I have not modified one but I do know there is power and rpm to be gained and that's the problem. For normal bashing, increasing the rpm too much in a large displacement engine usually ends in failure, you simply can't stroke a piston almost twice the size of the .28's at the same rpm, it will get torn up. Now with pulling things would be different as you have much more control over your rpm limits with gearing, clutching, drive line, and tires. Those engines could really benefit from a good modding. BoBo has a 5.9 that I did for him, he could tell you if I made a beast out of a turd, I haven't heard myself yet.
You mention using the aux tap to feed your fuel tank, but it says that it T's off to the exhaust as well. Would this not have a constant loss of boost leaking into the exhaust especially at higher rpm when the SC is making the most boost yet the pipe has the least amount of pressure in it. Most would assume the pipe has the most internal pressure at top rpm, in fact it is the opposite, the highest internal pressure in a pipe is made at low rpm and drops off as rpm is increased. This is the reason why high rpm engines have issues with pipes that have bigger stingers (10mm) the better 8mm stinger provides enough back pressure at high rpm so the engine doesn't lean out. Just something to think about.
As for the engine tech, I believe he told you they make 5+HP, this is not an argument more of an ongoing debate. BHP is a reading taken right from the shaft of the engine, no losses from gearing or drive line. HP is typically taken from the wheel and will be lower then the BHP due to losses. How these company's think they can fool us noobs with "power increasing" gears, bearings etc is pitiful to say the least. I'm sure he told you that under duress due to the fact the box probably says 5+ as well. In reality the numbers I posted are probably more accurate, I hate telling the truth sometimes 🙁.
1.8 X 5252 / 16,000 = .59 foot pounds = 113.28 in oz Reasonable expectation.
5.25 X 5252 / 16,000 = 1.72 foot pounds = 330.24 in oz The most powerful engine in the RC world.
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.
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.
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!
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!
