Feb 12, 2017 12:23:17 PM
- Carlos from Spain
- Rennteam Moderator
- Loc: Spain. , Spain
- Posts: 21156, Gallery
- Registered on: Feb 9, 2003
- Reply to: bluelines
Feb 12, 2017 12:23:17 PM
Feb 12, 2017 12:32:38 PM
Nick, who drives at full throttle? Very few... So the smaller turbo engine will use less. I went from 14MPG with the Cayenne to 19MPG with the Macan... In that department there is something fishy about the RRS supercharged, trip computer says 18.5 MPG, real measurements indicate 15.5 MPG which is quite disappointing vs the 8 year old Cayenne with more hp.
Engine designs are different for high and low performance application. Testing for consumption in a low performance car at high performance makes about as much sense as testing a high performance car at low performance.
The term "fuel efficiency" implies efficient driving. It doesn't really make sense to discuss the efficiency of an engine if you're not actually trying to drive efficiently.
noone1:
The term "fuel efficiency" implies efficient driving. It doesn't really make sense to discuss the efficiency of an engine if you're not actually trying to drive efficiently.
+1
2015 981 Cayman GT4 | Powerkit White - The fastest car on Rennteam
2013 Audi S3 | Glacier White
It's not even about full throttle.
For the government test cycles, the throttle application is so light that one only needs about 50hp or less to complete the test. Try doing that acceleration from a stop light in LA or Chicago or New York, you will be shot 100 times before you grab 2nd gear.
Even dip into the throttle partially, say 1/3 or 1/2, to mimic real world driving would have already greatly reduced the gas mileage of a boosted car.
All manufacturers 'cheat' this way. They know full well how much throttle application is during testing. The optics is good if they down size to a smaller capacity engine, people are stupid, they only see a smaller capacity engine, and it must be better on gas than a bigger one. Well that statement is partially true, there is next to nothing load on an engine at test cycles, zero boost needed, and with the smaller capacity of course they will tested to be more fuel efficient.
But at the end of the day, what is fuel efficiency? How do one define that? To extract the maximum energy out of a given amount of fuel? Or make a given amount of fuel goes the farthest?
High performance engines are designed to extra the maximum amount of energy from any given amount of fuel, so as to not waste any potential energy stored in fossil fuel. Isn't that efficiency?
One of the popular eco engine is the Ford 2.0L EcoBoost, 245HP. It runs 17psi of boost with a 10:1 compression ratio, quite high for a turbo car for 'efficiency' sake. But it actually only coverts to 56.7HP/L. Not so efficient now.
I think if the governments wake up and realize their testing cycle has nothing to do with real world driving, and start changing the tests to mimic real world, boosted engines will not be in favour again, and a come back for NA engines will be a real possibility. Especially after diesel gate, they finally realized their tests can be fudged easily.
--
Whoopsy:
One of the popular eco engine is the Ford 2.0L EcoBoost, 245HP. It runs 17psi of boost with a 10:1 compression ratio, quite high for a turbo car for 'efficiency' sake. But it actually only coverts to 56.7HP/L. Not so efficient now.
And that's one big problem with your argument -- Ford doesn't care how much power the car has or how efficient it is in power output. Ford needs an engine that is W big, gets X mpg on the highway, costs Y dollars, puts out a good-enough Z hp. Oh, and it has to have emissions of V.
HP/liter isn't really an important metric for all scenarios.
I'd also point out that the great NA engines in recent memory are horrendously inefficient regarding fuel consumption, no matter how you drive them, even using the crappy government texting standards. The Huracan is rated at an abysmal 13/21. The 458 is rated at 13/17.
Whoopsy:High performance engines are designed to extra the maximum amount of energy from any given amount of fuel, so as to not waste any potential energy stored in fossil fuel. Isn't that efficiency?
That's not how it works. If it did work like that, all cars would cruise at more or less the same fuel efficiency, but they don't. A Ferrari 458 won't get anywhere near the fuel economy of a tiny turbo engine on the highway.
Fuel efficiency is not simply based on power output.
noone1:Whoopsy:High performance engines are designed to extra the maximum amount of energy from any given amount of fuel, so as to not waste any potential energy stored in fossil fuel. Isn't that efficiency?
That's not how it works. If it did work like that, all cars would cruise at more or less the same fuel efficiency, but they don't. A Ferrari 458 won't get anywhere near the fuel economy of a tiny turbo engine on the highway.
Fuel efficiency is not simply based on power output.
And your idea of fuel efficiency is very different than mine.
I prefer not to waste gasoline into simply heat and friction. I would rather they be productive, making HP.
My Honda Odyssey is suppose to get 22 mpg combined, that's about 10.7L/100km. but because it has no power and has to be stepped on just to accelerate in a normal fashion, it ended up doing around 18L/100km. In comparison, my 918 does just under 15L/100km combined, My Cayenne Turbo S, supposed to be a gas hog because of the HP, is doing 16.8L/100km. Hell even my Huracan is only doing 16 and change L/100km.
Not counting the Ferraris, my least powerful car is the most fuel inefficient. Actually it tied with the SVR.
