APR/Revo fuel economy

[Leor604]

I don't believe this has yet been discussed. Most *discussions* are on performance and perceived reliability.

Can anyone comment on fuel mileage expectations of these two tunes? I know several people reported a slight *increase* in mileage with APR stage 1 (this is good!)

With the Revo tune seemingly running a lower AFR, I am wondering if the fuel mileage will be impacted. Also looking forward to logs of APR V2 to see if AFR's have changed. I prefer to use my fuel for power, not cooling, and am willing to sacrifice a few hp if necessary.

Trying to gather as much intelligence as possible. I'm weighing performance, mileage, probable reliability, dealer flash capability and cost before making a decision on which tune to go with.

Thanks.

[Tyman85]

I don't believe this has yet been discussed. Most *discussions* are on performance and perceived reliability.

Can anyone comment on fuel mileage expectations of these two tunes? I know several people reported a slight *increase* in mileage with APR stage 1 (this is good!)

With the Revo tune seemingly running a lower AFR, I am wondering if the fuel mileage will be impacted. Also looking forward to logs of APR V2 to see if AFR's have changed. I prefer to use my fuel for power, not cooling, and am willing to sacrifice a few hp if necessary.

Trying to gather as much intelligence as possible. I'm weighing performance, mileage, probable reliability, dealer flash capability and cost before making a decision on which tune to go with.

Thanks.

+1

[Dr GP]

+1

All good points to consider, but most looking for a performance upgrade realize that fuel consumption will usually be negatively impacted. So would you buy the tune based on fuel economy or performance increase? OR cost?

[tomh009]

For me, the cost ($200 one way or another) would be the last on the list. Like Leor604, I would prefer a balanced approach between power and fuel consumption.

[motionneon]

Not me. If I only averaged 16mpg but safely got considerable more lower than other tunes id do it.

[DATZ]

My mileage sucked before my APR Stg II tune and continues to suck post tune (~17 mpg over my first 10k miles). No significant difference between pre and post tune mileage.

[Tyman85]

For me, the cost ($200 one way or another) would be the last on the list. Like Leor604, I would prefer a balanced approach between power and fuel consumption.

Agreed! Being used as a daily driver, but still wanting a performance tune, there are going to be compromises. Would be nice to know to compare benefits/losses.

[misc720]

It might be a while before you get any user testimonials of revo mileage, everyone is probably still in the honeymoon/romp it silly phase.

I've got a few hundred miles on mine and haven't noticed any drastic decrease, even with the spirited driving. My computer was showing 24mpg avg after a 50 mile freeway drive at around 80mph yesterday, which is about what it was stock. This is just a casual observation.

Actually that makes me wonder... Is the trip computer measuring actual fuel spent? Or is it based on a factory pre-set log of gear/rpm mileage? In other words, if the revo tune does burn more fuel across the board, will the trip computer accurately measure that?

[IvanS4]

In the ~ month I've had the car with the tune I've seen no difference in mileage - ~ 17MPG when I drive it like I stole it and around 22MPG on mostly highway cruising. Previous to the tune, I maxed out at 24MPG on a 400 mi road trip trying to drive for mileage and I feel that the biggest impact on mileage is the right foot. All of the above is actual mileage, not the trip meter calculation.

http://www.fuelly.com/driver/IvanS4/s4-5/

[Leor604]

It might be a while before you get any user testimonials of revo mileage, everyone is probably still in the honeymoon/romp it silly phase.

I've got a few hundred miles on mine and haven't noticed any drastic decrease, even with the spirited driving. My computer was showing 24mpg avg after a 50 mile freeway drive at around 80mph yesterday, which is about what it was stock. This is just a casual observation.

Actually that makes me wonder... Is the trip computer measuring actual fuel spent? Or is it based on a factory pre-set log of gear/rpm mileage? In other words, if the revo tune does burn more fuel across the board, will the trip computer accurately measure that?

Agree, probably be a while before we get useful data. That's OK, I'm not in any rush (still waiting for APR dealer flashing, which should be very soon). Good to know you haven't noticed anything drastically different.

I *think* the computer is probably looking at distance travelled and injector duty cycle so I am guessing it would take into account the higher duty cycle of the Revo tune.

