There isn't a 4.5 liter forum so I figured I'd ask the questions here...

We have a few LCF trucks and one of them isn't really getting much use so I am tossing around a few ideas about what I can do with this thing. Before I come up with a plan, I need to learn a bit more about how this engine works. I can tell it's based off the 6.0 platform BUT these V6 engines have been super reliable so I don't mind playing around with it too much. Besides, I can probably squeak some more ponies out of this lump without too much effort.

At a minimum, I'll need a head stud kit. I don't see an EGR here....am I missing something or does this engine not have one?

So, here is my real question....
Why the two turbos? What are the benefits vs the VGT that is on the newer V8 engines? Looks like the up pipes feed into a collector box mounted on the turbine inlet side of Turbo 1 but there seems to be some sort of valve with an actuator. Is that a waste gate or is that a valve that routes the exhaust over to Turbo 2 at some point in the power band?

The way this is plumbed, it sorta looks like the little turbo starts the work but the larger turbo finishes it. Does this appear correct or am I totally confused?

 

Your totally confused, Greg... Got nuth'n to offer man, but too bad they didnt stuff that into a F150?

 

Looks like compound turbos to me.

LCF 200HP/440TQ

Another pic:



Here is a 6.4L compound

 

Thanks. What does 'compound' mean in respect to turbos? Are they both working in unison....one feeds the other? If so, then why does the exhaust go from small turbo to large while the intake is opposite?

Not doubting...just asking so I can learn.

 

Not really an expert on this, but the system is known as Compounds, and you are correct, the high pressure turbo feeds the low pressure turbo to remain in the engines effeciency MAP. There is a wastegate to bleed off excessive pressure. Not much to add or offer other than what you really already knew.

 

Yes. If you only had one large turbo they tend to be slow to spool up. One small turbo would spool fast but run out of legs so to speak and be inefficient and superheat the air. The VGT helped to gain better spool up by opening and closing vanes, but at a cost of more back pressure/heat.

 

A variant of the VT365 is the VT275 4.5*L V-6, which is basically a 6.0*L V-8 with two cylinders chopped off. However, it uses a sequential twin-turbocharger system, instead of the single variable-geometry turbocharger used in the VT365. It is used in the 2006 Ford LCF (Low Cab Forward) and International CF (Cab Forward) (later CityStar) series trucks. It produces 200*hp (150*kW) and 440*lb·ft (597*N·m) of torque and is backed by a Ford TorqShift 5 speed automatic.

 

Triple's....

 

Sequential turbos refer to a set-up in which the motor utilizes one turbocharger for lower engine speeds, and a second or both turbochargers at higher engine speeds. Typically, larger high-flow turbochargers are not as efficient at low rpms, resulting in lower intake manifold pressures under these conditions. On the other hand, smaller turbos spool up quickly at low rpms but cannot supply enough air at higher rpms. During low to mid engine speeds, when available spent exhaust energy is minimal, only one relatively small turbocharger (called the primary turbocharger) is active. During this period, all of the engine's exhaust energy is directed to the primary turbocharger only, providing the small turbo's benefits of a lower boost threshold, minimal turbo lag, and increased power output at low engine speeds. As rpm increases, the secondary turbocharger is partially activated in order to pre-spool prior to its full utilization. Once a preset engine speed or boost pressure is attained, valves controlling compressor and turbine flow through the secondary turbocharger are opened completely. (The primary turbocharger is deactivated at this point in some applications.) In this way a full twin-turbocharger setup provides the benefits associated with a large turbo, including maximum power output, without the disadvantage of increased turbo lag.

Sequential turbocharger systems provide a way to decrease turbo lag without compromising ultimate boost output and engine power.

 

I would rather have the compound setup over the VGT setup anyday.

Is that an egr at the elbow to air intake pipe? It is hard to tell what it is connected to.

 

I am not normally one to plagiarize, but I've actually been reading up on this lately and I stumble onto this on another forum.

• The exhaust goes through the "top" or "secondary" turbo which is the smaller one first. Exhaust is then routed down through the "hotpipe" to the "primary" or "atmospheric" charger on the bottom. After the exhaust gas passes through the bottom turbo turbine, then to down pipe and muffler.
• The top turbo should be wastegated. Failure to do so will result in overspeeding of the turbo and excessive drive pressure. The bottom turbo, if properly set up for the intended power level (appropriate exhaust housing size and turbine size) is usually not wastegated. The bottom is often wastegated when nitrous is introduced or the user wants very fast spool from the bottom charger.
• The whole idea of "compounding" is just that... the performance "map" as a single turbo no longer applies when adding the larger turbo. The larger turbo is feeding the smaller turbo compressed air. The smaller turbo compresses this air once again and sends it on its way. Now the air is very hot, but contains many more "air molecules" than before. The air has more "mass" to it. If the turbos are properly matched and tuned, they are both working much less hard than a single turbo trying to do the same thing. This keeps them both in their respective efficiency islands.

 

Thanks for the replies.
Now to find some batteries and get this thing started.....

 

The general diesel forum would have been more appropriate..... but NBD.