Fuel mileage thread

17/43 works fairly well on the 6th gens. You need a little more clutch to get out of the hole, but it is really nice on the highway.

 

I could see gearing up, possibly hurting city mpgs, while improving high speed cruising mpgs, just depending on the specific application.

The same or opposite can be said about gearing down, where mpgs could possibly be improved in the city, while highspeed highway cruising mpgs would drop.

Clutch slip and higher throttle openings are not good for mpgs.

 

LOL Well if that wasn't an over the top explanation, love it. All I know is I see the same fuel economy whether I'm doing 90 or 60 but that's also constant throttle, though on one trip mostly freeway Ekkk! One time I was stuck in nascar 50-55mph for a 100 miles. was curious so went and topped off the tank and saw that I got 52 mpg during that period so? Now on the frisky back rounds where the Rs are all over the place pulling out of turns and all, not surprising I will have to fuel up way sooner. It's expected.

 

The key is to have a cruising window in your mapping. Generally most tuners do 13.2:1 across the board. So if you're 13.2 across the board, you're not really going to see much different mpgs at different speeds, like you would with the factory mapping.

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2:1 says when you make your drag runs you don't do mileage numbers..

Good stuff on the mapping. If I ever get a bike that uses that then TIA..

I grew up in a house about two rock throws from the old LIONS dragstrip in SoCal. Mickey Thompson was the manager.

 

I am fairly certain I am geared a bit low for the range I am most interested in. With my weight it's hard for me to get out of first fast enough at WOT to keep the tach out of the deep red under power. I am happy to give up a little low end acceleration and always having just the right gear coming out of a curve (which often means 2-3 gear changes coming in) , more on the six speeds to get a few more miles to the tank.

I am loving the old 5 speed but would like to have the 6 gears of an 86 750f or 1000r either which can be had in nice shape for around $3-4K maybe less and still have that vintage flair , maybe a bit more.


My hopes is that a list of fuel mileages, and mods will help people to test and tune. It's not like most of us ride ten tenths on the street so absolute peak power, probably takes a back seat to not being the first guy needing to signal for a fuel stop or even getting an extra 20-30 miles between stations when solo.

Regards
db

 

Rode the 8th gen. today in the mountains, river valley, and twisties at a "quick" pace with two other riders and it got a measured 47mpg. Had I been alone (went with 2 other riders) I would likely have gotten the usual 45mpg at a very much faster pace. This bike just hangs out at 45mpg at a VERY quick pace. Doing much better than the 5th and 6th gens. I used to have.

 

Fuel injection definitely opens the door to not only better performance and fuel mileage ,but also adaptability / consistency across weather and elevation changes.

Although a well tuned FI engine will run better at sea level, as more and denser air equals more fuel charge equals more power, otherwise large changes in air pressure won't have the affect it does on carbureted engines.
Newer emission standards now not only require emissions monitoring, but also require certain fuel effeciency standards, this puts lean burn technology similar to described above into the programming and to a lesser extent mechanical design (high swirl combustion, to make the charge burn faster and more completely) into the factory design of nearly everything that hits the streets.

I remember a buddy of mine had an '87 Mustang LX 5.0HO 5 speed which has a higher geared rear end versus the GT as well as being a few hundred pounds lighter. That thing not only run way better than it should have being stock, but also would get about 40mpg.

With FI the cylinders being perfectly balanced as far as compression ,airflow and such can give results similar to perfectly balanced carbs in a V4.
There are some things we can do to help assure this balance, even on a FI bike. Most is just good maintenance, making sure we have good strong spark to each cylinder by keeping plugs, wires and coil connectors in top shape.
Fuel system maintenance...those that have weak pumps, dirty filters and/ or dirty injectors, not only don't give a good fuel spray, but may have less pressure available to the injectors at the end of the rail. Not alot we can do about equal ring seal or equal resistance to airflow. I do believe some A/M systems for the V4 allow tuning of the front and rear banks separately ,provided there is an oxygen sensor for each.
Hopefully someone who knows vfr's better can comment on what options are available .

