C turbo vs D turbo

[militarytrux]

Good evening all,

Just wanted to throw this out there and see what feedback I get,

I have had 8 duece's over the years, one NA, 4 with the C turbos and 3 with the D turbos, maybe its just the trucks in general but the NA & C turbo trucks seemed to start with a quick push of the button and fire right off, didn't matter how cold or hot it was outside or for how long they sat, (up to 6 months)

The D turbo trucks that I own will not start unless you sit in the seat and work the accelerator pedal while cranking?? then they all seem to run rough for a minute and smooth out as normal.

I'm in the process of shaking down the fuel system on the daily driver D turbo truck now to see if there is anything leaking or sucking air, I also took the advise from a previous link and left the shut off lever pulled out until the next time the truck got started and it seemed to help out a fair amount however I still had to be in the seat to keep her running.

Also just my opinion the C turbo trucks that I own seem to be a hell of a lot more powerful then the D turbo trucks? I know there could be a million reasons for this but with the 4 C trucks and 3 D trucks in here to compare odds are telling me there's a difference somewhere.

Looking for some feedback.

Thanks,,,

 

[BFR]

I would say just coincidence on speed of start.
also filter condition and pump "adjustments" are probably the cause of different performance from truck to truck.

 

[Blood_of_Tyrants]

My D turbos start with a push of the button even in the coldest Tennessee weather.

 

[MikeON]

I have both a C and D turbo for my truck. The D is on right now. No difference in starting. The D provided about 1 psi higher boost than the C.

 

[jrou111]

Both my D turbo trucks fire up instantly. Must be a yankee thing

 

[militarytrux]

Guys,

Thanks for the quick reply's I will continue with the fuel system review I just figured it was a D turbo thing any thoughts on by passing the FDC? it's still connected now but I read mixed reviews here.

 

[drgreg]

I don't think the turbo effects starting. I have read that the D turbo should produce more power.

 

[neb4x4]

I am new to military vehicles.... But got my first one about a month ago. I live in eastern Nebraska, and the day that I drove it home from Norfolk, NE it was -4 deg and my '71 AM GEN with the "D"turbo started up good with the "feathering" of the manifold heater. Now with it at home for a while; it is still very cold here at times, the worst that I started it was
-7 deg. And from my experience..... did not have a prolbem... But never owned a "C" truck.

 

[mudguppy]

theoretically speaking, it would be impossible for the turbo to affect starting time so long as the turbo is functional.

 

[wsucougarx]

Well as far as the C turbo going faster, I thought my Dodge Cummins went faster when I removed the silencer ring from the turbo. The whine made me feel faster

 

[CARNAC]

My D turbo fired up first crank since I got it in Jan. I run the engine about every 3 days and drive it every 2 weeks.

 

[elkhunter]

"D" Turbo

Mine just started the first time I tried. It has sat without running since Dec. It is a "D" Herc, a 1987 engine in a 1972 AM General. It came from Alaska where I was stationed at Fort Richardson. I was a parts specialist in an Army Aviation Battalion and ordered parts for M35A2,s, M151,s and M37,s. Also ordered parts for the U-1A DeHavilland Otter and U-21A Beechcraft twin turboprops.It,s amazing that I recognize some of the federal stock numbers after getting out 40 years ago. We had the "C" whistlers and were always having problems starting them!!! Got 8" of snow in just 6 hours today. Should have snowbirded a little longer in Arizona and Nevada. I like the "D".

 

[jwright]

Non turbo v. Turbo

How does a non turbo run Engine run v An engine with a turbo. Can you put a turbo on the non turbo Engine?

 

[gimpyrobb]

In speaking with people that work with these trucks and turbos, The D turbo is superior to the C. It has heat shielding and bearing protection from what I was told by one person. Another told me the C turbos whistle because they are under-sized for their application. I don't care what your oppinion is, these are people that have been there and done that and their wisdom is not taken lightly by me. The difference in how the trucks start and run has too many other influences to think it is a property of the turbo.

.02

 

[tsmall07]

My C turbo truck has a little trouble starting if it is below 50F outside but runs great once it gets going. The D turbo truck I picked up with it starts immediately, but doesn't seem to have nearly the power that the C truck does. The C truck also smokes a little more than the D truck.

 

[mudguppy]

...Another told me the C turbos whistle because they are under-sized for their application. ...

well, that dude is completely wrong. turbo whistle is created by the design of the turbine and compressor wheels. most cases, the turbine wheel is what is so pronounced.

need proof? first year of the 6.0 powerstroke ('03) are the "whistlers." the next year hardly any whistle at all. the difference: '03s have 10 blades on the turbine, '04s have 13. the next couple of years they went to 14 and finally 15.

all 3 turbo maps are basically identical.

whether the C may be slightly undersized or the engine could still benefit from a larger turbo is neither here nor there; turbos either whistle by design or they don't.

i would be more inclined to agree w/ "Guy #1", though. since a report of increased boost pressure across the rpm range on the same engine would indicate that the D is more efficient than the C. efficiency, also, has nothing to do w/ size.

 

[drgreg]

I thought they whistled because they didn't know the words.
I still think the turbo has jack siht to do with starting.

 

[kc5mzd]

Just a guess but I would say your "D" trucks have the fuel turned down. I would try turning up the fuel to see if that makes a diffrence. The "D" turbo design should be able to handle more fuel than a "C". Do any of the trucks have the FDC bypassed? This might make them start better in colder weather.

 

[ken]

The turbo won't have antthing to do with starting. The "D" can probude more CFM's of air than the "C" will. Both the turbine and the compresser wheel are larger on the "D" model. But the power output is controlled more by the fuel rate than anything else.

 

[jeff]

It takes heat to spool up the turbine side of the turbo so it has no effect on start up, the C does sound better if you want the whistle.