[Leor604]

All good points to consider, but most looking for a performance upgrade realize that fuel consumption will usually be negatively impacted. So would you buy the tune based on fuel economy or performance increase? OR cost?

True enough. I'm just looking at all the pros/cons before pulling the trigger. For instance, if one tune puts out 5 hp more but has a 2 mpg lower rating, I'd give up the 5 hp in a heartbeat. This *is* my daily driver so mileage and reliability are considerations for me. For others, it may be all about power and nothing else is a factor.

[LittleBlueGT]

Any tuner (unless they royally screw up something) will not affect mileage. In fact, you can sometimes get it a bit better, but only marginally.

As long as you keep your foot out of it, expect the same economy.

[Stereodude]

Any tuner (unless they royally screw up something) will not affect mileage. In fact, you can sometimes get it a bit better, but only marginally.

You must be assuming the tuner either didn't increase the duty cycle to the injectors and got all the extra power by running the engine leaner because you typically get more power by burning more fuel.

[PsYkHoTiK]

The consensus with the APR tune is you get more power with around the same amount of fuel (or a little bit less - slightly more efficient). Can't comment how the V2 will be. I can't give an accurate fuel efficiency count because I got mine tuned before the first service (still in "break in" mode). Though that being said, you tend to "stomp" on it more. Torque = addicting...

[tribe]

Looks about the same in my commutes. This is my first truly powerful car so it's going to be a while until I settle down and drive like a mature person; yes sir torque is very addicting!!

As I'm right now I'm using about $80 more gas per month than with my tuned A4 or roughly 40% more. It's a small price to pay ;)

[helix139]

With the V1 tune, it will give you equal or slightly better mileage cruising but with the increased boost above 5500rpms your mileage can go down a lot quicker if you floor it all the time.

[blazeblunts4]

Its amazing to me how you can afford a 50k$ car and worry so much about gas mileage (freakin americans!), just remember your gas mileage is way better than the s5!; lol, anyways, the gas mileage with a tune will be worse especially if your ragging on it

[LittleBlueGT]

You must be assuming the tuner either didn't increase the duty cycle to the injectors and got all the extra power by running the engine leaner because you typically get more power by burning more fuel.

You have lots to learn about tuning.

You don't just "increase duty cycle".

The ECU targets a certain AFR (Air Fuel Ratio). Our tunes make more power by running more boost, which increase airflow, which increases power. When there is more airflow, their is also more fuel being burnt. So at 400+ crank hp you will be burning more fuel then the stock car at 330+ crank hp at 6000+ rpm. When you are at 15% throttle at 2000-3000 rpm you will be flowing the same amount of air as stock, making the same 25 hp, and burning the same fuel.

Most tunes that I see do not change AFR or timing much or at all in the cruise ranges. Think less then 50hp between 1500-3000 rpm. But at 2000-7000 rpm at high throttle/airflow ranges they change AFR timing, and boost to maximize things.

I can't comment on what B8S4 tuners do with AFR while under boost, as I have only looked at logs of modded cars that have AFR parameters logged, I don't know what Audi does there.

In the 40-150 ish crank hp range there are gains to be had from timing, especially if on 93 gas, so it is possible that they have the engines running a touch more efficient in that range, IDK.

[Un1k]

I used to get about 380km-400km before the tune (may 10'- almost as soon as the tune came out)
Now i get around 385km-410km

[Stereodude]

You have lots to learn about tuning.

You don't just "increase duty cycle".

The ECU targets a certain AFR (Air Fuel Ratio). Our tunes make more power by running more boost, which increase airflow, which increases power. When there is more airflow, their is also more fuel being burnt. So at 400+ crank hp you will be burning more fuel then the stock car at 330+ crank hp at 6000+ rpm. When you are at 15% throttle at 2000-3000 rpm you will be flowing the same amount of air as stock, making the same 25 hp, and burning the same fuel.

That would explain why I totally forgot to mention running the engine leaner to get more power. Oh wait... That's right... I did mention that. I guess I don't have as much to learn about tuning as you think.

