Are turbo engines more efficient when driven hard?
07-24-2015, 06:33 PM
#16
Burning Brakes
To make horsepower you must burn fuel. If you are making 400hp with a 4cyclinder turbo intercooled engine, that engine will be burning very close to the fuel burn of a NA big inch V8 making 400hp. There is no free lunch. Electronic fuel injection and direct injection have increased thermal efficiency and lowered emissions as a result. When I was driving my 993tt in 6th at a steady 65mph it got 22mpg. My 991C2S, also a 400hp engine, driven the same way in 6th (I never use 7th) it returns 28mpg. The new Corvette delivers similar mpg with that big V8 lumbering along at 65. The coming prevalence of turbo 4's in pedestrian cars and SUV's has weight saving advantages, as well as power when needed and low power, and therefor low fuel consumption, when just cruising along. I agree with the previous statement concerning Porsche. The know turbo charging, and they definitely know their customer base....Chris
07-24-2015, 07:47 PM
#18
My brother and I just bought 2 new 2015 Ford F-150 Platinum trucks with the 3.5L twin turbo eco-boost engine. Both of us are previous Ford truck owners, he a F-250 diesel, me a F-150 302 V8. We have been blown away by this new engine and truck. He just drove to the Keys this morning and called to tell me he is getting 1.5 mpg better mileage than his diesel did pulling the same boat, and I am getting over 2+ mpg better mileage than my V8. These trucks are quick too. Car and Driver say 5.6 sec to 60 and a 14.4 sec qtr. That's just crazy for a truck.
Anyway, I love my normally aspirated 3.8L 991 GTS, but if Ford can pull this kind of performance off with a freaking truck one can only imagine what the Porsche engineers will be able to do.
Anyway, I love my normally aspirated 3.8L 991 GTS, but if Ford can pull this kind of performance off with a freaking truck one can only imagine what the Porsche engineers will be able to do.
07-24-2015, 08:00 PM
#19
Burning Brakes
Great post Chuck. It was sad to see that the Wittington brothers had to go to prison for distributing the drugs that I enjoyed at the time. They are both wiser now, as am I....Chris
07-24-2015, 08:03 PM
#21
Rennlist Member
Been lurking around these Porsche forums for a while now. I don't post since I am just here to gather some intelligence on any long term issues with the 991 generation before purchasing one a year or two down the road.
But responses such ones written in this thread is getting a little ridiculous. I get it, we all love fast cars, nice sounding exhaust, and engines with instant throttle response. But downsizing the displacement and emission of internal combustion engines is by all mean necessary given bleak environment issues that we are facing. You can rant all you want, but there is simply no way to make a emission friendly NA engine that can compete with the rest of the cars in this price range.
Truth is, technology moves forward, whether you like it or not. Or else we would all be stuck driving lead burning, carburetor fueled engines with flat tapped valves that needs to be manually adjusted every few thousands miles. Porsche knows what they are doing, putting a pair of turbos on the flat six makes total sense for the non-GT 911, given the much needed torque in the mid range and more linear power delivery than a high stun GT engine. And if you understand the specs for the current NA engines that Porsches uses for their 911 range, you will realize that the development for these engines have truly reached an dead end. There is simply no way to further increase the power output without drastically increasing the displacement (hence the rumor'd flat-8) or going with forced induction, which is the more reasonable choice of the two.
After all, these are still 2.7-3.0 L flat six enigne with a conservative boost pressure (my guess is 10-18 psi, given the expected power output of 420hp), so the so called turbo lag will be nearly indistinguishable to most drivers here on this sub forum, considering very few owners here are actually tracking these cars and have the driving skills to push the chassis and the engine to their limit. And I am not even sure why some people here think the 991.2 will weight hundreds of lbs heavier than the 991.1... A pair of turbos and some extra plumbing for the intercoolers will add 50lbs max., and I bet Porsche will figure out a way to further reduce that number given their expertise in these areas. And really, there is NO WAY you can tell the difference of extra 50lbs in a modern street car that weights +3000lbs.
