Official Carb to Fuel Injection Thread. (machinist and fabricator input very welcome)

[Freestyle72]

Ok so I am devoting this thread to fuel injecting my FZR400. Any and all input is very welcome in this thread. Although keep in mind I am going to try to keep costs down as much as possible and the whole execution of the project will hopefully be complete in the winter. But I am beginning the design now and will make and acquire the parts in the coming months so I can assemble through the winter.

Now I have purchased 03 04 R6 throttle bodies. These are nice because they are CV style similar to carburators. I want to use the R6 intake boots, so I think the best option is to use adapter plates to the head to accomodate the R6 boots. The r6 boots are nice because they are OEM and will fit the throttle bodies perfectly. Another nice thing of going with OEM intake boots is that they would be easily replaceable in case of damage or wear and tear etc.

I have made some solid works models to kind of outline what I am thinking with this. This drawing is not to scale and is not even properly dimensioned but I am just using it to deliver the design concept I am going for.

What are your guys thoughts on this design? One set of holes will be threaded (the ones the R6 intake boot will bolt to). The other set of holes is to bolt to the head. My main attraction to this is that it will help me keep my machining costs down as it is fairly straight-forward in design.

Some things that need adressing would be the shape of the R6 intake boot hole vs the the shape of the yzf's hole I still don't know how I can make one match the other, perhaps some kind of epoxy?

So what are your guys thoughts on this? Any suggestions? Any recommendations? Would love to hear them all. I would especially like to hear recommendations from machinists who may have any advice on how I can properly spec this stuff out to help the machining process and such.


Disclaimer: Please don't try to tell me it's more economic to buy an already fuel injected bike or some other jibberish about a well set-up carb being better than fuel injection. I want to do this as a project because I enjoy learning, and the engineering design process involved. Thanks.

 

[Freestyle72]

Actually the above pictures are incorect. This is more what I am trying for my bad.

Also on a side note I saw a guy fuel injected his RZ350 and he made his adapter plate on an angle (like a wedge). He said this let him inject his oil into the stream of the fuel which I understand because it's a two stroke, but he also mentioned he felt it would flow better that way. Any idea why it would be better like that? I am considering a wedged plate as well just because the YZF600 airbox has an angle to it and if I wanted to switch to an airbox from pods this would help clearance and stuff. If this question doesn't make sense to you just disregard it. I am half thinking out loud.

 

[Brian P]

Adapting the throttle bodies to mechanically fit, is going to be the least of your worries. Trust me, the headache is going to be in the electronics.

Have you looked at the type of crank pulse signal that the FZR flywheel and crank sensor will give, and compared that to the crank pulse signal that the EFI ECU is expecting? And, what EFI ECU are you going to use? And then there's the dreaded "mapping" ... you are going to be starting from scratch, not like fiddling with a Power Commander where you at least have a starting point. Part-throttle mapping, cold start and warm-up, altitude compensation, are all up to you to get right!

I'm not saying it can't be done. It CAN be done. Just making sure you know what you are getting into.

 

[Freestyle72]

I will use microsquirt. I will read spark from the trigger wire. Megasquirt is fine with this. I will use a wideband O2 sensor to help with the tuning. My main concern as you mentioned will be making the map. But I think if I can get it in a rideable condition I will pony up for some dyno time if need be.

One step at a time though. First I need a proper way to adapt the throttlebodies to the head. There is no doubt that megasquirt can handle the EFI as it has been done on many FZR1000s and a YZF600. The engine on my bike has the same head as a YZF600 so as far as it being impossible or not. It's definately possible. I only want megasquirt to control fuel for now. Controlling spark is beyond my comprehension level at this point and from what I understand complicates things a great deal. So I want to get it runnign fuel only first.

And of course I am always open to more experiences people giving me a hand.

 

[Franko!]

Cool project.

Some points to think about:
- fuel pump location, pressure regulation, control
- Is the cam position required or are you running waste spark?
- Is coolant temp going to factor in to your fuel equation?
- How are you going to drive the speedo and tach with MegaSquirt?
- You will have to figure out a your own way for the side stand / clutch ignition interlock.

I have thought many times about doing the same thing. BUT the sheer amount of fabrication, testing, troubleshooting, more testing, and money have kept my bike carbed.

