# Shell nitro+ no good?



## EvilTed (Feb 5, 2016)

Ok, so I've been feeding my TTS Shell Nitro+ (99RON) for my 6 months of ownership and my fuel consumption on my regular commute has always been just scraping in to the 30's. I'd say a general expectation is 31 with an all time high of 32.4mpg.

Out of necessity a couple of weeks back I put a tank of Esso super whateveritscalled (97RON). I was annoyed at first as it is 10p a litre more expensive than Shell but within a couple of journeys I saw 33.8 and 33.5mpg back to back on my commute. I wasn't taking it easy either.

Could the 99 Octane of Shell Nitro+ actually be harming our economy?

Edit: I should have said I've since returned to Shell Nitro+ and consumption is back to 29-31.


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## ZephyR2 (Feb 20, 2013)

Depending to some extent of the actual prices per litre but if you're getting more than an extra 2.7 or so mpg with Esso then it works out more economical. Also it usually take around 3 tank fulls for you to start getting the maximum benefit from a better grade of fuel so you should get even more than you have done if you persist with it.


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## EvilTed (Feb 5, 2016)

ZephyR2 said:


> Depending to some extent of the actual prices per litre but if you're getting more than an extra 2.7 or so mpg with Esso then it works out more economical. Also it usually take around 3 tank fulls for you to start getting the maximum benefit from a better grade of fuel so you should get even more than you have done if you persist with it.


I'm fine with all that but I'm actually getting better results from dropping down to a lower quality (based on RON rating alone).
It's counter-intuitive to me hence the post to see if anyone else has tried/seen the same?


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## Dreams1966 (Oct 27, 2014)

It's been debated on the forum a lot, especially when I was a MK2 V6 owner... I am a Shell Nitro convert and where possible won't use anything else. It made my previous car run better and did clean the system, as it cured a sticky fuel level indicator.

The opinions vary from 'why would you put cheap fuel in an expensive car' to 'Supermarket fuel is fine and makes no difference at all'....

Whether it's a placebo or not... I'm brainwashed into thinking that 99 RON is the way to go


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## EvilTed (Feb 5, 2016)

Dreams1966 said:


> It's been debated on the forum a lot, especially when I was a MK2 V6 owner... I am a Shell Nitro convert and where possible won't use anything else. It made my previous car run better and did clean the system, as it cured a sticky fuel level indicator.
> 
> The opinions vary from 'why would you put cheap fuel in an expensive car' to 'Supermarket fuel is fine and makes no difference at all'....
> 
> Whether it's a placebo or not... I'm brainwashed into thinking that 99 RON is the way to go


Me too. I just went Shell only from the start but now I'm doubting the wisdom.
I think I'll do the next fill with Esso Synergy again and see if I get better results.


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## R_TTS (Mar 16, 2016)

I only use Esso Synergy Supreme+ fuel, as it has one major advantage for me............... the garage is at the end of my road. I'm pretty sure most of the fuel economy benefit of the premium fuels is lost with the extra cost. Are you left with a cleaner engine and better performance? Who knows.

For some odd reason there are no Shell stations around my way.


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## JCS_AutoID (Apr 10, 2016)

I will only use Tesco Momentum if possible!


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## Xiano (Mar 18, 2016)

I use whatever petrol station is closest to me when I need to refuel :lol:


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## sherry13 (Oct 8, 2013)

I used Tesco premium the other week - didn't note any change in the usual bad economy figures. I have no idea if it makes much of a difference, would be interesting to see a motoring journalist do something on this.

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## rumblestrip (Apr 15, 2016)

Hhmm, interesting. I didn't take much notice at the time but on reading this thread...

Since my 1.8 TFSI was new, in late July, I have used Shell Nitro with just the odd fill of hi RON Tesco unleaded. No standard grade fuel used at all.

Did a return trip from Oswestry to Tonbridge over the weekend; c 220 miles each way, same route. On the trip out, the read-out said 41mpg. Was very happy with that. For the trip home I needed a 'splash and dash' at Cherwell Valley services so I squirted in about 10 litres of 'cooking' petrol. For that return trip home the car said 45mpg. And I wasn't hanging about.

