48.6 MPG Combined Hwy and County Rds.

[SkooterG]

I have often wondered WHY does the FJ get better mpg at altitude and hot weather. This I'm convinced of - FJ's get better mpg when the air-fuel mixture is richened-up. So why does the mpg take a **** on a cold day. I think the ECU is programmed to assist in maintaining a constant engine temp. On a hot day it richens the mixture. Conversely on a cold day it leans out.

Sorry, but I think you are completely wrong on this. Generally speaking, ANY vehicle is more efficient with a leaner mixture and less so with a richer one.

As for why better efficiency with high altitude and hotter temperatures? It's quite simple: Less air resistance. Period.

As altitude and temperature goes up, the air becomes less dense. Less dense air = less air resistance for any vehicle to overcome. Less air resistance means the engine needs to make less power, (which means less fuel) to maintain a certain speed.

 

[Top_Speed1]

If you really want better highway mileage and your doing the constant 70-80 (or more) mph's then I would seek a taller 5th gear. 4th gear is tall enough that you could change out 5th to turn the slower rips, this would get you your desired better highway mileage.

Haven't done this on my FJR (yet) but have done it on many of my other powersport toys. I actually may do this mod as I don't think Yami put quite enough of a gap between 4th and 5th anyway.

 

[gumba]

Had coffee with "Akron Arlin" (NHRA Hall of Fame) this morning and he explained how air density fits into this discussion. Hot day - low air density - richer mixture - better mpg. Higher altitude - lower density - richer mixture - better mpg. Cold day - higher density - leaner mixture - mpg takes a ****. In this day of EPA mandated fuel/air mixtures all vehicles are running on the lean side of 14.7/1. I agree that max. performance is in the neighborhood of melt down, but I don't want to run there. I agree that air foil has a place here, but not the answer I was looking for.

 

[wheatonFJR]

As for why better efficiency with high altitude and hotter temperatures? It's quite simple: Less air resistance. Period.

As altitude and temperature goes up, the air becomes less dense. Less dense air = less air resistance for any vehicle to overcome. Less air resistance means the engine needs to make less power, (which means less fuel) to maintain a certain speed.

:lol: :lol:

That's a good one.

:lol: :lol:

 

[SkooterG]

Had coffee with "Akron Arlin" (NHRA Hall of Fame) this morning and he explained how air density fits into this discussion. Hot day - low air density - richer mixture - better mpg. Higher altitude - lower density - richer mixture - better mpg. Cold day - higher density - leaner mixture - mpg takes a ****. In this day of EPA mandated fuel/air mixtures all vehicles are running on the lean side of 14.7/1. I agree that max. performance is in the neighborhood of melt down, but I don't want to run there. I agree that air foil has a place here, but not the answer I was looking for.

Well, the air density part is correct.

With the FJR's fuel injection, various sensors, and closed-loop mode via the O2 sensor, the mixture is constant and not changing regardless of temperature, altitude, and air density.

As for why better efficiency with high altitude and hotter temperatures? It's quite simple: Less air resistance. Period.

As altitude and temperature goes up, the air becomes less dense. Less dense air = less air resistance for any vehicle to overcome. Less air resistance means the engine needs to make less power, (which means less fuel) to maintain a certain speed.

:lol: :lol:

That's a good one.

:lol: :lol:

Huh?

 

[FJRMGM]

my '05 got in the upper 40's and low 50's while cruising the roads in Arkansas this month at SFO. It's always gotten 45-50 mpg which amazes me.

I have never gotten less than 41 mpg and the one time it did was loaded on a trip with a 35-45 mph cross or headwind.

I have done several tests without the bags and it never made 1 mpg difference in the mileage to leave them off - so I don't.

Clear air filter is your friend on this bike - Uni-Flow on mine.

 

[FJRBluesman]

I just got 54mpg on my trip and have not filled up from the second leg; however, I did go over 167 miles on half a tank, mostly in the twisties on hwy 162, going up in elevation too.

 

[Lowcountry Joe]

Its all about barometric pressure and the availability of O2. As you gain altitude, say you go from sea level to 10,000, the percent of O2 does not change, but what does change is the amount of O2 due to the barometric pressure. In a given volume of atmospheric air, the amount of available O2 decreases in this example by roughly 30%. Lots of good articles on the web explaining what happens at altitude. So if your bike is sampling the O2 in the exhaust flow constantly, and it is, then the ECM will make the appropriate adjustments to maintain the proper A/F ratios when at that altitude. An so will your body!!

 

[SkooterG]

52.4 mpg on a nice ride up to the Arizona high country yesterday. Hit reserve at 274 miles. I think that is a record for me.

