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Discussion Starter · #1 · (Edited)
Shooting Gallery Carryover, The Ultimate 4BT (Long)

I wanted to repost this over here from the old forum to get further insight into my theories. Sorry for the strange way I did it but, when I posted it on the old forum they strayed way off topic and onto a discussion about metallurgy. :(
 

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Discussion Starter · #2 ·
I'm going way out on a limb here, but I wanted yall to critique my
theories, and correct me where I am wrong. So here goes: It seems to me
that a diesel is the perfect engine. It will offer good
horsepower and torque, only lmited by boost pressure, the amount of air
flow into and out of the engine, the rate of fuel delivery, and the
exhaust gas tempuratures. On the other end of the spectrum it is the
perfect economy engine, only limited by running it to lean.

Now, what if you had an engine set up for high performance (ported and
polished head, Larger turbo, high flow injector pump) but simply
adjusted the variables down when you needed economy? Whats more if these
variables could be electricaly adjusted to a pre programed setting
couldn't you adjust it on the fly?

I know banks offers the six gun kit for a 6bt but, in theory wouldn't it
be possible to take a performance modified 4bt from one end of the
spectrum to the other like that? Furthermore how does the 6 gun kit
work on the fuel variable? Are the newer dodges common rail, adjusting
it through pulse width, or the old style mechanical pump adjusting the
rate of flow through line pressure?

Well, these are my thoughts and I decided to throw them out there for
yall to shoot holes through. So tell me what yall think.

Marty Galyean Replied:

If it weren't for the weight increase with the average diesel block per
HP, I'd totally agree.
Both hot rods and economy cars don't like that extra mass. But put a
turbo on it, or find ways to lighten the block (I think titanium alloy
has huge potential for this) and you are right on. Notice all the euro
diesel econo-boxes are turbo'd. A diesel begs for a turbo and a diesel
without one is so heavy per HP that it wouldn't be worth the effort of a
swap for me anyway.

Marty

Gene Climer Replied:

Basically, I think you have it right.
You are also limited by the burn rate of diesel.
You can only get so much rpm out of it.
Indy gassers run up around 20,000 RPM or more.
Gas burns in a flash.
A diesel rod is limited to something well under that.
Diesel burns really sloooooow comparatively.
Banks Racing runs diesels up to 7,000 RPM Redline:
http://www.bankspower.com/twin-turbo-performance.cfm

Let's assume you can run high boost safely.
You've got the right pistons, rings, head gaskets, rods, etc...
And you have enough intercooler capacity to cool the EGTs.
Now, you can dial up or down according to application need.

The 2003 and newer Cummins engines can do exactly that.
They have a new Common Rail system which can be programed on the fly.
That 6-Gun system you mentioned, for example.

That's partly why I went with the ISBe170 version of the 4BT.
It has common rail.
I hope to be able to modify a 2003-6BT control module.
Hopefully, I can get a mfgr to make one special for me.
Then I can dial my boost, fuel, etc, from settings in the cab.
Just need to make sure I don't exceed my "system's ability".
At this point it is not just about the motor, it is a system.

Gino

I Replied:

Does the ISB system have a mechanical fuel pump or electrical feeding
the fuel rail like a gas motor? Does it have a crankshaft positioning
sensor? The reason I ask is because I wonder how hard it would be to
assemble a system like that for a non-ISB 4bt.

Furthermore, how efficient would a de-tuned performance 4bt be?

Gene Climer Replied

Well, you are a little over my head at this point.
By the time you assembled this system, I think you could have bought a new ISBe170.
The ISBe170 has rear gear drive.
This means you can't re-use your front gear drive.
It also means you can't use your rear mount Flywheel housing of choice.
You have to buy new rear flywheel housings to mate to you bell housing.
The list goes on and on like that.
So, I don't think a commonm rail system is very accessible to the older 4BT.
I am not sure, but I think the pistons are a little different also.
Not to mention the turbo.
I have no idea how efficient the system would be when tuned or detuned.
Gene
 

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To turn a 4bt into a common rail diesel would be almost impossible from a shade tree mechanic standpoint. But, what you are asking for is possible on a VE or a inline through a piece called the Aneroid. you need a valve that opens and closes hooked up through a pententiometer. The less air that you supply to the aneroid the less fuel the Injection pump will supply.
 

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So you can take a pump and bring it to a Fuel Injection shop and have them turn it wayyyyy up then adjust your power through the switch. 350hp for the track 105 for the way home.
 

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Discussion Starter · #5 · (Edited)
Sweet.
First off, I appreciate the info, and now that I know that it wil work in theory I have several questions about how to turn it into reality. My goal is
-120, 225, and 350+ horsepower. Assuming that 120 is what would be needed to sufficiently move my cherokee at 70-75 mph while affording25-30 miles per gallon, 225 would give me more than enough to tow and off road, and 350 + for the hell of it and those pesky Z71s. :) Assuming, that I can reliably (150 200k miles) make 350+ horsepower.

