laextreme

ok so i have seen the rb innovations supercharger and realized that the carb is under the supercharger, which makes no sense as it just makes the engine run lean by fircing the fuel back into the line from the pressure. so would it be possible to mak it correctly by puttin a custom made setup under the carburator?? i am asking this as i have a trx .15 laying around and want to make a dragster out of it this summer with my dad. is it a waste of time or could it actually work??

nitroexpress

Waste of time.

laextreme

do you mind explaining why

Over_revO

The RB innovation doesnt make it run lean, you can adjust the needle to make it run well, but it just doesnt work, any type of force induction will not work whatsoever.

Its just not possible on a nitro engine since the exhaust and crank window port will be opened in the same time for a moment, you just cant build pressure.

bigdogkanicsar

so, i've been down this road and it does work but you do have to make a restrictor of some sort for the supercharger itself. it gives you instructions with the charger that are pretty explanitory. as far as the port timing, all intake ports close fully just before the exhaust port closes. while this takes place the piston is still on the rise and the intake window in the crankshaft is still open for a breif moment which allows a little forced air/fuel charge to enter the engine just before it closes. now, with the pressure build up that takes place before the next window opening as crazy as it sounds i think that the whole boost bottle theory might work well with this app. also there is a pressure tap hole on the supercharger body that allows you to run a fuel pressure line to the tank for a little boost in fuel pressure. tuning on this kind of app is a little different and takes a little figuring out. because of the extra pressure you can almost run your needles to what would seem like a leaner setting, but really isn't cuz of the extra pressure pushing the fuel through at a much faster rate. hope i did not cause any confusion. let me know if you need more help.

they do have overdrive pulleys for more forced induction.

Over_revO

Like you said, all the ports on the sleeve will close before the exhaust, any ''possible'' added pressure will make its way out of the exhaust...

No matter what kind of pressure you can add, it will go out of the exhaust....
I also dont see the need of adding pressure to the tank, unless your tuned pipe is not restrictive enought... You can tune the engine so rich that it will flood anyway


Its like blowing compressed air into the venturi while the engine is running, it act like it boost the power, but its only leaning the mixture and the rpm will change...

bigdogkanicsar

in a way you are right but the forced air creates a releif of low pressure vacuum created by the piston as it is on the up stroke. as a result there is less drag in the engine allowing it to unleash a little more power. an edge is an edge. every little bit helps when your trying to reach that top speed. it doesn't lean out the engine, it's like you said it almost wants to flood it, hense the leaner needle settings.

Shabbernigdo

Even if the supercharger did add some tiney ammount of power is it really enough to compisate for the added charger weight and power power it saps to turn the charger impeller? Not to mention the added complexity = more things to go wrong and have to fix.

bigdogkanicsar

i guess it depends on how much of a desire you have for tryin' something new. most of my time is spent in a think tank of rc bliss full of experiments. i have actually tried the supercharger and it does work, but it i guess it takes a technical mind and a lot of determination and patience to get it set right.

it is all ball bearing driven and really doesn't take much to spin it.

Shabbernigdo

even supported on ball berings its still more rotating mass. But its true to each there own. Personally i wouldent mind tryin one of the nitrous set ups.

skrilla

superchargers are good for one thing, they look cool.Do they add power? Maybe a little (I say none) if you tune them right, but you're not going to generate much/anyboost when the exhaust port is open as the intake charge comes in.

you'll actually gain more power in going from 20% to 30% fuel than you do with a turd like a supercharger

want more power?use highernitro % or get a better motor

those who actually believe a superchargercauses a decent power increase are the suckers the manufacturers are counting on to stay in business

bigdogkanicsar

you're right it is rotating mass however from personal experience they do make up the difference and a little more. i'm not sayin' it's a giant gain but an edge is an edge. i experiment a lot and some things work and some things don't. but i would hate to think that i might have missed out on some thing cuz some people don't beleive it works. in my experience most of the people that knock a new product are the ones that have never tried it or the ones that don't know how to use it. at any rate i appretiate the input.

