Would an induction kit kill the MPG(more!) on an S4?

[Russboy]

Obviously, it would if you play with the fun peddle to hear the charger screaming away, but what if driving sensibly?

Wife and 2 kids did the few miles trip to the mother in laws & she said normally she gets to improve the MPG after I have been driving (he, he!) and will get it up in to the 20’s. However yesterday she only got around 17mpg. Think we’ve done about 40 miles since fill up last Friday and over a quarter of the tank has gone. Normally I put 95 RON supermarket fuel in there, but last Friday filled up with V-Power, would that have any effect?

I would have thought consumption is based on how much you mash your right foot, or does the car need to learn it is getting far more air now? (sounds implausible I know).

Cheers,

Russ

 

[DieselJake]

I'd say it's probably the fuel more than the induction kit, every car I've ever owned has got more mpg with supermarket fuel. Funny really because one of the claims of better fuels is increased economy... still put V-Power in all my car's though

 

[xpoweruk]

Shouldn't make a difference TBH I can still get 30MPG if I try

 

[Dippy]

No, but with a caveat (and I am open to being proved wrong )

The B8 V6T ECU determines fuelling based on manifold pressure and engine revs rather than airflow (it has no MAF sensor). On the assumption (this is the caveat) that the OE intake provides adequate airflow for the OE mapping, then reducing the restriction in airflow will not have an affect on manifold pressure and therefore not on fuelling either.

Exactly how have you measured that the fuel efficiency was lower? If you relied on the DIS then you need to take account of how it is being calculated. There are a number of reasons why that figure could change other than the obvious. E.g. use of start/stop, how smoothly you accelerate from standstill, and so on. Audi tuned the engine for 95RON and so in theory the ECU should not make adjustments to take advantage of higher octane. But if it did fuel efficiency should improve. However if you really want to make comparisons over fuel efficiency then you really need steady-state conditions, so changing octane partway through your test is not ideal.

 

[Russboy]

Reason for asking the question is for the 6 mile round trip other half would get around 22-24mpg, but only got 17. Same driving style, kids on board etc, quite a substantial drop. DIS aside dropped to under 3/4 of a tank much much quicker that i've ever seen before.

Was virtually out of petrol when I put the v-power in there. Plan to run this down & go back to 95ron to see if any reversal at all.

 

[Dippy]

Not directly relevant but I discovered that my wife has a very different driving style from me, in her car. She permanently drives with her left hand on the gearstick and seems to be constantly changing gear for no apparent reason. When I drive it I tend to stay in gear until it is clear I need to change (maybe that's just my s-tronic conditioned mind trying to avoid the effort).

Just saying - perhaps you are only assuming that your wife has the same driving style - maybe you need to watch?

 

[Russboy]

I've seen her MPG figures though, much better than mine, and all of a sudden they've changed, she doesn't like to release all the horses like I do, lol!

Need a much longer term test anyway, good bit is that means I have to drive it