98 octane in Citigo

[NicRobinson]

Our 2017 Citigo is definitely our "second" car and as such I've never thought too much about the fuel I put in it.  Normally Esso or Shell, occasionally supermarket, but always regular 95 unleaded.

 

Anyway, I've always had a feeling that, under power, this car was very slightly pinking.  I never gave it too much thought, but it's always been there, in the back of my mind.

 

Today (yes it really did take me 3 years!) I tried a tank of 98 and instantly the pinking is gone.  Clearly this particular engine is just right for 98 octane fuel.  Fortunately here in France the price differential is very small between the grades (often the basic price is reserved for E10) so there's little extra to pay.  Can't yet say if it's quicker or more economical...those would be a bonus and, after all, it's a Citigo!

Edited 25 July, 2020 by NicRobinson

[Ootohere]

Good stuff,

Super Unleaded about £2 or less extra per tank @ Tesco or Sainsbury's in the UK.

 

 

 

There are no sellers of 98 ron in the UK.

So 97 ron at BP, Sainsbury, Esso, Gulf, Texaco, Costco etc.

 

99 Ron @ Tesco for Tesco Momentum 99  only 5 pence a litre more than their 95 ron

or Shell V-Power Nitro + which will be much more than just 5 pence a litre more than their 95 ron.

Edited 25 July, 2020 by Roottoot

[NicRobinson]

Interesting.  Never really noticed the ron numbers back home.

[freemansteve]

Tried both on mine (but I have only 2700 miles on the clock). Can't tell a difference...

 

These cars are supposedly set for 95 RON, so if you are pinking, your ignition timing is a tad too advanced, which can normally be fixed on a service. But having said that, all modern cars have knock sensors that should automatically retard ignition to match the fuel, so you may have spark or fuelling issues. Either way, get it checked, it's not good.

 

Many people assume that higher octane fuel will automatically give more power, but while that may well apply to many engines, it is not always the case - the point is that an ECU can and must limit the amount of ignition advance or retard (and fuelling)  to be with  certain limits, so 95 RON may be as good as you can get on a Citigo. The reason for this is to limit max cylinder temperatures, which in turn will limit NOx emissions for legal or longevity reasons.  It really is a lot more complicated than the average punter realizes! I used to have a couple of  people working for me on my team (hi-tech global product development in hardware and software) who had previously worked in the development shops for car engine makers, and this stuff is worked on by PhD level engineers and chemists - so 99% of everything you see on the internet is totally uniformed guesswork and anecdotes. Anecdotes are not the same as data, and the guy down the garage who tells you things, is, at the the end of the day, a parts fitter, not an engineer.

[Ootohere]

There is a Motor Engineer/ Mechanic / Master Tech or whatever on this forum that says he worked with whoever and when testing 1.0TSI's Super Unleaded supposedly reduced performance.

But then that is them testing, and others can actually be driving and take their science with a pinch of salt, which sodium and detergents pretty much are.

 

If for £2 extra or less you think the car feels smoother running then whats the harm.

Some ethanol octane boosting suits many people.

 

http://briskoda.net/forums/topic/469546-10-tsi-premium-fuel

 

Edited 25 July, 2020 by Roottoot

[NicRobinson]

36 minutes ago, Roottoot said:

...when testing 1.0TSI's Super Unleaded supposedly reduced performance....

 

I think, of course it's am SDi on the Citigo.  Our other car is a 1.0 TSi Octavia and that is more than happy with anything.  I don't think 98 makes a difference for that one.

[NicRobinson]

48 minutes ago, freemansteve said:

...get it checked, it's not good...

It's always done it and has had 3 services now.  Plus it's always been so faint as to be only noticeable by the terminally anal (me).  That the tiny sound now seems gone is probably a good thing.

[NicRobinson]

I think I'll continue with 98.  This car might be in France permanently now so I need to find a good specialist to take over looking at the Citigo.

[freemansteve]

It may be you have been using fuel that is under spec for 95 ron....

 

[NicRobinson]

2 hours ago, freemansteve said:

It may be you have been using fuel that is under spec for 95 ron....

 

How so?

[Blackcountryman]

Re octane rating -  we have no guarantees that the octane is as stated on the pumps.It can save the conglomerates a large amount of money.without Trading Standards being involved to do an octane test.They leave sleeping dogs lie.........

My Citigo handbook states there will be an decrease in fuel consumption if you use higher than 95 octane.As I use the car as a glorified shopping trolley,I go cheap for fuel.

[Ootohere]

^^^ That is nonsense.    HMRC would be who is involved.  Just as they are with short measures of fuel or alcohol.

Lots of Tax and VAT paid on fuel and fuel is traceable and nobody in the UK is refining fuel and distributing any that does not meet the required spec.

 

As it is 95, 97 & 99 ron are the minimum octane rating of those fuels and the 97 minimum and 99 might well exceed that ron but it will not be lower than that.

 

'On vehicles using prescribed unleaded petrol of min 95 RON, the use of petrol with a higher octane number than 95 RON can increase the power and reduce fuel consumption'. 

