general diesel discussion: power vs. smoke

Just back out of the throttle to keep EGT's in check. You shouldn't have a big EGT problem with just a plate & GSK.

High HP guys have put valves in the boost reference line going to the fuel pump, so the pump (The AFC, to be exact) doesn't see the boost coming up, and therefore, won't dump as much fuel in...
 
Flex5 said:
Greg,
What do you mean by a tow/play mode? What exactly have you done? Im looking at putting a fuel plate and governor spring in my 97 12v. Is there a way to turn the fuel back down to reduce EGTs w/o having to take it all back apart?
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I'm not sure exactly how the pump on the 2nd Gen CTD's works...because you use a fuel plate and a governor spring, while mine uses a fuel pin and a governor spring...


the AFC housing on the top of the pump has a boost line from the intake manifold...as boost builds, it pushes down on a diaphragm, and our fuel pin is attached to the other side of the diaphragm...the farther it goes down, the deeper the cut so the more fuel...I've seen a fuel plate off a '94, so the concept appears to be somewhat similar...

I have an air solenoid plumbed into the boost line, and in "tow" mode, the air supply is cut off, so no extra fuel given based on boost...I just turn up the full power screw on the pump so that it'll run 1200F with the pedal mashed...

when I turn the solenoid "on" (or "play" mode) it allows the boost to push the diaphragm and the extra fuel is provided...

I'm just not sure if you have the AFC housing...if you have something that gives fuel based on boost, you could probably rig something up...


here's the write-up I did at DTR:

http://www.dieseltruckresource.com/dev/showpost.php?p=1162445&postcount=226

Greg
 
Greg,

First off....i didnt read anything above...so if this is a repeat...sorry

Depends on when it is smoking....

smoke before the turbo spools up doesnt really mean anything....before the extra air the turbo pushs in...the mixture is obviouly rich = BLACK SMOKE

Once the turbo reachs max pressure...smoke should go away which would "give you ideal" mixture.

But then you have two more factors to look at....to rich - black smoke and slightly higher EGts....run to lean and possible risk burning up more. (i dont have that problem)

Either way...i have the feeling that my truck is going to run aways from yours if you ever decided to go wheeling with me.....:huggy:

Seth
 
rocktoy4me said:
But then you have two more factors to look at....to rich - black smoke and slightly higher EGts....run to lean and possible risk burning up more. (i dont have that problem)
Click to expand...

No such thing as "too lean" on a diesel. ;)
 
Something Ive always wandered about lean conditions on a diesel. When a gas motor runs too much NOS it creates a lean condition and starts burning stuff up. Since diesels arn't effected by lean conditions does that mean they can run as much nitrous as they can burn with their current fueling setup.
 
As long as your EGT's stay under control ANNNND you don't end up with too much cylinder pressure, you're good.. that's the biggie with tons of boost, advanced timing, and "drugs"..

How much is too much? can't say for sure, it depends on the setup. You could pop a headgasket with 25° of timing at 35psi, or 50psi at 16° (just examples, not real limits).. it all depends.
 
Rich said:
As long as your EGT's stay under control QUOTE]

So since adding nitrous to your system adds oxygen thus creating a more efficeint burn..does that mean that a small shot would lower EGT's or raise them? Assuming you have a situation like mine that already has way too much fuel.
Click to expand...
 
Rich said:
As long as your EGT's stay under controlQUOTE]

So since adding nitrous to your system adds oxygen thus creating a more efficeint burn..does that mean that a small shot would lower EGT's or raise them? Assuming you have a situation like mine that already has way too much fuel.
Click to expand...
 
IIRC, the nitrous helps control EGT's.. keeping it cooler.
 
Rich said:
ANNNND you don't end up with too much cylinder pressure, you're good..
Click to expand...
TheGeneral said:
So since adding nitrous to your system adds oxygen thus creating a more efficeint burn..does that mean that a small shot would lower EGT's or raise them? Assuming you have a situation like mine that already has way too much fuel.
Click to expand...


Dont forget the 2nd part...
 
Flex5 said:
Greg,
What do you mean by a tow/play mode? What exactly have you done? Im looking at putting a fuel plate and governor spring in my 97 12v. Is there a way to turn the fuel back down to reduce EGTs w/o having to take it all back apart?
Click to expand...
There is no way to turn the fuel down without messing with the fuel plate. It depends on what plate you are going to use as to how high the EGT's are. I run a #0 plate slid all the way forward, afc forward, and stock turbo with a homemade intake and my EGT's run high. Im talking playing around, 3rd gear, 2,000 rpm, and full throttle running around 1,100 to 1,200 degrees and you dont want to know how bad it is towing something, so just choose the plate wisely.
 
fuel

The easiest way to control egt's is let up on the throttle and or down shift. Why go to the trouble and expense of "turning" it down, just let up a little. You could adjust the throttle control cable so it won't go wot.
 
i just put a new fuel plate on my 97 d/d and i havent had that high of egts , atleast i dont think so. but it really made a difference in the accleleration. its a hole new truck. how did u like taking thoe bolts out of the afc housing with the hand impact tool?
 
LARRY SMITH said:
The easiest way to control egt's is let up on the throttle and or down shift. Why go to the trouble and expense of "turning" it down, just let up a little. You could adjust the throttle control cable so it won't go wot.
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True, but if you've got an auto, letting up can create other undesirable side effects like lower line pressure, too-soon shifts, soft shifts, etc.
 
yup. Of course, those who like to pull 12 second 1/4 mile times in a 7000lb truck can't really use a straight drive.. :p
 
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