive increase in PM10 emissions. My view is the government should be going after this rather than worrying about brand new vehicle emissions.

Saving money in fuel also helps you pay for a window cleaner on your house too. It’s about as relevant to the fuel system as engine oil.

A well known tier one supplier of diesel injectors banned their employees from using supermarket fuels in test cars due to the potential for injector failures.

Premium would be stuff like v power, Bp ultimate and 99 momentum.

All of which have many more cleansing properties than their non premium counterparts.

The whole supermarket fuel being bad is a myth. It's just that premium removes carbon build up. We have a golf TDI we have had from new in 2003 run on nothing but Asda fuel and its injectors are fine. It's done nearly 200k miles too.