ESE's works engine tuner

[husaberg]

The Hillborn and similar systems (Crower, there may be others) are pretty crude. Big pump as you say, and the fuel regulator is basically a variable restrictor on the tank return line. What doesn't go back to the tank goes into the engine. (the systems I have experience with, anyway - V8 speedway motors running methanol, and possibly "additives" if no-one is looking) WOT was the only parameter they cared about.

the BMS 1000 851 Steve Roberts framed bike bike ran a hilborn injection system not because it was great but because no one could tech the webber injection back then.

[adegnes]

Yes, there seems to be some sort of limit. Speedpros turbo twin (18,000 rpm) four stroke would never go over 16,000 rpm with his Ecotrons unit.

Ecotrons turn off the VE table of their four stroke EFI firmware so that only the Alpa-N table is active and sell that as their two stroke EFI version.

My single cylinder two stroke was naturally limited to less than 13,000 rpm so I never found out if that 16k limit applied to two strokes.

My opinion, for what it is worth:-

I found Ecotrons help dept unable to help very much with experimental two stroke tuning and is the main reason I moved onto another EFI system that I could modify for myself.

At 16k two stroke rpm you are running into serious “Time” issues as you have only 3,75mS to get everything done and just opening/closing the injector takes up most of this time without delivering any fuel.

Assuming “B” port or case injection. The good news is, that because there is always carry over fuel from one cycle to another and it takes six or so crank revolutions to completely consume the cloud from any particular crankcase injection event it is possible to get away with averaging the fuel required over two cycles.

KTM take advantage of this cloud averaging for their staged injection by alternating their “B” port injectors side to side and when they need more injector capacity to cover the reduced time available at higher rpm they fire both “B” port injectors together.

I think that due to cloud averaging it would be possible at 16,000 rpm to fire twice the fuel required and spread it over two cycles and still have pretty much the correct air/fuel ratio in the cylinder all the time.

Staged injection. Roughly. The volume of fuel required each cycle at Idle is not much different to the volume required at peak torque. Just at peak torque less fuel is wasted. You don’t need the bigger injector at peak torque because you need more fuel than at idle. You need the bigger injector so you can deliver the same amount of fuel in the reduced amount of time available at higher RPM. Staged injection allows you to use a small injector at idle and reduced throttle and engine loads for refined fuel tuning and a bigger injector to get the job done at higher engine loads and rpm.

Because Methanol is so forgiving of rich mixtures and your going to basically run at WOT and high rpm I would consider using an Arduino Nano and write my own fuel injection firmware. You don’t need a lot of the refinements found in regular EFI systems.

Nitro carries slightly more fuel than oxygen. So if a motor is already jetted to run correctly and then you add Nitro through another jet, like a solenoid power jet the air/fuel ratio automatically gets richer. Nitro could be switched in/out as desired.

The inputs required for a basic EFI are fairly simple.

TPS … throttle position.
RPM … revs.
IAT … inlet air temperature.
Baro … barometric pressure.
LCT… liquid coolant temperature.

TPS and RPM for the Alpha-N fueling table that is used to predict engine load (air being consumed).
IAT and Baro for Air density.
LCT for fuel enrichment. Both when cold starting and enriching again when the engine starts operating in the golden zone and controlling the water pump for consistent engine temperature.

The Arduino Nano with some MosFet add on boards could easily handle all of this.

A Nano can easily count in steps of 4 millionths of a second without tricky coding. Not that you will require very accurate injection positioning. As with cloud averaging you will completely inject for the first cycle and part of the second so accurate positioning becomes a bit moot. But if you have a choice, the end point of injection is more important than the beginning. Making the end point at BDC or just before the transfers close seems to be best. Unlike a four stroke you don't need a complicated multi tooth wheel because you don't need to know which cylinder is up or down and who is next for a squirt of juice.

The EFI algorithm for Methanol can be quite simple. Fuel load is a math calculation based on air density and fuel required for the air consumed at the engine load as predicted in the Alpha-N table.

A simple fuel injection setup like this could easily compensate for changes in air temperature and elevation making tuning at home for all out WOT runs at Bonneville easy. No mucking about with carbs and jetting when you get there as the EFI system will have automatically adjusted for changes in environmental conditions with the on board IAT and Baro measurements.

As an aside, instead of being able to just predict air flow (Alpha-N) for a good drag at WOT. For road racing, due to changes in the pipe resonance effect at low throttle settings. To get good throttle response you have to actually measure changes in the air flow through the motor to keep the air/fuel ratio correct when trailing the throttle through a corner.

