# Silly question but I'll ask... fuel



## AMT (Apr 8, 2019)

Ok so random one here, as I search and post up questions to find out more info in my research for buying a TTS. Fuel... the last thing I was in had 309bhp (apparently) but following a good bit of investigating and speaking to specialists who dealt with the aftermath of some of these cars it was advisable to run super only...... does the Audi TTS need to run on super unleaded or regular ? Or is it ok on both?

My last car did have knock sensors but really wasn't advisable to run it on normal, as after a year as the pistons would do that nice thing and sort of burn away at the top to an extent.

I would think a 2.0 Turbo thats used in other cars would surely be ok on normal or do we have any reasons otherwise?

Cheers again for the help


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## ross_t_boss (Feb 28, 2017)

I wouldn't run a TTS on anything less whenever possible, I'd get a lower spec engine more suited for the fuel available.

There were logs posted on a Golf R group recently (uses the same engine) showing consistent 5-6deg timing pull on 95RON fuel. That's alot. Yes you can run it, the car will be warrantied for it, and adapt it's targets accordingly to avoid knock, but you're paying a premium price for a premium engine and losing a significant chunk of horsepower. "FInger in the air" but probably in the region of 20-30hp.

The recommendation is always to avoid running the engine hard on octane below what it's calibrated for, but you won't be damaging the engine if you do so with a fuel grade lower on your daily commute. As Shell VPower is such a premium nowadays I run Tesco Momentum most of the time.


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## Hoggy (May 8, 2002)

Hi, Engine is designed to run most efficiently on Super unleaded & performance will be lost if using 95 octane fuel.
It will run O.K. on 95 as knock sensor will control any pre-ignition, but why buy a TTS if you don't want to use the performance. 
As it will run more efficiently on 99 octane you may even see better MPG.
Hoggy.


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## MClaine55 (Feb 16, 2018)

I started off with Momentum as it has a higher octane rating than other super unleaded. Never tried V-power it's over priced IMHO. However I read in an Honest John article that the Tesco petrol has fewer additives than some other brands. Currently I use Sainsbury's Super which seems ok and supposedly has more additives. Only in an emergency would I use lower grade fuel and only enough to get to better fuel.

If it was me with a TTS I'd stick with super unleaded.


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## chelspeed (May 6, 2017)

AMT said:


> does the Audi TTS need to run on super unleaded or regular ? Or is it ok on both?


General comment not TTS specific

Modern engines and ECUs have a knock sensor to retard the ignition if they see detonation or knock. This will cost performance but keep your engine alive. So put super in and the engine will gradually advance the ignition to take advantage of the better performance of the super petrol. This will take many hours to map the optimum advance at all combinations of revs and throttle position.

Stick normal petrol in and you will get knock and the ECU will pull back the advance to keep safe. To keep the engine safe this will take seconds. This will take the edge of performance (maybe noticeable maybe not).

So you can run either. Run purely on super and you will get the best performance all the time. Run on a mix or alternative tankfuls and you will get a little bit of the benefit when on super.

Personally when I first started running on super I found I got at least 10% better mpg and the fuel was only 5% more expensive. So worth doing just for that. Then the extra performance is a bonus.

For TTS specific advice read the manual or look inside the filler flap. Does it day 98RON only or 98RON recommended? Super is 98 or 99 RON, normal is 95 RON. My TTRS says "RON 98, min RON 95". So I take that to mean recommended 98, minimum 95.


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## phazer (Apr 2, 2018)

MClaine55 said:


> I started off with Momentum as it has a higher octane rating than other super unleaded. Never tried V-power it's over priced IMHO. However I read in an Honest John article that the Tesco petrol has fewer additives than some other brands. Currently I use Sainsbury's Super which seems ok and supposedly has more additives. Only in an emergency would I use lower grade fuel and only enough to get to better fuel.
> 
> If it was me with a TTS I'd stick with super unleaded.


Tesco's fuel is boosted with bio-ethanol to give it 99RON. Shell Vpower and others are 97RON base and then additives boost the rating to their rated 98/99 plus add a bucket load of cleaners and other things.

FWIW I've run mine of Costco 99, Costco 97 (as they provide now which is probably the same as Esso or Sainsburys Super) and Vpower.

Vpower and the Costco 97 are on par with each other both outperforming the 99. Our S1 loved the 99 and is fine on the other two. Go figure!!


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## phazer (Apr 2, 2018)

chelspeed said:


> For TTS specific advice read the manual or look inside the filler flap. Does it day 98RON only or 98RON recommended? Super is 98 or 99 RON, normal is 95 RON. My TTRS says "RON 98, min RON 95". So I take that to mean recommended 98, minimum 95.


The TTS is the same as the RS. You can run 95 but I wouldn't. It says in the handbook that performance is affected on lower grade fuel. Can't remember if it mentions fuel economy but I'd expect this to suffer too.

Whilst I'm here...the 245 engine is still an EA888 derivative and in the Golf GTI Performance it too specifies 98RON fuel.

