Im going to be turbocharging my f4i sometime soon, so ive been
looking at fuel management options. There is no way im going to use an FMU, so thats out of the question. Ive searched around quite a bit, and so far havnt found anything solid. The closest thing to a standalone seems to be the power commander. Since it controls the injectors directly, it should be able to take care of fuel control quite nicely. Of course it will take a while to set up a decent map.

As far as i can tell, the f4i relies strictly on rpm and throttle position to reference the fuel map. The power commander of course is setup in the same way. Setting up a map is going to depend a lot on the motor and turbo size.

For fuel, all we should need is a set of higher flow injectors. In my case, im thinking about maybe some cbr954 or cbr1000 injectors which should be roughly 40% bigger. Basically all that should need to be done, is to lower the injector duty cycle about -40% accross the board. This should have it running like stock with the bigger injectors. In the sample map i rigged up, im assuming that the turbo will start spooling at about 3500rpm, and about 20% throttle. This is pretty similar to the afc hack.

Assuming that the injectors your using are 40% bigger than stock, then at an indicated '0' on the power commander, you'll be supplying 40% more fuel over stock. Of course, ignition retard per lb of boost will be figured into this as well, and be just as easy to set up an a power commander IIIr.

Keep in mind that this is all relevant to the amount of boost your going to run. The base part throttle settings are going to stay the same, but if your only running a few psi, you might only have to go back up to, say, -25% in the high rpm/high throttle regions. This is the part thats different from the afc hack, since changing the boost level would necesitate creating a new map.

PLEASE post back your thoughts on this setup. Im positive this will work, but how good it works will wait to be seen. Also post any other ideas you may have on fuel management for fuel injected bikes.



-Ben

 

you are assuming a lot of factors...

I wouldn't go ahead and assume that 954/1000 injectors are going to flow 40% more fuel based on displacement differences of their application

I wouldn't assume linear relationships between duty cycle and delivery volume. Pintle movement is key here. Especially w/ shorter than designed cycles

You're looking at a lot of time to get a decent basemap

Be careful w/ the ignition timing, I'm not too familiar w/ the f4i program but many times its not based on rpm alone. pcr may not cover all levels.

I don't know what you're looking for out of the setup but I rarely pin the throttle... its all part throttle 99.9% of the time

Also physically fitting a turbine and hardware is a pita. Especially if you want to keep some resemblence of bodywork/ground clearance. Also oil lines are especially painful given the orientation of the pan during riding. Baffling must also be considered as well as total volume of oil. Your turbine may get feed from a baffle during a turn but it may also starve the main pickup or vice versa due to the smaller amount of baffled oil.

That's all I can think of. It's too damn late. On a brighter note, it's a very interesting idea. Please do keep us posted. Also if you wanted to go into more detail...

 

perhaps even car injectors may work? something small, like hf or cx injectors? guy around here used s2000 injectors on his turbo hayabusa setup.

 

Where are you going to find a turbo small enough to start making boost at 3500RMP on a 600cc motor? Also boost is not linear, were it starts at a certain RPM. It is a variable that Engine load, Temp, RPM and a few other things can greatly affect it. And starting the injector too soon will give you a very rich situation and a very lean if it is too late (pistons will blow very quickly like this)

My bike usually starts making boost at around 5.5K Rpm but on hot days not until 6K and under loads (high gear and or low temp as low as 3.5K Rpm.) Also you will need a raising rate fuel regulator to increase fuel pressure at a constant rate as compared to your boost. Also as your boost increases you need more fuel not just a flat increase as show on the power commander map.

My system uses a separate controller for an extra set of fuel injector to handle the extra fuel needs the turbo creates. Thus keeping a very good stock throttle response and idle off boost.
Are you planning on reducting the Compression ratio? If not you will be very limited on the boost pressure you can run.

Good luck on your project.

 

I was really just using most of the numbers i thew out there for example. Everthing is of course going to be relevant to the setup. I really dont expect
to find a turbo that spools that fast, or have such an incredibly basic map.

Ill probably just go with a set of civic injectors. At stock fuel pressure, they should
provide more than enough fuel for anythin under 175hp. The pcIIIr does do
ignition timing as well, exactly in the same way it does fuel. Just gonna have to
spend some time setting up a map.

My wideband controller (techedge 2.0) can be easily used to datalog with my
cheapo palm. Shouldnt be too incredible difficult. Just set the map on the extreme
safe side and datalog RPMs/throttle position/af ratio.

The only major downfall i can see is that any changes to the boost level will require
an entirely new map to be made. I still havnt even got a chance to start pulling the
bike apart though, so i dont know every last detail of the FI system for sure yet.

Ill keep everyone posted. Any ideas, please post them back. Also any other helpful
criticism is appreciated

 

i have a pdf that documents turboing an f4i with motec, i dunno if whoever sent it to me got it from here and im just blind, but if you would like it, my AIM is cartoysrus03.

 

Holy **** busa1300!!

I dont have a bike, rode smaller when i was younger, just ventured into here, sorry i know this is off topic.

I read your sig, 310whp??? on a bike.

Your ****** crazy man...

but i like it....

 

Depending on work I may be adding anouther 100Hp to that. I am getting a little complacent with 300.