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You got 37MPG in a (I guess they're technically "compact") SUV with a gasoline (petrol) engine? I'm just having a really hard time with that. That's in the same

by zucked 4y ago

You got 37MPG in a (I guess they're technically "compact") SUV with a gasoline (petrol) engine? I'm just having a really hard time with that. That's in the same ballpark as what diesel wagons get (the TDI Sportwagen sees a real world ~43 MPG) and the Q5 isn't exactly a svelte profile, aerodynamically speaking. Did this roadtrip consist of large amounts of elevation loss? I just have a really hard time understanding how you bested the EPA estimates by almost 28% while cruising at 70+ MPH. I roadtrip in an Outback wagon that can manage somewhere near 30MPG if I keep my foot out of it and is a similar footprint to a Q5, if not a bit more aerodynamic.

selykg 4y ago
If you tailgate someone you can get that magical reduction in air resistance which can increase fuel economy. I hate driving on busy roads for this reason, some jack hole will always be right on my ass and I can't even see their headlights.
- zucked 4y ago
  If OP has their cruise control set at 72MPH and is tailgating close enough that they benefit from the slipstream, I'm 1.)impressed at their precision driving 2.) terrified we may share the road some day. I don't doubt that we may someday achieve more autonomous highway cruising where vehicles take 'lead' and 'follow' positions within feet of each other to benefit from drafting, but humans doing it scares me senseless.
  - aaaaaaaaata 4y ago
    In both cases, it's a 10MPH collision at worst...unless car in front is a talentless driver.
t-3 4y ago
He filled up with 93, that's where the gains are from. Try it sometime, you'll be surprised!
- elil17 4y ago
  That's not true. Gasoline has approximately the same energy content per gallon regardless of octane rating. In Car and Driver's tests, high octane fuel made a difference of less than 1 mpg. Some high performance engines are designed to use high octane fuel, but there is no reason to use it on normal engines in normal conditions. https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/ https://www.caranddriver.com/features/a28565486/honda-cr-v-v...
  - aaaaaaaaata 4y ago
    > Some high performance engines Which are...almost every lease I see running around, now. Lots of cars adjust based on what's flowing in, too.
    - elil17 4y ago
      Even those don't see an MPG benefit from high octane - just a torque benefit.
- taylodl 4y ago
  Seriously? Honest question - how does that work? I've always heard that paying for a higher octane fuel than required by your engine is just "throwing your money away." But if you're saying, at least on the highway, if I can get a 28% gain in fuel efficiency while only paying 20% more for the fuel then I'm interested!
  - chucksta 4y ago
    No, thats not what that number is for at all. You heard right, octane is a rating for its stability to premature detonation https://www.eia.gov/energyexplained/gasoline/octane-in-depth.php#:~:text=Octane%20ratings%20are%20measures%20of,ignite)%20in%20a%20testing%20engine https://www.eia.gov/energyexplained/gasoline/octane-in-depth....
- yodon 4y ago
  Every car I've owned, I've done a compare and contrast on 91 or 93 vs 87 octane gas. Each time I do the comparison I find that the cost per mile (not cost per gallon) is lower with the higher octane gas. The only time I buy 87 is if I need to fill up a rental car just before returning it.
elil17 4y ago