Thanks for the the advice!
I might try to make/modify something arduino based to suit my needs.
My constant load transmission should make for a really simple AlphaN map.

There's a few reasons I want to go EFI.

- As you stated it will self adjust to elevation/temp changes.

- I won't need a carb body hanging off the side of the engine - slide valve in the rotary valve cover.

- No vibration induced fuel foaming at higher rpm(float carbs)

- "ram air" should be possible/easier to do.

One small point not to ignore - running Meth you need more than twice the fuel flow per injector on cycle.
So every part of the delivery system has to be sized to deliver this extra amount over petrol injection.

then add in more than about 15% nitro and fuel demand starts to increase quit alot. with just meth i had one pj basically fully open. with 35% nitro i tried four pj fully open and it was just barely starting to get to rich.

there wasnt much trouble getting full throttle sorted out. was just a matter of turning all the pj full open then close them little by little until it ran good. but closed throttle and idle was a different story. i grinded my own needle in increments until it was rich enough at idle but when the throttle shut after full throttle ,the rpm would run away for several seconds, althought it sounded scary, it never seized. . all the while i was fighting a flooding crankcase at idle so im not sure if richening the needle further would of helped the run on. perhaps it would of helped but the crankcase flooding would of been even worse im sure. i did find a simple solution to the run on, after throttle closes just wait a few seconds before pulling in the clutch. this prevented the piston from running away, while giving the crankcase time to refill with fuel. for a standard gearbox it worked great but that method likely wont work if you have a clutchless gear box that cant tolerate a load on the coast side of the gear dogs. which is going to be my main problem with nitro in this yami twin. how will i stop the run on, without back loading the trans. but i love a good challenge so we'll see what happens when i get to that point

i wanted to try a hilborn mechanical injector but that requires a large pump, driven by the crankshaft or some other meens. alot of money and time to figure it out. special made pulleys and brackets. in the end, would it even work. fuck it. i didnt even want to try. ill keep the shitter lectron instead

i hope adegnes gets his idea working good

forgot to mention fuel consumption of that particular engine [527cc single] was around 2.3L for 370meters with %35 mix. so yes the fuel system needs to be free flowing

Yeah, I remember when I was experimenting with 30% nitro RC fuel.
On gas I ran a 110 main and 55 pilot, on RC fuel I ran 2.5mm main, 1.5mm pilot, drille out the pilot circuit, and a 1mm powerjet fully open.
Unburnt fuel was dripping out the exhaust at peak power.
Consumed about 1l in two dyno pulls.

There is a big difference between nitro mixed into the methanol and nitro inducted separately to the methanol.

It might be worth trying the motor setup for methanol only and using a separate system for dropping nitro into the inlet when you need it. It could be as simple as a gravity feed system from a header tank with a valve that is opened by a re purposed auto lube oil pump cable at WOT. And if you want to go richer when the nitro is dropped in then mix a little extra meth with the nitro.

I really like this solution but can't get pure nitro in Norway.
Fractional distillation of RC fuel is a possibility, but probably quite hard as the boiling point of nitro is very close to methanol.
Also Norwegian authorities wouldn't be too happy about it...

My break at work is over, I'll be back

[peewee]

Bell said something like the comp ratio for Meth vs comp ratio for Nitrometh mix needs to be dropped a couple of whole numbers for what it could run on Meth alone.

i believe its common practice to drop com ratio. ive no idea what the perfect com ratio is for a given nitro percent [i guess it would depend on many factors] but i droped mine from 16 to 12.5:1 just to be on the safe side. perhaps i went to far. i dont know

[adegnes]

i believe its common practice to drop com ratio. ive no idea what the perfect com ratio is for a given nitro percent [i guess it would depend on many factors] but i droped mine from 16 to 12.5:1 just to be on the safe side. perhaps i went to far. i dont know

I remember doing calculations(with numbers I can't remember) and ending up with 30/70 nitro/methanol roughly needing the same comp as pump gas.

Probably something crude like this:
(70%methanol x 18:1 compression) + (30%nitro x 6:1 compression) = 14.4:1

[adegnes]

Just thinking out loud here.

I might go no-intake-valve with this engine.
It's ment to run at a very narrow rpm range, should be possible to tune the intake duct to suit. Probably needs to be quite long - a good thing. Isolating the carburetor from vibration would be easy with a long softish rubber spigot.
Intake could be typical reed style behind the Cport pointing forward.(upside down engine)
Maybe I won't have to dive into Efi after all.
Could use a super simple flat reed block that pulls out of the way when on the pipe. Like a flat slide with reeds.

I would have room for a magneto ignition once again, something fierce that can cope with the alcohol/nitro, wouldn't have to be programmable either.

