![]() |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
![]() |
lapuwali |
![]()
Post
#1
|
Not another one! ![]() ![]() ![]() ![]() Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 ![]() ![]() |
1 US gallon of gasoline contains 104,000 BTUs of energy.
1hp = 2,540 BTU/hour of energy consumption. A typical car requires about 9hp to cruise at 60mph, given aero loads and rolling resistance from tires. So, if engines were 100% efficient at extracting energy from gasoline, you'd get 273 mpg at 60mph in a typical car. Since most cars actually get less than 30mpg, most engines are extracting roughly 10% of the energy in the gas and applying those to actually propelling the car. Most of the energy is being thrown out as waste heat directly out of the exhaust, or in heating up the coolant, the engine itself, the gearbox, and the tires. btw, hydrogen has 180,000 BTU/US gal, so if a liquid H2 fuelled engine were produced that only had the same efficiency as a 27mpg gasoline engine, you'll see 45mpg typically. Pure ethanol has only 70,000 BTU/US gal, for only 18mpg. E85 would bring this up to 20mpg. Britt noted E85 where he lived was $2.10/gal v. $2.58/gal for gasoline, meaning E85 costs 81% as much, but only takes you 74% as far... Now, as for the efficiency of a Mr. Fusion powered car... |
![]() ![]() |
TimT |
![]()
Post
#2
|
retired ![]() ![]() ![]() ![]() Group: Members Posts: 4,033 Joined: 18-February 03 From: Wantagh, NY Member No.: 313 ![]() |
I get 22 mpg out of my F250 when unladen, when Im towing I get about 14 mpg
Home brew biodiesel is something to consider, though you have to use some nasty chemicals to make the diesel, and are left with glycerin as a byproduct that you have to dispose of in a nutshell you take Lye, and Methanol, and mix that, which become methoxide... some nasty schtuff mix that with veggie oil.. swirl wait... pour off the diesel, dispose of the glycerin, wash the diesel. Ive read of people brewing their own BioD for about sixty cents/gallon. Im not sure if these people factor there own time into the equation though. (IMG:http://www.914world.com/bbs2/html/emoticons/hijacked.gif) |
![]() ![]() |
![]() |
Lo-Fi Version | Time is now: 16th July 2025 - 03:51 PM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |