5th around town? (MT)

[FittJedi]

Hey,
Anyone ever notice that the Fit seems comfy in 5th gear at lower speeds than many cars (that I've driven)? Say you're cruising at 30, you can pop it into 5th and it hums along just fine, as long as you don't accelerate. So is anyone getting better fuel economy by using 5th in situations where it would be more convenient just to stay in 4th (like around town, where you'll have to constantly shift down to 4th, then back up to 5th as traffic fluctuates)? It seems to bring the meter up a bit, but I'm wondering if real world numbers would show it being worthwhile. . .

[ken_vs_ryu]

I think Honda made the engine most comfortable between 2000 and 2500 rpm. I see the mpg meter a bit higher in 3rd at 30mph than 4th.

[2trips]

I am a habitual upshifter, but I've noticed that I get better MPG keeping it around 3K, even if I can putt around at 1.5K or 2K.
Even on the freeway up hills, I could have it floored in 5th for 20MPG or pulse and glide in 4th for a little more. Compulsive upshifting is a hard habit to break though, and I still occasionally find myself 2 gears higher than I ought to be. Get a scanguage and test the MPG effects yourself.

[boojum]

My experience is the same. There is an rpm band where the engine is more efficient and economical and I agree with the poster above that it is in the 2000 to 2500 range. I have downshifted from 5th to 4th and seen the MPG go up.

[huisj]

I'm with you on the habitual upshifting. I just got my Fit, and I'm quickly learning that it seems to be just as happy and efficient at 2500 RPM in a lower gear than at 1500 in a higher gear. I drove a Focus for years that had a lot of low end torque but didn't seem to enjoy revving much, and it's tough to break the habit of super early shifting that I have from driving that car so long.

[Buzzbomb]

With mine, I get the best MPG at 35-40 in 5th according to my Scangauge.

[solbrothers]

its all about the throttle position. if you have to floor it in 5th gear, or barely touch the throttle in 4th, you will get better mpg in 4th even though the rpm's are higher

[rosswond]

Originally Posted by solbrothers

its all about the throttle position. if you have to floor it in 5th gear, or barely touch the throttle in 4th, you will get better mpg in 4th even though the rpm's are higher

Actually, I'm not so sure about that. remember what the throttle does, it controls the airflow into the cylinders by restricting the intake.

Provided you are within the engines comfortable operating range, and all other things being equal, you will use less fuel in the higher gear and with a wider open throttle, because the engine is losing less energy to overcome pumping losses.

This is one reason why diesel engines have such good part throttle fuel economy. There is no throttle butterfly, and engine output is modulated by the amount of fuel injected. That means the cylinders are always filled and pumping losses are minimal.

Now if you are making your engine operate below it's most efficient range, then you should change down.

[SanDan]

Originally Posted by FittJedi

So is anyone getting better fuel economy by using 5th in situations where it would be more convenient just to stay in 4th (like around town, where you'll have to constantly shift down to 4th, then back up to 5th as traffic fluctuates)?

I don't think there is any difference between gears on an mpg basis unless you obviously need to shift and are above 3k rpm.

The only difference I can think of is the fact you are disrupting gas flow. Ie. you are most efficient with milage when you maintain a constant gas flow. Changing gears disrupts this..

[Buzzbomb]

Originally Posted by SanDan

I don't think there is any difference between gears on an mpg basis unless you obviously need to shift and are above 3k rpm.

The only difference I can think of is the fact you are disrupting gas flow. Ie. you are most efficient with milage when you maintain a constant gas flow. Changing gears disrupts this..

There is a big difference. Cruising at 35 in forth vs fifth is a 10mpg difference according to my scangauge. I agree with solbrothers about throttle position. You CANNOT bog the engine down, doing so is counterproductive. Carefully modulating the throttle to maintain speed yields the best results, based on my experience anyway. If I need to accelerate for any reason, I downshift to forth.

[huisj]

Originally Posted by Buzzbomb

There is a big difference. Cruising at 35 in forth vs fifth is a 10mpg difference according to my scangauge. I agree with solbrothers about throttle position. You CANNOT bog the engine down, doing so is counterproductive. Carefully modulating the throttle to maintain speed yields the best results, based on my experience anyway. If I need to accelerate for any reason, I downshift to forth.

