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Old 05-05-2003, 08:25 AM
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duffman
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I was wondering if there was a kit to convert a carbuerated nitro motor into a fuel injected nitro motor. I am thinking about putting one of those RB innovations superchargers on my savage and fuel injection seems like it would make the setup work a whole lot better and make tuning the motor with the supercharger not a problem like it seems like it would be. I have seen fuel injected airplane motors but they are around $1000.
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Old 05-05-2003, 02:11 PM
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If you want a faster Savage spend the 170$$ on a Picco .26 engine and not the super charger.I have serios doubts on the power increase of the supercharger
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Old 05-06-2003, 06:43 PM
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I am probably going to go with the picco .26 because it seems like the most powerful engine that is a direct bolt in for the savage, the fuel injection and/or supercharger would just have huge wow factor and would be pretty damn cool still.
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Old 05-06-2003, 06:47 PM
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It would be pretty cool but it would cost allot of $$$ if it's even possible.The RB concepts super charger is 170$ for that you could have the pico .26 and it would be faster than the super charger would be.There are better engines out there but for the price you can't beat the pico engine.
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Old 05-06-2003, 07:40 PM
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Fuel injection would not work (as in provide a performace gain) on a R/C Nitro engine. Remember that the fuel goes through the crankcase and is metered by the piston/crankshaft. It would make little difference how the fuel gets to the crankcase. And just so you know the "supercharger" is a complete scam. Fuel and pressue would just be blown out of the exhaust. The power/intake stroke of a 2 cycle gets fuel from both the crankcase AND exhaust pipe (called scavenging), there are no valves to keep the presure "in" like on a 4 stroke. Save your money and get the pico.
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Old 05-06-2003, 08:09 PM
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Actually I have a tower hobbies catalog and it has two different nitro airplane motors that are fuel injected with a computer that automatically calculates the air fuel ratios. They have what looks like a little billet throttle body with a fuel line and wire for the fuel injector, it also has a plug in the head and the crankcase that send tempatures and rpms to a tiny computer. They are both made by O.S., ones a 1.60 and ones a 1.40 they both look just like a normal nitro motor with a smaller head and the 1.40RX-FI makes 3.5 bhp while the 1.60FX-FI makes 3.7bhp. A Fuel injected motor deliveres fuel through the same passages that a carbuerated motor does so I dont see why it wouldnt work with a nitro motor. I was just wondering if there was a kit that you could convert your motor to fuel injected by adding the throttle body, injector, sensors and computer because the O.S. motors are around $1000.
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Old 05-06-2003, 09:24 PM
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You are 100% correct

I mis-spoke, actually I should have said, there would be little benifit from fuel injecting a RC nitro Car or Truck motor. Instead of "it wouldnt work" A plane would certianly benfit by virtue of their extended run time at inverted and vertical flight angles. I couldnt possibly see a Tangible performace gain on a car or truck, it would certianly "work", but other than saying you have done it, I see little benifit, especially for the $$$
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Old 05-07-2003, 07:11 AM
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I do not think fuel injection is a "non beneficial" upgrade to any engine. It is simply better than a carb, period. Here are a few reasons why:

Fuel flow from carb is controlled by fixed-position needle valves. This leaves a "sweet spot" of operation, but at the expense of diminished performance somewhere along the RPM range of the engine. Fuels and air are not "metered" in any way by carbed engines...metering implies that there is some kind of active measuring taking place -- of which there is none. Carbs allow only for preset values.

A Fuel injection system provides constantly variable fuel rate based on engine speed, temp, and amount of unburnt fuel in the exhaust. This enables the engine to run optimally in all conditions, regardless of outdoor temps, humidity, engine temp, etc.

You will certainly be able exploit the full potential of ANY internal combustion engine when using fuel injection rather than carbs. There used to be a universal RC fuel injection system made by PC-RC products that sold for $160. Unfortunately, I was unable to purchase one before they sold the rights to that product off to another company. So this particular product is no longer available.

