|
09-05-2007, 06:13 PM | #1 |
Drives: 2007 Black Yaris sedan Join Date: Sep 2006
Location: Atlanta
Posts: 884
|
MUST READ!!! MPH to RPM to Time ratios,gas savings!
Mph /Rpm /Rpm÷mph /Time to drive 60 miles
45 /1940 /43.111 /1h20m 50 /2150 /43 /1h12m 55 /2360 /42.90 /1h6m 60 /2575 /42.916 /1hour 65 /2770 /42.615 /55minutes 70 /2990 /42.714 /51m 75 /3200 /42.666 /48m 80 /3380 /42.25 /45m 85 /3660 /43.058 /42m 90 /3840 /42.666 /39m I understand these ratios only stand true for my 1NZ-FE 1.5,but yours are very similar,if not exactly the same.So it looks like your efficiency actually improves slightly at higher MPH's until you hit 85mph,this is shown by dividing the rpm by the mph. Now on to the time issue,so the car is just as efficient at higher mph's,so you should only be worried about how fast you need to be some where.Please feel free test this yourself,use cruise control at set speeds on flat road,take the average rpm (it was easy for me,I have scangauge,set to update fast),now write that down,use 5mph levels. Last edited by eco; 09-05-2007 at 10:29 PM. |
09-05-2007, 06:28 PM | #2 |
Steals terrorist's lunch
Drives: 2007 Yaris Liftback Join Date: Mar 2007
Location: Reno, Nevada, USA
Posts: 1,299
|
Your data is severely flawed as it omits 3 critical factors:
1) Engine resistance at high RPM 2) Wind resistance 3) Rolling resistance With those in place fuel efficiency begins to fall off above 55 MPH, drastically so above 65 MPH.
__________________
- Brian Share the Road I often carry 2 carpool passengers and mountain bikes or snowboards/skis over a 4,500 foot elevation difference. Click the graphic above to see my detailed mileage logs. |
09-05-2007, 10:28 PM | #3 |
Drives: 2007 Black Yaris sedan Join Date: Sep 2006
Location: Atlanta
Posts: 884
|
That may be ture,I always thought your rpm was the true test of what forces are being put on the car,picture yourself going uphill,higher rpm,even though your trying to stay at a set speed,think about it.If the car was being affected so much,then why dosnt it show in a higher rpm/mph ratio when divided compared to a lower mph.
|
09-05-2007, 11:46 PM | #4 |
Drives: 2007 Black Yaris sedan Join Date: Sep 2006
Location: Atlanta
Posts: 884
|
Also,I was not behind any car while testing,but in real world conditions,driving in this area,its hard not to be near a car any where from 55-95 here in Atlanta,and metro Atlanta.So if even minor drafting,lets say wind resistance is dropped by 20-30%,and keep in mind "TIME IS MONEY",its still way better then driving 55mph,you might remeber that song.
|
09-06-2007, 05:19 PM | #5 |
Drives: 2007 Black Yaris sedan Join Date: Sep 2006
Location: Atlanta
Posts: 884
|
I guess no one else has any feed back,damn,I can take negative feed back,but I still believe in my numbers.
|
09-06-2007, 09:49 PM | #6 |
Desperauto's Son...
|
Here's good data to include as well....
Realistically, the force of air resistance from 55+ is crazy.... and it takes much more hp at 65 than 55 to go against the wind resistance of a vehicle... even more so at 75,85, 95, etc.... Here's info from a physics dude who worked out for a situation about how much HP is takes to overcome wind drag at certain speeds... (HIGHLY effecting MPG) These are for the drag of a CORVETTE, so our drag is probably MUCH, MUCH more... making these numbers worse... 30 MPH - 1.16 hp 55 MPH - 7.14 hp 65 MPH - 11.8 hp 75 MPH - 17.12 hp 90 MPH - 31.3 hp 120 MPH - 74.2 hp
__________________
Scion/Toyota Junky... Retired Mod Freak, Current Paleo-Mini Enthusiast! I am the artist formerly known as WeDriveScions... |
09-06-2007, 09:54 PM | #7 |
Drives: 07 Sedan S Join Date: Sep 2006
Location: Stolen
Posts: 39
|
maybe there would be more to be said if you explained how you got your data?
