We run nitro on glow ignition race engines. It really helps the smaller engines (2.5 cc) where 66% nitro is common. I ran 60% nitro on all my engines, but the consensus for engines over 10cc was 50% is plenty. We did some limited testing on 26cc ignition engines. They ran fine on 15% nitro standard fuel, but burned the electrodes off the plug, denting the piston on the way out, on 40% nitro. We did a series of fuel tests on a 26 cc engine setup for gasoline. We only changed the needle settings to best power for the various fuel mixtures. All this convinced me that fuel cheating in our racing wouldn't matter and extensive fuel testing like that used in larger racing classes wouldn't be needed. See the test results below.
So could a switched PJ be used to add the nitro at the desired RPMs?
I could see adjusting timing to coincide with the nitro but compression would be a bit beyond me.
Suitable compression plus switched PJ and Ignition map is the plan if I ever go there. A thumb trigger button, digital ignition and peristaltic pump.
Remember, With a properly jetted carb for petrol you don't have to enrich it if you are just squirting raw Nitro into the inlet tract. The added Nitro brings its own fuel in the correct (actually slightly rich) proportion with it.
What amazes is the dyno traces of TZ350 50cc on Avgas and Avgas + nitro apart from the Avgas + nitro coming in a thousand rev's earlier they match each other curve for curve up to full power. Which I think would point to much more power with the carburation and ignition sorted all out to suit the nitro.
Compare Pornography now to 50 years ago.
Then extrapolate 50 years into the future.
. . . That shit's Nasty.
Suitable compression plus switched PJ and Ignition map is the plan if I ever go there. A thumb trigger button, digital ignition and peristaltic pump.
Remember, With a properly jetted carb for petrol you don't have to enrich it if you are just squirting raw Nitro into the inlet tract. The added Nitro brings its own fuel in the correct (actually slightly rich) proportion with it.
When you did the squirt bottle testing, why do you think it acted too rich at higher rpm? Not enough timing? Too large fuel droplets not contributing to combustion?
I may or may not have snuck some pure nitro across the border from Sweden, not allowed in Norway.
Setting up a Derbi GPR50 as a test bench for nitromethane injection alongside normal carb on gas, and also continuos methanol/nitro injection.
For nitromethane injection I will try a 0.9mm water-injection nozzle + high pressure efi pump. Might need a smaller nozzle.
What amazes is the dyno traces of TZ350 50cc on Avgas and Avgas + nitro apart from the Avgas + nitro coming in a thousand rev's earlier they match each other curve for curve up to full power. Which I think would point to much more power with the carburation and ignition sorted all out to suit the nitro.
If one can make it work in a two stroke, power should pretty much only be limited by how much properly atomized fuel you can manage to shove in there and still have combustion. If combustion doesn't hapoen it hydro locks and grenades.
As the fuel class at Bonneville is unlimited(before you suggest Flourine/Lithium/Hydrogen, within reason.), effort into making nitro work is worthwhile.
As stated before, experimental stuff will be kept away from the main engine until it's no longer experimental stuff. No free jazz.
So how can the dyno trace slope backwards? Is the sw getting creative? I've dynod quite a few engines and never seen that.
Two different power measurements for same rpm points i suppose. Maybe rolled off throttle a little slow.
If you run up and down in revs a few times during a run and plot hp vs rpm you get loops and stuff. With practice you could probably draw a nice picture.
When you did the squirt bottle testing, why do you think it acted too rich at higher rpm? Not enough timing? Too large fuel droplets not contributing to combustion? For nitromethane injection I will try a 0.9mm water-injection nozzle + high pressure efi pump. Might need a smaller nozzle.
RG50 Petrol Carb plus a squirt of Nitro runs.
This engine was tuned for petrol. It seemed to me, that with the added squirt of Nitro, the engine became distressed when it got near maximum torque. I concluded the ignition and or compression was suboptimal for added Nitro. I wasn't going to change anything because this Nitro thing was just for shits and giggles and maybe future reference.
I started shutting off early on runs that had more Nitro. The test was to prove that Nitro squirted into the inlet on a properly carbureted engine on petrol would run without blowing up. Clearly my engine would need some ignition/compression adjustment to be able to use Nitro at maximum power but the basic idea worked on the dyno.
I just used a squirt bottle that squirted a raw liquid stream of Nitro into the carburetors' throat. The first runs were done with a careful squirt, the last (Red Line) was pretty heavy handed.
Could you squirt in enough Nitro so that the surplus fuel that comes with the Nitro itself made the engine over rich, possibly but I don't think that was happening to me.
Given proper ignition and compression, I don't think there are any real limits to the amount of Nitro you can use other than wetting the plug, hydraulic locking or over stressed mechanical breakage.
A pump with an atomising injection nozzle sounds like a good idea. Being able to turn the Nitro on/off as required is a great idea too.
While we are on weird dyno curves, my early attempt to tune the H100 onda with an MX type power decades ago I designed a pipe using TSR software. It was quite fat and the curve had about 3 peaks. Chris's dyno, he teased me making Rooster head shape with his hand on his head.
I assumed that the pipe was just too fat for the transfers, but any ideas?
I kinda smoothed it out a bit and made a boost bottle to that aim, it was only the spare bike for a bit of fun.
Don't you look at my accountant.
He's the only one I've got.
I always find it funny when I manage to get negative power in simulations.
Also, when testing a centrifugal blower on my 50 I got to a point where it would rev to pretty high rpm and just stay there, dyno reading 0hp. That's efficiency for you, 0%. Blower was in constant surge.
High pressure gear pump for my electromechanical fuel injection system arrived from china.
Ignitech Dccdip1/2race has input for TPS, and can output PWM.
Looks like I'm stuck with four throttle position points, and five rpm points which is restrictive, but might be enough when WOT at pretty much constant load is all that matters anyway.
I'm assuming there's interpolation between these points, can anyone confirm?
You see where I'm going with this?
No RAD compensation, if only the Ignitech could accept TPS and some other sensor simultaneously.
Easy enough to shift the whole map according to conditions, or even have the pwm signal pass through an Arduino that modifies it based on RAD.
I wonder how long those hydraulic pumps will last without oil to lubricate them
I'm hoping 5-10% oil will be sufficient to keep it happy.
I just realized RC ESCs for brushless motors want special servo PWM, they care about the width of the pulse, not on/off time.
Is this special servo PWM what comes out of the ignitech "servo" output?
If so we just got a much higher resolution fuel map.
Regardless of what it outputs it should be possible to use that signal and convert it through an Arduino.
Edit: Is the servo output like: Send power to one wire until there's this set voltage on another wire? That's annoying.
Yes the processor interpolates between data points.
Talk to Jiri at Ignitech he does the programming.
You will have to do the dyno " best power egt " , then learn and construct a Density Altitude/Jet size graph manually first, to then be able to use the data for auto compensation , no matter how you do it.
EDIT , yea the servo uses the position 0-5V output and continuously tries to correct the as read number to equal the table number - within the hysteresis allowance.
And to use two sensors to manipulate an output you would need a 3D table
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
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Originally Posted by 136kg136ps
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