In any case, I would easily pay $150-$160 for a quality fuel injection system for my RC car. And why not? How is it not worth it? Tell me how can the same people who spend hundreds, if not thousands of dollars for aluminum hop-ups and what not have a problem shelling out a buck fifty for something that can be used with the current engine, and any future engine down the line? And not only that, but this unit will prolong the life of any given engine by ensuring a perfect A/F ratio 100% of the time.
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Old 05-07-2003, 07:32 AM
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Ya! what he said
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Old 05-07-2003, 07:44 AM
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Sszero...so your saying that is that they actually make computer controled fuel injection just like real car, for r/c 2 strokes????That is crazy!!!How practical is that?I guess some people get really involved in this hobby!!!! Do you have a link with some pics of this setup because I gotta see this to believe it.That has got to be one of the coolest things i've ever heard of!!!
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Old 05-07-2003, 07:47 AM
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A question... so if this fuel injection thing is true and can be replicated on trucks, do we need the carb at all? From what sszero said about that ideal a/f mix that's wat i concluded.
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Old 05-07-2003, 07:53 AM
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If it's like a real car than it would be a throttle body instead of a carb and it would have to have sensors in it to calculate the air/fuel mix and a computer to adjust the mixture.Would the system have something like fuel injectors?
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Old 05-07-2003, 07:58 AM
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The question then becomes whether or not it is worth fuel injecting a little 2-stroke motor RC Motor. To be able to run it as you said, i.e. by monitoring engine speed, temp, and amount of unburnt fuel in the exhaust, you need to have a some kind of ECU to process and change the fueling values. IMHO this just complicates everything and makes it less reliable. The reason i say this is that this ECU would have to be housed in a fairly durable case (with my kind of driving at least), and if anything goes wrong with the ECU then you'd have to have some kind of specialist or someone who knows what he's doing look at it and fix it, in addition to this, any of the sensors (air/fuel monitor, engine speed, air flow meter, etc) could be stuffed, then you have to go through the whole process of figuring out which one of them is stuffed. Carbies are mechanical the beauty in that is that there isn't anything electrical to stuff around with, if something's wrong, it's normally a case of take it apart and see whats wrong. That's my 2 cents worth.
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Old 05-07-2003, 07:58 AM
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Sounds complicated... but i like things I don't understand Is there really a market for this? Any links or dealers whatever to back this up? This is the 1st time I've heard about this for RC cars. Thought it's only for planes.
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Old 05-07-2003, 08:02 AM
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The two motors I saw in the tower hobbies catalog have little computers that look to be about 1inch by 3/4inch by 1/4 inch in diameter. The rpm sensor is mounted where the pullstarter would be on the motors so some trucks like my savage wouldnt work with it unless they made the rpm sensor on a other side of the crankcase than the pull start side. It seems like it would'nt be that hard to make a kit, all the parts bolt on accept the temperature sensor in the head and they could just put a head with a sensor in the kit for your perticular motor
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Old 05-07-2003, 08:03 AM
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If it's monitering unburnt fuel and cycleing it back through the engine then it would also have to have some sort of and egr system on it.Maybe I'm making this more complicated than it needs to be but.......
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Old 05-07-2003, 08:06 AM
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The ones i saw didnt look to have a sensor for the exhaust, i dont think it is necessery if you have the temp and rpms.
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Old 05-07-2003, 08:06 AM
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What gidzilla said is true too... what if something does go wrong, how would you know what's the matter with the setup? A carb is straightforward for someone like me who doesn't dabble much in gadgets. MAintenance cost could be high for all thos sensory stuffs
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Old 05-07-2003, 08:07 AM
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and it doesnt have to cycle the exhaust back through the motor to monitor the exhaust, its not a smogged motor.
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Old 05-07-2003, 08:08 AM
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There would only be a few sencors so trouble shooting wouldn't be to hard unless it was the ecu
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Old 05-07-2003, 08:09 AM
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Originally posted by duffman
and it doesn't have to cycle the exhaust back through the motor to monitor the exhaust, its not a smogged motor.
This is true...I guess I just got a little carried away...LOL

I'm still not seeing a practical application for fuel injection with cars/trucks.All these electronics will have to mounted somewhere and will have to be vibration proof and water proof and fuel proof and have to be very durable.Does this system actually increase power or does it just make better use of the power that's already there?It would be nice not to need to adjust needles anymore but It might be a bigger pain to adjust if something go's wrong.You have to factor in all the equations of nitro on or off road......like run aways,roll overs,jumping,crashing and the occasional stray cat.This system would have to be extremely durable and reliable for there to be a big market for it and it would have to have significant power advantages also.
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Old 05-07-2003, 08:13 AM
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Keep it coming Will this be a snug fit where the carb used to be or will there be a significant mod? Or do we have to get an entirely new engine which has this fuel infection setup?
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Old 05-07-2003, 10:26 AM
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Originally posted by SsZERO
Fuel flow from carb is controlled by fixed-position needle valves. This leaves a "sweet spot" of operation, but at the expense of diminished performance somewhere along the RPM range of the engine. Fuels and air are not "metered" in any way by carbed engines...metering implies that there is some kind of active measuring taking place -- of which there is none. Carbs allow only for preset values.


I would have to disagree with you, a carbs metering works on the Venturi effect principal which is a very effective, naturally efficient metering system. Just becuase its not "electronic" doesnt mean it doesnt work. Also, Fuel injection derives most of its benifits on a conventional engine from spraying a finely atomized air/fuel mixture directly into the combusion chamber allowing for less intake tract turbulance, and optimal air/fuel atomization, and therefore, more complete combustion. On a 2 stroke RC engine that gets its fuel from the crankcase AND the exhaust pipe through "scavenging", that benifit is completely negated. While it is probable that the AFR will be more precisely metered, it would not be leaps and bounds better then a properly tuned carb. This little bit of benefit will undoubtedly be MEGA expensive and not exactly "smart money spent". I agree 100% with your analogy as compared to the all aluminum Tmaxx, which also doesnt give you any performance for the money. Its heavier, has less flex and give, which leads to lots of bent parts in any kind of crash. It basicly becomes a shelf queen, which in my estimation is what a fuel injection system on a RC truck is good for, Just show. IT sure would be cool, but IMO... thats about it.
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Old 05-07-2003, 11:26 AM
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fuel injection makes no more power than a carb, but whats better is its like haveing a perfectly tuned carb all the time and the perfect jet at every rpm and temp. It also runs good at any angle, like upside down, and it always maintains a nice idle when it starts to lean out on an empty tank. And a super charger definatley wouldnt work on a 2 stroke. it would just supercharge fuel out of the exhaust port and shorten your run time per tank.
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Old 05-07-2003, 06:37 PM
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Yes, it is controlled by a computer, an ECU if you will. Here is a link to the old PC-RC page:

http://www.iwc.com/pcrc/news.html

There's a small pic on the side. This fuel injection system is like having a perfectly tuned carb all of the time. You install the injector in place of the carb, or in the carb. You then drill a small hole in your exhaust header and insert a small O2 sensor. Some kits even have a feature to monitor engine speed, but I do not think this one does. The one from OS does, but it's only available on the more expensive airplane engines.



Originally posted by Rex2342
Sszero...so your saying that is that they actually make computer controled fuel injection just like real car, for r/c 2 strokes????That is crazy!!!How practical is that?I guess some people get really involved in this hobby!!!! Do you have a link with some pics of this setup because I gotta see this to believe it.That has got to be one of the coolest things i've ever heard of!!!
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