Like that one speed no intake old engine, going forward by going backwards...

Have to get this modeled up and see what intake length would work.

[Flettner]

or run vairable rotary valve housing on one side of the crank case, and just a butterfly valve ditect into the other side, only opens at full throttle. A straight in hole, when the butterfly valve is open. Both sides of the crankcase get feed.

[adegnes]

or run vairable rotary valve housing on one side of the crank case, and just a butterfly valve ditect into the other side, only opens at full throttle. A straight in hole, when the butterfly valve is open. Both sides of the crankcase get feed.

Yeah!
Only problem is it would make for a wider engine than with the "central" intake.
How about a small reed intake on the exaust side + a huge slide valve on the opposite side?
Would require injection or two carbs, but actually less complicated than the sliding reed thing. The big carb could be without a slide, no throttle control.
The small carb could be fed gasoline to get things going, then the big carb/injection would switch over to nitromethanol at wot.
Maybe not so good for cooling... Would make purging a breeze.

[SwePatrick]

Respect Adegnes,, you sure pick a lot of fights to fight.
Almost that i wonder if you have a fetish to get beaten again and again. =)

[adegnes]

With my one rpm constant load engine and a small carb taking care of of everything except WOT, efi could be REALLY simple couldn't it?
Just one injector in the intake duct, duty cycle controlled by temperature and air density.
No timing or anything.

[adegnes]

Respect Adegnes,, you sure pick a lot of fights to fight.
Almost that i wonder if you have a fetish to get beaten again and again. =)

Haha, thanks! I think I do.
Learnt a lesson this year at Bonneville though, even if the event was canceled
- Win the fights before you get there!

[yatasaki]

Yeah!
Only problem is it would make for a wider engine than with the "central" intake.
How about a small reed intake on the exaust side + a huge slide valve on the opposite side?
Would require injection or two carbs, but actually less complicated than the sliding reed thing. The big carb could be without a slide, no throttle control.
The small carb could be fed gasoline to get things going, then the big carb/injection would switch over to nitromethanol at wot.
Maybe not so good for cooling... Would make purging a breeze.

Reminds me on this engine
Hope you'll go step by step. Personal would go for100% exhaust working. Rest issues are more or less fixable.

[TZ350]

With my one rpm constant load engine and a small carb taking care of of everything except WOT, efi could be REALLY simple couldn't it?
Just one injector in the intake duct, duty cycle controlled by temperature and air density. No timing or anything.

Good idea Adegnes, I like it.

The carb could be a small but suitable size to get the engine up to speed and at the right RPM and WOT you could open a 24/7 inlet and have an injector squirt a predetermined amount of extra fuel. At 15,000 rpm the fuel might have to be delivered over two crank cycles to give the injector enough time to open, deliver a measured amount of fuel and close again.

The injector could be running a different fuel (say 30% nitro/methanol) to the carb which could be running plain Av gas.

A simple Arduino Nano could easily be trained to watch the rpm and throttle and open a 24/7 inlet at the right time and squirt a fixed amount of extra fuel.



I am building a F5 50cc road race engine that is just begging for a down draft resonant tuned length 24/7 inlet.

You have got me thinking about how I could apply your idea to my bike ..... ... it would solve a few EFI problems and with a tuned inlet length, add a bunch of power.

[adegnes]

Good idea Adegnes, I like it.

The carb could be a small but suitable size to get the engine up to speed and at the right RPM and WOT you could open a 24/7 inlet and have an injector squirt a predetermined amount of extra fuel. At 15,000 rpm the fuel might have to be delivered over two crank cycles to give the injector enough time to open, deliver a measured amount of fuel and close again.

The injector could be running a different fuel (say 30% nitro/methanol) to the carb which could be running plain Av gas.

A simple Arduino Nano could easily be trained to watch the rpm and throttle and open a 24/7 inlet at the right time and squirt a fixed amount of extra fuel.

You have got me thinking about how I could apply your idea to my bike ..... ... it would solve a few problems and with a tuned inlet, add a bunch of power.

Thanks!
Exactly, and in my case that nano could take care of variator control(tensioning the belt) with a linear actuator too.

Got to clean up the garage and start working!

[speedpro]

Or you could simply open the injector, and run it at 100% duty cycle, at the same time as the inlet and have the fuel flow controlled by an adjustable rising rate fuel pressure regulator. In other words the injector would be an on/off tap and the adjustable fuel pressure used to control fuel flow.

[F5 Dave]

Or create a pool of petrol and resting in it a wick you could raise or lower in the airstream.

Whoops, wrong century.