Interest in efi?

[x7rocks]

So i started piecing together an efi kit for 2 stroke engines using a microsquirt style setup.

I specifically got a hold of a manufacture (not eco tron) to make something for our minarellis, and so far the results are promising.

Im using my imported 97 aprilia sr50 as a test mule to work all the kinks out from cold start tuning,to timing control,etc
.

Id like to release a kit by the fall time but would like to gauge more interest before going all out and introducing this new tech to the community.

[x7rocks]

youtu.be/evobn5Qsfw0

Here's a small vid.ill be posting updates once theres more funds for more development,right now awaiting a wide band before going on the road,then the dyno.

[90GTVert]

More info on the system components and requirements and ballpark price figures may help some decide if they're interested.

I'm curious if you're pre-mixing. I don't know much about watercraft, but I think ski and outboard EFI owners do... but I recall one member doing an EFI swap with IIRC and ecotrons kit and saying that premix was not good for the injector.

Also curious what data it uses to adjust the tune on the fly. Is it using an o2? My understanding has been that those are prone to fouling in 2T apps.

Sorry if those are noob questions, but I've never been around an EFI 2T or followed them.

[x7rocks]

Jul 28, 2018 19:35:19 GMT -5 90GTVert said:

More info on the system components and requirements and ballpark price figures may help some decide if they're interested.

I'm curious if you're pre-mixing. I don't know much about watercraft, but I think ski and outboard EFI owners do... but I recall one member doing an EFI swap with IIRC and ecotrons kit and saying that premix was not good for the injector.

Also curious what data it uses to adjust the tune on the fly. Is it using an o2? My understanding has been that those are prone to fouling in 2T apps.

Sorry if those are noob questions, but I've never been around an EFI 2T or followed them.

Tuning will be done using a wideband and adjusting the fuel map that matches the afr range youd like to have, 12:1 wot 13.5 quarter throttle, 14.5 coasting and idle etc.

For 2 stroke guys i recommend premixing,i don't see much issues with premix and fuel injection as many rotary engines run premix with no issues.

The ecu uses crank signal and map sensors to make adjustments on the fly, so no 02 sensor will be needed once the maps are dialed with a wideband.

Price for a minarelli fuel injection is looking to be 350 for the entire kit.

It will include fuel pump throttle body, injector, ecu,adjustable cdi (no longer need to buy 500 dollar inner rotor kits to control timing)
Throttle cable,map sensor,tps sensor and fuel lines.

Tuning software and a tuning cable also come standard.

[190mech]

I follow KiwiBiker Buckets,those guys are a sharp bunch,they've been trying to get a good mapping for a while,seems that a strong piped motor is difficult at best to tune with EFI,many big companies have tried it,all have fallen short.Good luck in your adventure!!

[x7rocks]

Jul 28, 2018 20:01:17 GMT -5 190mech said:

I follow KiwiBiker Buckets,those guys are a sharp bunch,they've been trying to get a good mapping for a while,seems that a strong piped motor is difficult at best to tune with EFI,many big companies have tried it,all have fallen short.Good luck in your adventure!!

I'll try to use my degree in racing technology to the best of my knowledge for this project id like to bring as many scooters as possible to the 21st century as far as reliability goes, even for a sport build, we will offer a 19mm throttle body for a nice 70cc standard will be 28mm for the mid race guys.which is what this test mule is,70cc italkit on a c16 (gonna be c21 soon and s6 racing mk2)

But i do agree! Getting the map just right is a chore,but i will be persistent in this endeavor:)

I may even look for a beta tester in the coming months.

[pitobread]

I have had an EFI 2T trials bike. It worked pretty great. No O2 only TPS/AIT/CLT and RPM for map scaling.

I actually have one of the ECU's here, and fully plan on rigging it up to run on a scooter. I have the injectors already, just need to make throttle bodies.

You could use the o2 just for setup, but you wouldn't want to run it full time.

[ThaiGyro]

I have worked with many EFI's over the years. Four strokes mainly, but 2 strokes as well. Affordability is the big deal, as there is not much economic value in a $400+ dollar cost to gain 2 or 3 hp, or mpg.

The reason I follow it is that it is becoming easier and easier to tune. Not intelligent yet, but getting there. Ecotrons and microsquirt are using old technology and cost too high. There are a few on the web, one China, maybe Hong Kong based that sells hardware packages for under $200, with free, open sourced software.

