Power Problem with FM260

[mog]

Does anyone here have enough experience with torque and HP curves to evaluate the ones in my post #135?

It is my impression that both the HP and the Torque curves may be shaped 'wrong' - should the Torque curve have its peak lower [at closer to the ~1400 rated max point] and then NOT drop off so precipitously at higher RPMs? And should the HP curve be more like an ascending curve from low RPM to a high at its rated 2600 RPM and then drop moderately?

Maybe this is just silly on my part? Maybe its a function of my axis scales, but they don't look like I'd expect them to. Not at all sure why!

John

Your engine's (6M60) predecessor so 230HP-521Tq (not your 243HP-516Tq) but basically the same 7.5 liter engine
Click to enlarge:

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Your lines look off. Of course for max Power/Torque, but the 'curves' look way off.
Click to enlarge:

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And some non-uber Fuso (aka"FE/FG engines) for reference:
Click to enlarge:

 

[mog]

While I cannot be sure, I think the 195°F temp was engine coolant temp. There is no sensor on intake air temp.

Just an FYI
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10 Engine speed sensor - Sensing of engine speed G : Engine speed signal
11 Boost temperature sensor - Detection of engine intake air H : Boost temperature signal temperature
12 Meter cluster — —
13 Tachometer — J : Tachometer drive signal
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It is Pin 32 on connector BZ16a (Ohms) on the ECU

 

[Ruderacing]

I reckon you really need a proper dyno run mate with some decent readings taken otherwise you will chase your tail with guess work.

 

[gait]

Like I've been saying repetitively, you need a pyrometer. That simple measurement will tell you if you are getting enough fuel. If your preturbo temp is say only 900F instead of 1150-1200F UNDER FULL LOAD you need to have the ECU worked on to increase fuel delivery. If that is the case, your turbo boost will "automatically" increase to 22 psi since the hotter exhaust flowing thru the turbine will increase compressor rpm.
This whole thing may simply be insufficient max fuel delivery.

Charlie

temperature sensor sounds good for indication of air/fuel, easier than O2 ...

Separately, are you suggesting that the wastegate control of boost pressure is exhaust gas temperature dependent?

 

[JRhetts]

11 Boost temperature sensor - Detection of engine intake air H : Boost temperature signal temperature

Nice catch. I had not caught that drawing, and still have not found it in the FM Manual. However, under diagnostic codes, I did find the following:
• Boost air temperature is assumed as constant -20°C {-4°F} during engine startup and as constant 25°C {77°F} while vehicle is being driven. [13E-23]
and
• Water temperature is assumed as constant -20°C {-4°F} during engine startup and as constant 80°C {175°F} while vehicle is being driven. [13E-24]

So, the 195°F number given on the dyno report still seems more plausible to me as a coolant temp. But now I also am aware that the ECU does have Boost Air Temp, which is a valuable input variable. Seems like its range is quite a bit lower than coolant temp, and if I understand things is partially regulated by the input of more or less EGR.?

BTW, I did a search in the Manual for "MAF" and "mass air flow" and nothing turns up. So this engine does not have that available, tho the Boost Air Temp may be a good approximation.

Also I really appreciate the graphs you posted above. They really show how the curve of my data [not sure the data really represent the engine very accurately] don't make sense. Thanks for finding that!

John

 

[JRhetts]

...Separately, are you suggesting that the wastegate control of boost pressure is exhaust gas temperature dependent?

I'll be very interested in Charlie's and other's reply, but I would certainly think so. The hotter, the more volume and pressure 'trying' to push thru the turbine blades. Interested to see if I got that right.

John

 

[mog]

BTW, I did a search in the Manual for "MAF" and "mass air flow" and nothing turns up. So this engine does not have that available, tho the Boost Air Temp may be a good approximation.

No, two different data point inputs
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Engine input:
Engine speed sensor
Boost pressure sensor
Coolant temperature sensor
Boost temperature sensor
Transmission input:
Transmission neutral switch
Injector Pump input:
Backup engine speed sensor
Control rack position sensor
Pre-stroke position sensor (integral part of pre-stroke actuator)
Sub control rack position sensor

 

[JRhetts]

...
I could be wrong, but I’ll throws this out so the smart guys can correct it if necessary but a dyno measures ‘moment of force’, what we call torque, not horsepower. Horsepower is unit of measure for power, in this case torque. So they measure torque and calculate horsepower. It is ‘strange’ they give it to you the opposite.