 

Worth anyone going and reading the Owners Manual that their Citigo came with and look in the fuel flap at you prescribed fuel and the Min RON that you can use.  Does it show 95 / (91)  or just 95  ??

 

A00_Citigo_OwnersManual (1).pdf

Edited 26 July, 2020 by Roottoot

[freemansteve]

I thought the poster lived abroad, but I may be wrong. I believe there have been a few cases where fuel is adulterated to save costs, almost certainly with something combustible that saves costs, like ethanol or paraffin.

 

The UK is well regulated and inspected, or at least used to before everything got cut, but I wouldn't assume it is entirely fraud-free!

Edited 26 July, 2020 by freemansteve

[Ootohere]

It is certainly not Fraud Free in the UK or the Irish Republic, but then if you drive to a Farm or Industrial Site to buy you fuel with cash money and get not receipt you buy many fuels.

LPG is quite a good one as used in grain dryers / & heating, no markers there.

 

UK / Multinational fuel retailers or the Independent Operators selling hooky fuel at road side filling stations in this day and age is something that there are plenty that are going to be aware of.

Edited 26 July, 2020 by Roottoot

[J.R.]

19 hours ago, freemansteve said:

 

 

These cars are supposedly set for 95 RON, so if you are pinking, your ignition timing is a tad too advanced, which can normally be fixed on a service.

 

You are at least 30 years behind the time in thinking that the ignition advance could be altered during a service, back in the days of points & condensor yes, in the very early days of electronic ignition when they still used a distributor yes also but since the advent of ECUs & closed loop lamda control not on your Nelly!

 

And those were also the last days that you would ever have been able to hear or detect pinking unless the vehicles knock sensor is faulty which would throw up a fault code, the ignition timing and fuelling are adjusted in milliseconds as the piezo sensor detects the combustion is approaching the knock threshold.

 

The OP's vehicle may well perform better on 98 fuel and be more economical because the ECU can run more ignition advance but he wont have felt or experience pinking.

 

It has been probably 30 years since I heard a vehicle on the road pinking and then it was an old schnorrer.

[freemansteve]

I believe ignition is setable via ECU access. Obviously there are not points anymore!

This is how they adjust for various local markets where fuel quality may be  less than 95 or 91 RON, and it's how you remap a car - I don't think rely entirely on knock sensors

 

As I went on to say in the bit you missed, it could be an electrical issue (including faulty sensors or plugs/coils) or a fuelling problem!

 

 

Edited 26 July, 2020 by freemansteve

[Phil-E]

Have you also tried the 95 E10? Although the overall energy content is very slightly lower, the octane level is supposedly slightly higher.

[Gerrycan]

I tend to agree with the sensor issue theory although I remember carbon build up could cause some pinking in old cars.

[Ootohere]

Citigo are not old cars, and the op's 1.0 MPI is a 3 year old car if that.

[NicRobinson]

Thanks for all the input guys.  I think I'll stop worrying!

[Miller73]

This has been done to death for years on various car forums. There is no benefit using 97/98 Ron petrol on bog standad engines like the Citigos, literally none.

 

Edit: You may get an extra 2-3% MPG, but that is offset by the extra cost over standard petrol. You will get zero performance benefit.

Edited 27 July, 2020 by Miller73

[Phil-E]

Yeah I've seen a few tests done between standard and premium fuels. There is a small difference to power and MPG but the cost far outweighs the benefits.

 

It should run perfectly fine on any fuel and shouldn't need 98+ to run smoothly. It suggests a problem if you're getting pinking.

 

Pinking or knock is basically fuel detonating when it shouldn't.

 

It could be as simple as faulty spark plugs not igniting all the fuel at once. And the higher octane fuel detonates quicker and hides the problem perhaps.

 

Turbo engines don't seem to fussy since they overcome knock by running a bit richer.

[J.R.]

On 26/07/2020 at 17:13, freemansteve said:

I believe ignition is setable via ECU access. Obviously there are not points anymore!

This is how they adjust for various local markets where fuel quality may be  less than 95 or 91 RON, and it's how you remap a car - I don't think rely entirely on knock sensors

 

 

Lots of people believe in the tooth fairy and Santa Claus but would they believe that the garage reset the timing on their 3 year old EU6 vehicle when it was in for service because of the local fuel quality?

[Phil-E]

They can run on 91 ron anyway as standard.

 

Although 95 minimum is recommended.

 

A slight performance drop may occur on 91.

 

They can't run on anything less than 91. They probably can but Skoda says engine damage may occur.

[Ootohere]

@Phil-E

Can all Citigo in all World Regions run on 91 RON ?

 

  Do the Euro 5 & Euro 6 Citigo sold in Europe / EU have on the Filler Flap 95 / (91)  ?

 

Bottom filler flap in red is a Euro 5 Mk2 Fabia 1.4TSI Twincharger 136kW. 

Prescribed fuel is 98 ron and 95 ron minimum as sold in Europe.

 

Edited 28 July, 2020 by Roottoot