3B, turbos and more fuel, thought on getting rid of a governor (1 Viewer)

[Fantom]

So I just spent too much time online reading too many threads and am still wondering.
After talking to John at ATEB I got to think about the 3B and the fuel control and the governor setup.
Why can't you bypass the venturi system, the butterfly, make the intake constant from the turbo (or even if you don't have one) and just control the fuel, via cables, where the diaphram normally connects.
Would that not get you instant response in the engine? If you set all the limits properly so you don't damage the engine, what is negative about that setup?
I would, of course have some kind of shut off valve fo the air system as a safety, and leave the EDIC in place, but re route the "throttle cable" to go to where the diaphram was connected.
Now this is just a theory and I might be playing with it in real life just for the fun, but giev me all the possible negatives and positives.
Thanks

 

[Fantom]

87 views and not a single comment? I can't be the first one to think of this and more shockingly no one is yelling - Don't do it! you dumb a$$!

So, seriously, no one has thought about it? what can possibly be the negative aspect of this (if the limits are set right)?

 

[amaurer]

87 views and not a single comment? I can't be the first one to think of this and more shockingly no one is yelling - Don't do it! you dumb a$$!

So, seriously, no one has thought about it? what can possibly be the negative aspect of this (if the limits are set right)?

Its just not a good idea.

For one, I don't know if your assumption that the diaphragm being "slow" is true. If I had to guess I'd say that the time it takes for the diaphragm to move is unnoticable.

But...

Even if we assume that bypassing the diaphragm would give you more instant power, in fact the pneumatic governor is a very clever mechanism that you probably wouldn't do a good job of "faking" with a cable.

The diaphragm position is a function of BOTH the throttle cable position AND the amount of airflow moving into the engine. Its really kinda like a mechanical computer. If you were going to replicate the function with a servomotor (which I've though about) then at a minimum you'd need to collect data for both the accelerator position and the current engine speed. If you tried to fake it with a manual system I'd bet you'd just wind up with a smokey, unruly, system.

 

[amaurer]

I should add that I'm speaking from experience, as I tried to bypass the butterfly on my 3B once too:

https://forum.ih8mud.com/diesel-tec...-how-i-once-again-failed-outsmart-toyota.html

My comments at the time:

It did manage to throttle the engine, however you'd have to hold the pedal "halfway" down to maintain speed, let it up to slow down, and press it in to speed up.

Eventually I did test drive that system and it was a huge pain in the ass to drive.

 

[Fantom]

Interesting experiment and information, thank you.
I know the diaphram and venturi system works like a fuel/air regulator, and very effectively for that matter. My thinking was based upon this: diesel engines are controlled by the amount of fuel that is injected into them, not air (as long as the air is not restricted). When the truck is running, the vacuum created by the venturi system, when you open the butterfly more, it changes the vacuum and adds more fuel. The vacuum controls the amount that the diaphram is allowed to move (from the pressure of the spring that is there), and in turn changes the position of the fuel rack linkage (internal of the IP).
When you remove the vacuum line, the engine screams as the RPM skyrockets, but you have not change the air intake or butterfly position. So more fuel, same air, more RPM, more power. Am I wrong? and at least in my engine, it does not pour clouds of black smoke either indicating over fueling.
Also, since it is controlled by vacuum, notice how when you are going up a hill, and the butterfly is (for the sake of the example) half way open and your pedal is half way down, and the engine is going as fast as it will up the hill. When you press the pedal down further and open the butterfly even more the engine does not go any faster nor does it generate any more power. That's because the vacuum created has not changed. So what would happen if you controlled the rail manually at that time? it would possibly feed more fuel to generate more power.
You wouldn't over fuel it since that is still controlled by the EDIC and the settings there.
I'm trying to understand why it would not work. Especially if you have an EGT to see what the engine is doing.
Thanks