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Comments
On flat ground that would be true. On those long upgrades where a lot of throttle is required to maintain that 1800rpm, I believe a downshift would yield the better mileage.
Same reason an auto would downshift.
Kip
True, because they recognize that at a certain point more power will get the job done with less throttle, resulting in better MPG.
Kip
I think you're not quite "getting" the concept of gearing and how it relates to torque curves. If an engine is turning at too few RPM's to develop sufficient torque, adding more fuel is not going to accomplish anything positive. That is to say, it's not about getting better fuel efficiency, it's about getting the job done, period...in this case, getting up the hill. You downshift to place the engine in a more powerful RPM range. Power=energy usage.
We got our Fit last weekend, and so far very happy with it.
Once a mechanic told me to put 93 octane gas in my '95 Saturn to eliminate knocking, and added that I will have fewer problems with the engine in the long run if I consistently used 93 octane. He was right, I had no knocking since then and it has been a problem free car at 160k until we sold it last weekend.
I wonder if using 93 on the Fit will bring in better milage, more power and longetivity to the engine.
Thanks
The gain from using higher octane than you need will go to the oil companies, not you.
Engineers spent an enormous amount of time designing an engine to run on a specific grade of gasoline -- trust them! If by some slim chance, your Fit develops an engine knock, have that problem fixed instead of increasing octane.
Spending $.20/gallon more is wasteful and will not provide longer life.
I hope the person that bought your Saturn knows that they will have to use 93 octane now -- if they put regular in the tank, it'll probably cough up engine parts.
[riposte] I agree completely. Re read my post!Possibly when you clicked on the REPLY button you meant to click on the other guys. You and I seem to be on the same page. :shades:
This is what I said! On flat ground that would be true. On those long upgrades where a lot of throttle is required to maintain that 1800rpm, I believe a downshift would yield the better mileage.
Same reason an auto would downshift.
When it becomes necessary to "PUSH" the throttle hard to attempt maintaining speed, the engine is not in a happy torque curve and not up to the task at hand. A down shift will put the engine in a better position to do the job. Most of the time the throttle can be lightened, resulting in better fuel economy.
Attempting to pump more fuel into an overloaded engine will NOT yield better mileage. Pumping less fuel into an engine running at the correct RPM for the task will!
Kip
And the enough/correct power to get the job done will not necessarily be in the highest gear on the stick.
If the engine has enough torque to go up the hill in 5th at 2000rpm, then dropping it to 4th and going 2500rpm will result in worse mpg.
Not if you are having to use excessive throttle to force it up that hill. If you do, the engine rpm/torque was not in a good place.
.. On the other hand, if the car's engine isn't powerful enough to maintain 2000rpm going up the hill in 5th, saving mpg doesn't matter because the car will stall out,..
Ahhh... now we are getting together. Sort of! The engine won't necessarily stall out! It may simply maintain that rpm or drop some before reaching the top, even though the throttle was on the floor. Downshifting and using less throttle will yield better mileage for that task as well as putting a lot less strain on the engine itself!
...so for best mpg you're trying to be in the highest gear possible without stalling out...
Agreed, as long as the engine is producing enough torque to not require excessive throttle to do the task.
Keep the engine in a happy place and it will last a long time and yield the best mileage. I've seen too many engines ruined and heard too many complaints of poor fuel mileage from those that refused to believe that keeping the engine happy will help to keep you happy.
Kip
Granted that if you're trying to drive in 5th gear at 10mph with the gas pedal to the floor, then you're doing something wrong. Or if you're in too high of a gear and the car is jerking and about to stall. But I'm talking about for normal driving, getting into a higher gear will result in better mpg. Now if you're in 5th gear and the RPMs are dropping to the normal idle RPM range for whatever reason, then you better shift...that's just common sense.
I have another question...what's better on mpg on the long downhills...leaving the car in 3rd gear for example at 3000rpms for engine braking, or putting the car in neutral and letting it coast and just tapping your brakes?
OK...Try running your car at a steady throttle on flat ground. When you get to a grade, don't change a thing.I believe you will find that the car begins to loose speed.
Flat or a hill does make a difference!
Going up hill creates additional load like putting three 300lb guys in the car with you.
Yes it does make a difference!
I'm not sure what you mean by "excessive throttle to force it up that hill. If you do, the engine rpm/torque was not in a good place."