[gringoloco2000]

My around town mileage since the Revo tune has gone down maybe 3mpg or so, but I blame that on my lead foot which can't get enough of the power. I have not taken any long highway trips to compare yet. When I was doing 130 mile trips to Tampa prior to the tune, I was averaging about 24mpg going 80-85mph with the same lead foot. When I did autocross this past weekend, I averaged 17.5mpg.

[LittleBlueGT]

That would explain why I totally forgot to mention running the engine leaner to get more power. Oh wait... That's right... I did mention that. I guess I don't have as much to learn about tuning as you think.

Not looking down on you buddy, but you really don't understand, and I am not going to write 10 paragraphs.

The logs I have seen from APR show they run it leaner then REVO, but like I said IDK how that compares to stock.

At any rate, as far as gas mileage goes it is a moot point for the most part, as in the cruise range the car will run 14.7:1 anyways. Technically it will have some variance from that for emissions running the cats slightly lean and then slightly rich................

You are thinking about what tuners do at high load areas on the map, adjust AFR, adjust timing.

When most people think about fuel economy they think about non WOT driving.

The vast majority of tunes do not at all affect what the car does when you are going 70 mph at 2200 rpm (or whatever it actually is) at very low throttle settings.


So your statement of running it leaner might be true, but that is not an across the board running it leaner, it is much more complicated then that, and they adjust the AFR based on engine load/rpm and possible other things.

OEM does a very good job of getting the best economy/emissions at low load, and a tuner will have a hard time bettering that. Is it possible to get better fuel economy from a tune? Yes, but almost always at the expense of emissions, as the economy/emissions are not the same things. Either way, most tunes don't touch this stuff.

If you still don't understand, I can post up screen shot of AFR tables to illustrate.

[NWS4Guy]

APR runs leaner than stock.

I have an observation, possibly a concern. If running a lower F:A (richer, more fuel, whatever you want to call it) to get more performance, it only stands to reason that there will also very likely be a larger % of unburned fuel per 4 stroke cycle. With the DI and notoriously inefficient factory solution to remove the garbage that is unburned and put back into the system to reburn - will a richer tune be more likely to have faster/more CB?

[jeffc31337]

One thing to keep in mind here is that we are basing all this conversation off of logs from WOT runs. A tuner may choose to run richer than stock at WOT but at the same time run leaner at part throttle operations where drivers spend most of their time and mileage is affected most.

If a driver was at WOT all the time then we could tell something from the logs. However without access to the calibration in the ECU or part throttle logs there is no way for us to know how mileage will be affected. Other than annecdotally after people have used it for a while.

[SpeedSourceS4]

I've had the APR Stage 1 tune since about 1000 miles. Fuel economy is about the same as stock for me, but I put my foot in it multiple times a day.

http://www.fuelly.com/driver/justingr/s4

[Leor604]

Thanks, everyone, for the replies. Great stuff!

It seems in normal daily driving, there isn't any real penalty (and maybe a tiny bonus) with APR V1. Revo, not enough data other than those who are legging it and getting worse mileage. Of course, this is totally expected. You simply can't expect to hoon it, stock or tuned, and get good mileage. Even stock I was only getting 7 mpg on the track. How much worse could it get, lol.

jeffc31337, you're totally right. Revo is running richer than APR at WOT but we don't know what is happening under normal conditions. Hope Revo (and GIAC) users will continue to add to this thread as they gather more data.

If the only differences are at WOT, then mileage differences probably won't be a factor in deciding which tune to get. Just don't want a major hit for the 98% of the time I'm not at WOT, but that doesn't seem like it will be an issue with any of the tunes.

Keep the info coming!

[dawei213]

Revo tune here. Just took a 290 miles, 100% highway, round trip from Philadelphia to Washington, D.C. Average speed, 70 mph. Here's the reading with the calculated mileage left and the fuel gauge.



Here's the calculated mpg.


I fueled up before I left with the calculated mileage left right around 5 miles and right at the bottom of the fuel gauge. I added 15 gallons. Based on that, the actual or closer real world mpg is 27.3 mpg.

I took an identical trip last month to the same destination. I don't have any images but I remember the calculated mpg just below 27 mpg (I was trying to break the 27mpg mark). Around the same average mph. Weather condition was slightly warmer.

