whats more efficient (mpg wise)
02-11-2004 | 06:30 PM
#1
Thread Starter
Registered User
iTrader: (1)
Joined: Nov 2002
Posts: 352
From: LA, 91355
Car Info: '03 WRX WRB
whats more efficient (mpg wise)
say I'm going to cruise on the fwy at about 85~90
I can do this in 4th at about 4k or in 5th at about 3k. in 4th my turbos sleeping, but 5th wants about 5lbs. I've done a couple road trip experiments cruising in 4th or 5th and it seems like cruising in 4th gets better mpg. its close tho.. anybody know for sure?
I can do this in 4th at about 4k or in 5th at about 3k. in 4th my turbos sleeping, but 5th wants about 5lbs. I've done a couple road trip experiments cruising in 4th or 5th and it seems like cruising in 4th gets better mpg. its close tho.. anybody know for sure?
02-11-2004 | 07:48 PM
#4
Registered User
Joined: Sep 2003
Posts: 313
From: Atlanta/Cayman Islands
Car Info: 2002 White WRX Wagon (WWW)
Originally posted by gordy
thats what I thought, but then I again I think the boost is offsetting the rpm and actually drinking more gas
thats what I thought, but then I again I think the boost is offsetting the rpm and actually drinking more gas
02-11-2004 | 08:18 PM
#5
Thread Starter
Registered User
iTrader: (1)
Joined: Nov 2002
Posts: 352
From: LA, 91355
Car Info: '03 WRX WRB
I have a boost gauge. A constant 90 on the fwy in 5th gear tends to pull 2 to 5lbs.. it probably depends on how level the fwy is. I've never seen vacuum in 5th tho unless I'm actually slowing down. In 4th gear its vacuum for the most part unless I'm going noticeably uphill, but even then it definately pulls less boost than 5th
I guess the real question is whats more fuel efficient, rpms or boost?
I guess the real question is whats more fuel efficient, rpms or boost?
02-11-2004 | 08:41 PM
#7
Thread Starter
Registered User
iTrader: (1)
Joined: Nov 2002
Posts: 352
From: LA, 91355
Car Info: '03 WRX WRB
Originally posted by wrex04
I always knew it as 5th gear was the overdrive gear. Of course that's w/ NA engines, so I'm not sure w/ turbo'd engines. My guess is keep running your experiments for the good of all of us and let us know
.
I always knew it as 5th gear was the overdrive gear. Of course that's w/ NA engines, so I'm not sure w/ turbo'd engines. My guess is keep running your experiments for the good of all of us and let us know
.
then again if 5th was that inefficient why would subaru gear it that way?
02-11-2004 | 08:55 PM
#8
Registered User
Joined: Sep 2003
Posts: 313
From: Atlanta/Cayman Islands
Car Info: 2002 White WRX Wagon (WWW)
Originally posted by gordy
I have a boost gauge. A constant 90 on the fwy in 5th gear tends to pull 2 to 5lbs.. it probably depends on how level the fwy is. I've never seen vacuum in 5th tho unless I'm actually slowing down. In 4th gear its vacuum for the most part unless I'm going noticeably uphill, but even then it definately pulls less boost than 5th
I guess the real question is whats more fuel efficient, rpms or boost?
I have a boost gauge. A constant 90 on the fwy in 5th gear tends to pull 2 to 5lbs.. it probably depends on how level the fwy is. I've never seen vacuum in 5th tho unless I'm actually slowing down. In 4th gear its vacuum for the most part unless I'm going noticeably uphill, but even then it definately pulls less boost than 5th
I guess the real question is whats more fuel efficient, rpms or boost?
02-12-2004 | 04:33 AM
#11
Registered User
Joined: May 2003
Posts: 149
From: Pennsylvania
Car Info: 2002 WRX
"say I'm going to cruise on the fwy at about 85~90
I can do this in 4th at about 4k or in 5th at about 3k. in 4th my turbos sleeping, but 5th wants about 5lbs. I've done a couple road trip experiments cruising in 4th or 5th and it seems like cruising in 4th gets better mpg. its close tho.. anybody know for sure?"
OK on my car 02 WRX crusing at 75MPH=3,000 RPM in 5th gear
You said 85~90??? Kph or MPH?
I asked subaru this question about a year ago and they told me that "the 2.0 WRX engine is most efficient running at 3,000RPM"
So 5th gear at 3000RPM, sure there is more wind drag while in 5th vs 4th. But when in 4th the trip takes longer and that uses more fuel than less time with slightly more wind drag...
