I do scientific method stuff all day long at work, but when it comes to cars, i'm a kind of a shoot from the hip kind of guy

My conclusion is simply based on real world experience in my GE, and anything over about 67-68mph starts killing mileage exponentially as you have to open the throttle more to maintain speed even on flat ground. The same has been reported by several other posters as well. If the GE had an even taller 5th gear than it has now with no improvement in aero and the same motor you'd have to put the pedal down EVEN FURTHER to maintain speed because the motor would be lugging down in the 1500rpm range where it's making no power, no torque, and is getting no assistance from the gearing. It's dimishing returns right, you can throw a long gear at it but that doesn't mean the motor can make use of it.

I think the GK will do better at higher speed than the GE if it indeed has better aerodynamics like i've been reading. That and the added power together should see an improvement.

Read: Not because of taller gears, because the gears aren't any taller, there's just an extra one.

 

There's a huge difference between the current 2900 rpm at 60 mph and 1500 you're talking about. Not even the automatic goes that low. I don't know of any 4-cylinder car, manual or automatic, that runs that low at highway speed. The Fit's automatic does 1800, Chevy Sonic also runs 1800, Versa with CVT runs 2000 rpm.

The whole point of having multiple gear ratios is that you can use whichever one is right for the situation. If top gear is too tall for climbing the Rockies, you downshift. When it's flat, you drop into top "overdrive" gear. If you need to pass, you downshift. That's what the automatic does, but I guess Honda thinks manual drivers are too lazy/incompetent to do the same.

Lower rpm is clearly a benefit for highway mpg, shown by the epa ratings. LX auto (1800 rpm) gets 41 mpg compared to LX manual (2800 rpm) getting 37 mpg. Even the EX auto gets +1 mpg to 38 compared to the manual. The only relevant difference in these pairs is the transmission's lower rpm cruise.

Even if it has to downshift now and then for power, most of the time it can run at lower rpm, for lower overall consumption.

That's good for mileage, up until you get to WOT.
Here's a good explanation of how it works. Brake Specific Fuel Consumption. AutoSpeed - Brake Specific Fuel Consumption

 

Yes, and we all know the EPA ratings are always spot on.

I said 1500 range, just threw a number out. 1800, whatever.

I should be getting 33mpg highway on my 2010 MT... if I would have gotten an AT i'd be in way better shape according to the EPA. Somehow I always get 38-40mpg going 70 mph sitting at a stratospheric 3500rpm. Go figure.

Don't jump to conclusions until we have real world mileage, that's all just numbers BS, I don't believe the hypebeast until I see it. You may very well be right, but i'll wait until the fuelly numbers start rolling in, I could care less what Honda or the EPA have to say about it.

In their magic world Hyundais are getting 40

 

I. See from your signature over on the cleanMPG forum that you have averaged better than 60MPG on your 2009 fit MT. That is spectacular I am sure that you work very hard for the fuel economy you achieve. Understanding that, I can see where you were hoping for a taller top gear for the possibility of even better fuel economy. But I would bet most of us over here on fitfreak have no idea how to get that kind of economy.

Do you care to comment on how you achieve such stellar fuel ecomony? What type of a commute and what types of speeds do you drive?

 

How dare we question a fellow FFreak!!! Its so obvious how that type of "stellar" mileage is achieved.
Have your Fit FLATBEDDED up to Haleakala (for us islanders or Guadalupe Peak for Texans) and coast down at idle in neutral to your destination of choice!!!!!!!!!!!!

 

I agree, I don't know how I could ever get 60MPG, short of coasting down the mountain!

 

Tailgate a big truck at 50-55 mph for 3 hours on flat, flat ground ... I did it, just once. It's no fun (dangerous actually) but returns big #s.

 

But won't this be the new paradigm with radar cruise and "road-train" (sorry, don't know the term) technologies? Of course, the lead car will pay a fuel penalty. Maybe the cars in the "train" can tip him in Dogecoin? Enough to buy a coffee, for obvious reasons. Or maybe not. Maybe he'll be sleeping too...

 

Sure thing. I've been doing this for a number of years, first in a Civic and now in the Fit. They're fairly similar in how they respond for mileage.

First, NO TAILGATING or drafting. It's stupid and unsafe. I've done it for testing and it provides similar gains to just slowing down 5 mph.

I live in Texas. The weather is better for mpg here. Cold kills it. AC hurts too, so I minimize using that as well.

I commute ~10 miles each way, on rural/suburban routes. Mainly 45 mph limit with a couple spots of 55. That's one way I manage good numbers despite the silly gear ratios. I've done a number of 60 mpg tanks, but when I did a long highway trip I barely managed 50. Silly gear ratios.

Pulse and Glide, engine off glide. Pulse up to speed at optimum BSFC (see article above). Basically, low rpm and medium-high gas pedal. Open throttle is more efficient. Then when you're at speed, shift to neutral, cut the engine and gliiiiiiiiide. (key back to "run" as soon as the engine has stopped for ABS and airbags) I love that the Fit has electric power steering that stays on during the glide. Brakes are good for a couple solid pumps and if I use them a couple times I'll bump-start to restore vacuum boost.