Did the Revo tune cause the bump in mpg? I can't say. It may or may not have. This is only one sample. But it sure didn't hurt or decrease it.

As for my city driving, it's definitely lower, but that's my fault. I've gone WOT almost everyday. Just too hard and to resist the power and it's just so much fun.

[clochner]

28.3mpg?? That's insane, man! I barely touch 20 when driving for a while on the highway . . .

Do u drive in Comfort mode (assuming u have sport diff)?

[Lloyd_Christmas]

I have APR stg II and track my fuel consumption on Fuelly - I saw no discernible change in fuel economy when I switched from stock.

[Lloyd_Christmas]

I have APR stg II and track my fuel consumption on Fuelly - I saw no discernible change in fuel economy when I switched from stock (but I only average 17mpg - damn LA traffic!).

[mkato13]

when I drive on the highway(all highway) I can get 27-28mpg for he trip. I have seen a projected 400-410miles for the tank. Didnt get it cause I cant keep foot off gas

[dawei213]

28.3mpg?? That's insane, man! I barely touch 20 when driving for a while on the highway . . .

Do u drive in Comfort mode (assuming u have sport diff)?

I was on a 290 mile trip. Pretty much all highway, save the 0.5 miles from the gas station to the highway on ramp. You should definitely get more than 20 mpg. Yeah, comfort mode on highway.

[tomh009]

Revo tune here. Just took a 290 miles, 100% highway, round trip from Philadelphia to Washington, D.C. Average speed, 70 mph. Here's the reading with the calculated mileage left and the fuel gauge.

(...)

I fueled up before I left with the calculated mileage left right around 5 miles and right at the bottom of the fuel gauge. I added 15 gallons. Based on that, the actual or closer real world mpg is 27.3 mpg.

That's very impressive ... is that pretty clean cruising at 70-75 mph, or a fair bit of traffic with sprints to higher speeds? (I cruise at 130 km/h ie 85+ mph so that hurts my mileage some.)

[dawei213]

That's very impressive ... is that pretty clean cruising at 70-75 mph, or a fair bit of traffic with sprints to higher speeds? (I cruise at 130 km/h ie 85+ mph so that hurts my mileage some.)

Clean cruising around 65-75 mph, hence average around 70 mpg. The stretch of highway for the round trip is pretty flat. I wanted to see if I can break the calculated 27mpg again but was surprised I got the the calculated 28.3 mpg.

[Stereodude]

Clean cruising around 65-75 mph, hence average around 70 mpg.

There's no need for anyone to buy a Prius then.

[socfan12]

That's very impressive ... is that pretty clean cruising at 70-75 mph, or a fair bit of traffic with sprints to higher speeds? (I cruise at 130 km/h ie 85+ mph so that hurts my mileage some.)

That is impressive. The best I get on a highway is around 24mpg, cruising around 80-85. Around town, I get just 17mpg.

28.3mpg?? That's insane, man! I barely touch 20 when driving for a while on the highway . . .

Do u drive in Comfort mode (assuming u have sport diff)?

clochner, that sounds pretty low for highway. How heavy is that right foot of yours? Are you constantly doing sprints for passing? What's your cruising speed?

[PsYkHoTiK]

That is impressive. The best I get on a highway is around 24mpg, cruising around 80-85. Around town, I get just 17mpg.

I get around the same as well. How many miles do you have on yours Allen?

[socfan12]

About 6500. And you?

[clochner]

clochner, that sounds pretty low for highway. How heavy is that right foot of yours? Are you constantly doing sprints for passing? What's your cruising speed?

Haha - well I really don't drive the car that often (none @ all lately since my car has been in the shop for the past 2 1/2 weeks ), but my low fuel economy is probably b/c I don't shift higher than 5th most of the time on the highway. I love having all the power ready at every second - rather than waiting for the tranny to select the right gear before the power kicks in. Needless to say, I ALWAYS drive in Dynamic. I don't think I've spent more than 2 minutes w/ Comfort mode since buying the car.

[PsYkHoTiK]

About 6500. And you?

~11000. I recall that fuel mileage improved as the car got more "broken in" to a certain degree.