Sure, exhaust might sound different, and might lack the iconic raspiness of the NA flat 6. But it is a very minor trade off for the extra performance and better emission. And there are aftermarket solutions for these issues if you really care enough. Personally, I am very looking forward to a RWD 991 chassis paired with a potent turbocharged engine and latest PDK that I can enjoy on the street and track, without the harshness and compromises of the last gen GT2s. And honestly, if you want a "pure" 911 experience, just get a old gen like the 964, or the original 911 for god's sake... Even the 993 wasn't a "true 911" by the strictest definition, given the move from the traditional, lift-off oversteer happy, rear trailing arm suspension to the more modern and predictable multi-link setup in the 993.
But responses such ones written in this thread is getting a little ridiculous. I get it, we all love fast cars, nice sounding exhaust, and engines with instant throttle response. But downsizing the displacement and emission of internal combustion engines is by all mean necessary given bleak environment issues that we are facing. You can rant all you want, but there is simply no way to make a emission friendly NA engine that can compete with the rest of the cars in this price range.
Truth is, technology moves forward, whether you like it or not. Or else we would all be stuck driving lead burning, carburetor fueled engines with flat tapped valves that needs to be manually adjusted every few thousands miles. Porsche knows what they are doing, putting a pair of turbos on the flat six makes total sense for the non-GT 911, given the much needed torque in the mid range and more linear power delivery than a high stun GT engine. And if you understand the specs for the current NA engines that Porsches uses for their 911 range, you will realize that the development for these engines have truly reached an dead end. There is simply no way to further increase the power output without drastically increasing the displacement (hence the rumor'd flat-8) or going with forced induction, which is the more reasonable choice of the two.
After all, these are still 2.7-3.0 L flat six enigne with a conservative boost pressure (my guess is 10-18 psi, given the expected power output of 420hp), so the so called turbo lag will be nearly indistinguishable to most drivers here on this sub forum, considering very few owners here are actually tracking these cars and have the driving skills to push the chassis and the engine to their limit. And I am not even sure why some people here think the 991.2 will weight hundreds of lbs heavier than the 991.1... A pair of turbos and some extra plumbing for the intercoolers will add 50lbs max., and I bet Porsche will figure out a way to further reduce that number given their expertise in these areas. And really, there is NO WAY you can tell the difference of extra 50lbs in a modern street car that weights +3000lbs.
Sure, exhaust might sound different, and might lack the iconic raspiness of the NA flat 6. But it is a very minor trade off for the extra performance and better emission. And there are aftermarket solutions for these issues if you really care enough. Personally, I am very looking forward to a RWD 991 chassis paired with a potent turbocharged engine and latest PDK that I can enjoy on the street and track, without the harshness and compromises of the last gen GT2s. And honestly, if you want a "pure" 911 experience, just get a old gen like the 964, or the original 911 for god's sake... Even the 993 wasn't a "true 911" by the strictest definition, given the move from the traditional, lift-off oversteer happy, rear trailing arm suspension to the more modern and predictable multi-link setup in the 993.
07-24-2015, 08:04 PM
#22
Rennlist Member
Pssst. No government regulations did this:
https://en.wikipedia.org/wiki/1979_24_Hours_of_Le_Mans
https://en.wikipedia.org/wiki/1979_24_Hours_of_Le_Mans
07-24-2015, 08:35 PM
#23
Rennlist Member
Pssst. No government regulations did this:
https://en.wikipedia.org/wiki/1979_24_Hours_of_Le_Mans
https://en.wikipedia.org/wiki/1979_24_Hours_of_Le_Mans
The manufacturers, in turn, know what's coming based on regulatory pressures. In the near-term future they expect to be building cars with smaller engines with FI, and they expect to be building hybrids, and it is not the least bit coincidental that these trends are also emerging in F1 and LM.
In any event, this whole debate is transitional in nature, as almost anyone who has driven a Tesla will agree. Turbos (and hybrids, and anything else with an internal combustion engine) are a stopgap.
(Edit: I didn't see the '1979' part of your link earlier and thought you were referring to the 919's recent victory at LM, but the larger point stands.)
