LDS VS LDT and the real differences

[Katahdin]

I found some relevant information in the attached lubricant fleet study, there's nothing I think this thread has missed, but it does document the differences in a nice little summary. There might be other details of interest in the study of wear on the various engine components in the report.

"5-Ton M54A2 Trucks - The LDS-465-1A engines are the turbocharged version of the 478-cu in. displacement, multifuel engine used in the 2-1/2-ton M35A2, and those involved in this program were built prior to the introduction of the derating modifications. In addition to the turbocharger, major items included in the LDS version are different pistons with an oil cooling annulus, changes in the delivery rate of the injector pump, different injectors, flywheel and flywheel housing, clutch, and inclusion of a power steering pump on the front timing gear cover."

 

[Blackmagic94]

I still want to see specs on the turbos as that will really settle this.

Has anyone ran an aftermarket turbo on these?

 

[patracy]

I don't have specs on any of the turbos, but there are certainly differences between the C and D turbos the LDT's have and the wastegated LDS turbos.

The turbos weren't added for power on these trucks. They were added to clear up some of the smoke.

 

[Blackmagic94]

Boost will make more air which allows more fuel to be burned. Knowing the exact lb/min of airflow at a given PR will let us be able to plot if the turbos are maxed out to begin with or not. I have a hunch that a T54E would probably make one of these trucks scream. Also upgrading the fuel lines to a bigger ID would help the IP as well. Anything can be hot rodded my friend, anything.

 

[Katahdin]

According to this lab report, the C turbo gives the LDT-465 17 more horsepower over the non-turbo model. That would suggest there's a real power increase relationship with having a turbo.

http://www.steelsoldiers.com/deuce/76508-ld-ldt-465-oil-endurance-lab-test.html

 

[patracy]

Oh yes, I'm not denying there's power to be made, but the original intent was to clear up emissions. There's just not the same punch to be packed as a modern MATCHED turbo. I know I instantly loose 100hp or more when I blow an intercooler boot on my dodge. LOL

 

[doghead]

According to this lab report, the C turbo gives

That info does not state what turbo is on the engine.

 

[Katahdin]

The lab test started in 1978 so I presumed D turbos were not mixed and matched onto C model engines at that time. If I am incorrect I apologize.

 

[doghead]

The engine version (1-C) has nothing to do with the turbo model. It's a reference to an engine model that was revised.

As for the C or D designation of the turbo model, I am not sure where that "name" came from. Does anyone have any info on that? Direct from Schwitzer , maybe...

 

[Heath_h49008]

My logic on the turbos is this...

Any one of the 3 are capable of boost exceeding the engines ability to handle... 25psi+

I don't believe there is a significant difference in exhaust restriction/flow, barring the wastegate which would simply allow for more boost at low RPM levels without overboosting at high exhaust flow/high rpm.

I think that was why the turbos were ruled out earlier in the thread as the source of the difference... the wastegate can only move the power lower, not raise the upper limit.

Double check me here, I might have missed something.

 

[Loco_Hosa]

I believe someone also stated that LDS engines are still Superior with the C or D turbo. The injectors have also been mixed and matched. Leaving the pistons and injection pump.

My money is still on that injection pump.

 

[Heath_h49008]

I believe someone also stated that LDS engines are still Superior with the C or D turbo. The injectors have also been mixed and matched. Leaving the pistons and injection pump.

My money is still on that injection pump.

The pump would make the power, the pistons and the turbos would keep the engine alive while it did so...

Logical.

 

[doghead]

If you read the troubleshooting the LDS manual or the IP manual, you would know there is a difference in the IP/governor advance spring rate, and fuel rate etc

 

[Blackmagic94]

Turbos simply move air and you need a certain amount of fuel to meet the proper fuel ratio in response which makes power. Upping the fuel rail pressure and upping the boost equal more power. Now the factory turbo might be close to out of steam. Need those stats. What mm is the turbine and compressor. What a/r is the housings?

 

[patracy]

Turbos simply move air and you need a certain amount of fuel to meet the proper fuel ratio in response which makes power. Upping the fuel rail pressure and upping the boost equal more power. Now the factory turbo might be close to out of steam. Need those stats. What mm is the turbine and compressor. What a/r is the housings?

Fuel ratios, fuel rail, upping the boost. Sounds like someone is going off half cocked and misinformed/mixing facts.

Diesel engines don't have fuel to air mixture ratios. They adjust power and rpms by the fuel delivery amount and duration.

These engines are a rotary pump. Not a common rail design, like current diesel.

Boost pressure is not a clear indicator of power. PSI is actually a measurement of restriction. You're on the right path with the turbo specs. But mearly forcing more boost dosent always increase power. This can happen when a turbo is ran outside its map. Remember, compressing air increases its temperature.

 

[doghead]

C or D or the old LDS turbos will all make more boost than the engine can handle.

This thread is supposed to be about the differences in an LDT and an LDS motor.

The turbo has nothing to do with the differences in the motors.

 

[Blackmagic94]

All fuels have a Stoichiometry ratio so you are flat wrong.

 

[doghead]

Whats that have to do with the differences of an LDT or an LDS?

 

[Blackmagic94]

I have repeatedly stated I want to find the info on the details of the turbochargers, simply saying is bigger then enough doesnt cut it for me. That is relevant to the differences in the motors and cannot be ignored.

 

[doghead]

Then start a new thread on turbos, or find an old thread and add to it.

Have you contacted Borg Warner?

Have you driven an LDT or LDS with any other turbo(to compare)?

A 478 ci diesel will only rev up to 2600rpm, just so fast.

What is your goal?