The other is near beta testing phase, which I may be lucky enough to get involved with. Also open sourced, but being developed by a scooter guy/software designer. NanoEFI: www.nanoefi.com

The guy's name is Travis and is not only doing EFI/ignition control, but his interface is going to be via wifi, so you can tune with a phone app. That, for me, beats a PC any day. (Since I am a Mac guy) I will be able to use EFI on any of my singles and twins, 2 or four stroke, with software designed for either. (Not both) One software set for 4T, one for 2T...maybe one package in the end, who knows?

I see what 190mwech said regarding big companies falling short. My belief is that they fall into the power band versus EPA requirement sink hole. They KNOW how to make power, but cannot get there in compliance with standards.

I cannot either...but I can get more mid range on a 2T...just waiting for NanoEFI so I can map both fuel and ignition curves. My thought is to find the right overlap between the two. In the future, we will use smart technology like Ford and others, that adjust as you drive, based on the sensors...I don't mean simply adjust injection events, but adjust everything according to demand, as opposed to having to select a single map. Some have three modes, such as "Lean", "Stoichiometric" and "Power". Lean or ultra lean is where a conventional 2T falls apart. It requires direct injection to the cylinder, thus a 2T would have to be re-designed greatly. Switching from a stoichio target for economy and a power map that is achievable is not so hard to consider.
Fun if you can find the parts for low money!

[190mech]

Here is some of the comments from EFI builders at KiwiBiker,this one is from "TZ350";

My first 2T EFI attempts were with an air cooled Suzuki GP125 engine and they don't have power valves. Made 31 RWHP @ 12250 RPM but still had the throttling problem below 25%.

Attachment 337065Attachment 337063Attachment 337064Attachment 337062Attachment 337066

The first air cooled cylinder had direct through the B port and under piston injection. The second air cooled cylinder had under piston injection and injection across the A and B port entrance at the crankcase. I liked that arrangement, it gave promising results.

Flettner has talked about something similar, two primary injectors firing against the air flow in the B ports and secondary's in the A ports but with them all firing when the trapping efficiency is peaking and the motor is making real power. This arrangement would keep fuel away from the exhaust port when the trapping efficiency was not that great and air was spilling out the exhaust.

The water cooled cylinder has B port injection but squirting against the air flow. All the cylinders have three physical injectors but only two logical injectors as the B port injectors are fired together. The fourth picture shows the underside with the piston at TDC.

I have tried a lot of different combinations, primary injector in the inlet, in the crankcase, in the B ports with the secondary in the alternative injection ports. And all sorts of other combinations like firing from one side of the crankcase across the top of the flywheels and directly into the incoming inlet air.

The least successful was direct inlet injection from the outside (the 5th picture), my favorite was under the piston and horizontal across the transfer ports but that is difficult to arrange with the water cooled cylinder. But under piston for the slow injector and injecting in the B ports against the air flow makes good power and looks to be more economic than a carburetor too. With EFI there is much less of a fuel puddle on the dyno deck beneath the inlet. With a carb there is a much bigger puddle.

Along the way I have learnt a lot and figured out most of the puzzle but I am just missing that last piece of the jigsaw, how to account for randomly changing air flow through the motor below 25% TP. It seems that the more highly strung the motor the more unstably changeable the air flow is below 25% throttle position.

Its like trying to sail an unstable "P" class learner yacht in gusty changeable wind conditions, its much easier when the wind is steady and consistently from one direction.

Attachment 337067

I am hoping that a MAP sensor in the crankcase and an Arduino Nano interpreting what it sees might be able to make sense of the air flow below that troublesome 25% throttle position.

[190mech]

Another from "Nath88";
Hi All,
Thought I’d drop by to share the findings of my YZ250 EFI project. It has a 2009 CRF450R 50mm throttle body, 3D printed polyurethane throttle boot to a Boyesen RAD valve. Fuel system is returnless with a Walbro GSL-414 pump controlled by a Madhu PWM pump controller/pressure sensor. Fuel filter is a Sytec mini bullet. Injector is the CRF450R 12 hole injector (440cc/min @ 4 bar). It’s controlled with a Microsquirt V3 running MSextra code, triggered by a 20-1 tooth wheel welded to the ignition rotor and a crank sensor from a YFM350.