 

[wheatonFJR]

52.4 mpg on a nice ride up to the Arizona high country yesterday. Hit reserve at 274 miles. I think that is a record for me.

No corn in your gas?

 

[FJR Bill]

52.4 mpg on a nice ride up to the Arizona high country yesterday. Hit reserve at 274 miles. I think that is a record for me.

No corn in your gas?

Good question I think. My other bike was owned before and after corn (ethanol). A consistent 10% MPG decrease for all types of riding. This is documented for 10's of thousands of comparison miles. Bill

 

[SkooterG]

52.4 mpg on a nice ride up to the Arizona high country yesterday. Hit reserve at 274 miles. I think that is a record for me.

No corn in your gas?

Oh yeah. Standard 10%,

High altitude and high temps. It's all about the air resistance I am telling you! :lol:

Too much partying the night before had me tired and mellow, so throttle-wise it was a fairly relaxed cruise. However that didn't stop me from scraping the crap out of my pegs on my favorite road in Arizona - the back way up to Prescott on 89. In fact, I was in 'the zone' on the twisties. Besides grinding a significant amount of aluminum off of my pegs, I noticed my sidestand on the left, and rear brake lever on the right were getting a bit scuffed. :blink: I guess it's time to back off a bit. Or better yet, put the car tire back on so I can get some more ground clearance.

 

[SkooterG]

My favorite stretch of Arizona asphalt: Clicky.

Another nice stretch a bit further on: Clicky. Also where my last crash occurred but they have since repaved so all the crappy pavement is gone! :yahoo:

And never saw him before, but now a 'Killboy' copycat is located there. Wish he would have been in a better corner. My 'action' shot: Clicky.

 

[Wolf_in_Cheapclothing]

52.4 mpg on a nice ride up to the Arizona high country yesterday. Hit reserve at 274 miles. I think that is a record for me.

No corn in your gas?

Good question I think. My other bike was owned before and after corn (ethanol). A consistent 10% MPG decrease for all types of riding. This is documented for 10's of thousands of comparison miles. Bill

Why would ethanol lower mileage by 10%? Alcohol has 90% of the energy of gasoline. E10 Gasohol has 10% alcohol. Shouldn't there be a 1% decrease? What have I got wrong?

 

[Bungie]

Fuelly stats for my FJR

Fuelly stats for my CBR250R

 

[Bungie]

52.4 mpg on a nice ride up to the Arizona high country yesterday. Hit reserve at 274 miles. I think that is a record for me.

My best is 269 miles. My current tank is just over 250 miles. But I got the dreaded blinking light after taking a run through town last night.

Leaving on a 2K jaunt camping jaunt this weekend over Lake Superior, I don't plan on hauling much ass so it'll be interesting to see how the bike does. Most of my trips, and therefor mileage history, are running on the hard side as I'm usually slabbing it to get to the good stuff.

 

[wheatonFJR]

...

 

[SkooterG]

Fuelly stats for my CBR250R

84.9 freaking mpg!!! Yowsa!

 

[Bungie]

Fuelly stats for my CBR250R

84.9 freaking mpg!!! Yowsa!

<commercial start>

Yowsa is right. That's NOT riding for mileage. Thats just bombing around town. One of the guys on the CBR forum competed in the Eco Challenge at Watkins Glen a month or so ago. Except for going up 1 tooth on the front and down 2 on the rear, the bike was bone stock.

Tucked and pulsing and gliding he managed 140mgp (US!).

He wants to build a streamliner with it and do the Craig Vetter Challenge (bike has to be capable of sustained 70mph and be able to carry 5 bags of groceries).

Another guy rode his CBR from FL to Alaska last summer. That's just bonkers in my book but it proves a point. That A) there are wingnuts everywhere, and B) you can tour on a loaded 2-fitty on normal hwy speeds if your so inclined. I expect he needed an ass transplant after though.

This little CBR is a good piece and just ridiculously fun to ride. At the end of the day, it costs me about $10 to run 200 miles.

<commercial over>

The CBR will never replace my FJR though. 50mpg on a comfy rocketship is a good tradeoff!

 

[FJR Bill]

In addition to my FJR I have a 2008 250cc Ninjette. Its a hoot and my commuter of choice. Keeps miles off my FJR tires which I like to save for long trips. My little Ninjette doesn't set fuel records but gets 60 MPG in city traffic. I love it. Evidently the CBR gets a better average, but lacks Interstate/freeway performance. The Ninjette will cruise at 80+ all day long and still has some punch remaining for passing. Bill