07-24-2015, 08:42 PM
#24
The move to turbos by all the manufacturers is 100% due to fuel economy/emission standards, period. Without the government mandates, the 911 would not be getting these turbos, so it is entirely tied to government regulations. And they've all said as much. I've yet to hear a single auto manufacturer say, 'yeah, we suddenly realized that turbo charging is the better way forward to getting a higher performing sports car…', but every one of them has started the discussion with 'in order to meet the pending fuel economy standards...' Do you think Ferrari would have gone turbo in the 488 if it didn't have to?
07-24-2015, 08:45 PM
#25
Instructor
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MORE GOVT B.S
07-24-2015, 09:12 PM
#26
Burning Brakes
Without government mandates there would be no EPA, FAA, FDA, etc. Read qSinclair Lewis to see what our country was like back before government regulation.
07-24-2015, 09:35 PM
#27
Race Director
Are turbo engines more efficient when driven hard?
Take the time to read. A very good article ...
"WE DON'T LIKE THE TURBO," SAID THE MAN WITH THE ITALIAN ACCENT
I'd like to hear any debate from anything in the article!
http://www.roadandtrack.com/car-cult...turbocharging/
"WE DON'T LIKE THE TURBO," SAID THE MAN WITH THE ITALIAN ACCENT
I'd like to hear any debate from anything in the article!
http://www.roadandtrack.com/car-cult...turbocharging/
Last edited by STG; 07-24-2015 at 10:03 PM.
07-24-2015, 09:42 PM
#28
Rennlist Member
The move to turbos by all the manufacturers is 100% due to fuel economy/emission standards, period. Without the government mandates, the 911 would not be getting these turbos, so it is entirely tied to government regulations. And they've all said as much. I've yet to hear a single auto manufacturer say, 'yeah, we suddenly realized that turbo charging is the better way forward to getting a higher performing sports car…', but every one of them has started the discussion with 'in order to meet the pending fuel economy standards...' Do you think Ferrari would have gone turbo in the 488 if it didn't have to?
That being said, one thing I definitely don't like is that turbocharging isn't cheap. Assuming these cars were priced correctly for their market before, they will now have to be priced too high to accommodate the new engines that are more expensive to build and warranty. Either that, or -- worse -- the value will be taken out of the car somewhere else.
If there is not a substantial price increase on the 991.2s, it will mean the latter has happened. Porsche will not give up their margins, not even at gunpoint.
07-24-2015, 09:46 PM
#29
Race Director
Are turbo engines more efficient when driven hard?
Originally Posted by Noah Fect
Porsche will not give up their margins, not even at gunpoint.
07-24-2015, 10:04 PM
#30
Rennlist Member
Take the time to read. A very good article ...
"WE DON'T LIKE THE TURBO," SAID THE MAN WITH THE ITALIAN ACCENT
http://www.roadandtrack.com/car-cult...turbocharging/
"WE DON'T LIKE THE TURBO," SAID THE MAN WITH THE ITALIAN ACCENT
http://www.roadandtrack.com/car-cult...turbocharging/
That particular article skips a lot of technical details just FYI.
Now remember the turbines are powered by the exhaust flow, and the only way to notice any significant lags in these turbo setups, which typically uses an undersize turbine/compressor combo to drastically minimize the spool up time, is by flooring the engine at very low rpm range from 1500-2000rpms, considering the engine is producing a lot of exhaust gas volume to spin up the turbines to the full boost. You are really not losing much, because if you do the same in a high revving NA engine like the flat 6 in these cars, you won't get much tq/hp out of them at that rpm range anyway. At higher rpms, with the correct fueling and wastegate mapping of the turbos, lag should be virtually unnoticeable for these engines (these are not some heavily boosted inline-4 with tiny 1.4-2.0 L displacement after all...)
Seriously, I am a little tired of these "turbo bashing" that's going on these days on the forums. Turbos are the best technical solution we have at the moment to meet the emission standard, which honestly should be there to push the manufacturers to develop cleaner technology so our cities don't end up covered in smog like 1950s London or Beijing is like these days.
If you like NA engines that's fine, but these blind hate toward new technology is just silly. Go take a extended test drive on a modern turbocharged sports car, or better yet, take one to the track, turn off the stability and traction control, explore its limit if your driving skills are up to the challenge. And then let us know if you still think turbo engines are craps...