I can do this in 4th at about 4k or in 5th at about 3k. in 4th my turbos sleeping, but 5th wants about 5lbs. I've done a couple road trip experiments cruising in 4th or 5th and it seems like cruising in 4th gets better mpg. its close tho.. anybody know for sure?"
OK on my car 02 WRX crusing at 75MPH=3,000 RPM in 5th gear
You said 85~90??? Kph or MPH?
I asked subaru this question about a year ago and they told me that "the 2.0 WRX engine is most efficient running at 3,000RPM"
So 5th gear at 3000RPM, sure there is more wind drag while in 5th vs 4th. But when in 4th the trip takes longer and that uses more fuel than less time with slightly more wind drag...
02-12-2004 | 07:47 AM
#13
Guest
Posts: n/a
hehehe I did this test when I first purchased my WRX Wagon and after the break in period. I am actually still doing the test but I have been testing for about a month now. This is how the test was done:
I drive the car on the beltway and the city but do not switch any lower than 4krpm. Second test I drive on the beltway and City but switch below 4krpm.
On the first test i got approx 18-19 mpg. On the Second test I got 20 mpg. I drive the car in the City at 4krpm but as soon as I hit the beltway and there are a normal amount of cars on the road I cruise in 5th gear. What makes this weird is that with my normal driving which includes beltway and city runs I get 19 mpg.
On the first test although I was in 4th gear at 70-80mph cruising the boost wast on until I tried to accelarate. The engine is cruising at approx 4500rpm but the response is better than 5th gear at 3krpm (obviously). The second test I was cruising at 70-80mph in 5th, approx. 3300rpm.
I also did a 3rd test which was drive the summama***** hard! in the City at 5krpm (i hardly used the brakes due to engine braking) and on the beltway at nothing lower than 4krpm. With that I averaged 18mpg at the most. I was expecting 16mpg but the lowest i got was 17mpg.
In conclusion: If you accelarate hard (using more boost) then you will lose alot of gas. If you accelarate moderately (not alot of boost) then hold in the high rpm (4k) you wont loss as much gas vs when on full boost. Boost is a MPG nightmare but a Performance fantacy... What a trade off.
Turbo cars are new to me and have a different characteristic vs N/A cars. In N/A cars the higher the RPM the more gas is used. In Turbo cars the case is the same but when in the boost is on the gas is sucked up alot regardless what the RPM.
Well thats my .02 and if you dont like it take this
I drive the car on the beltway and the city but do not switch any lower than 4krpm. Second test I drive on the beltway and City but switch below 4krpm.
On the first test i got approx 18-19 mpg. On the Second test I got 20 mpg. I drive the car in the City at 4krpm but as soon as I hit the beltway and there are a normal amount of cars on the road I cruise in 5th gear. What makes this weird is that with my normal driving which includes beltway and city runs I get 19 mpg.
On the first test although I was in 4th gear at 70-80mph cruising the boost wast on until I tried to accelarate. The engine is cruising at approx 4500rpm but the response is better than 5th gear at 3krpm (obviously). The second test I was cruising at 70-80mph in 5th, approx. 3300rpm.
I also did a 3rd test which was drive the summama***** hard! in the City at 5krpm (i hardly used the brakes due to engine braking) and on the beltway at nothing lower than 4krpm. With that I averaged 18mpg at the most. I was expecting 16mpg but the lowest i got was 17mpg.
In conclusion: If you accelarate hard (using more boost) then you will lose alot of gas. If you accelarate moderately (not alot of boost) then hold in the high rpm (4k) you wont loss as much gas vs when on full boost. Boost is a MPG nightmare but a Performance fantacy... What a trade off.
Turbo cars are new to me and have a different characteristic vs N/A cars. In N/A cars the higher the RPM the more gas is used. In Turbo cars the case is the same but when in the boost is on the gas is sucked up alot regardless what the RPM.
Well thats my .02 and if you dont like it take this
02-12-2004 | 09:22 AM
#15
Registered User
Joined: May 2003
Posts: 149
From: Pennsylvania
Car Info: 2002 WRX
I probally should have said that I get bewteen 27-29MPG mostly highway..
And also with the windows closed and the air conditioner on I get ONE MPG BETTER than with the air conditioner off and the windows open
And also with the windows closed and the air conditioner on I get ONE MPG BETTER than with the air conditioner off and the windows open