Pressing the throttle to or near the floor to ask the car to try keeping the same speed. That "Heavy" throttle position burns extra fuel that would not be used if car was in proper gear to allow the engine to operate in the correct RPM range for the task at hand.
Anytime you're driving you're forcing the car forward...that's physics.
True and if the engine is at the proper RPM for the load all runs smoothly. Introduce a long grade or your 3 overweight friends and more torque through engine rpm is required for that task. An engine that is beginning to stress from the tranny being in the wrong gear, for whatever the load, may react to more and more (excessive)throttle. However at a cost of more fuel burned. You said that yourself. "Now if you're in 5th gear and the RPMs are dropping to the normal idle RPM range for whatever reason, then you better shift...that's just common sense."
You are right, just not going far enough with the process. The engine doesn't have to be jerking and trying to stall for common sense to dictate downshifting. With a few exceptions, anytime a little more throttle doesn't result in a rise in speed/rpm it is a good time to think about downshifting. That is what the ATs do. Better for economy and better on the engine.
Granted that if you're trying to drive in 5th gear at 10mph with the gas pedal to the floor, then you're doing something wrong.
We agree again! If you are driving in any gear with the throttle to or near the floor and are simply trying to maintain a speed, you are doing something wrong. Time to down shift until conditions dictate upshifting. The exceptions to that are if trying to accelerate quickly or run at top speed. Again you are burning more fuel!
...what's better on mpg on the long downhills...leaving the car in 3rd gear for example at 3000rpms for engine braking, or putting the car in neutral and letting it coast and just tapping your brakes?
Good question! In our studies we haven't dealt with that. Gut feel is that if it is left in say 3rd gear and that seems to satisfy the desired speed, then little fuel is being used. However, if it becomes apparent that 3rd is a bit low and some throttle is occasionally necessary, fuel will be burned. Leaving the car in nutral and idling will burn very little fuel considering the distance you travel.
Personally I will usually lock out OD and use the brakes when necessary. If the brakes begin to feel like they are fading, a lower gear gets found real fast!
I hope this helps.
Kip
Oh the dilemma of the true curve of the physics equation.
In terms of pure physics there IS an equation, which I dont know.
That being said...some of the differences discussed here on this topic are a question of auto vs manual.
There is local area with sharp incline. If you get going fast enough before the hill you dont need to downshift but if someone is lagging in the lane where you cant pass (or want to pass) one needs a lower gear.
If you were to compare MT vs AT I could probably do so only when the MT is in cruise or the AT is on paddles.
Used to be if I could get good speed going up a sharp 50 mph hill in cruise in my current beater (still waiting on my Fit), I wouldnt have to downshift ever with good rpms. But if someone was lagging or blocking passing lane I would have to downshift. Of course that uses gas.
IMO its simply a question of individual situations but to be fair, I think more accurate comparisons are in place (ie use of cruise in either vehicle.)
I have another question...what's better on mpg on the long downhills...leaving the car in 3rd gear for example at 3000rpms for engine braking, or putting the car in neutral and letting it coast and just tapping your brakes?
See now...thats what I am talking about.
My housemate just critized my assessment of cruise for getting best mileage. But thing is you arent supposed* to use it on hills and his thing was about going down the hill and not up. I dont disagree that cruise is bad for downhills. And I too wonder about tapping ones brakes vs downshifting.
I live on a hill and I know that I have to keep it in lower gear just to keep from wearing out my brakes, but I cant go down in first either.
Not deliberately pulling out of context. Just trying to address your points, in the order that you made them, even when we agreed! Look again. Sorry you don't see that. You seem to be more interested in winning than reasoning!
If you wish to believe that a heavy throttle, while an engine is struggling to keep up, will get better mileage than one turning a few more rpm but within the torque curve for the task at hand, and requiring less throttle. Go for it!
My apology for upsetting you.
When you find that physic formula, Please post it.
Thanks,
Kip
Here is what we found on cruise control:
On reasonably flat roads, you can let it do its job. Your speed will be constant, throttle relatively steady, and about as good mileage as your car is capable of for the speed selected and so forth.
On hilly terrain the cruise reduces the throttle going downhill to maintain the desired speed. Going uphill it will strive to keep the car to selected speed which can burn extra fuel.
You can sort of have the best of both worlds (and experiment some) by leaving the cruise on and gently over riding it with the throttle on down hill. You may wish to build an extra 10 MPH or so while gravity is helping. Keep your foot steady on the throttle and eventually, on the uphill grade, the cruise will pull the pedal from under your foot toward the floor. If you had not allowed a bit of extra speed on the down hill the cruise would have "Pulled" the pedal away sooner.