I read a bunch of articles on Hp and Tq. To distill what I think I learned:

What an engine naturally produces is torque. Think about one piston in an engine. When the fuel ignites, it pushes on the piston, and the piston exerts pressure on the crankshaft, causing it to turn. The crankshaft feels some number of foot-pounds of torque in the process. There are three variables that affect torque:

• The size of the piston face
• The amount of pressure that the ignited fuel applies to the face of the piston
• The distance the piston travels on each stroke (therefore the diameter of the crankshaft). The bigger the diameter of the crankshaft, the bigger the lever arm and therefore the more torque.​

Horsepower is a measure of work. The amount of work that is performed is not only related to the force applied, but the speed at which the force is being applied. A unit of work [horsepower] is ft-lbs/sec. You can think of it as a combination of rate and force.
There is a direct relationship between horsepower and torque. You can convert torque to horsepower with the following equation:

Horsepower = ((speed--RPM) x (torque--ft-lbs)) / 5252​

...I'd sure like to know...what is Mitsubishi’s official drivetrain parasitic loss percent?

YEA!! So would I. The Fuso shop with whom I spent Monday relayed Mitsu corporate's characterization of 77% as "slightly low." But I have absolutely no confidence that this was not more to get me off their backs than to convey even an impression of an “official drivetrain parasitic loss percent”. I have absolutely no problems accepting a difference between flywheel and on the ground Hp. I just wish they'd give me some honest, concrete help in interpreting the numbers. They have to have measured them, and they are the only ones who have access to the numbers of trucks to get a statistically reliable and accurate number.

 

[kerry]

http://www.modified.com/tech/modp-1005-drivetrain-power-loss/

 

[JRhetts]

Injector Pump input:
Backup engine speed sensor
Control rack position sensor
Pre-stroke position sensor (integral part of pre-stroke actuator)
Sub control rack position sensor

Interesting. I cannot find any of those four terms in my FM manual anywhere. As far as i can tell, the FM engine does not have those sensors.

I do have a "Supply Pump" for the common rail, which is spec'd to supply 32,050psi ± 1,310 psi pressure. The injectors are spec'd to operate at between 24,890 and 3,480 psi. This may be analogous to the "injector pump".

From various sections of my Service Manual it would seem that my FM model fuel control system uses data or actions from the following:

1. common rail pressure sensor
2. accelerator pedal position sensor
3. boost pressure sensor
4. boost air temp sensor
5. water (coolant) temp sensor
6. fuel injector rate adjustment resistor
7. suction control valve
8. fuel temp sensor
9. engine speed sensor

I can list those out, and although I think I understand each of them individually...at least for right now it is WAY over my pay grade to fully understand how they all actually work together.

 

[charlieaarons]

Does anyone know if there is a "power chip" made for this vehicle?
That would be the easy solution, but again, if upfuelling a diesel, a pyrometer is essential to keep EGT within bounds.

Charlie

 

[FusoFG]

FWIW

Here's some interesting information from the Fuso factory web site about torque, HP, truck performance including driveline efficiency:

http://www.mitsubishi-fuso.com/en/technology/index.html

 

[kerry]

I was thinking this same thing although I suspect a chip might void the warranty which could be an expensive problem. I linked a thread here a few months ago from IH8MUD. It is by a forum member here who transplanted a 4DB4 into his Toyota 80 and my recollection is that he took the ECM apart and had some ideas about how it might be modified. Don't know how similar the FM ecm is to the FE/G ECM.

 

[mog]

Interesting. I cannot find any of those four terms in my FM manual anywhere. As far as i can tell, the FM engine does not have those sensors.

John, I am using a prior to your year FM manual. Email sent.

Here's some interesting information from the Fuso factory web site about torque, HP, truck performance including driveline efficiency:

http://www.mitsubishi-fuso.com/en/technology/index.html

WOW ! Very informative. A lot of 'learning' there. Thanks,

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One more graph

 

[JRhetts]

Does anyone know if there is a "power chip" made for this vehicle?
That would be the easy solution, but again, if upfuelling a diesel, a pyrometer is essential to keep EGT within bounds.
Charlie

Charlie

I posted a thread on this a while ago. Extensive [but undoubtedly incomplete] research turned up two chips that could work on the Fuso.

One, from Australia, was tried by the owner of my twin; he has variously reported modest to undetectable gains in performance; his descriptions do not reveal whether his chip has variable settings.

The second chip plugged into the common rail pressure sensor; it purported only to change the attack time of pressure increase, and not to exceed the ECU's programmed max pressure; it was a resister box with 9 settings on DIP switches; up to a point it had no measurable effect on performance, and then it did but also consistently caused fault codes. It was rated unacceptable/unworkable with the FM.

John