10 mpg difference in which way? Better in 5th, or better in 4th?

How low an RPM do you mean by "bog the engine down"? Below 2000? Below 3000? Are you talking about during acceleration only?

[SanDan]

Originally Posted by Buzzbomb

There is a big difference. Cruising at 35 in forth vs fifth is a 10mpg difference according to my scangauge. I agree with solbrothers about throttle position. You CANNOT bog the engine down, doing so is counterproductive. Carefully modulating the throttle to maintain speed yields the best results, based on my experience anyway. If I need to accelerate for any reason, I downshift to forth.

Yes, maintaining constant speeds + costant gas flow is optimal.

If you are using 5th gear traveling 35mph, you will continually be disrupting your throttle and speed by having to change gears frequently, and nullifying any mpg gain.

As for getting 10mpg advantage, your probably going uphill or accelerating while in 4th, and going downhill or cruising while in 5th.

[Buzzbomb]

Originally Posted by huisj

10 mpg difference in which way? Better in 5th, or better in 4th?

How low an RPM do you mean by "bog the engine down"? Below 2000? Below 3000? Are you talking about during acceleration only?

10+ MPG advantage in 5th.

I'm talking mainly about acceleration, however if you are going too slow in 5th, merely trying to maintain speed will bog down the engine.

If you don't know what I'm talking about when I "bog down the engine", then I'm not sure I can explain it.

Get in your Fit get to 25mph and go to 5th. Then try to accelerate like you were in 2nd and you'll know what bogging is.

For me I can maintain speed in 5th, on a flat road with very little ups and down, without bogging. I downshift if I need to accelerate for any reason.

Originally Posted by SanDan

If you are using 5th gear traveling 35mph, you will continually be disrupting your throttle and speed by having to change gears frequently, and nullifying any mpg gain.

As for getting 10mpg advantage, your probably going uphill or accelerating while in 4th, and going downhill or cruising while in 5th.

We're talking about cruising in 5th on flat stretches of road. 35 in 5th gear just wouldn't work on a hilly city street. It very easy to maintain speed in 5th with minuet throttle changes on long flat straights.

[huisj]

Originally Posted by Buzzbomb

10+ MPG advantage in 5th.

I'm talking mainly about acceleration, however if you are going too slow in 5th, merely trying to maintain speed will bog down the engine.

If you don't know what I'm talking about when I "bog down the engine", then I'm not sure I can explain it.

Get in your Fit get to 25mph and go to 5th. Then try to accelerate like you were in 2nd and you'll know what bogging is.

For me I can maintain speed in 5th, on a flat road with very little ups and down, without bogging. I downshift if I need to accelerate for any reason.



We're talking about cruising in 5th on flat stretches of road. 35 in 5th gear just wouldn't work on a hilly city street. It very easy to maintain speed in 5th with minuet throttle changes on long flat straights.

Gotcha. Yeah, I know the feeling of the engine bogging down--I used to have an 88 hp Escort wagon back in the day, and that thing would bog, especially with the air on. I thought I'd ask because sometimes people have different ideas of how they think an engine should respond and what they consider "bogging" (mostly that is from people I know who have downsized from big cars to small cars and are still expecting instant neck-snapping torque that their big V6 or V8 used to give them and think that if the engine doesn't do that, it's being overloaded and needs more RPM).

[BlackUp]

1800 rpm
***with my foot BARELY pressing the pedal***
on a flat surface
in 5th
FTW


even better= a decline
if your GE8 fuel gauge isn't off the map, you likely aren't being light enough on the pedal
maybe try driving with your shoes off

[pb and h]

5th is the gear to be in for mpg at 25mph and up. Shift at 2k and accelerate such that you don't bog or keep the LOD under 70. LOD is key more than the TPS. The TPS has a very narrow range and moves around too quickly unlike LOD which has a wide range(it too can move quickly depending upon your foot). I have noticed that LOD under 50 will give you 50+mpg in any gear.(2007 Fit manual sport) It is not about maintaing a constant gas flow but a constant LOD(since LOD is measured with the SGII) which is not easy. Practice and technique are key.

Good luck

[SanDan]

What is LOD?