B9 S4- Which fuel?

S19 MYD

S19 MYD

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Interested to know if anyone has any varying experience with different fuels?

With the B7 S4 I religiously ran it on 97 and 99Ron fuels.

I’ve read that the B9 is mapped to run more efficiently on 95Ron.

Anyone got any views or differing experiences?
 
Had a quick look for a thread and you’ve shared 4! Read them all and think I’m further behind than I began lol.

Thanks mate. Looking like vPower.
 
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S19 MYD said:
Had a quick look for a thread and you’ve shared 4! Read them all and think I’m further behind than I began lol.

Thanks mate. Looking like vPower.
Click to expand...

. VPower on a stock engine is not going to give you any benefits as such. It neither improves your economy nor gives you an increased performance. Modern engines have sensors to automatically adjust their timing to suit different grades of fuel, but if they are optimised for the best they will always give inferior performance and poorer economy and emissions on poorer fuel.

I ran VPower on my stock S4 as well currently on the A3 that I have. However, on A3 is 1 tank of VPower after every 3 normal ones. One of the reasons for doing such is that VPower has more 'cleaning agents' compared to an Unleaded fuel. Although all manufacturers claim improved efficiency and performance it is yet to be proven.

It is an ongoing discussions on all car forums and unlikely going to get resolved even in this thread.

My S4 is tuned and is set to run on 99RON be it Vpower or Momentum (). I run it on VPower.
 
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Mine is tuned with a full Milltek runs noticeably better on 99. Stock it didnt make any real noticable difference. My stock Golf R however ran much better on 99 than standard - it was more responsive. It's a minefield of a subject as mentioned above!
 
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I ran Vpower religiously for around 5 months then began going for the most convenient option instead as the Shell garage is 5 miles from my house. I noticed my average MPG dropped from 36mpg to around 31mpg on Momentum and Esso premium. One thing that did surprise me was the car would pop/bang a lot more on Momentum. As for Esso premium...it’s crap.

Back on Vpower now after getting a £10 voucher through loyalty points. The difference is night and day.
 
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StretchS4 said:
I ran Vpower religiously for around 5 months then began going for the most convenient option instead as the Shell garage is 5 miles from my house. I noticed my average MPG dropped from 36mpg to around 31mpg on Momentum and Esso premium. One thing that did surprise me was the car would pop/bang a lot more on Momentum. As for Esso premium...it’s ****.

Back on Vpower now after getting a £10 voucher through loyalty points. The difference is night and day.
Click to expand...

Thanks for all the feedback. Stretch is yours stock?
 
The difficulty with owners assessing different fuels is there can be so many variables causing a placebo effect. These can be due to local climate conditions of that the manner in which the car is driven.

Any 'scientific' tests have only really proven that 'tuned' engines benefit from the extra octane other than any additional additives.

All fuel in the UK, whether it be supermarket or premium fuel, is made to the exact same standards and is tested regularly...
 
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I thought that the problem tended to be that most newish cars left in their factory tune state will better "better" with 99 fuels as you always get better low end drivability, but at the top end get a reduction in power due to the "juice" added to improve the octane rating up to 99 has a much lower "energy value" than the base petrol, so that leads to a reduction in MPG along with lower top end power output.
Also, while these cars in factory tune must be optimised for 95 fuel most/all will show improvements if ran on 97 fuel, but after that it is a waste of time - except for the extra cleaning properties that tends to come with V-Power etc at the higher octane ratings, so as a periodic cleaner, yes run a tank through, for higher ultimate power on a factory tuned car, keep to 97 at the highest.
 
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StretchS4 said:
https://drive.google.com/file/d/1GruL4CARAbo_0WL8zUZc5usiiT1IXD7M/view

This document states our engines are built to run on 95RON premium fuels.

So all in all V power is probably a placebo (except for it’s proven cleaning ability) which I am happy to pay for if it makes me feel like the car is faster.
Click to expand...
To appease your concerns there is no harm to be done if you fill up every 1000 miles or so, but there is probably no need to use the fuel constantly. But any benefits with any additional 'cleaning agents' may well be dependent upon the mileage you do, how long you are going to keep the car and it's driving conditions.

With my engine, it is equipped with additional injectors to that spray fuel directly into the inlet valves, not just ones directly into the cylinder, hence the term 'direct injection', to keep the inlet valve clean of any sooting, if indeed it would take place. I know other 2.0l EA888 engines do not have these other injectors, the 252ps output engine doesn't have these and neither are they fitted to any engines for the US market, thus they may be fitted for markets other than the UK that only have poor quality fuel.
I don't know about your particular engine.

Again the benefits of these 'cleaning agents' is open to debate, with modern engine oils and fuels, along with the engine design itself I would say there is probably no need.
 
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Thanks for sharing that SSP @StretchS4 - it was missing from my collection. I can't see any references to octane other than in the specification table, but based on the fact that it states 95 RON instead of a range, it seems likely that like most of the modern Audi engines, the OE ECU won't adapt for a higher octane. I suspect that due to the design goals and that fact that this engine uses the Miller cycle, adding the extra ECU function to change timing to adapt to higher octane would likely have not been in the design remit.
 
Surely all though these engines would also possess a knock sensor, which will alter the ignition timing, this would be required for such countries where the ron is below 95?
 
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cuke2u said:
Surely all though these engines would also possess a knock sensor, which will alter the ignition timing, this would be required for such countries where the ron is below 95?
Click to expand...

Correct. It would ****** the timing but won't advance it for higher octane fuel.
 
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If its stock, and you don't drive hard for prolonged periods of time run it on 95ron and save some money.

If its tuned or you are a track day fan (not really the sort of car a track day fanatic would enjoy but hey) run it on the high octane fuels.
 
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I think we covered this on a previous thread ...

The octane rating of the fuel dictates the max compression ratio that it can stand before pre-ignition (pinking) occurs. Running below 95 RON will likely cause damage to the engine over time that can’t be prevented by adjusting the timing. The engine will effectively behave like a Diesel engine where detonation occurs due to compression.

Shell V Power uses a slightly different blend of components to achieve the higher octane rating which makes the fuel slightly more dense than 95 octane. This increase in density provides slightly more calorific value for the fuel which partly accounts for an improved mpg. It also burns more uniformly so allows the engine to more reliably advance the ignition to get the most power from the power stroke.

As Cuke says, it’s almost impossible to reliably prove this by monitoring your daily drive ... too many variables affect your mpg, including variations in the blend components from week to week.
 
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