Hi, Definately E5, Shell VPower 99 Ron, minimum.
Hoggy.

 

Thanks Hoggy for quick response. I think I have been using wrong grade. Probably need it drain or let it get to its minimum and start using correct grade? Theo.

 

So, I have been using E10, Esso mostly but did a research on performance and it did advise to check best fuel type so thought to check here with members. I will switch to E5 when fuel is low but not sure I should mix fuel types or perhaps get a full fuel drain and start or it’s not needed?

 

Hi, Mixing will be fine, if will probably require another tank before ECU adjusts Ign timing to suit.
Hoggy.

 

Excellent Hoggy! Much appreciated. Brilliant forum😀

 

It's a very good question. I've always used E5 in both my TTS unless it was unavailable and I'd put a tenner of E10 in, never any issues with mixing it. The price difference used to be around 5p a litre, which I thought was worth the extra benefits you get, but just looking around recently and in most places the gap between the two is now more like 20p per litre which is roughly a tenner for a full tank. This is very sneaky trading if you ask me, everyone watches the price of petrol and we are aware when it goes up and down, but it seems like super went up at the same time as regular did but then hasn't come back down again, and lets be honest, when you fill up do you really look?

 

Thanks TTS OAP,

Probably that was the initial thought on posting and I was watching the price and also different forecourts cost different. I use an app😀. It’s not the cost though it’s the performance. So provided I change to E5 and get good performance, will be a bonus..

 

My car runs smoother on E10, but it is snappier and gets better mpg on E5. It may well be that the less potent fuel needs a bit more loud pedal so I get through it quicker. When it was a fiver a tank I never thought about it but now it’s significantly more I’m starting to question it.

 

Ethanol has a lower energy density than gasoline / petrol (approx 30 -35% less) per given volume.
So a 10% (E10) petrol blend will have ~ 3 - 3.5% less energy than straight petrol.

The biggest issue with ethanol when used with older cars is ethanol can attack certain rubber components (i.e fuel lines) but anything built later than 2001 (and likely much earlier) should be a E10 compatible. The other negative is ethanol (affecting all cars) is it's hydrophilic, meaning its miscible with water. Because of this you don't want to store your car for any period of time with a half-empty tank.

The upside, ethanol increases the octane rating of petrol making it perform more like 'premium' fuel. This allows you to push your engine harder, advance timing, etc without increasing the chance of pre-detonation (aka knock) so you might actually make more power on a tuned engine running E10.

There should be labeling on your fuel door or cap specifying the minimum octane your engine requires. This is more important than whether the fuel is E0, E5 or E10. Running anything lower than the recommended octane rating can cause problems. Running a higher octane than needed won't hurt anything but it is a waste of money. Tuned motors should always run high octane fuel as spec'ed by the tuner.

 

The 2.0Ts--both the EA113s and EA888s...they all run better with ethanol than without even bone stock. Proven many times in lots of places. Most likely the EA855 (RS) as well given pretty much every Audi TFSI engine follows the same "rule of thumb". VR6 may be the only exception for Mk2 gasoline engines--but honestly I don't know one way or the other how they behave.

So given the choice, def. E10 is desired so long as you're constantly running the car and it isn't driven only a few times a month or stored for long periods. For example I seek out ethanol free fuel only right before I put any given car away for a season for storage, then use that tank and replace as quickly as possible (with ethanol-laced) coming out of storage when the car is used again. But storing for ~6 months at a time is not a huge deal even with E10 fuel if the car is both stored inside a garage and the tank is completely full; however outside storage/sitting is more of a concern on e-laced fuel. In those cases you would do well to seek out ethanol-free fuel, yes.

 

Just as an FYI as you wouldn't know how it does work on our little island. Ethanol isn't really what's being spoken about, although it is as much information given.
In the UK - E10 is only 95 RON, E5 varies but at the 'best' garages (Tesco & Shell) this is 99 RON (pretty sure lowest E5 is BP - 97 RON)
So with the extra information of what really matters, RON rating - I think you'd likely agree 'E5' aka the premium 99 RON is the much better option of the 2

 

there's a lot of ethanol in E10 which engines don't like
I was always told that if you use best fuel when new and for the first 100k miles the the engine will go forever
my MK2 bought new 2008 serviced regularly now has 310,000 miles on and runs like a dream

so if you can use the best the pump has to offer and it will serve you well

 

I have always used Tesco momentum 99 in my Mk2 TT, and wouldn’t use anything else.

 

I tend to have a +10% limit, at which point Super Unleaded pays for itself. Usually opt for Tesco Momentum 99 as it is always well priced, but BP Ultimate 97 actually seems to perform just as well for me, at least as far as additional mileage can be measured.

I try and avoid regular 95 unleaded, but not for any other reason than reduced mpg.

 

I had a 2013 mk 2 for 12 years and 48k miles which I have only recently sold. Always ran it on E5 predominately Shell (99 octane and supposedly lots of beneficial additives)) but sometimes TESCO E5 which is also 99. Never missed a beat the whole time and once returning 48 mpg average on a fast run up to Scotland. A bit expensive but well worth it I reckon.