As other's have said, I don't see the point in paying extra for a TTS to then hobble the performance/economy of it. You may as well save your money and go for a lower output engine but then you'll need to know what the fuel flap says :lol:


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## ross_t_boss (Feb 28, 2017)

phazer said:


> Shell Vpower and others are 97RON... Vpower and the Costco 97 are on par with each other both outperforming the 99. Our S1 loved the 99 and is fine on the other two. Go figure!!


Just to point out the Vpower has also been 99RON for a while, and may contain Ethanol, they seem to keep it a closely guarded secret. I'm tempted to get jerry can full and test it actually, as I can't see that anyone ever has.

Tesco 99 runs the max permitted 35% aromatic content, 5% MTBE and 5% Ethanol to achieve the extra RON points - the 97s don't run Ethanol which is about that difference.

My TTRS has no preference between Vpower and M99, I've logged on both with stock and remapped. I saw the same timing up top, 13.5deg - I did get a bit more with a dash of alcohol in the tank, the car does love high octane. But the fella testing on the Golf R saw an extra degree of timing pull with Tesco99 vs Vpower in his tests so there is something to be said for your conclusion. I've never tried a 97RON.


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## phazer (Apr 2, 2018)

ross_t_boss said:


> phazer said:
> 
> 
> > Shell Vpower and others are 97RON... Vpower and the Costco 97 are on par with each other both outperforming the 99. Our S1 loved the 99 and is fine on the other two. Go figure!!
> ...


I meant to write 97+ additives to make it 99, will edit my post!

The rest of your post is interesting, thanks


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## Alan Sl (Nov 11, 2009)

I will be getting my first TTS shortly so finding this thread interesting. Would it be possible for someone with a TTS to actually check the inside of the fuel flap of their TTS to see what Audi actually say about fuel recommendation.


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## phazer (Apr 2, 2018)

Alan Sl said:


> I will be getting my first TTS shortly so finding this thread interesting. Would it be possible for someone with a TTS to actually check the inside of the fuel flap of their TTS to see what Audi actually say about fuel recommendation.


See my post above. My TTS says 98 is big bold letters with a small 95. It means you *should* run it on 98RON but you *can* use 95 if necessary.


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## powerplay (Feb 8, 2008)

I don't think there's a car in the UK where you can't use regular 95, but why would you buy a performance car and not use the best possible fuel?

I always use Tesco99, tuners recommend Tesco or Vpower, I avoid other fuels at all costs - especially Sainsbury's - I put this in once and noticed reduced top end performance within a few miles 

When you're not using all the available performance you get better economy from higher octane fuels too.

This is my RS fuel cap, also helpfully advises not to remove the filler nozzle while fuel is still gushing :lol: Pretty sure it's identical on TTS.


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## phazer (Apr 2, 2018)

That is indeed the same on the TTS.

From the handbook, based on the sticker shown above:

"*Unleaded fuel only RON/ROZ 98 Super Plus or min. RON/ROZ 95 Super, Premium*
The use of Super Plus petrol (98 RON / 93 AKI) is recommended. If that type of fuel is not available, premium petrol (95 RON / 91 AKI) can be used with a slight loss of power.

If premium petrol is not available, the engine can be run on regular petrol with 91 RON / 87 AKI as an emergency measure. In this case only use moderate engine speeds and a light throttle. Fill up with premium or Super Plus petrol as soon as possible."

and one of the pertinent caution notes at the bottom:

_High engine speed and full throttle can damage the engine when using petrol with an octane rating lower than the correct grade for the engine._


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## ross_t_boss (Feb 28, 2017)

So just to conclude the Vpower and Ethanol thing - I put a couple of litres in a jerry can while topping up today.

(1) I forgot how distinct the smell is, after using T99 only the past few months!
(2) It contains 4% ethanol.

My method was to add 25ml of Vpower to a measuring cylinder, add 25ml of distilled water, mix and let settle for a few minutes before separating each layer. 24ml of fuel left, 26ml of Ethanol/Water (to 0.1ml accuracy).

Technically that could be 50:50 Ethanol/Methanol but I've only seen that approach taken in Tesco 95RON, instead of using MTBE.


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## Barmybob (Nov 4, 2015)

Got caught short in the RS this week and had to squirt some 95 in there - noticed an immediate difference (WORSE). As soon as possible back on 98 but it took a while for the car to get it's crisp throttle back  :x


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## macaddict111 (Jun 13, 2018)

I'll keep this short but sweet: plenty of more-normal modern cars can happily accept normal gas in exchange for less fuel economy and peak power (Mazda even lists the HP and MPG losses in the manual if you choose to do normal vs premium). Audi sport models are NOT like this, and will retard timing to _prevent damage_ to the engine, but are NOT designed to run this way as a choice, only as an accident.


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## AMT (Apr 8, 2019)

Super it is then lol My old Z was ran on nothing but super (usually Tesco Momentum...cheapest, most ron..whatever lol). It did have knock sensors on the last of the line model,which mine was but it didn't stop me one night panicking as I was nearly out and went through 2 petrol stations with no super before finally finding one lol. Apparently you should keep it below 5k if you abosloutely need to put a small amount of regular in, so just wanted to see where the TT's were at with fuel.

Thanks for the replies, much appreciated!


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