Pretend you have no brakes. Play far ahead and anticipate everything that could happen. Watch the light cycle a mile ahead if you can see it and adjust your speed to hit it on green. Leave enough following space so a sudden right turn or lane change in front doesn't force you to brake. Of course, use the brakes when needed, just work hard to minimize those times.

Scangauge-II tells me in great detail what works and doesn't. It's adjustable so it's more accurate than the onboard gauge (especially for my '09 ). It shows both trip average mpg and instant mpg, along with vacuum and engine temperature and volts and more. I couldn't do what I do without it.

A manual shift allows ME to control the combination of rpm and load and speed. Automatics are programmed to shift and rev up when you apply more gas pedal, moving back out of the efficient range of low rpm and high load. I'm running below 2000 rpm most of the time, except when I'm above 42 mph because the gears don't give me the option of staying lower.

Basically:
Low speed
short shift for low rpm
Moderately high load for accelerating, with low rpm
pulse-and-glide
fanatical anticipation and situational awareness, minimized braking

 

I have never tried to pulse and glide, engine off and I am wondering how this works with push button start?

 

You can get some big gains even just idling in neutral.

I don't know the details of how the Fit's push button works. I drove a Fiesta with one, and you push and hold the button to shut down. Then you push again to reboot the car. If you have the clutch pedal down, it restarts the engine. Clutch up (in neutral) and it just turns the car on with no engine. Then you can gently bump-start it later.

 

Acura start button cars are "press and hold" or "three rapid pushes" to turn off the ignition. I'd imagine that the Honda's would work the same.

 

Good to know. The important thing is to turn it back on as soon as the engine has stopped spinning. That's where the trick is - turning the car on but not the engine.

 

"Don't draft because it's dangerous, but use pulse and glide which is illegal in many places" ... okey dokey

 

No idea what you guys are talking about (few random posts here)

I had over a thousand pounds inside the Fit when I was moving back to Wisconsin from Fort Hood, TX.

I averaged 32mpg, over 70mph, and managed to do it on only 4 gas station stops.

The Fit was still able to move through traffic just fine.


I think you guys just like to nitpick quite a bit.

EDIT the extra weight pretty much told my rear shocks to act like they have 200k miles. Its bouncy now.

 

That mileage at that speed w/ a 1k load is excellent!!! As for shocks, time for some KYB's.
My Fit back in '08 was rated EPA 34mpg hwy. Can get pretty close to this, if not better at times with ordinary driving habits (am not a hypermiler).
Was time for a change and if the GK can give me close to 37mpg, that 10% increase will be satisfying.
AS they say: "can please some of the people, some of the time. Can't please all the people, all of the time".

 

colder sparkplugs, no cats, better flowing exhaust, and 91octane gas make a difference.

Couldnt stick to 93 since very few stations up north stock them around me.

In LaCrosse, there is only 1-2 stations selling 93, and theres something like 90-100k people around here? lol

 

I've been wondering about your claim of improved mileage with 91 octane. I've done back and forth testing on mine and found no difference. Then I found this quote of yours and now it makes sense.
Using the same calibrated Scangauge on both. LOD is Scangauge calculated value, with 80% matching about 12.5 psi MAP. In other words, with the same conditions and load on the engine, there was no more timing advance for premium fuel compared to regular. Under load is where you get timing retard to prevent knock, so that's the real test.
Premium 91 fuel, warmed up, ~90F ambient, 2000 rpm, 80% LOD = 20 ign.
Regular 87 fuel, warmed up, ~90F ambient, 2000 rpm, 80% LOD = 20 ign.

Of course, adding or removing ethanol makes it a different story. I'd go with the pure gas if I could find it.

 

well, most of my testing was with E10 87, 91, and 93

In my vehicle, all threee had differences, with the biggest between 87 and 91. jumping from 91 to 93 didnt really do a WHOLE lot. the difference was there in the datalogging, but not so much at the butt-dyno.

Remember, the octane switch should be ran for a tank or two before attempting to datalog. The Fit ecu is very conservative in ignition adjustments. Very much UNLIKE the Civic SI K20's ECU, which can adjust in less then half a tank.

EDIT and if you do not drive like a teenager, it takes LONGER to adjust. Go find an empty backroad and have some fun.

 

You know how I know the ECU advances timing according to fuel?

If I run 91 for two weeks and pump 87 for a roadtrip the motor pings everywhere under heavy load until the ECU adjusts. I don't need any datalogging for that, just my ears. As long as I run 91 it doesn't ping pretty much ever, but it will on 87.

Partial throttle you can definitely feel a torque difference on 91. I can easily pull grades and maintain speed at the bottom of 4th that I would have to downshift to 3rd on running 87.

I went into all this with a bit skeptical in the first place so i'm not just trying to justify the cost or whatever, just my observations. I did not feel any difference switching to 91 for my first tank but resisted giving up on it. I kept up with it for a month or so and there was definite improvement over time. I also find 13fit's comment about the teenaged driving if you don't test the knock sensor the ECU won't do much as far as advancing timing because it doesn't have any parameters to work with.

There's been plenty of proof using datalogging posted on these forums that higher octane advances timing. While I don't see 91 improving fuel mileage for 95% of driving that I do, I definitely believe there are some situations where it does help, like grades and hills where I don't need to use as much throttle to make it up there.

Then again I don't run 91 for fuel economy, that doesn't really make sense in the first place since Premium fuel is not really economical.