Performance fuel

[monkeyhanger]

min 95 ? any thing higher better
smoother and better mpg with v power no brainer

Min 95 and anything higher is OK too, but won't improve performance or economy. EA888 is set up for 95, EA113 is set up for 97+.

The EA888 won't compress 97/98/99 any further than it would 95, 99 is no more calorific than 95, in some cases it is less energy dense because they use more ethanol content to raise the RON number and ethanol only has 2/3 the fuel density.of petrol- so no performance gains or fuel economy gains to be had. A 95 RON optimised engine doesn't run better on RON99.

As an aside, I saw a YouTube video with a US guy who seems to be a VW nut. He opened up the intake of his 10000 miles old GTI (EA888 v3) and the backs of the valves and seats were quite gummed up with carbon (more tar like than hardened carbon) already - especially for cylinders 2 and 3.

[BobbyT]

The US version of the EA888 doesn't have the port injection so this will add to the carbon build up process.

[monkeyhanger]

The US version of the EA888 doesn't have the port injection so this will add to the carbon build up process.

Neither does the European one for those Golf GTIs new enough to have a GPF fitted. EA888 3b (Budack cycle capable) as found on Arteon and Passat (190ps 2.0TSI) and on Polo GTI (200ps) still have port injection in addition to direct injection.

[mistac]

min 95 ? any thing higher better
smoother and better mpg with v power no brainer

Min 95 and anything higher is OK too, but won't improve performance or economy. EA888 is set up for 95, EA113 is set up for 97+.

The EA888 won't compress 97/98/99 any further than it would 95, 99 is no more calorific than 95, in some cases it is less energy dense because they use more ethanol content to raise the RON number and ethanol only has 2/3 the fuel density.of petrol- so no performance gains or fuel economy gains to be had. A 95 RON optimised engine doesn't run better on RON99.

As an aside, I saw a YouTube video with a US guy who seems to be a VW nut. He opened up the intake of his 10000 miles old GTI (EA888 v3) and the backs of the valves and seats were quite gummed up with carbon (more tar like than hardened carbon) already - especially for cylinders 2 and 3.

Thanks - any idea why VW say they recommend 98 ron then - all seems a bit odd?

[karlos]

As an aside, I saw a YouTube video with a US guy who seems to be a VW nut. He opened up the intake of his 10000 miles old GTI (EA888 v3) and the backs of the valves and seats were quite gummed up with carbon (more tar like than hardened carbon) already - especially for cylinders 2 and 3.

I just seen that video: https://www.youtube.com/watch?v=CB5ThYfX7ag

That's a lot of build up for 10k miles considering it has a catch can and he has changed the oil twice since new. Feeding it nothing but vPower hasn't prevented the injectors getting quite mucky as well.

[BobbyT]

The US version of the EA888 doesn't have the port injection so this will add to the carbon build up process.

Neither does the European one for those Golf GTIs new enough to have a GPF fitted. EA888 3b (Budack cycle capable) as found on Arteon and Passat (190ps 2.0TSI) and on Polo GTI (200ps) still have port injection in addition to direct injection.

Indeed, I'm glad I have the pre GPF version 

[monkeyhanger]

min 95 ? any thing higher better
smoother and better mpg with v power no brainer

Min 95 and anything higher is OK too, but won't improve performance or economy. EA888 is set up for 95, EA113 is set up for 97+.

The EA888 won't compress 97/98/99 any further than it would 95, 99 is no more calorific than 95, in some cases it is less energy dense because they use more ethanol content to raise the RON number and ethanol only has 2/3 the fuel density.of petrol- so no performance gains or fuel economy gains to be had. A 95 RON optimised engine doesn't run better on RON99.

As an aside, I saw a YouTube video with a US guy who seems to be a VW nut. He opened up the intake of his 10000 miles old GTI (EA888 v3) and the backs of the valves and seats were quite gummed up with carbon (more tar like than hardened carbon) already - especially for cylinders 2 and 3.

Thanks - any idea why VW say they recommend 98 ron then - all seems a bit odd?

Do they? Where do they say that? Go with the guidance on the fuel filler flap sticker.

For EA888, that's "minimum 95RON" i.e. for markets where lower RON fuel is available, don't go lower. You can go higher, with no tangible performance/economy benefits.

If you have EA113 (R, CS, CSS, TCR, Audi S3, Leon Cupra), they recommend 98RON. It's not obligatory because VAG acknowledge that 98RON+ might not be widely available in some markets. If you stick 95RON into the aforementioned EA113 variants, the ECU will detect its use and adjust timing accordingly to prevent knocking and reduce the power accordingly (to about 285ps, I believe) because you can't inject that much 95RON fuel into the engine in the conditions required to run at 300ps max without it pinking. That's primarily the reason you generally don't see lower output cars with requirements for 98RON, unless the engine is running a high compression ratio all the time.

[monkeyhanger]

As an aside, I saw a YouTube video with a US guy who seems to be a VW nut. He opened up the intake of his 10000 miles old GTI (EA888 v3) and the backs of the valves and seats were quite gummed up with carbon (more tar like than hardened carbon) already - especially for cylinders 2 and 3.

I just seen that video: https://www.youtube.com/watch?v=CB5ThYfX7ag

That's a lot of build up for 10k miles considering it has a catch can and he has changed the oil twice since new. Feeding it nothing but vPower hasn't prevented the injectors getting quite mucky as well.

Yep, surprised me too. One thing about that video - he makes it clear that it's a Golf R he's working on (the twin pipes seen on the LHS of the rear bumper would back that up), but he's talking about it being an EA888 engine. Bit confused by that unless they have something like a 280ps EA888 based R rather than a 300ps EA113 R in the US because they have much less access to high RON fuel, with most of their cars being lazy low compression ratio V6 and V8s? Or maybe a genuine slip of the tongue and his was an EA113 R?

[mcmaddy]

They don't use ea113 engines in Rs or CS or even gtis do they? They are all ea888.

[monkeyhanger]

They don't use ea113 engines in Rs or CS or even gtis do they? They are all ea888.

You're right. Thought R still had EA113 (as per MK6), but after looking into it, they're all EA888. There'll still be some differences between higher output (CS/CSS/R/TCR and S3) and standard (245ps) for the higher output variants to be optimised for 97/98/99RON with the ability to drop performance for 95RON use.

APR state the following differences for 2019 R vs 2019 GTI:-

Cylinder head (made from a different alloy compared to other engines in this module because of higher thermal stress)
Exhaust valves (hollow, higher Ni content, nitrided)
Exhaust valve seat rings (improved temperature stability and wear resistance)
Exhaust camshaft (adapted valve timings)
Compression ratio 9.3:1 with different pistons
Piston cooling jets (higher flow rate)
High pressure injectors (even higher flow rate)
Exhaust turbocharger
Charge pressures of up to 17.4 PSI (1.2 bar)
High performance main radiator with 1-2 auxiliary radiators (depending on country specifications)
Additional acoustic modifications have been made in order to achieve a sporty sound - use of a sound actuator (for the occupant cell) and active exhaust flaps in the exhaust system

There's no reason for RON99 fuel to cost any more than RON95. There's nothing in there upping the RON that's any more expensive than the constituents of 95RON. There's just the marketing opportunity to charge more for something perceived as better. They justify the difference with detergent additions. Doesn't account for any meaningful price hikes, assuming that the 95RON fuel doesn't have the same level of detergents.