HP differences out of same engine???

[ozzie tractor]

skypup, im sorry but you are wrong, it is the injector pump which contols the fuel andd thus HP. the injector is only a thing which sprays the fuel at a set pressure, return to tank is internal by pass of injector,
inside the pump is a pistom in a bore, the bore has a hole in the side, fuel enters as piston is down, as piston travels up it blocks the hole and pressurises the fuel, starting injection. in the side of the piston is a slot at an angle which is linked to the top of the piston, so this slot is pressuresed with fuel as the piston goes up, once the piston travels up far enough, this slot opens up the inlet hole and pressuised fuel exits back through the inlet hole, dropping the pressure and stopping injection. because the slot is at an angle, if you move the position of the hole around in regards to the slot in the piston, the piston travels futher up before injection stops, which gives more fuel. i hope i didnt confuse matters futher with that description.

 

[ozzie tractor]

back to the question at hand. the manufactures do it to save money, they make a motor thats reliable at max hp, then de rate it till it becomes inefficient. its easy to derate an motor, there is a max fuel screw, and no im not saying where it is, because its illegal to touch for emmisions regs. (this is all mechanical injection only here people). once you add more fuel than a engine can burn you get lots of black smoke. the fix to this is as CurlyDave mentioned, a turbo. much more air in there now, so we add mcuh more fuel again. remember with a diesel, fuel equals HP or smoke, plus heat.
Example Kubota M95X Vs M105X (hope you get these models over there). 95 has turbo, no intercooler. 105 has turbo and intercooler, its my guess the 105 is running more boost (which creates more heat in the inlet) and needs the intercooler to keep inlet temps under control. more boost means they can add more fuel to make more power.

 

[SkyPup]

Larger hole in the injector flows more fuel during the injection crank angle window of the pump, simply works great for me.....

 

[machmeter62]

I added hp to my 92 Ford 250 7.3 liter diesel engine via a BANKS TURBO CHARGER, and the hp increased from 180 to 265 hp, but the cost was a couple of thousand dollars. I needed the power because of operating at higher altitudes by towing a large boat over the Sierra Nevada Mountains. I got an additional 10 inches more manifold pressure with the TC, to maintain seal level conditions. They also installed a pyrometer, along with the boost gauge, but mentioned the pyrometer was the limiting factor!! Don't exceed 1100 degrees F., where "piston melt" will start to occur!! There are times on those grades where down shifting was required, because of cylinder temperatue, and not lack of torque or horspower! The positive side of the TURBO, I was able to maintain freeway speeds most of the time. Under certain conditions, with larger fuel injectors, will heat be a damaging factor, by "piston melt", with a 15% hp increase to smaller cu. in. tractor engines under stressful conditions?

 

[RobJ]

Larger hole in the injector flows more fuel during the injection crank angle window of the pump, simply works great for me.....

Now I understand, you are talking about a gocart.

 

[ozzie tractor]

Larger hole in the injector flows more fuel during the injection crank angle window of the pump, simply works great for me.....

if you fit larger injector nozzles, the pump may well flow more fuel due to less restriction, BUT at the expense of injection pressure. this will affect atomisation of the fuel. drastically reducing the efficiency of the engine. bigger fuel drops in the chamber means less area of fuel expesed to the hot air. which means slower burning and dare i say it more diesel knock. this is not how you up rate a diesel engine, to do that you increase the injector pump flow (as i covered earlier or with a new pump with larger pistons in extreme situations) and then you match the injectors so they can move the required amount of fuel in the available time. most injectors can handle a bit more fuel without making the injection event become to long and run outside of the injection window which you speak of. fuel injected outside this window is wasted and ends up going straight out the exhaust and it is still burning as it goes. i have seen a MF 3505 which had the fuel pump output turned up shoot a 10" flame out the exhaust at WOT as it neared full RPM. it went ok, but very bad on fuel.

 

[ozzie tractor]

Larger hole in the injector flows more fuel during the injection crank angle window of the pump, simply works great for me.....

now have you actually dont this? would love to hear of examples. i know the way i have been taught to do things and im not silly enough to close my mind to all other possible methods of achieving the same result. but i know that the way in which i have outlined works. just fitting a bigger nozzle is like pulling the end of you garden hose. instead of a high pressure spray, you get a low pressure flow, it may well flow more water due to no restriction, but only to a point. then what ever is pushing the water becomes the restriction. diesel injection must be at extreme pressure for atomisation (yes we are talking from about 10 000psi all the way up to nearly 20 000psi in some systems) the better the atomisation the more efficient the motor uses the fuel.

 

[Egon]

I'm kinda confused with all the statements made on this thread. I'll also admit I am not very knowledgeable about the mechanics of diesel injection pumps or injectors.

I went out and looked at my Kubota B7100 HST. Its probably as simple as an injection system can get.

Gravity feed to injection pump
a steel line to the top of each injector
another steel line from the midpoint of the injector that conects all three injectors and teminates in a low pressure line to the top of the fuel tank

My 1996 12 valve dodge cummins diesel has:

Low pressure line to fuel heater and lift pump
steel line to injector pump
steel line to each injector
steel line from injector pump terminating in low pressure line to fuel tank

From internet reading I understand one can increase the horse power of this engine by some very simple means.

Open up the injector pump plate
install larger injectors
and then there are a host of other things that can be done.

Now I surely do not know how this all works but I'm sure one of you fellows out there does!

 

[SkyPup]

Now I understand, you are talking about a gocart.

Nope, just the two diesels I already modified with custom larger injectors. Like I said, it works great if you don't mind a little lower fuel mileage and a little more smoke, espcially under load.

 

[ozzie tractor]

Nope, just the two diesels I already modified with custom larger injectors. Like I said, it works great if you don't mind a little lower fuel mileage and a little more smoke, espcially under load.

that'd would be the side effect of the lower fuel injection pressure now wouldn't it.this certainly isnt how a manufacturer would up rate an engine, because as you noted you get more smoke. you cannot have that with an OEM aplication, so they turn up the fuel pumps, as a result of this they may bump up the injector nozzle size, hence keep the pressures up as well as getting the extra fuel in within the required time.
now i am not going to start on the subject of pollution and what the authority's think of all this