what is the ultimate aaz?

[jtanguay]

i wouldn't say mech PD is impossible... in fact some of the very first diesels can be considered PD...  Pump Duse meaning Unit Injector.  of course some of the early versions didn't have as sensitive equipment as the pump duse engines, but the principles are the same.  one injector for each cylinder fired by a camshaft.

the PD engine can rev quite high.. just as high as the IDI's.  puts more stress on the camshaft (camshaft fires the unit injectors), but it can do it.  the main part holding back most TDI's is the pump.  Tintin wrecked some pump heads while revving too high...

simple electronics can control PD engines as well.  i'll be looking into that when i start getting my conversion done.

for your IDI you actually want more fuel, and not so much pressure.  the high pressure will help atomize the fuel under boost a bit better, but too much and it may reduce performance.  it also messes up the timing.  if you increase breaking pressure, you need to advance timing as the pump takes a bit longer to build up more pressure to the injector.  with the PD's electrically actuated injection the injection is much more precise and super accurate, giving you the ability to fine tune the engine with some crazy power.

but enough about PD's  :lol:

[jimfoo]

I doubt making a simple circuit to control a PD would be terribly hard, but would probably require a lot of experimenting to get it to run really well. A pulse to let fuel in, then a pulse width modulated signal controlled by the throttle to adjust fuel quantity with the rpm controlling the start time of that signal. But it would be harder if you wanted multiple pulses per injection.

[jtanguay]

I doubt making a simple circuit to control a PD would be terribly hard, but would probably require a lot of experimenting to get it to run really well. A pulse to let fuel in, then a pulse width modulated signal controlled by the throttle to adjust fuel quantity with the rpm controlling the start time of that signal. But it would be harder if you wanted multiple pulses per injection.

true... i've heard PD's running simple electronics... and they sound louder than our IDI's, but the factory running cars sound surprisingly quiet compared.  basically pilot injection, and multiple injections per cycle really help quiet things down, and probably put less stress on the engine parts.  i can't wait to start messing around with mine  :wink:

[Alleslowbuged]

Hi,

just to came back to the rev issue compare of DI and IDI engine, one of the guys before is right. The cause for the early speed end for producing more HP at all actual DI engine is the fact, that there is not enough heat in the cylinder room to burn the fuel as fast as needed, strangely enough also becuase of the efficiency of a DI engine. The swirl chamber in the IDI engine, is all the time so hot, that  there is enough heat to burn the fuel fast enough to reached 6000rpm with increasing of hp, as several runing engine has documented, there for the fuel pump modification is the big deal.

So my summary is, in efficiency the DI is better in all, thats clear and fine describe here in a early post. But in get hp from cylinder capacity, in my oppion there is no advance in DI to IDI, i even think that du to the rev issue is possible to get more hp from a IDI than a DI engine.

And also i wand to state, that hp will winn race and not torque. Don't forget, rev's don't weight, torque weights al lot, because every think must be very strong. Try to use a 200 hp motorcycle tranny with the 75 hp aaz engine, it will not survive one time pull down in a bigger gear, but is reliable for 200hp.

Best regards Clemens

[Slave2School]

Didn't read the whole thread, but have you seen the progress that RedRotors was making with the computer controlled IDI?  That seems to me to be a pretty cool step in helping things along with higher rpm control.