fuel mileage, how to improve...

[bitabur]

Tonight I stopped for gas, and after resetting the trip meter, I tried to figure out how to get the best mileage at different speeds.

I've heard here before that the engine seems to be the most efficient at about 4000-5000 rpm, which I tested, and I found that indeed, on the freeway, cruising at an indicated 70-75mph, I get better mileage in 5th than 6th gear. *Ok, people were right.

Since that test, I've tried to keep the engine in roughly that rpm range most of the time when I'm traveling steady speed, figuring it was the most efficient. *Tonight I found that my bike seems to get the best mileage in 5th gear (at low speeds even 6th gear) all the time, even down to an indicated 25 or 30mph, with the engine under 2000 rpm.

I have a hypothesis about this, but first, is there something about the 5th gear fuel map that would make it more efficient? *I always heard that 5th/6th was richer because of compensation for forced air into the intake, which would make it less efficient, right?

My hypothesis is that at lower speeds, where aerodynamics don't matter as much, simply turning the engine slower saves fuel, as long as you're keeping a steady hand on the throttle and not bogging the engine to accelerate. *On the other hand, at higher speeds, the engine needs to fight much more wind resistance, and because the engine is more efficient at higher rpm, overall mpg is better with the engine revving up a bit more.

Does any of this make sense, and has anyone else had the same results?





PS. *My absolute most efficient, steady speed freeway cruising, tucked-in mpg is about 44, while for short spirited stints I've had it down below 25. *My average since I've had the bike (haven't reset trip1) is about 33 mpg. *I weigh ~280 lbs without gear, and always run 87 octane.

Does this sound about right or should I get a PC and get a few maps made?

[TheAtomicAss]

I've heard of better, like low 50's at highway speeds, but I don't know what speeds attained those results. I'm fairly certain that 6th was used, though. I'm of the belief that the Busa gets it's best economy significantly above the speed limit. Try 6th gear at 85-90 and see what that does.

Personally, I would match the display to pump results, as it's possible that it's reporting better or worse than you are actually getting. If you've got anything affecting the odometer, such as sprocket changes or a different sized tire, that needs to be taken into account.

And depending on the way an engine is tuned, it's efficiency can be all over the map, or not at all. Highly likely that the slight extra fuel added in 5th adds enough torque to overcome consumption in comparison to lower gears.

[AZIROC]

i have 16/42 gearing and if i hold around 4500 rpms in 6th gear i get between 48-51 mpg

[Bokey]

80-85 on the Highway the MPG on the bike stays @ 50. using 6th and tucked as much as possible.

[DEVLDOG]

I have 17/43 gearing and im mapped out 10% fat because of the NOS,I average btwn 25-30mpg...Im not real concerned with it,im just out for fun,if i was worried about fuel miliage id buy a geo metro for 55mpg *

[dadofthree]

I get my best below 70 MPH. If I hit 4000 RPMs I can see the mileage begin to fall below 50 MPG.

[Rayabusa0818]

Mine is stock and I usually see about 50mpg on the interstate and about 44-45 on surface roads.

The most efficient speed seems to be running down the interstate about 80mph.

[Turbo-Torch]

80 mph in 6th gets me 49.6 mpg. Below that or above 85 it starts to drop. If I put a 120 lb passenger on the back (which would bring me up to your 280 lbs) I could easily see it dropping to 44 mpg. I'd say your engine is at peak efficiency. Around town it's going to drop no matter what.

One of my favorite things about the Busa is its great highway mileage for those 1000 to 2000 mile weekend road trips. If all I did was ride around town all day, I'd by a mountain bike.

[Nekosohana]

Hmmm. I have neve peaked higher than 41. But then again, never lower than 29. Still sounds like a good range to me.

[NCpanther01]

Great info! I tried holding it in 6th doing 70 this weekend in SC. I saved some gas but made a contribution to the state PO PO!!!

[TallTom]

I am right in there with Dadofthreee, Rayabusa and Turbo-Torch. I find that if I drive very easy and shiftthrough at 2K or so I can stay at 42-4 in town. And about a steady 75 in 6th yields a 50-2, non tucked on cruise control.

But if you ask it for power, it drops quickly. I can easily see it go to 29 in town and 36-8 on highway if I'm twisting the wrist agressively.

I also noticed an improvement when I installed a PC III and loaded a stock map.

BTW the bike is stock in the engine dept.

[Justyntym]

I'm around 34-38 mpg....I think I got wrist problem

[04gtstang]

Over the past 2XXX or so miles (havnt cleared the odometer in a LONG time lol. (29XX on the bike) I have adveraged over 45MPG. I rarely tuck in while riding BTW.

I cleared it before and on the highway @ 70ish it pegged the reading @ 50MPG....I have also tested it at the pump vs miles and it came up with like 45-48 MPG.

Stock gearing and all that...all I have are frame sliders and factory lowered rear..... and at that time it was totally stock.

[MET]

Hmmm at 184mph and above I get about 12mpg and keeping the RPMs at 4500rmp out of 12,000rpm (modified) can get about 46mpg

[DaCol.]

Hummmmmmm, I guess that means I want be using 6th gear until I hit 7,000 in 5th !!! ALLLLLLLLLLLLL Right * *

Yeeeeeeeeee Hawwwwwwwwww *

[BUSADOOK]

I have never tried to check when i have maximum efficiancy, but i notice it go down when i'm on the throttle alot, and go up when i'm smooth. However when driving normal it is always at 34mpg in town. Keep in mind it has 36K miles on it so i'm sure i'm losing a little there.

[bitabur]

I wouldn't be surprised if an older bike got better mileage... engines tend to loosen up, and there aren't any feedback sensors in the FI to get old and mess up the mixture...

[xx2busa]

I have been very impressed with the mileage I get on the bus, 49-50 indicated and @ the pump 47-48 mpg average. This is 80%+ highway 75 to 85 indicated without a speedo healer on 87 octane. This was one of the largest reasons I got the bus instead of the zx-14. BTW my XX returned about 42mpg.

[Luvanicebum]

I just saw this thing on myth busters about drafting behind other vehicles.
Even at a safe 2 to 3 second following rule behind another car, your vehicle can increase it's fuel efficiency by 10-12%. At a 1 second distance, it can increase by as much as 25-30%. So, if you're commuting all the time and always on the highway/interstate, I guess it does pay in the long run to follow behind someone.

[DEVLDOG]

<div>
(Ninja Eater @ Jul. 11 2007,09:31)</div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">Hmmm at 184mph and above I get about 12mpg and keeping the RPMs at 4500rmp out of 12,000rpm (modified) can get about 46mpg</div>
ahahaha....12mpg...a hummer gets bettr miliage!!