bigdogkanicsar

wow, do you feel better now? i hope you do. i won't disagree with the power increase when changing to a higher nitro content. however, have you ever tried one, or are you hangin' on the word of someone else that new someone who had one that didn't know how to use it. either way ,in my experience most of the people that knock a new product are the ones that have never tried it or the ones that don't know how to use it. if you disagree, by all means disagree but don't start callin' people suckers cuz they might understand something that you don't. that's just ignorant.

bigdogkanicsar

laextreme, you don't have to take my word for it. if you want to build a drag car i think that's awsome. just don't exhaust your options without a bunch of research and testing to find that edge you're lookin' for. there are people out there that have been tryin' new things for years and these are the guys that hold the records. and trust me they didn't get there by believing everything that people said on a forum. if they did ,none of us would even have R/C . good luck with your project.

also like shabbernigdo said , the nitrous set ups add a nasty punch.

skrilla

I didn't post that to make myself feel better, andplease don't act like you havethefirst clue what I door do not understand.Forgive me for not blowing smoke up your ***,I prefer to say it like it is. Superchargersare not worth the moneyand I know that first hand. Yes, it is my opinion, and I'm sticking to it. They look pretty cool and I can see someonewasting theirmoney on onejust for that reason, but ifyou buy one because you believe the power increase is worth the $150 it costs, then yes, you're a sucker.

If you want a real power increase, one that is worth the money,get agood tuned pipe and/or have your engine modded. You could probably do boththe tuned pipe and engine mod for the cost of the turd, I mean supercharger.

Here's something to think about if the above doesn't sink in. Have you ever seen a supercharger on a vehicle at a big racing event? Hint: answer is NO.I suggest you thinkabout why that is. I would think everyone would be using one if they were worth it.

bigdogkanicsar

so, when is the last time you have watched an rc drag? those guys will try anything, and i myself have owned the "TURD" and also KNOW first hand that they do work, but i'm not the only one who has had this experience, i have a couple friends that have owned them and they had great luck with them as well. as far as BIG racing events go, do you mean like roar nationals or sanctioned races. FYI, they don't allow those kind of mods. see, it's obvious to me that you like to talk a bunch of junk, so, this is where this ends. you don't like something ,fine. don't buy it. just don't come up in here tryin' to make people feel stupid when you don't the know the equipment, and if you did have one, it's not my fault you don't know how to tune. i'm done.

here is a couple links just for you.
http://www.youtube.com/watch?v=rtnLCOdVJwc&NR=1
http://www.youtube.com/watch?v=r44IJ...1&feature=fvwp

http://www.youtube.com/watch?v=CyUA1...eature=related

skrilla

Yes, you are "done", because the accusation "you don't know how to tune" or "you don't own the equipment" is at the end of every losing argument about nitro engines. Assumption helps make one more comfortable in a debate, but itis not a good way to prove a point, and it just shows your ignorance.

I'm not trying to make you feel stupid, you already are for believing a nitro supercharger is worth the money. I just wanted to post some facts about superchargers so a beginner doesn't come in here and get misled into thinking they're worth it.

bigdogkanicsar

uh, ok! nobody is trying to "mislead" anybody. like i said to the original poster don't take my word for it. reveiw it. you're funny.

Snook Man

If you want to try it with your father for the sake of trying, then you would probably get to spend some quality time withhim during the setup and testing process which is worth every penny.
Otherwise, your money would be best spent on other upgrades that are known to work.

bigdogkanicsar

i agree, see some others could learn alot from you bud.

Colt4g63

No need in wasting your $. If you want a faster engine send it in to me. You wont be disappointed! [8D]

bigdogkanicsar

there you go, that would be a direction to go well worth the cash.

skrilla

Agreed, engine modding is a great way to go when you wanta real power increase.The choice is a no brainer when your options are'best bang for your buck'or 'least bang for your buck'

SAVAGEJIM

RB Innovations is nothing but a way overpriced toy that simply does not deliver.