Makes you think doesn't it?


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## Hoggy (May 8, 2002)

Hi, Perhaps the MK 3 has been tuned to use 95 Ron fuel. What does it state on fuel cap.
Hoggy.


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## ZephyR2 (Feb 20, 2013)

When I had my Scirocco I did some tests over several weeks comparing standard 95 RON petrol with Shell V-power (as it was then). The manual stated that the car would perform better with higher octane fuels and it did. I got 3.5 more mpg using V-power which more than covered the additional cost.
When I got my Mk2 1.8 TT I thought I'd repeat the tests, even though the manual said it just needed 95 RON petrol. Like rumblestrip found I actually got LESS mpg using Shell high octane than using their standard fuel. :?


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## rumblestrip (Apr 15, 2016)

Hoggy said:


> Hi, Perhaps the MK 3 has been tuned to use 95 Ron fuel. What does it state on fuel cap.
> Hoggy.


Inside the fuel cap (1.8TFSI) the sticker shows 91 and 95. I'm going to stick to 95 for two or three fills and see what happens.

Derek


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## ianle (Apr 2, 2015)

Curiously on my TTS, the tech pack gives me fuel prices for (only) 98 RON fuel (not that I use it for that), but it does seem to suggest that 98 RON is 'supposed' to go in the TTS...


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## EvilTed (Feb 5, 2016)

rumblestrip said:


> Hoggy said:
> 
> 
> > Hi, Perhaps the MK 3 has been tuned to use 95 Ron fuel. What does it state on fuel cap.
> ...


Inside the cap of the TTS it says 95 and 98.


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## ZephyR2 (Feb 20, 2013)

ianle said:


> Curiously on my TTS, the tech pack gives me fuel prices for (only) 98 RON fuel (not that I use it for that), but it does seem to suggest that 98 RON is 'supposed' to go in the TTS...


That's interesting. So the car tells you what fuel it prefers.


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## EvilTed (Feb 5, 2016)

I filled up with Esso again this morning so will report back if there's a change through this tank.

I also (before filling up) had my easiest journey back on Shell. All traffic lights were green, traffic never backed up and everything moved along at 75 on dual carriageway and 40-50 on A roads. It couldn't have been more efficient.

Managed 32.8mpg. A new PB with Shell which sets a good benchmark but is still under what I saw on my last tank of Esso Super Synergy+

This is almost scientific....


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## Dash (Oct 5, 2008)

95 is a regulatory requirement for manufacturers selling to the UK market. The car may be designed for something higher, but it has to be able to run on 95.

You can put in low-grade petrol, run chinese plastic tyres and fill your washer with blue nun. It's not necessarily the best choice. Of course, there is a point of diminishing returns on many things and you have to decide where that line is for you.


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## EvilTed (Feb 5, 2016)

Dash said:


> 95 is a regulatory requirement for manufacturers selling to the UK market. The car may be designed for something higher, but it has to be able to run on 95.
> 
> You can put in low-grade petrol, run chinese plastic tyres and fill your washer with blue nun. It's not necessarily the best choice. Of course, there is a point of diminishing returns on many things and you have to decide where that line is for you.


I get the impression people may not be reading this thread properly.
This is not quite the same old discussion - Is super plus better than regular.

Both fuels in my OP are super plus (Esso Synergy+ and Shell Nitro+) but at 97RON and 99RON respectively.

My assertion is that the lower RON actually gives better consumption results than the higher.


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## ZephyR2 (Feb 20, 2013)

EvilTed said:


> .......
> 
> This is almost scientific....


Don't forget to take account of ambient temperature, wind speed and barometric pressure. Oh, and how much you ate for lunch as well.


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## Hoggy (May 8, 2002)

rumblestrip said:


> Hoggy said:
> 
> 
> > Hi, Perhaps the MK 3 has been tuned to use 95 Ron fuel. What does it state on fuel cap.
> ...


Hi, You are wasting money & performance if you use 98+ fuel & it's designed to use 91/95.
Hoggy.