Good luck and keep us posted.

 

[Freestyle72]

Cool project.

Some points to think about:
- fuel pump location, pressure regulation, control
- Is the cam position required or are you running waste spark?
- Is coolant temp going to factor in to your fuel equation?
- How are you going to drive the speedo and tach with MegaSquirt?
- You will have to figure out a your own way for the side stand / clutch ignition interlock.

I have thought many times about doing the same thing. BUT the sheer amount of fabrication, testing, troubleshooting, more testing, and money have kept my bike carbed.

Good luck and keep us posted.

- May use some kind of intank walboro or such pump, pressure regulation the throttlebodies have a built in FPR.
- No CPS to use so I will read off the trigger wire running wasted spark
- Will use coolant temp sensor I have an R1 sensor I can get mega squirt to read
- I have R1 guages and they read spark off the trigger wire for I believe, and then it's corrected via some relay box
- I have have no diea what clutch ignition interlock is, I Guess I will have to cross that bridge when I get there lol.

 

[Red_Liner740]

other than the fuel pump and spark i dont see how any the other points apply. Hes keeping the ECU thats on there now that controls the spark and has the hook ups for everything else. Megasquirt will only be used for fuel and it wont have anything to do with the other functions already on the bike.

Regarding fuel pump and control? how do the R6's feed the fuel? return flow? FPR? if it already has a fuel rail system with a FPR, obtaining a fuel pump to feed enough flow and pressure shouldnt be too hard. the FPR and the fuel rail do the rest.

Megasquirt (or Microsquirt) needs a few input signals, it gives a few output signals but like someone said. the hardest part will be tuning the sucker...

does the FZR have a TPS? can a secondary TPS for the MS be installed on there? will u use a MAP or a MAF sensor for fuel metering? IAT and Coolant temp are straight forward. Only other input signal it needs is for RPM. You said u got that figured out. In theory, lol, it doesnt sound too bad.... :lol:

Cool project.

Some points to think about:
- fuel pump location, pressure regulation, control
- Is the cam position required or are you running waste spark?
- Is coolant temp going to factor in to your fuel equation?
- How are you going to drive the speedo and tach with MegaSquirt?
- You will have to figure out a your own way for the side stand / clutch ignition interlock.

I have thought many times about doing the same thing. BUT the sheer amount of fabrication, testing, troubleshooting, more testing, and money have kept my bike carbed.

Good luck and keep us posted.

 

[Brian P]

Okay, are you proposing to use the FZR's existing ignition system, in combination with the Microsquirt to handle the fuel injection? The FZR's crank trigger gives several short pulses and one big one per revolution, so that the electronics can more accurately calculate the ignition timing. If you are using the *output* of the ignition ECU, i.e. one of the ignition-coil-fire signals, that is one pulse per revolution.

If I remember right, the Microsquirt/Megasquirt systems are only batch-fire, not sequential. They fire all the injectors once per revolution simultaneously. Thus, each intake stroke gets the total of two injection cycles. Unless you are really fussy-finicky about getting the absolute best possible emissions and fuel consumption, this is ordinarily not meaningful.

If you are using the FZR's original ignition ECU then you can use the FZR's original tachometer connected in exactly the same way it is now, and the speedometer is mechanical. Why complicate matters by using instruments from something else.

Most EFI systems nowadays use an in-tank pump and regulator assembly with a single outlet hose going to the injectors, and there is no downstream pressure regulation. But, the early Yamaha systems were oddballs and it's possible that they differ. Where are you going to put the pump? Custom fuel tank? You're going to be cutting and welding anyway, might as well just make a custom tank. This way you can probably solve some of the airbox clearance headaches that you haven't run into yet but soon will ...

 

[Brian P]

few folks typing at the same time. The FZR has no throttle position sensor (TPS), but the R6 throttle bodies that Freestyle wants to use, have this sensor.