It is kind of interesting to do and to find ways of doing it better. Reason for leaving the cruise on was to let you get a feel of what is happening. And the cruise would still be ready for the flats.
Best mileage is acquired by turning off the cruise, building speed down hill and actually loosing some going up the next. A steady foot will accomplish that. Just keep an eye out behind you.
Kip
Never knew I could learn about physics and driving up and down hills.....
first - most manufacturers (owner's manual) will tell you if you are in a hilly area NOT to use cruise control. You use cruise control for better gas mileage (maintaining a constant speed and the lowest rpm) and reduce driver fatigue (shake your legs out on a long drive).
Second - If you are going downhill, please do not shift into neutral. yes you will get phenomenal gas mileage but remember you have to shift back into gear doing 55 mph. Also what happens if a deer crosses the road (or some other emergency), you have only one thing you can do and that is brake. there are times when you need to actually speed up to avoid a mishap.
I'm eager to read about the Fit mpg since I will likely look fro anew car in the next 6 months. My 2000 Intrigue (126k miles) gets 25-28 mpg (depends on how much in town driving I do) on my daily 43.6 miles (EW) commute. Would love to purchase something that gets in the mid 30s.
I've made several trips driving over the Appalachian Mountains on road trips between Virginia and Ohio and kept the cruise on at about 70mph. The revs go up on the uphill and downhill but that’s okay. If you’re driving 70mph on cruise and come to a hill, sure you can turn the cruise off and go up the hill at 60mph to save gas. Or you could just reset the cruise to 60mph on the uphills to save gas. It’s not the use of the cruise that’s affecting mpg but the speed. All that cruise does is make it easier to maintain a constant speed. Or you could just reset the cruise to 60mph on flat ground to save even more gas and reduce speed to 50mph to save gas on the hills. Or if you have more passengers in the car, which increases the load on a car in the same way as going uphill does, then by this logic you shouldn’t use cruise control either, or you should reduce your speed. What about a strong headwind? Should the drive reduce their speed in a strong headwind to save gas? And you could go on and on and on.
Bottom line is that going uphill, driving on flat ground against a strong headwind, towing something, putting a lot of weight in or on top of a car all will reduce your mpg. But my goal isn’t to have the exact same mpg uphill, downhill, flat, hilly, windy, with/without heavy cargo, etc. My goal is just do get the best mpg for my driving. I’m not saying this will work for every vehicle out there, but I’m not willing to drive 55mph to get the best possible mpg. For me I want to get the best mpg while driving 70-75mph, so this is what I do. If mpg is the most crucial thing, then keep the car at 55-60mph on the highway, up shift as quick as possible in a manual, or in an automatic don’t put too much pressure on the gas pedal to get the automatic to upshift faster.
And I won't make anymore posts to this forum on this subject, so I'll give the last word (of course in a bold email) to someone else :P
Shneor
We also have a 01 Odyssey, and the specs say:
Horsepower @ rpm(SAE net): 210 @ 5200*
Torque (lb.-ft.@rpm): 229 @ 4300*
* With premium unleaded fuel (205 hp/217 lb.-ft. with regular unleaded fuel).
It looks like with that engine, 93 brings in a few ponies extra. How come this is not the case for Fit?
Thanks
You are most likely using only a fraction of your car's maximum horsepower in day-to-day driving, so I wouldn't worry about 5 HP. No reason or real advantage to use premium fuel.
On a steep down grade our Pilot will shift down to 4th the first time the brakes are used or when starting from a stop on a steep down grade. It stays there until the bottom has been reached, then shift into 5th. Suspect it senses the travel speed is faster than the throttle input calls for. Or maybe it has a "Tilt" box somewhere that senses the angle. :confuse:
Kip
Some have posted here that they actually got worse mileage with 93 octane. A while back I picked up a propaganda pamphlet at a shell station. It stated that if your car is designed to burn regular, nothing would be accomplished by burning premium. :confuse:
Kip
In my first car, a 1987 Accord with very high miles, I used higher octane fuel to combat occasional spark knock. Although it stopped the noise, my average fuel economy went down the equivalent of about 2 mpg in normal driving and I could feel a drop in performance.
I see no benefit to using high octane fuel in the Fit (either mileage or performance-wise) since it will probably decrease both.