Do you know anybody that is currently running a setup such as this?

An Aneroid is basically like a small pnuematic cylinder?

Also, I don't know much about turbo charged systems, would you need to adjust boost pressure? If so how would you do it?

I thought about using an oxygen sensor and gauge to monitor the air fuel ratio and keep from running it to lean.

I may be aiming high but it is better to aim for the moon and miss, than to aim for a cow pie and make it. Once agian thanx for any info.
 

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There are a couple of problems I see (not insurmountable though).

1. Is injector flow. The injectors which can dump serious amounts of fuel in for serious power don't atomise that well at low flows. So you don't get as clean a burn at low power and your fuel economy suffers.

2. Turbo sizing. Putting more boost into an engine increases it's efficiency. With big power you're talking big turbos which either won't spool or won't provide much boost when the engine is running at low power levels and putting out cooler exhaust and less of it.


Titanium is a way over-rated material. Stiffness to weight it is beaten by both steel and aluminium. Price aside which is why steel and aluminium are commonly used engine materials and titanium isn't.
 

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I kind of like where this thread is going... I could see doing this in a 105-155-205 fashion with just an intercooler and hx35... It would be cool to be able to turn up to get on to a packed highway, then back down for economy once up to cruising speed... But would it have to be 3 stages or could your poteniometer be a rheostat to be completly variable between high and low?
 

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I thought about using an oxygen sensor and gauge to monitor the air fuel ratio and keep from running it to lean.
Looks like you should go do some basic diesel theory research. There is never really a lean condition on a diesel.

If you run lean on a gas engine, you may pop a head gasket due to the high temp and pressure.

If you run "lean" in a diesel engine it cools down.

The AFC atop the Injector pump head is a little pressure activated pin which will deliver fuel proportional to boost applied. If you shut off the line from the manifold to the AFC, you will lose this feature therefore less fuel. People sometimes hook up a "Valet switch" to tow and keep the EGTs down. Then flip it off to let the AFC work and go into performance mode.

Diesels are far from perfect but are a lot better than gassers IMO!

Once they have nuclear cars then we'll be all set.
 

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Like Mooktank said, and especially the valet switch. Not to sound like a broken record, but there's another important factor: GEARS. A 5 speed with an auxiliary overdrive/underdrive splitter can give tire roasting, neck snapping acceleration and turn around and give excellent mileage too. Just build the engine for strong performance in the upper middle of your two extremes and let the gears and valet switch do the rest. Lots cheaper and more dependable and way easier to figure out, without one-off cu$tom part$.
 

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Discussion Starter · #11 ·
Looks like you should go do some basic diesel theory research. There is never really a lean condition on a diesel.
Are there any really good resources online? What about books?
 

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OK, heres my opinion for what its worth. I dont read up much or think much about the late model engines because I dont have one.( I dont waste what little memory I have on things that dont pertain to me.) So this is how i understood the late model engines work. A common single outlet fuel pump supplies fuel to a common rail at a constant high pressure (23000-25000). The computer tells the electronic injectors when to fire and how many times per stroke (most have multiple injections per stroke), via a crank position sensor. So, if you have enough money/know the right people, you could: 1] make a set of these electronic injectors to fit the 4bt head. 2] custom mount a cp3 fuel pump where your injector pump is or run it off the belt and make an idler shaft for the injector gear, (other options here also). 3]Install a crank position sensor. 4] Write a custom program for your onboard cpu, ( the high HP guys do it all the time), and you would be set. Nothing to it until someone set off an EMP pulse. As I said from the start I dont keep up with this stuff so if Im wrong I will gladly take the verbal spanking.
Carl
 

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Good stuff, Carl! Would your custom CPU program include turbo control through variable pressure wastegate? Will tin foil stop the EMP's :nuke: ha haha....?
 

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You could probably rig up a Megasquirt (google it) to use as a computer. You could have it control a wastegate if you wanted as well. (Who needs a wastegate anyway?)
Not so much a wastegate. But variable vane turbos (necessary if you want performance and economy) typically use a vacuum actuator which is controlled by a vacuum valve driven off a computer of some description.
A 12v PLC would be the easiest and most customisable controller to use.

For diesel engine reference books.
I recommend the "Diesel Engine Reference Book" from SAE.
You need nothing else.
http://www.sae.org/technical/books/R-183
 

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I don't run a VGT and I have performance and economy... :happyfinger:
Obviously you don't have enough of either.:grinpimp:

Take a look at the fuel consumption curves of a 4B and a 4BT, see how the min fuel consumption of the turbo'd engine coincides with the boost arriving? You need boost to deliver high efficiency.
Maximum power demands max boost at maximum revs.
Maximum economy demands max boost at cruising speed.

You can't do both with a single fixed geometry turbo.
 

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So more about doing this, If I would go to a diesel injection place to get the pump worked and say the word aneroid valve, would they know what the hell I'm talking about?
 

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