Typical EFI systems have, at a minimum:
- TPS (throttle position) - built into the EFI throttle bodies
- Crank position - will be obtaining from the ignition-fire signal from the existing ignition ECU, correct?
- Barometric air pressure (Where is this? Built into the throttle body? Some vehicles have it in the ECU since this doesn't actually need to be part of the engine; barometric pressure at the ECU won't be appreciably different from what it is at the engine! But, it needs to be somewhere, for altitude compensation. Do you know where it is?)
- Manifold air pressure (normally built into the throttle body - But I think the Megasquirt/Microsquirt system is capable of running purely N-alpha without relying on MAP, so you might not need this, although low-RPM cracked-throttle driveability might be a bit of an issue if it doesn't run speed-density at small throttle positions the way most bike EFI systems do nowadays)
- Intake air temperature. Ordinarily this is a separate sensor in the airbox, although it's possible that it is in the throttle body
- Coolant temperature. Needed for cold-start and warm-up compensation. Normally this sensor is remote from the throttle bodies. It shouldn't be too hard to put an extra fitting someplace in the cooling system to allow this. This should preferably read temperature at the engine block, not at a coolant hose or thermostat housing that is remote from the engine, to give the best shot at getting the cold-start compensation right.

If the EFI system has provision for being connected to a lambda sensor so that it can run in closed-loop mode, at least over some portion of the operating range ... I'd strongly recommend that you do that. Doesn't mean you get out of mapping - it needs a basic open-loop map to use for the first couple of minutes until the lambda sensor starts giving a reliable signal, and usually full-load wants to be a bit richer than stoichiometric so you can't run in closed-loop there. But, it could make the mapping chore a lot easier by covering up inadequacies in your map once the engine warms up.

 

[Freestyle72]

does the FZR have a TPS? can a secondary TPS for the MS be installed on there? will u use a MAP or a MAF sensor for fuel metering? IAT and Coolant temp are straight forward. Only other input signal it needs is for RPM. You said u got that figured out. In theory, lol, it doesnt sound too bad.... :lol:

The R6 throttlebodies I am using have a TPS on them. I will use a map sensor, IAT, coolant temp sensor to keep megasquirt happy.

Okay, are you proposing to use the FZR's existing ignition system, in combination with the Microsquirt to handle the fuel injection?...

Yes

If I remember right, the Microsquirt/Megasquirt systems are only batch-fire, not sequential. They fire all the injectors once per revolution simultaneously. Thus, each intake stroke gets the total of two injection cycles. Unless you are really fussy-finicky about getting the absolute best possible emissions and fuel consumption, this is ordinarily not meaningful.

I actually do kind of care about mileage so this is something I should look into. Did some quick reading, looks like it can do sequential but mit requires a cam and crank sensor input to megasquirt. So I cannot do that. However I don't think the mileage will suffer any worse than carbs so I am ok with that.

If you are using the FZR's original ignition ECU then you can use the FZR's original tachometer connected in exactly the same way it is now, and the speedometer is mechanical. Why complicate matters by using instruments from something else..

The bike came with R1 guages on there. Which I actually find to be nice because it reads from the transmission, so when I switched to the GSXR front end the bike still reads speed fine which is nice.

Most EFI systems nowadays use an in-tank pump and regulator assembly with a single outlet hose going to the injectors, and there is no downstream pressure regulation. But, the early Yamaha systems were oddballs and it's possible that they differ. Where are you going to put the pump? Custom fuel tank? You're going to be cutting and welding anyway, might as well just make a custom tank. This way you can probably solve some of the airbox clearance headaches that you haven't run into yet but soon will ...

I have no problem with modifying the tank. However I will probably be running pod filters so I am not to worried about clearance issues.

 

[Brian P]

If I were in your position, I'd make sure that you can go back, in case things don't work out. If you want to cut and weld a fuel tank, I have one with a small hole that needs welding up anyway (used a too-long screw at one of the fuel tank cover mounting holes and it punched through) so you can avoid cutting up your original and presumably good-condition tank. That metal is really thin - I can't weld it myself.

 

[ChrisR]

I have done this before, except with the electromotive tec3 and tec3r. (on Formula SAE)

You're on the right track, that's really all I can say at this point re building it.

In terms of tuning, getting it running really isn't all that hard. Brian P is making all good points, but don't let him scare you lol. You can do a lot with logging and 'seat of the pants', certainly enough to make a 'safe' rich map, if not an efficient/powerful one. If you tune it filthy rich, when it doesn't bog, it'll run f*n great.

If you can get rpm, tps, map/maf, and fuel all working together, tuning will be the fun part.