Very interesting topic, but maybe too much on therory and not practical?
Whenever I care about fuel efficiency, it is always because I try to stop less often at the pump, not because about the price to fill up the tank. For example I was hoping to fill up every three trips vs two that I do weekly with the Macan and RRS. They both fail despite being turbo engines and driven mostly with auto cruise control on. They are "inefficient".
Your RRS is turbo? I thought they were supercharged at least mine is.
on a similar subject, I has my RRS and Targa in for service. For loaners Iwas given a Discovery and a 2017 Cayenne with 400 miles on it. Both were a huge disappointment. My Honda CRV at a third of the cost of the Discovery was a much better SUV in every way. The Cayenne felt like was I was driving a bloated behemoth. It struggled to get off the line smoothly and was subject to frequent surges if you gave more throttle. Just a horrible driving experience.
Also, the Discovery sucked fuel worst than my RRS. 😩
"A man wrapped up in himself makes for a very small bundle."
No the SVR is supercharged. That's why I used boosted, not turbo-ed.
Discovery is one of the worse ever SUV, it moves like a giant elephant, I had one before, the only other SUV that I got rid of faster was a RX300.
I agreed, the regular Cayenne, with the V6 is a pig, that's why I have the Turbo S
Feb 13, 2017 9:47:44 AM
noone1:No, you'd prefer to waste gasoline by pointlessly accelerating quicker simply because you think it feels slow.
It may be pointless to you but driving styles differ and you are not the judge of which is right, personally I cannot stand "Sunday drivers" in traffic for example... safe to say it appears I will much rather be behind Whoopsy in traffic than you
⇒ Carlos - Porsche 991 Carrera GTS
Feb 13, 2017 3:42:14 PM
Whoopsy:No the SVR is supercharged. That's why I used boosted, not turbo-ed.
Discovery is one of the worse ever SUV, it moves like a giant elephant, I had one before, the only other SUV that I got rid of faster was a RX300.
I agreed, the regular Cayenne, with the V6 is a pig, that's why I have the Turbo S
Latest Sport Discovery looks nice though.
noone1:No, you'd prefer to waste gasoline by pointlessly accelerating quicker simply because you think it feels slow.
I drive all the time as fast as traffic and traffic laws permit. Only exception is when driving in the city, I am more relaxed in the city. Wasting gasoline? Maybe. Do I care? Not really.
RC (Germany) - Rennteam Editor Porsche 991 Carrera 4 GTS Cabriolet (2015), Porsche Cayenne S Diesel (2017), Audi R8 V10 Plus (2016), Mini JCW (2015)
Feb 14, 2017 9:16:04 PM
Feb 14, 2017 9:24:33 PM
Feb 14, 2017 9:29:47 PM
I won't have my own pics for a while.
Car is not local, by the time everything is said and done it should be at my dealership next week. But I won't be around as I am flying off to Europe Monday night. Not returning till March 12th. I guess I won't miss it much as I will be driving my 911R in Europe first, and then when I come back I can drive this thing while I wait for the 911R to come back
My dealer is going to give it a once over, pretty much a standard service with oil change, brake adjustment and possibly engine tune up and stuff while I am gone. Hell I might even have the tires changed. I believed someone had put Cup2s on it right now. I think i might even have them install the Porsche Classic Radio too. Car currently has an aftermarket exhaust on it, I am debating whether to take advantage of Porsche Classic to install the OEM exhaust back on.
As for back story, well it was for sale and I and the seller agreed on a good price and be done with it. It was originally an American car that got imported to Canada, so I won't have to do the dirty work of importing a car. It has like 31k miles on it.
--
Feb 14, 2017 9:37:04 PM
Carlos from Spain:964T 3.6L? ...called it!! was wrong on the first one but not the second... I was just too far ahead
To be picky, the Turbo version of the 964 is actually designated a 965...
73 Carrera RS 2.7 Carbon Fiber replica (1,890 lbs), 06 EVO9 with track mods. Former: 16 Cayman GT4, 73 911S, Two 951S's, 996 C2, 993 C2, 98 Ferrari 550, 79 635CSi
Whoopsy:I won't have my own pics for a while.
Car is not local, by the time everything is said and done it should be at my dealership next week. But I won't be around as I am flying off to Europe Monday night. Not returning till March 12th. I guess I won't miss it much as I will be driving my 911R in Europe first, and then when I come back I can drive this thing while I wait for the 911R to come back
My dealer is going to give it a once over, pretty much a standard service with oil change, brake adjustment and possibly engine tune up and stuff while I am gone. Hell I might even have the tires changed. I believed someone had put Cup2s on it right now. I think i might even have them install the Porsche Classic Radio too. Car currently has an aftermarket exhaust on it, I am debating whether to take advantage of Porsche Classic to install the OEM exhaust back on.
As for back story, well it was for sale and I and the seller agreed on a good price and be done with it. It was originally an American car that got imported to Canada, so I won't have to do the dirty work of importing a car. It has like 31k miles on it.
--
Congratulations! Nice addition- I have a predilection for modified 964s .