Hi, I recently bought a MK5 GTI DSG, I looked long and hard for one and now I have it I love it but the economy its returning is putting a large hole in my wallet. I don't get more than 29MPG out of it! - and thats driving it as slow as Miss Daisy would to try and max the economy!...which is really no fun at all. I had a 225BHP TT Roadster prior to the GTI and that would return 37MPG on a run and 32MPG around town...so I was expecting more from the GTI. Is this normal MPG figures for a GTI? If not what could be wrong with it? VW have had it for 2 weeks, done their 'standard tests' and can find nothing wrong with it. They advised I should run it on Super Unleaded but it did even less MPG with that in the tank! Any ideas? Any one had similar experiences?
I used to regularly get around 30mpg on my Mk5 GTI with DSG, but i didnt buy it for economy. If you want an economical car, get a TDI. I could get over 40mpg on a slow motorway run though, which was quite impressive. Make sure the PCV valve is ok (i bypassed mine with the BSH PCV Stage 1 fix), also check that the dump valve isnt leaking and doesnt have a torn diaphragm.
The 1.8T is far more efficient on fuel than the 2.0T unit. FSI engines seem to suffer poorer economy in general and are very fuel sensitive. My Edition 30 always hoovered between 28-29mpg with sub 15 on a blast round Combe. Heavy foot and it was down to 22-23mpg. When I had it mapped with APR stage 1 it helped on economy but only marginal. It's not cheap motoring anymore TBH at 1.29 per litre for SUL!!i
One of THE most crucial things for fuel economy on FSI engines - is that you MUST always run them on Super Unleaded fuel (and at least 98RON - which rules out ALL UK Super Unleadeds - apart from Shell V Power and Tesco Momentum - both 99RON). Super Unleaded allows FSI engines to run 'lean burn' mode - which is basically a fuel economy mode. And even when not in lean burn mode, Super Unleaded burns far more efficiently compared to poverty-spec standard unleaded, which means the engine can run a greater ignition advance, therefore greater 'efficiency'. Greater engine efficiency can either give more 'power', or more 'economy'.
Not personally, but many others have - and the retardation is quite noticeable. Anything other than 98 or 99RON fuels - especially in a 'GTI' are really defeating the object - both in terms of general 'GTI-esque performance', and also specifically in FSI engine operation. Just to clarify an important side note. The Mk5 GTI (and its related EA113 engine users) need a minimum 98RON (ie Super Unleaded). However, the latest EA888 engine in the Mk6 GTI have lean burn mode disabled, and can happily use normal 95RON standard unleaded (on the standard VW engine map - Revo, el al, will still be advisible for a 98+RON brew).
being a bit of a geek im looking to do a bit of logging to see if there is a measurable difference in knock detection for various fuels. ive only got a 1.8t at the moment, remapped and ive altered the ignition timing to add more advance. so far ive done this on optimax fuel (98ron i think). im eventually going to run a tank with tesco 99 and later on others to see what the differences are, if any in terms of igntiion
But the fuel system, pistons, intake tract, and compression ratios are quite different between the 1.8 20vT and the 2.0 TFSI engine. The 1.8 20vT were designed to use manifold injection, and without any kind of 'lean burn'; so even if any 1.8 20vT motors were specifically OEM mapped for 98RON - the ignition characteristics (mapping: spark duration, coil voltage, advance/retard profiles, etc) will be quite different from an FSI engine. FSI engines have very different piston crown profiles, differing intake tract profiles (both specifically designed to produce very high 'swirl' action with minimal throttling action) - to cope specifically with the direct fuel injection. Trying to compare an FSI engine to a 1.8 20vT engine is like trying to compare a modern direct injection diesel engine to an old skool indirect injection diesel engine. Shell Optimax was 98RON - but 'was' is the crucial word - Optimax was discontinued about five years ago! Tesco 99 (now 'rebranded' Tesco Momentum) has been independently proven to outperform Shell V-Power. Tesco 99 is actually equal to BPs 102RON brew - which is about 2.60 a litre! Search for Thorney Motorsport and their fuel test results.
FSI should stand for Fuel Stratified Injection, but I have been reliably informed that we can't use the stratified to describe FSI technology in VAG cars because of the poor fuel quality here in the UK they ideally need 98/100 octane fuel to run right. I'd expect to see 25/40MPG, it might be DSG but don't confuse them with an autobox regarding mpg
im doing it for the sake of being nosy. obviously theyre very different engines. didnt know what about tescos rebrand. id take thorny's info with a big pinch of salt too. so ill see what my findings say tbh
my gti dsg would do about 30 more miles to the tank if i filled up with super. You culd actually feel the diference aswell! i'm rocking a new tdi passat estate....49 on a run with the climate on!
And indeed it does! You have been mis-informed. That advice is valid for North America - but here in the UK, our fuel is actually very high quality. It is high (relatively) sulfur content which does not allow for stratified (lean burn mode) - but in the UK, our petrols (even poverty spec 95RON standard unleaded) have complied with European Norm standards (EN***) for years, and that specifically means all EU standard unleadeds must be 'Ultra Low Sulfur Petrol' (ULSP) - hence can happy run in stratified mode - as long as an high enough octane rating is used. This is why lean burn or stratified mode is disabled in North America - hence why it is also not a good idea to use a US remap company (unless they have extensive R&D facilities in the UK too). Correct. Although any quality 98RON brew will do. Sadly though, the UK standard for 'super unleaded' does not comply with EU standards - super unleaded in the UK can be 97RON, whereas in mainland Europe it is 98RON minimum! Yeah, its fairly easy to get mid 40s with a DSG if driven carefully - but start to spank it, and it can be as low as high teens!
Why? Of all the so-called 'fuel comparison' tests, NONE, appart from Thorney have used a 'control', and none, particularly BP (with their shyte, overpriced 'BP Ultimate') have ever run consistent and full scope tests. The Thorney tests, whilst not being done on any FSI-type of engine, are by far the most reliable tests - which have been published in full in the public domain. Certainly don't belive all the Shell 'fan boys' - who would have you believe that V-Power is far better than anything else on the market. Yes, V-Power is very good - and it is probably the best fuel at very low revs (below 1,500rpm) - but at mid range, and especially top-end, then Tesco 99 (and BP 102) gives a noticeable gain over V-Power. At the end of the day though, either Tesco 99 or Shell V-Power will both be excellent in an FSI engine - and it is probably unlikely that the Mark 1 butt-dyno could tell the difference between the two.
Exactly! Whilst some peeps may whinge at the extra 5-6p a litre premium for super, you actually nigh-on get that back with the improved fuel economy - not to mention lower emissions, and the reassurance that your engine is actually 'working better' (not having to constantly retard the timing, and not working as efficiently as Fritz designed it!) Haaaa - but now swinging that shifter twice as often!
