MP36 insights

There are many factors to consider to explain the MP36 base sound. It is right to say that the Metra MP36 runs faster than F40PH-2's @ 8th notch: 954 rpm vs 916 rpm. Not significant but makes a difference in harmonic vibration calculation. Also the Metra MP36's is equipped with an F3B engine using a E3B turbocharger. Here are other design criteria to consider to explain sound difference with F40's:

MP36 - F40PH-2
Power: 3600 hp - 3200 hp
Compression ratio: 16:1 - 14.5:1
Fuel injector: MUI CBOI - MUI standard
Turbo Aftercooler: Split cooling (4 pass) - OEM (2 pass if not retrofitted)
Locomotive overall length: 70' 0" - 56' 2"
HEP stand by speed (rpm): 510 - 720

Clyde

Please note that the MP36's do not run at full speed for HEP. I greatly desire to have a look at the document that states that, as otherwise that is information I didn't know.

Since the MP36PH-3S is equipped with static inverters, HEP power can be obtained at any speed from Idle to to N8 inclusivelly. When loco. is idling HEP power is available on loco ONLY to power up MP36 cab AC and few other things. When HEP power is distributed on the rest of the train, engine speed is maintained between N3 and N8 depending of throtthe position.

In other words, when HEP power is set on the entire train, if loco. engineer moves the throttle lever back and forth from Idle to N8; engine speed will be limitted to N3 and traction power will be controlled as a loco. with no HEP. Even if HEP altrnator speed follows engine speed, HEP output power and freqeuncy will be steady (480 VAC 60Hz).

Clyde

...I mean;
...In other words, with HEP power is set on the entire train, if loco. engineer moves the throttle lever back and forth from Idle to N8; engine speed will be limitted *between N3 and N8 inslusivelly* and traction power will be controlled as a loco with no HEP. Even if HEP altrnator speed follows engine speed, HEP output power/frequency will be steady (480 VAC 60Hz).

Sorry..
Clyde

OK, I now see what you mean. My appologies also. I wonder though what an MP36 would sound like in run 8 HEP verses an F40PH...

OOOO, OOOOO, CAN I ANSWER! It would sound like an MP36 in run 8! YAY, I WIN! Actually, they don't sound that different in run 8, btw. The MP36's pitch is just a bit higher. When throttling up, though, the units do sound practically the same.