Here are the reason why:
Our model engines benefit very very little from the forced induction of a supercharger.
As already said, the exhaust port remains open even after the intake ports have closed, so by law of physics, the built-up pressure is ejected out the still open exhaust port. This also gives another problem: the return pressure wave of you tuned pipe is now fighting against the out rushing and release boosted pressure coming out of the cylinder. Your tuned pipe is no longer re-packing the overscavanged fresh fuel/air back into the cylinder; the releasing pressure is instead pulling more out with it. 9 times out of 10, the boosted charge releasing into the pipe and fighting the return pulse overpowers the pulse. So, adding a supercharger does not only ad weight to your RC, it can render your pipe useless.
A supercharger is supposed to pump more fresh fuel/air into the combustion chamber and leave in there for the next combustion. The still-open exhaust and the port defeats that purpose.

As for the carb issue and how airflow dictates fuel metering. as from experiments by several people who have put more air flow through our model engines, the air flow is simply too much.
I cannot remember the numbers, but our nitro engine carbs are designed for a certain flow rate. Anything above that designed flow rate, the carb cannot keep up with the increased flow and is only dumping the maximum amount of fuel it can. Thus, the engine runs lean. Our nitro carbs cannot dump an infinite amount of fuel flow, and this is why they will run leaner with supercharging.

Let's say our nitro engine carbs are designed to feed fuel for a maximum air flow rate of 1 or 2 CFM flow rate (this is not exact, it is some number I am using only for an example).
Putting forced induction, the RB Innovations one for example, or even putting leaf blower over the open end of your nitro carb, will greatly exceed that max designed fuel feeding capability. So, if the RB Innovations supercharger is increasing fuel flow by 5CFM, and you engine can only dump in enough fuel for say 2 CFM air flow even with the needles turned all the way out as rich as possible, it is running lean.
The only way to correct this is to pull off the cab and mod it so that it can supply much more fuel to meet that CFM demand.
Don't think our nitro carbs can dump more fuel for that much more air flow, they simply cannot. You will have to drill out the fuel hole passageways to larger diameters. For as small of diameters they are now, substantial pressure increase in the fuel tank is a must, and even the pressure line from the pipe will not be able to put this pressure to push more fuel through the tiny stock fuel passageways that feed the carb ventri.
Aside from modding the carb like this, your other option to supply enough fuel for the increased air CFM is to put on a fuel pump (more weight on the RC).

The most important part why our model engines cannot benefit substantially from supercharging is because they have no VALVES. Months ago, a man form the Navy came on and said his Navy ships all have supercharged two-stroke engines. He was adamant that superchargers working on his ships also means that supercharges on our model engines will work.
The problem with is his argument is his ships' two stroke engines all have exhaust VALVES. The valves prevent the boosted fuel-air charge from leaving the cylinder and that is why they work on his ships.
As said above, our nitro engines are valveless and the exhaust remains open even for a long time (relatively speaking) after the intakes are closed.

Aside from all this stuff I just said which is rather simple (there are more more intricate details to describing this complication), there are people who HAVE tested these and actually put them on dynometers.
As discovered, there is very little power increase.
They did discover that why people are fooled into thinking they work is because they lean the engine out like mad which also causes the engine to rev higher; the higher revving sound is what makes you think you are getting more power.

A magazine bought a RB Innovations unit and tested it on a dyno. Compared to running the engine without one, they found that when they put it on, less than 3% power increases were gained.
3% is an absolute far cry from the RB Innovation's advertised "up to 15% increase."
I cannot remember the exact magazine that tested it, but I am thinking it was either RC Driver or Xtreme RC; those two magazines have, or have had, dynometers in which they did/still do all their engine/pipe tests and expriments.

A rather avid RC fan and tester bought one of tested it:
http://www.youtube.com/watch?v=u4yTADlRuF0
http://www.youtube.com/watch?v=NwH7lgbc18s

supertib

Increase air density, you increase HP..plain and simple..... no different then going from high altitude to low altitude...