It’s tuned in Alpha-N strategy (TPS vs. RPM table), with barometric pressure sensor and intake air temp sensor for compensation. It uses a Wideband O2 and logs either EGT or Fuel pressure.
First start was about a month ago, have put 3 tanks of fuel through it so far. Most of the tuning has been automatic based on AFR targets, except idle, light throttle and overrun where it needs to be tuned manually. 50mm throttle feels just as linear as the 38mm carb. I haven’t used any accel pump fuelling yet, so I’m hoping that will sharpen the throttle up a bit more.

Throttle transition at high rpm has been the main tuning issue. When closing and reopening the throttle, the motor would flood and not refire until the revs dropped, so I figured the airflow must drop off at some throttle value. I tried tuning a ledge into the fuel map, it was better than before but still hit and miss, fast roll on was ok, slow roll on or steady part throttle would still flood.
Then I figured that the airflow wasn't just related to the throttle, but when the engine is firing, the airflow is significantly higher than when it isn’t firing, due to the exhaust vacuum after blowdown pulling charge through the engine.
Therefore the fuel required for a cycle can be predicted by whether or not the engine fired on the previous cycle, in addition to engine speed and throttle position.
So my solution is to check whether the cylinder has fired, then adjust the fuel table for the next cycle. The throttle body MAP sensor is connected to the exhaust port and samples the pressure during blowdown. I’ve set up a 2nd fuel table in the ECU with a multiplier for when the pressure is above a threshold, corresponding to the cylinder firing. When the exhaust pressure is high, the main fuel table is unchanged, when low, it is reduced by 50% (will need to be dialled in for various RPM, but seems to work so far). The main fuel table is tuned with the wideband when the motor is firing, then extrapolated into the non-firing low throttle/overrun area. On closing the throttle, once the motor stops firing, fuel flow drops to match the airflow, so the motor doesn’t flood. On opening the throttle, the mixture is correct to initiate firing, then after the first fire fuel flow goes back to the main table value.

I think with some tuning I should be able to get the transition pretty much seamless. At the moment I'm working on getting the fuel table just right around the transition area, then I'll work on the switch threshold and multiplier values. That said, it's pretty decent already, but I'm a perfectionist.

Nathan

www.youtube.com/watch?v=4Zsz26QmfAU

[x7rocks]

Jul 29, 2018 1:40:02 GMT -5 ThaiGyro said:

I have worked with many EFI's over the years. Four strokes mainly, but 2 strokes as well. Affordability is the big deal, as there is not much economic value in a $400+ dollar cost to gain 2 or 3 hp, or mpg.

The reason I follow it is that it is becoming easier and easier to tune. Not intelligent yet, but getting there. Ecotrons and microsquirt are using old technology and cost too high. There are a few on the web, one China, maybe Hong Kong based that sells hardware packages for under $200, with free, open sourced software.

The other is near beta testing phase, which I may be lucky enough to get involved with. Also open sourced, but being developed by a scooter guy/software designer. NanoEFI: www.nanoefi.com

The guy's name is Travis and is not only doing EFI/ignition control, but his interface is going to be via wifi, so you can tune with a phone app. That, for me, beats a PC any day. (Since I am a Mac guy) I will be able to use EFI on any of my singles and twins, 2 or four stroke, with software designed for either. (Not both) One software set for 4T, one for 2T...maybe one package in the end, who knows?

I see what 190mwech said regarding big companies falling short. My belief is that they fall into the power band versus EPA requirement sink hole. They KNOW how to make power, but cannot get there in compliance with standards.

I cannot either...but I can get more mid range on a 2T...just waiting for NanoEFI so I can map both fuel and ignition curves. My thought is to find the right overlap between the two. In the future, we will use smart technology like Ford and others, that adjust as you drive, based on the sensors...I don't mean simply adjust injection events, but adjust everything according to demand, as opposed to having to select a single map. Some have three modes, such as "Lean", "Stoichiometric" and "Power". Lean or ultra lean is where a conventional 2T falls apart. It requires direct injection to the cylinder, thus a 2T would have to be re-designed greatly. Switching from a stoichio target for economy and a power map that is achievable is not so hard to consider.
Fun if you can find the parts for low money!

This is where i disagree, im trying to enter the market for 350 to control timing without the need of a 36 wheel pickup,or the need of a 500 dollar inner rotor kit from malossi,or stage6 racing.(im also tuning via mac)

What you're asking for is a simple map switch, on this ecu you're not going to get that as that is something that will rise up cost,(the ability to switch without going into tuning software i mean)im trying to keep it simple. But it will be a nice touch for options!