One thing to keep in mind is the better an engine runs the better the fuel mileage and the more power it makes as well.

 

I've got four o2 sensors and four separate fuel maps. It's like syncing your starter valves times ten, for the entire powerband, not just the 0-5% throttle.

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That's awesome, how much of this is this stock on the '07 800 I assume, and how much is aftermarket?

I am definitely intrigued by the 800's particularly the v-tec ones, with an O2 sensor per cylinder and the fuel mapping valve and ignition timing of am A/M computer. I could see how really experimenting with the tuning could be a techies dream. Since I owned my first FI cage I have often dreamed of getting and eeprom burner , decoding and rewriting FI software and maps so that I would have the ability to custom tune anything , time, a failed marriage ,lost school time, and lack of interest /money has prevented this ,but fortunately almost anything that runs on a Computer can be run with a mega squirt, power commander and possibly a sensor change or two.

It would be cool to take a v-tec bike , drop the compression, and add an A/M controller and small turbo even 1 bar of boost could make a huge difference.

So many dreams and so little time and money. Time to go for a ride.

Later
Db

 

I have an aftermarket "Rapid Bike Racing" fuel and ignition controller, which allows use of 1, 2, or 4 wide band o2 sensors for real time closed loop fuel tuning.

The factory o2 sensors (there are two) are narrow band, and only used by the ecu for light throttle cruising. They go offline during anything resembling acceleration. They need to be disabled for tuning.

Power commander 3 and 5 require disabling the factory narrow band o2 sensors, which forces the ecu to run open loop.

The power commander 5 can use an optional "auto tune module" to use one wide band sensor, as a data logging device to create maps, but it doesn't actually work in closed loop/real time.

Rapid Bike can use the two factory narrow band o2 sensors to tune in real time closed loop. It can also use optional 1, 2 or 4 wide band o2 sensors to tune closed loop real time, more precisely and faster.

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That is so sweet.
Of course I would have to do a $250 injector mod (fits in place of the Cv carbs diaphragm) to use a simple standalone ecru such as microsquirt.
Then add a TPS ,WB O2 sensor, possibly more to have decent functionality.
Will check out rapid bike tuner for sure.

 

No point in looking at rapid bike, if you're not already factory Fi.

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When I first got my 06 and it was all stock I was getting into the 50 mpg range but I was riding it easy and getting a feel for it. After installing the Power Commander 5 and trying various U.S. based maps my mileage was in the high 30s to low 40s and the bike ran ok but felt lethargic. I tried the Power Commander European spec tune for a stock bike with a slip on and it ran so much stronger and smoother and my mileage was a pretty consistent 44 mpg. I've since found an Austrailian/Euro based tune for stock filter, flapper and snorkel mod and slip on exhaust that runs even smoother, stronger, and has gotten as good as 46 mpg. The U.S. based tunes add a lot of fuel everywhere and the Euro based tunes by in large pull fuel from most everywhere other than the VTEC engagement. I've ridden several thousand miles with no ill effects on 87 octane.

 

1.) You should try a custom dyno tune actually made for YOUR bike, by a competent tuner with your bike on a dyno.

2. Vfr800's are made to run on regular unleaded, no fuel only map will change that. Ignition tuning, compression, boost, excessive heat etc are what call for additional octane.

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I know a custom tune would be the most ideal but this is working just fine. I was really hoping there would be enough support that Guhl Motorsports would follow through with their 06+ VFR 800 tuning. A rapid bike system would be great but I can't justify the cost when the bike runs significantly better than it did in stock form.

 

Take how it runs now. Multiply that by 3 or 4. That is rapid bike. I wanted an ecu flash, until I realized that a flash won't get you closed loop fuel tuning, quickshifter, launch control, on the fly afr trim adjustment, afr readout, engine brake control, traction control, Individual cylinder wide band tuning and no need for custom dyno tunes after each mod.

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