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## moro anis (May 27, 2010)

All engine sizes and poweer output? Petrol of course.


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## Dash (Oct 5, 2008)

EvilTed said:


> My assertion is that the lower RON actually gives better consumption results than the higher.


Problem is it's really hard to do tests on the road. All you can do is average four tanks of each and then switch. Hopefully over a year you might have some useful numbers.

Otherwise there are too many variables to detect a few mpg difference.

I've never found the extra mpg of super to really warrant the extra cost. It's the extra power, and additives in the premium brands that do it for me.


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## Charlie-B (Feb 20, 2014)

Hoggy said:


> Hi, You are wasting money & performance if you use 98+ fuel & it's designed to use 91/95.
> Hoggy.


+1

Using a higher octane won't give you more power if the engine isn't tuned for it - in fact it could be the opposite. It's intended to allow car manufactures and tuners the ability to run at higher compression ratios and use advance timing without getting knock. I don't know Audi's standard on this but as they state 91/95 I would guess they designed the engine for 95 and then retard the timing if lower is detected to avoid knock.

As a result I would expect to see increased fuel consumption outside the 91/95 parameters due to inefficient burn and timing. Below 91 there's a real risk of knock and engine damage. Above 95, the fuel will probably help clean the engine due to a higher level of cleaning agents, but it won't do any damage.

I should add I don't consider myself an expert; just applying engineering knowledge and a keen interest.

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## EvilTed (Feb 5, 2016)

Just in case anyone is interested in my results so far:
Journey home last night, green lights, no queues. Just like the day before. I had a light lunch and was wearing a medium weight suit. I carried some papers home which obviously will have added to weight and impacted economy. :roll:

02/10: Shell nitro+ (99RON) 31.6mpg
03/10: Shell nitro+ (99RON) 32.8mpg
04/10: Esso Synergy+ (97 RON) 32.7mpg

So far so similar as you'd expect with first fill of a new fuel. Perhaps there will be a difference today.


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## John-H (Jul 13, 2005)

There are a number of variables here. If your engine won't advance to take advantage of a higher RON then it won't gain in efficiency. How many mpg you then get depends more on the calorific value of the fuel. Higher RON fuels can be a lower calorific value in order to achieve the higher RON. A remap might help.

I did some careful measurements over many tanks full with Shell 98 Opimax on my Mk5 RS2000 4x4 and the Optimax paid for itself then compared to Shell 95 RON. It's not an easy test to do on the road as the conditions vary so much and so does the weather so you need to do lots of repeating and averaging.

Freegeek did some measurements using his Liquid BHP estimates. He reset the ECU between fresh tanks and tried to test at the same temperature. He found that there were efficiency gains from 95 RON to 99 RON but BP 102 RON dropped back to near 95 RON results. This was with his remapped Mk1 TT.


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## EvilTed (Feb 5, 2016)

John-H said:


> There are a number of variables here. If your engine won't advance to take advantage of a higher RON then it won't gain in efficiency. How many mpg you then get depends more on the calorific value of the fuel. Higher RON fuels can be a lower calorific value in order to achieve the higher RON. A remap might help.
> 
> I did some careful measurements over many tanks full with Shell 98 Opimax on my Mk5 RS2000 4x4 and the Optimax paid for itself then compared to Shell 95 RON. It's not an easy test to do on the road as the conditions vary so much and so does the weather so you need to do lots of repeating and averaging.
> 
> Freegeek did some measurements using his Liquid BHP estimates. He reset the ECU between fresh tanks and tried to test at the same temperature. He found that there were efficiency gains from 95 RON to 99 RON but BP 102 RON dropped back to near 95 RON results. This was with his remapped Mk1 TT.


Now this IS interesting!

Your final summary of Freegeeks results are exactly what I'm trying to recreate. Does using a higher than recommended RON actually get you degraded results. 
The TTS is designed for 98 and tolerates 95 so we know 98 will get better outcomes than 95.
However, could "over-octaning" actually deliver worse results? That's what my unscientific observations suggested and seems to be what FreeGeek also discovered.