[x7rocks]

Jul 29, 2018 5:01:23 GMT -5 190mech said:

Here is some of the comments from EFI builders at KiwiBiker,this one is from "TZ350";

My first 2T EFI attempts were with an air cooled Suzuki GP125 engine and they don't have power valves. Made 31 RWHP @ 12250 RPM but still had the throttling problem below 25%.

Attachment 337065Attachment 337063Attachment 337064Attachment 337062Attachment 337066

The first air cooled cylinder had direct through the B port and under piston injection. The second air cooled cylinder had under piston injection and injection across the A and B port entrance at the crankcase. I liked that arrangement, it gave promising results.

Flettner has talked about something similar, two primary injectors firing against the air flow in the B ports and secondary's in the A ports but with them all firing when the trapping efficiency is peaking and the motor is making real power. This arrangement would keep fuel away from the exhaust port when the trapping efficiency was not that great and air was spilling out the exhaust.

The water cooled cylinder has B port injection but squirting against the air flow. All the cylinders have three physical injectors but only two logical injectors as the B port injectors are fired together. The fourth picture shows the underside with the piston at TDC.

I have tried a lot of different combinations, primary injector in the inlet, in the crankcase, in the B ports with the secondary in the alternative injection ports. And all sorts of other combinations like firing from one side of the crankcase across the top of the flywheels and directly into the incoming inlet air.

The least successful was direct inlet injection from the outside (the 5th picture), my favorite was under the piston and horizontal across the transfer ports but that is difficult to arrange with the water cooled cylinder. But under piston for the slow injector and injecting in the B ports against the air flow makes good power and looks to be more economic than a carburetor too. With EFI there is much less of a fuel puddle on the dyno deck beneath the inlet. With a carb there is a much bigger puddle.

Along the way I have learnt a lot and figured out most of the puzzle but I am just missing that last piece of the jigsaw, how to account for randomly changing air flow through the motor below 25% TP. It seems that the more highly strung the motor the more unstably changeable the air flow is below 25% throttle position.

Its like trying to sail an unstable "P" class learner yacht in gusty changeable wind conditions, its much easier when the wind is steady and consistently from one direction.

Attachment 337067

I am hoping that a MAP sensor in the crankcase and an Arduino Nano interpreting what it sees might be able to make sense of the air flow below that troublesome 25% throttle position.

So far i have the smoothest control of power below 25% soon i will be making adjustments for higher rpm.as this engine makes peak power at 12,500 rpms. For shifter bikes(and cars) anytime i experienced that issue of bogging in throttle transition was due to lean settings on the throttle enrichment values on the ecu.specially when in boosted vehicles.

As far as injectors go,im staying the ol reliable route of keeping the injector on the throttle body itself,which i see as beneficial as i can get the best map readings at the throttle butterfly for injection and map readings when i see the change in kpa on the fuel/timing map.having this in mind direct injection would require way more r&d and raise cost. Im trying to avoid this.



I look forward to hear more from you guys on this matter

[pitobread]

Vertigo makes the trials bike I used to own. They used to use an ECU from a company called Skynam, they recently switched to Athena GET Ecu's. The Skynam are 1k, the GET's are around 500. $500 for better starting, a few HP and better fuel economy is cheap in my books.

The Vertigo was flawless, power was smooth and linear, and they made the most HP in their engine class and for a 300 it was pretty decent on fuel. The majority of the new KTM and Husky 2t dirtbikes are also EFI (no O2)

There are many China ECU's that use a version of Megasquirt code(still uses Megatune, or a modified version of it) They don't acutally use the same processor as the Megasquirt, or Micro.  They are 200 USD shipped for a 2t kit with MAP Sensor.
Aliexpress ECU Kit

There are 3-4 Arduino ECU projects
speeduino.com/wiki/index.php/Speeduino
techestigate.com/arduecu-the-worlds-first-arduino-ecu/
www.hainesengineering.com/rhaines/aircraft/hainesecuarduino.htm

There are now hardware kits you can also get to turn a Rasberry PI into a fully functioning ecu.

There are many cheap options.

[pitobread]

For any of the Megasquirt based ECU's you can solder on a 7 dollar TTL or RS232 bluetooth(depending on how you hook it up) module to communicate and use any of the phone based tuning apps that are available.

Would probably require cutting the potting off the case, or could be attached via a sub harness.

I did that years ago to a MS3X when the Dsub to Bluetooth adapters were 80 dollars.

[ThomasTPFL]

I just want twin fuel systems and ignition maps so I can flip a switch to swap from pump gas to an alcohol/nitromethane blend.