Long trips with no traffic in warm weather (but not so warm as to require a lot of AC) are more efficient for an ICE vehicle per mile than the average trip. OP probably lucked into the right conditions
- azth 4y ago
  Why is warm weather more efficient than cold out of curiosity? I would have guessed that cold air being denser means better efficiency.
Kon-Peki 4y ago
Excellent questions. It was a there-and-back trip, so every foot of elevation lost was also re-climbed (about 100 feet overall - the midwest is pretty flat). This car has Audi's "energy recuperation system", which is actually a "mild hybrid" system but you'll never see those words on the website or Monroney or any advertising - "mild hybrid" has a terrible public reputation despite the fact that it works (but doesn't have much of an effect on the EPA test cycle). Almost every single Audi (and Volvo) sold in the US has this system. It is also the base model, so the tires and wheels are the base 18-inchers which weigh a LOT less than the 20+ inch wheels that everyone loves (and kill fuel economy). The transmission gear ratios are perfectly matched for the speeds I choose. I use high-quality gasoline from Costco, etc. Go read other people on Audiworld or other forums. I'm not an outlier. These modern turbo engines are great for highway cruising, but drink fuel like it's free if you want "spirited driving".
- zucked 4y ago
  As far as I can tell, you won't see "hybrid" on Audi's site because the "energy recuperation system" isn't a hybrid system at all -- it simply banks energy from the alternator and then reduces the load on the alternator (and the load on the engine, as a byproduct) when requested, allowing the car's energy needs to be drawn off the battery during that time instead. From Audi's literature: >While the vehicle is coasting or braking, the alternator voltage is raised above the level of the basic electrical system. During these phases the alternator can convert the vehicle’s kinetic energy into electrical energy, which is stored temporarily in the vehicle battery. When the vehicle subsequently accelerates or is driven at constant speeds, this energy is used to relieve the load on the alternator, allowing a fuel saving of up to 3%, depending on the driving cycle. I am fully aware of how efficient a modern turbo engine can be, and perhaps you did, in fact, best the EPA estimates. Did you calculate these numbers yourself, or rely on the onboard computer?
  - Kon-Peki 4y ago
    I keep track of everything myself. That's fine, we don't have to call it a mild hybrid. But whatever you want to call it, it's working really well on my car. It only has about 7k miles on it, but the efficiency keeps getting better as it breaks-in. I have to imagine that this is probably as good as it will get. Let me ask you something, though: if I went back and edited the original post to say 30 mpg, would you agree that how someone drives makes a huge difference in their fuel costs. Because that was my main point :)
phil21 4y ago
Sounds about right to me. I have the wagon version of this vehicle (A6 Allroad) which has pretty much the same engine and similar weight, just different aerodynamic profile. If you put it in cruise and don't go fast I can hit just under 40 - but I've only had it for a couple months. This is for a 21/28 rated vehicle. Forum posts seem to validate this as well. City driving it's exactly what you'd expect - couple miles under EPA estimates. Edit: this is manually calculated, but with a sample size of one. Strangely the onboard computer seems to underestimate in this vehicle, which is the exact opposite of every other car I've driven. Probably the most unexpected bit of owning this car so far.