The hard parts are making it run efficiently, making it start properly (hot/cold), and making it idle properly. We never had much trouble with accel/decel enrichments...the ecu manual had some recommendations, we followed them, and they worked well.

I would recommend a downstream fuel pressure regulator with a tank return, regulated by intake manifold pressure. This maintains a constant pressure across the injectors with changing intake pressure. (Older cars use this method. New cars often use pulsewidth modulation of the fuel pump to control pressure.)

It's not really a requirement, but it makes life a lot simpler, because in that case injector pulsewidth has constant proportionality with air/fuel ratio at any spot on the map. Ie if you need 5% less fuel, reduce pulsewidth by 5%.

Without a constant fuel deltaP, the coefficient changes with intake pressure and velocity, and the calculation makes me want to cry.

 

[luffy]

In browsing through this thread, all I can say is that I felt my brain implode a little. Kudos for taking it to this level!

Adam

 

[Brian P]

When you consider how complex some of the control algorithms are in EFI systems, it's a miracle that carbs worked at all. And when you consider how sophisticated carbs on later model engines are, it's a miracle that old less-sophisticated carbs worked at all. 'Course, they didn't care about emissions and didn't care much about fuel consumption back then. In the beginning, it only mattered that the engine worked most of the time.

It's been stated that a carburetor is a device for making an incorrect air/fuel mixture at every operating condition. If you watch what a wide-band sensor does on a carbureted engine, you'll go nuts. And then go even more nuts after you rejet it according to what the wideband says, but have mystery driveability issues due to momentary transient conditions that the wideband sensor doesn't pick up and display quickly enough (or you can't see it quickly enough).

 

[Freestyle72]

If I were in your position, I'd make sure that you can go back, in case things don't work out. If you want to cut and weld a fuel tank, I have one with a small hole that needs welding up anyway (used a too-long screw at one of the fuel tank cover mounting holes and it punched through) so you can avoid cutting up your original and presumably good-condition tank. That metal is really thin - I can't weld it myself.

I am using a YZF tank. Is your extra tank a YZF or is it an FZR tank? I was thinking about getting a 95/96 YZF tanka s it fits exactly the same as the 97+ yzf tanks (like the one I am using). But it looks slightly uglier and uses an in tank fuel pump like the r6 does. And you can mod the R6's fuel pump aluminum tie down to bolt into that tank.

In browsing through this thread, all I can say is that I felt my brain implode a little. Kudos for taking it to this level!

Adam

Thanks!

I have done this before, except with the electromotive tec3 and tec3r. (on Formula SAE)

You're on the right track, that's really all I can say at this point re building it.

In terms of tuning, getting it running really isn't all that hard. Brian P is making all good points, but don't let him scare you lol. You can do a lot with logging and 'seat of the pants', certainly enough to make a 'safe' rich map, if not an efficient/powerful one. If you tune it filthy rich, when it doesn't bog, it'll run f*n great.

If you can get rpm, tps, map/maf, and fuel all working together, tuning will be the fun part.

The hard parts are making it run efficiently, making it start properly (hot/cold), and making it idle properly. We never had much trouble with accel/decel enrichments...the ecu manual had some recommendations, we followed them, and they worked well.

I would recommend a downstream fuel pressure regulator with a tank return, regulated by intake manifold pressure. This maintains a constant pressure across the injectors with changing intake pressure. (Older cars use this method. New cars often use pulsewidth modulation of the fuel pump to control pressure.)

It's not really a requirement, but it makes life a lot simpler, because in that case injector pulsewidth has constant proportionality with air/fuel ratio at any spot on the map. Ie if you need 5% less fuel, reduce pulsewidth by 5%.

Without a constant fuel deltaP, the coefficient changes with intake pressure and velocity, and the calculation makes me want to cry.

The throttleboddies already have an FPR and return on there and TPS. I already have an R1 coolant temp sensor for my R1 guage that the bike is using so that is useable as well. I will get a wideband O2 sensor, map sensor, and IAT sensor and I think I am pretty much good to go. I am actually more concerned about modding the fuel rail. I been looking into the process of brazing as it is the way to go with fuel lines. I am thinking I may actually tackle this my self. I know fuel lines are definately not something you want to screw with. But I figured I can always braze the line myself and then run a pump into and see if it leaks before I actually run it on the bike.