Otherwise they're the same gas. Just use 87.
Ask yourself this, why should i put premium gasoline (more expensive by at least $0.20/gallon) in a vehicle that is design to maximize fuel economy and lower my gas bill?
IF you want to experiment and post your results, I'm sure others (including myself) would be interested.
That Accord used a 2.7L C-series (C27) engine. That is a relatively old engine design which dates back to the first Acura Legend. The individual who posted here has a 2001 (2nd generation) Odyssey which has a J-series engine. It has nothing to do with the older Accord V6.
Even then, the Accord V6 might have needed premium... but the Fit doesn't!
I do agree no need for premium or even 89 octane in the Fit.
It is nice to see people are getting good gas mileage with these vehicles. I like the Versa with the CVT but the gas mileage being reported is discouraging.
People buy wagons for that "bulky cargo" handling feature.
What in the world was Nissan thinking about to take a real nice car and do that back seat thing? :sick:
By the way, about the Versa's rear seat the way it is, Nissan did say that they wanted to give the Versa a full-sized seat, front and back, and to do that, they had to have the rear seat that way. To make it flat, the Versa would not get that kind of comfy rear seat. There were enough complaints about the non-flat cargo area, though, so that in Japan Nissan gave the Versa's little brother, the NOTE, a flat cargo floor. But you don't get a full-size rear seat in the NOTE.
~marc
~marc
Should I be worried? Is something wrong? I've seen other people posting that they are getting about 30MPG with 100% city driving. Please help. Thanks.
What I would suggest is the next time you have the opportunity to go on a longer highway trip, take your car and try to put at least 200 miles of just highway driving. Then fill up. It won't be the most accurate, since it's better to do this on a closer to empty tank, but at least it will give you a rough estimate. Hopefully the number will be above 30.
Also, my interpretation of city driving (since I don't live in an extremely congested area) is different than if I was constantly driving in the downtown of a big city...particularly Chicago.
As a good sample, Consumer Reports gives three mileage numbers for each vehicle tested: City, Highway, and Overall. Their city mode is true city. Their current issue has the Fit, among others, tested. The Fit Automatic got 22 MPG in their city mode, with the manual getting 26 MPG. The highways numbers are 43 and 39 MPG, respectively.
Your numbers, while on the lower end, are within a reasonable range of CR's numbers for the automatic Fit (you did not tell us which transmission your Fit has).
I used to live in Japan near Tokyo. In its extremely congested city streets, even a 1.3 liter Fit (smaller than the US-spec Fit and is more economical) can easily get a mileage like 18~19 MPG. It is not unusual for a car with 2.5 liter displacement there getting 12 MPG or less driving in Tokyo.
Just as others have suggested, I would take your Fit out for an extended highway driving. If your mileage is still poor after that, then I would be concerned and recommend that you take your Fit to your dealership for a checkup. Let us know how that goes.
I was going to say that I hope r2g finds out what is causing those poor results, but I guess it might be normal given the conditions.
~marc
1st tank 43.1 mpg (I really don't count this since it was filled by the dealer, it seems a little high)
2nd tank 38.5 mpg
3rd tank 37.5 mpg (the weather is starting to get cold)
on 87 octane, mixed rural,hiway, very little real "city" driving. Drove nice, rarely exceeding 3500RPM, 60-60 on highway speed. Tank #7 was 10% ethanol blend.- Milage dropped to 30.9, which is right in the expected 10% reduction using 10% ethanol. I do fill up until I need 9 or more gallons, fill to same level always. have about 2400 miles on car between 10/10 and 11-6. Oil is at 80%.
Hope milage improves. Car is fantastic to drive. Handles well, has as much power as you ever need. headlights ok.
The dims literally "turn off" at a certain distance. I had some similar lights(That were from Europe) on a jeep a few years ago. I have no problem with them. My dealer checksheet showed the did the ILP prior to delivery. Do not know if they actually did or not though. Been mostly using wal-Mart gas. I will go to synthetic oil when I get a change. I will keep posting as miles go on the car
Wulybugr- Southern Missouri
Ya know when I figure mileage, I take the Miles driven and Divide by the Gallons I just pumped. That will change your numbers I'm pretty sure. I think that's the opposite of what you are doing.
I should also add, that I haven't used the AC while driving and my tire pressure was fine. Also, I only have about 550 miles on the car. I think I might be stuck with the low MPG as long as my driving is circumscribed to Urban Chicago. Will post when and if things change.