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## ZephyR2 (Feb 20, 2013)

Over-octaning did seem to produce worse mpg on my 1.8 Mk2. 
You need to run at least 3 consecutive tankfuls of each fuel- so about 3-4 weeks driving on each. 
Ambient temperature has a big effect on economy (not to mention possible different winter fuel mixes) so you are looking at conducting any test over 6-8 weeks of fairly even temperatures. 
Also commuting in the dark after the clocks go back has a big effect. Slowing traffic and the greater use of lights, heater etc. 
These factors need to be consistent throughout the test. I'd reset my long term memory at the start of each test and refer to that.


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## EvilTed (Feb 5, 2016)

ZephyR2 said:


> Over-octaning did seem to produce worse mpg on my 1.8 Mk2.
> You need to run at least 3 consecutive tankfuls of each fuel- so about 3-4 weeks driving on each.
> Ambient temperature has a big effect on economy (not to mention possible different winter fuel mixes) so you are looking at conducting any test over 6-8 weeks of fairly even temperatures.
> Also commuting in the dark after the clocks go back has a big effect. Slowing traffic and the greater use of lights, heater etc.
> These factors need to be consistent throughout the test. I'd reset my long term memory at the start of each test and refer to that.


You are absolutely right about all the elements of a good controlled test.
I'm not going to do it, but you're absolutely right :lol:

I will continue to make a decision based on my own meandering mathematics, some uncomparable and only mildly controlled tests over the course of a few journeys. But hey, if I wanted to spend my life on mpg tests I'd be in a hybrid right?


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## ZephyR2 (Feb 20, 2013)

Lol. Yes, unless you were just curious. But you know what curiosity did to the cat.


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## EvilTed (Feb 5, 2016)

ZephyR2 said:


> Lol. Yes, unless you were just curious. But you know what curiosity did to the cat.


That should be a thing, I'm not totally Hybrid, I'm just Hycurious.


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## iainfrmeastkilbride (Feb 19, 2016)

Hi Guys
Might be a bit off topic as car is diesel but here goes.
Since I left the TT fold and went back to 320d M sport I have also been trying different fuels.
My conclusion is that Supermarket fuel is crap.Tried this 1st.Service interval started at 19000mls,after 1000mls of driving it went down to 16000mls to 1st service. I changed to Diesel ultimate in BP? Now done 2500mls and service still reading 16000mls till service. Average went from 43 to 45 per gallon,mainly short driving{wife}.Conclusion therefore is its certainly more friendly to the engine. One long journey,Glasgow to Southampton and back,£100 round trip. Dont know why I am bothered though as they gave me 5 years free servicing as part of the deal.
Ps No paint issues either lol


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## EvilTed (Feb 5, 2016)

So after a completely unscientific assessment over a couple of tanks I have come to a startling and quite incredible conclusion.

97 vs 99 RON makes chuff all difference.
Put what you like in your tank.

(P.S> When I say "what you like" I really mean "whichever premium fuel you choose". All the evidence from others suggests that standard 95 RON stuff is going to reduce performance and economy.)


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## Dash (Oct 5, 2008)

Now we just need somebody willing to put in Tesco super for the life of their car, and somebody else only V-Power - drive in similar styles, service them the same, and then crack them open at 50,000 and 100,000 miles and see if there is any difference.

Maybe too have somebody who uses Tesco for everything apart from the last 3 months of the experiment and then switches to V-Power and see if it can clear up a life time of alleged super-market gumph.


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## waynej46 (Sep 15, 2016)

Dash said:


> Now we just need somebody willing to put in Tesco super for the life of their car, and somebody else only V-Power - drive in similar styles, service them the same, and then crack them open at 50,000 and 100,000 miles and see if there is any difference.
> 
> Maybe too have somebody who uses Tesco for everything apart from the last 3 months of the experiment and then switches to V-Power and see if it can clear up a life time of alleged super-market gumph.


I used Tesco Supreme in my A45 with the odd BP Ultimate and couldn't feel any difference at all. Still squeezed 32MPG on a good, very steady day and 14MPG on a thrash. Only difference I felt was in my wallet.


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