Supercharger / To have or not to Have?

[wildchild27]

i don't think the SC is a good idea as robin has clearly stated but each to his/her own and with multiple articles concerning the SC kit most if not all have stated they(whether they are new or have been around a while in this hobby) have had more problems than not with the SC. yes they are very effective on 1:1 motors do to they can retain the pressure charge with the valves unlike a hobby grade mill that has no valving and relies on the tuned wave and back pressure that is built from the pipe, here is a vid that was made by squirrel from thetoyz forum that did a review on one.

http://www.youtube.com/watch?v=u4yTADlRuF0

eric....

 

[IncredibleHULK]

Alright, You can mod these motors and get more power and rpm out of them, your statement on getting a 8.0 to spin the same rpm as a .28, cannot be done, they are two totally different motors with two totally different powerbands, I already knew that. Increasing the rpm on a large displacement motor will lead to motor failure? That previous statement has nothing to do with modding a motor, that is all in owner's responsibility to not over rev. the motor. As far as pulling goes, it's about horsepower and torque.Your examples that your using go for any r/c vehicle, not just pulling. As far as making a beast out of a turd, the 5.9 is already a great motor that puts our great power already, if they didn't, they wouldn't sell. Engine modding helps out alot, and depending on what stage you do depends on the purpose of the motor and vehicle.

I wasn't very clear, I was referring to increased rpm through modification will cause failure which is a given, if the engine is abused. Doubling the rpm on the .50 wasn't meant as a doable statement either, my bad. I have done one and only one 5.9, stock this engine falls very short of great! You can't take a .28 engine and hog out the block and just use a bigger piston and sleeve and expect it to be a performer. It has the same crank, bearings, rod and block porting, which limits your port size in the sleeve to what the .28 had? In comparison the 5.9 has tiny ports that aren't even shaped or aimed in the right direction (imo), I know as I had to change all that. Why do so many blow up? maybe because the crank was kind of balanced for the weight of the .28 piston, now that it has a substantially bigger piston what was done to counteract this additional mass....... nothing. Look around the sites and you will find that most people will agree with there own experiences.

The boost from the supercharger also goes thru the aux. port and travels down to the T fitting, the T fitting joins the boost line, the exhaust pressure return line, and the return line to the tank. The boost is going to go to the tank and not out the exhaust, you have two lines at a T, one line(exhaust) has pressure coming from the pipe and traveling to the tank, the other line(tank) is drawing vacuum, the boost is going straight to the tank line because there is no resistance, the exhaust line has return pressure, the boost will take the path of less or no resistance therefore adding more fuel pressure to the tank to meet the demands of the supercharger.

Lets say you have a (T) bottom being the SC, top left being Exhaust, and top right the tank. If point S had 5psi and point E had 3psi, point T is not going to have 8psi right, it will have 5psi, which will overcome point E causing leakage of the SC/tank pressure to the exhaust. Another interesting point is the aux tap feeds the tank, once the pressure is built up in the tank it will equal the pressure being applied to the carb which would mean there is no positive fuel supply from the tank. Being an open system there is also the possibility that "if" the pipe made more pressure then the SC, it would back feed into the SC via the aux tap causing oxygen spent fumes to be re-used. Too bad they don't give more specs, but maybe they don't want to.

High rpm engine's run poorly do to pipes that have bigger stingers than others? That's a huge blanket statement. What determines back pressure is not the size of the stinger, it's the lenght of the pipe, circumference of the pipe, the shape of the pipe, and most importantly, the inside construction of the pipe, not just how big a stinger is. These manufacture's create many pipes for many application's, it's up to the buyer to determine what kind of driving they intend to pursue, what motor they want to run, and what pipe they intend to use for low,mid,top,all around power. The construction of the pipe and the internal construction of the pipe is going to determine the amount of back pressure and where it comes in at, not just the size of the stinger!

The only pipes that are internally restricted are the Buku and Cvec style pipes, the cone regulates back pressure because it has to contain pressure for it to move. Conventional pipes have big holes or sections cut off the end of the internal cone much larger then the stinger, this does not create back pressure. Exhaust pressure is regulated by the smallest opening which is the stinger, a smaller and longer stinger will reduce exhaust flow and raise back pressure even more. Exhaust pulses are influenced by internal design and length. My statement is true and been proven many times. I do know a bit about pipes as I hand made the pipe on this engine from my own design. It has an 8mm stinger and I reassure you, if I put on a 9mm stinger it would fail.
http://s99.photobucket.com/albums/l291/purenitro/?action=view&current=MOV08749.flv

And as for the engine tech that I spoke to, he told me what the BHP was, and then told me what the calculation from BHP to HP was. BHP in this conversation is Brake Horse Power, and that is how much power the motor makes at a certain rpm range with a load on it, what is not inclosed is the % of load that was put on the motor. HP is the obvious Horse Power, and that is how much power the motor puts out without load on it. BHP is signifigantly less that free HP, and with the converstion from BHP to HP will tell you what the motor makes. Now, if you call a manufacture that builds the motors and speak to the engine tech that help create the engine, your going to find out what the correct power output is of that motor. The 8.0 puts out 5.2HP, this information comes from the company who built,designed,and tested this motor, they know what they have. Your comment at the end about "I hate telling the truth sometimes", I don't think that's the message your customers wanna read before they send you their motor. Oh, and the breakdown you provided, here it is:

5.25 x5252/16,000= 1.72 foot pounds = 330.24oz The most powerful r/c engine in the world....well times that by 2, cause that's what I have and it is fact!

People who are newbs will be impressed.
People who know will smile and nod.

I don't hold back the truth from my customers just to make a buck, I have turned away piles of rtr's and sport mills. I state my honest opinion and they make their own choice, usually it's an upgrade to a better engine, no use throwing money into a sub par engine that won't last. Do I benefit from this? NO, do they? YES, am I happy in the end? VERY!

I'm not here to flame you bud, you have a sweet truck and it hauls the mail! I'm just sharing info that may benefit you, take it as you will.

You won't be able to make a 5.9 perform like a 4.6, there is a significant difference between the two, the .28 has good power and more rpm than the 5.9, and the 5.9 has more power and torque, but has lower rpm's than the .28. For a big picture example, you won't be able to make a 5.9 spin the rpm of a .15, the rotating mass is alot more than the smaller motor and you would have to remove aot of material to get that motor to spin a crazy amount of rpm and weaken the engine and the chances of engine failure are out the roof.

If you have the example that you mentioned for the SC, there is pressure from the SC going to the T, that pressure is greater than the return pressure coming from the exhaust, both lines meet at the T and travel to the line going to the tank. What we don't know is how much the pressure is from the lines. You have a line that has forced air, a line that has return pressure from the exhaust and you have the line going to the tank with no resistance, both lines of pressure are going to travel to the line with no or less resistance. You have a forced air line and you have a line that has return pressure from the exhaust, how is the return line gong to over ride the forced air line? It won't. therefore the inquiry of backfed to the sc is nolinvoid.

Cvec or buku pipes have internal moving parts, those pipes are not what I was refeering to, tuned pipes have large or small stingers, depending on the manufacture there are deflectors at the end of the pipe that are various lenghts, cut to various sizes, and may have a certain pattern cut in the deflector to reach a certain backpressure that the pipe company is looking for.

You want the info about a motor, you don't call up a engine shop that mods, you call the company that built,blueprinted,tested, the motor and you speak to them about all the important info on the motor that you have a q's about.

Yeah I know i'm not being flamed, usually the people that get flamed are the ones that don't have and idea of what they're talking about. I'm not scared.

I appreciate your point of veiws and your infomation that you have shared.