by zucked 4y ago

selykg 4y ago

If you tailgate someone you can get that magical reduction in air resistance which can increase fuel economy. I hate driving on busy roads for this reason, some jack hole will always be right on my ass and I can't even see their headlights.

zucked 4y ago
If OP has their cruise control set at 72MPH and is tailgating close enough that they benefit from the slipstream, I'm 1.)impressed at their precision driving 2.) terrified we may share the road some day. I don't doubt that we may someday achieve more autonomous highway cruising where vehicles take 'lead' and 'follow' positions within feet of each other to benefit from drafting, but humans doing it scares me senseless.
- aaaaaaaaata 4y ago
  In both cases, it's a 10MPH collision at worst...unless car in front is a talentless driver.

t-3 4y ago

He filled up with 93, that's where the gains are from. Try it sometime, you'll be surprised!

elil17 4y ago
That's not true. Gasoline has approximately the same energy content per gallon regardless of octane rating. In Car and Driver's tests, high octane fuel made a difference of less than 1 mpg. Some high performance engines are designed to use high octane fuel, but there is no reason to use it on normal engines in normal conditions. https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/ https://www.caranddriver.com/features/a28565486/honda-cr-v-v...
- aaaaaaaaata 4y ago
  > Some high performance engines Which are...almost every lease I see running around, now. Lots of cars adjust based on what's flowing in, too.
  - elil17 4y ago
    Even those don't see an MPG benefit from high octane - just a torque benefit.
taylodl 4y ago
Seriously? Honest question - how does that work? I've always heard that paying for a higher octane fuel than required by your engine is just "throwing your money away." But if you're saying, at least on the highway, if I can get a 28% gain in fuel efficiency while only paying 20% more for the fuel then I'm interested!
- chucksta 4y ago
  No, thats not what that number is for at all. You heard right, octane is a rating for its stability to premature detonation https://www.eia.gov/energyexplained/gasoline/octane-in-depth.php#:~:text=Octane%20ratings%20are%20measures%20of,ignite)%20in%20a%20testing%20engine https://www.eia.gov/energyexplained/gasoline/octane-in-depth....
yodon 4y ago
Every car I've owned, I've done a compare and contrast on 91 or 93 vs 87 octane gas. Each time I do the comparison I find that the cost per mile (not cost per gallon) is lower with the higher octane gas. The only time I buy 87 is if I need to fill up a rental car just before returning it.

elil17 4y ago

Long trips with no traffic in warm weather (but not so warm as to require a lot of AC) are more efficient for an ICE vehicle per mile than the average trip. OP probably lucked into the right conditions

azth 4y ago
Why is warm weather more efficient than cold out of curiosity? I would have guessed that cold air being denser means better efficiency.

Kon-Peki 4y ago

Excellent questions. It was a there-and-back trip, so every foot of elevation lost was also re-climbed (about 100 feet overall - the midwest is pretty flat). This car has Audi's "energy recuperation system", which is actually a "mild hybrid" system but you'll never see those words on the website or Monroney or any advertising - "mild hybrid" has a terrible public reputation despite the fact that it works (but doesn't have much of an effect on the EPA test cycle). Almost every single Audi (and Volvo) sold in the US has this system. It is also the base model, so the tires and wheels are the base 18-inchers which weigh a LOT less than the 20+ inch wheels that everyone loves (and kill fuel economy). The transmission gear ratios are perfectly matched for the speeds I choose. I use high-quality gasoline from Costco, etc. Go read other people on Audiworld or other forums. I'm not an outlier. These modern turbo engines are great for highway cruising, but drink fuel like it's free if you want "spirited driving".

zucked 4y ago
As far as I can tell, you won't see "hybrid" on Audi's site because the "energy recuperation system" isn't a hybrid system at all -- it simply banks energy from the alternator and then reduces the load on the alternator (and the load on the engine, as a byproduct) when requested, allowing the car's energy needs to be drawn off the battery during that time instead. From Audi's literature: >While the vehicle is coasting or braking, the alternator voltage is raised above the level of the basic electrical system. During these phases the alternator can convert the vehicle’s kinetic energy into electrical energy, which is stored temporarily in the vehicle battery. When the vehicle subsequently accelerates or is driven at constant speeds, this energy is used to relieve the load on the alternator, allowing a fuel saving of up to 3%, depending on the driving cycle. I am fully aware of how efficient a modern turbo engine can be, and perhaps you did, in fact, best the EPA estimates. Did you calculate these numbers yourself, or rely on the onboard computer?
- Kon-Peki 4y ago
  I keep track of everything myself. That's fine, we don't have to call it a mild hybrid. But whatever you want to call it, it's working really well on my car. It only has about 7k miles on it, but the efficiency keeps getting better as it breaks-in. I have to imagine that this is probably as good as it will get. Let me ask you something, though: if I went back and edited the original post to say 30 mpg, would you agree that how someone drives makes a huge difference in their fuel costs. Because that was my main point :)

phil21 4y ago

Sounds about right to me. I have the wagon version of this vehicle (A6 Allroad) which has pretty much the same engine and similar weight, just different aerodynamic profile. If you put it in cruise and don't go fast I can hit just under 40 - but I've only had it for a couple months. This is for a 21/28 rated vehicle. Forum posts seem to validate this as well. City driving it's exactly what you'd expect - couple miles under EPA estimates. Edit: this is manually calculated, but with a sample size of one. Strangely the onboard computer seems to underestimate in this vehicle, which is the exact opposite of every other car I've driven. Probably the most unexpected bit of owning this car so far.