I figured I could get a decent enough base map like 20:1 AFR to be conservative and then actually buy some dyno time to get it dialed in. I really do care about fuel mileage. And I want this to at least approach factory quality injection I don't want to be some unreliable piece of junk.

When you consider how complex some of the control algorithms are in EFI systems, it's a miracle that carbs worked at all. And when you consider how sophisticated carbs on later model engines are, it's a miracle that old less-sophisticated carbs worked at all. 'Course, they didn't care about emissions and didn't care much about fuel consumption back then. In the beginning, it only mattered that the engine worked most of the time.

It's been stated that a carburetor is a device for making an incorrect air/fuel mixture at every operating condition. If you watch what a wide-band sensor does on a carbureted engine, you'll go nuts. And then go even more nuts after you rejet it according to what the wideband says, but have mystery driveability issues due to momentary transient conditions that the wideband sensor doesn't pick up and display quickly enough (or you can't see it quickly enough).

I absolutely love my first bike. It was carburated and I thought it was great that I could clean them with total ease and make minor adjustments etc. That is until I got fuel injected bike, and my bike would actually idle in the rain and other stuff my carbed bike hated doing lol. Although I really have to admit the carburation that is on the bike as it is is really good. It's using a 97-07 yzf600 carburator and I must say they are damn smooth. But I would like it to autochoke and all that good FI stuff .

The main reason I really care about getting the adapter plates right and the mechanical fit of the throttlebodies on there is because this could potentially govern the cost of the project. I would like to do my best to keep cost under control for this project. Also I would like to keep it on schedule so I am aiming for a pre-march completion during next winter so I can be riding in April. Depending ont he adapter plate design the cost could vary HUGE. When I get back from my vacation I think I will take measurements on the head of the critical dimensions.

Unless someoen has a YZF head laying around I can buy or borrow to make my measurements and possibly help me brainstorm good throttlebody adaptation methods.

 

[Brian P]

My extra tank is an FZR400 tank. Re the YZF in-tank fuel pump ... That will be a low pressure pump, probably 3 or 4 psi (for carburetors). You are going to need a high pressure pump (about 40 - 50 psi).

 

[Freestyle72]

My extra tank is an FZR400 tank. Re the YZF in-tank fuel pump ... That will be a low pressure pump, probably 3 or 4 psi (for carburetors). You are going to need a high pressure pump (about 40 - 50 psi).

Ya my above post wasn't perfectly clear. The 95/96 tank will accept an 03-05 R6 in tank fuel pump almost bolt on. It requires some minor modification to the aluminum bolt down rim that goes around the fuel pump. Other than that it's a basically a bolt in application. I want to use an 03-04 R6 fuel r6 fuel pump in a 95/96 yzf tank. From what I can tell by looking at pictures the 03 04 R6 high pressure fuel pump has the return built into it, correct me if I am wrong. And if this is the case it will save me welding such thin material.

 

[ChrisR]

For fuel lines and fittings we always used military-style AN hardware from Leavens and some place called Earls which was the cheapest source at the time....braided stainless over teflon hose etc.

Never had any leaks or even the smell of gas...but the fittings are expensive. What you want to stay away from is rubber hose...swaging fittings on the end is something only factories can do, and barbed fittings are not appropriate for fuel.

 

[Freestyle72]

For fuel lines and fittings we always used military-style AN hardware from Leavens and some place called Earls which was the cheapest source at the time....braided stainless over teflon hose etc.

Never had any leaks or even the smell of gas...but the fittings are expensive. What you want to stay away from is rubber hose...swaging fittings on the end is something only factories can do, and barbed fittings are not appropriate for fuel.

How might I install AN fitting in the middle of my stock fuel rail lol? I was just going to cut the existing fuel rail and braze in some fuel rail stock to make up the gap.

 

[Freestyle72]

How might I install AN fitting in the middle of my stock fuel rail lol? I was just going to cut the existing fuel rail and braze in some fuel rail stock to make up the gap.

Can I just thread the fuel rail and put those fittings on? That might actually be easier/safer than brazing for me. And it would also offer me repeatability if I wanted to do this again, or another bike.