|
09-07-2007, 01:58 AM | #8 |
Drives: 2007 Black Yaris sedan Join Date: Sep 2006
Location: Atlanta
Posts: 884
|
I have measured many tank fulls of gas,at set speeds aswell,my trips are 95% highway,and I can still get 32-34mpg at 90mph,and I have been able to hit 47mpg at 55mph,this is very hard to achieve.So for a car that is only supposed to get 39 highway,and I can get 32-34 semi-speeding,then its still more efficent time wise to go this speed,because the mpg and the mph do not change at the same ratio.Say I was going 50mph and was able to get a steady 42mpg,so if I was going 100mph and only got 21mpg,it would be the same diffrence compared to time,but I bet I would still get about 30mpg,only losing about 25% in mpg,but going twice as fast.
And if wind resistance affected a car so much after 55mph,you might think you would only get 5mpg at 100mph,thats just plain BS.Remember there was a time when the experts and guinesses thought you would be ripped apart if you went over 50mph,what a crock of shit,so dont forget things that are thought to be true,arnt always true. |
09-07-2007, 02:51 AM | #9 | |
Desperauto's Son...
|
At 90 MPH, it takes approxamently 31.3 hp just to overcome air resistance on a corvette, I'd say much more on a much less aerodynamic yaris... at 120 mph, is takes approxiamently 74.2 hp to overcome air resistance alone on a corvette... it gets crazy past that...
It's just physics. overcoming air resistance on a yaris past 55 just takes more and more fuel. and the reason why going faster than around 55-65 results in a less efficient consumption of gas, as at a speed like 75, the engine is using at least 15 more hp to maintain speed than at 55, just solely due to air resistance alone, no matter what the RPM of the engine is. LoL... I'm sure scientists are wrong on all this though... after all, Indy Racers and their fuel consumption isn't important, and the science behind drag, HP, and top speed has nothing to do with Race car design.... (Satire!) Here's a bit more from my source regarding hp to speed... Quote:
__________________
Scion/Toyota Junky... Retired Mod Freak, Current Paleo-Mini Enthusiast! I am the artist formerly known as WeDriveScions... |
|
09-07-2007, 02:56 AM | #10 |
Desperauto's Son...
|
BTW- IF your curious.... read up...
What I've thrown in is from articles and info tied to, or referring to this document, which is widely recognized as an amazing source of info regarding the physics of racing and race car design. http://autopedia.com/stuttgart-west/...Physics01.html
__________________
Scion/Toyota Junky... Retired Mod Freak, Current Paleo-Mini Enthusiast! I am the artist formerly known as WeDriveScions... |
09-07-2007, 01:36 PM | #11 |
Drives: 07 Sedan S Join Date: Sep 2006
Location: Stolen
Posts: 39
|
what do you consider speeding if that is only semi speeding? If you are basing this logic on a cost efficiency basis. Wouldn't the impending speeding tickets also come into play?
|
09-08-2007, 02:37 PM | #12 |
Drives: 2007 Black Yaris sedan Join Date: Sep 2006
Location: Atlanta
Posts: 884
|
No because the speed limits in metro atlanta range from 55-70mph,add 10mph to that,because most cops arnt going to pull you over if your doing 80mph in a 70mph zone,now add the extra 5mph that 50% of the drivers here do,so the average speed in some parts is 85mph,so if Im doing 75-85mph in a 70mph zone,then Im semi-speeding reletive to everyone else.
|
09-29-2007, 07:05 PM | #13 |
Drives: 2007 Black Yaris sedan Join Date: Sep 2006
Location: Atlanta
Posts: 884
|
Bump,still wondering if anyone has any other thoughts,I also forgot to mention the effect of momentum on air resistance,its not fully defeated,but at a higher speed,momentum is increased aswell.
|
09-30-2007, 02:00 PM | #14 | |
Drives: 06 3-dr auto RS Join Date: Jan 2006
Location: BC
Posts: 1,051
|
Quote:
Thanks for bringing up this interesting subject! Here is an article about air resistance. Enjoy! http://www.edmunds.com/advice/fuelec...4/article.html If you have time, I recommend all the articles about fuel economy the links to which can be found in Post #1716 of the Fuel Economy thread. I think if you like the subject of fuel economy, you will like them. |
|
|
|