Fuel Milage

[tweiss3]

Don't laugh, the FC is better than the truck on milage.

However, I use fuel milage as a huge indicator for determining if something has gone wrong quick. The cold has killed milage (happens every year on all cars) and its down to about 14.7-15.5 mpg. This is mostly highway and some city mixed in. The question I have is, is that normal? I know edmunds lists 18 highway for NA's but 15?

Anything I can do to improve this (i know me) but i have adjusted my driving style for rotary (keeping it above 2500 with any throttle over 5%) and do 3k oil changes, checking oil every other fill up (about every 6 days).

[My5ABaby]

When I tracked my mileage I was getting about 23-24 highway and 14 city, averaging around 17.5 for me with mixed.

[MmSadda]

I dunno, that DOES seem pretty low... I usually get gas mileage that low when I thrash on it. I'm running a pretty much stock s4 n/a, with a cat-less exhaust. Shortly after a rebuild I saw as high as about 27-28mpg, pure highway miles. I swapped to a different intake and now see low-mid 20s (likely because the AFM doesn't sit perfectly flat anymore; I need to fix that) and a bit under 20 on a normal tank of gas with a mix of freeway, around down, and hard driving mixed in.

[tweiss3]

Hmmm. Its a stock S5 NA. Magnaflow cat, rebuilt air pump, corksport 2.5" catback with silencer installed, and a cone filter intake. I was up about 18 before the cold weather set in. Could it be the emissions bullshit?

[Rotary Evolution]

sounds about average to me, the rotary really suffers in town for gas mileage so if you are doing more in town that highway it will drop like a rock.

my TII with a fairly aggressive fuel mileage tune gets 24mpg highway but about 13 in town(probably due to my lead foot..). my F-250 4X4 almost trumps it in town. granted it has a fairly large turbo(capable of 600WHP) to spool up so that hurts it more in the stop and go traffic than an n/a does.

[tweiss3]

Hmm, I haven't had it on a highway trip yet, maybe I will find out how well it does soon enough.

[Pete_89T2]

Another factor to consider with mileage, besides the mix of highway/city driving is the length of each of your trips (i.e., run time). If a large percentage of your trips were made doing short runs (city or hwy driving), where you spent most of your time getting up to operating temps, it will drag your average mileage down.

[sv51macross]

Originally Posted by Pete_89T2

Another factor to consider with mileage, besides the mix of highway/city driving is the length of each of your trips (i.e., run time). If a large percentage of your trips were made doing short runs (city or hwy driving), where you spent most of your time getting up to operating temps, it will drag your average mileage down.

Hmm...I'm averaging 11-12mpg with Lucy. No O2, possibly bad thermo, and rusty BAV/IAC. Mostly trips back and forth to class. The college is 10 mins away and it's almost all 'city'. I keep RPM between 2 and 3 thousand. Nowdays I just let her idle a couple minutes to warm the oil and go.

Guess I know why my mileage is so bad.

[tweiss3]

I always start my car, let it run for 15 minutes till its warm before beginning my trip. Also, its always about a 30 minute drive, close to 25 miles each way. If that helps determine my driving habit.

[RETed]

I assume you're talking about your location "Akron, Ohio"?
I assume that you're running that OXYGENATED gas crap?
If so, that explains it.
Oxygenated gas will kill, on average, 5% - 10% of your mileage.
The oxygenated additive displaces gasoline, so it takes more of this crap to power the engine.
Oxygenated gas is a @#%*(_%_ conspiracy.

Non-turbo FC's should easily do 15mpg.
Mix in some highway / freeway driving, and it should start to head towards 20mpg.
Start doing some serious freeway driving, and you can easily break 20mpg and start heading towards 25mpg.

At best mileage driving conditions, it'll get close to 30mpg...
To do this, do all your driving in top gear and at 3,500RPM - the key is the RPM's, cause you want to keep it right under the secondary fuel injector crossover point.


-Ted

[tweiss3]

Originally Posted by RETed

I assume you're talking about your location "Akron, Ohio"?
I assume that you're running that OXYGENATED gas crap?
If so, that explains it.
Oxygenated gas will kill, on average, 5% - 10% of your mileage.
The oxygenated additive displaces gasoline, so it takes more of this crap to power the engine.
Oxygenated gas is a @#%*(_%_ conspiracy.

Non-turbo FC's should easily do 15mpg.
Mix in some highway / freeway driving, and it should start to head towards 20mpg.
Start doing some serious freeway driving, and you can easily break 20mpg and start heading towards 25mpg.

At best mileage driving conditions, it'll get close to 30mpg...
To do this, do all your driving in top gear and at 3,500RPM - the key is the RPM's, cause you want to keep it right under the secondary fuel injector crossover point.


-Ted

Yes, we don't have real pure gas here, fucking tards.

Also this makes complete sense. 3500rpms in 5th gear is quite quick, too quick for being legal around here (fucking 65 max state limit). I may end up trying to see if I can break 20 this summer. Before the cold set in, I was getting 16 pretty easily, and defiantly not taking it easy.

So, my car "should" be in good operating order based on fuel usage. I just need to:
1) stay out of the city all together
2) run real gasoline (fuck this shitty winter mix)
3) stay in a warm area
4) drive faster, but stay in the primary injector range.

[Rotary Evolution]

Originally Posted by tweiss3

I always start my car, let it run for 15 minutes till its warm before beginning my trip. Also, its always about a 30 minute drive, close to 25 miles each way. If that helps determine my driving habit.

it tells me you like to waste gas. i start my car and boost it to 15psi within a few minutes at times, most of the time it's very rare that i let it warm up more than 30 seconds before driving off.

[Pete_89T2]

Originally Posted by tweiss3

I always start my car, let it run for 15 minutes till its warm before beginning my trip. Also, its always about a 30 minute drive, close to 25 miles each way. If that helps determine my driving habit.

That would explain the lower than average MPGs. In terms of your run time, for each of your average trips, your car is running for a total of 45 minutes or so, with 15 minutes or so spent idling. Idle = 0 MPG, and if ~33% of your run time is spent at idle, it's easy to see how this would effect your average MPG. Skip the warm up time idling - just drive off but don't beat on it until it's up to operating temp.

[infernosg]

Not much warmer down here in Cinci and I average about 18 mpg (75% city, 25% highway) although it doesn't get driven too much in the winter. I've seen 25+ mpg at least once during a trip to and from Akron. I agree with Rotary Evolution above, there's no need to let your car idle for 15 minutes before going anywhere. From what I read these cars idle at relatively rich air-fuel mixtures. I usually wait about 1 minute before going anywhere (longer if it hasn't been driven in a while) and then just keep the engine speeds lower until it's fully warmed up.

[Ender]

My TurboII seems to hover around 18mpg most of the time with mixed driving, and I rarely have a trip that I don't wind it up hard at least a couple times. I have gotten 25mpg before, but it was straight from a gas station to the interstate with a tailwind to the next gas station like 300 miles later. I don't think I've seen over 20mpg more than a couple times in three years. I would think an NA should have no real trouble doing this though.