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3 cyl Detroit

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Altitude vs. Performance

On a 2 cycle Detroit diesel the blower does not pressurize the intake, it is used to blow the exhaust out when the piston is at the bottom of the stroke. The turbocharger pressurizes the intake to the blower the blower then transfers the already pressurized, much denser charge to the cylinders. Clear as mud huh :)

Jared
 
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In 1978, before you could purchase a factory-built diesel pickup,

I repowered my '74 International 200 4x4 with a 3-53 Detroit

Diesel that originally saw life in a bread truck. It was coupled to

a Clarke 280VO 5 speed OD, but gear ratios were not perfect.

Lots of noise, absolutely no power below 1500 rpm, but was

geared well for freeway driving. I was the only guy on the block

who had one of these. Paid $4500 for the truck new in 1974

w/345 gas engine, and sold it with the 3-53 in 1978 for $7200,

plus $500 for the oringinal engine. I also knew several contemporaries who had 4-53's in Chevy suburbans- that was

a better package, but only 140 HP. Both rusted away, but I

believe these engines are still worth quite a few$.
 
Originally posted by jrobinson2

On a 2 cycle Detroit diesel the blower does not pressurize the intake, it is used to blow the exhaust out when the piston is at the bottom of the stroke. The turbocharger pressurizes the intake to the blower the blower then transfers the already pressurized, much denser charge to the cylinders. Clear as mud huh :)

Jared



A 2 cycle detroit does not have a turbo. All it has is a blower that is driven off of the gear train. The only intake port on a detroit is where the blower pushes air into the cylinder at the bottom of the stroke. Thus is the reason why 2 cycles do not have intake valves in the head.

Paul
 
Well, alt, I have to disagree with you. A lot of Detroit 2 cycle engines have turbochargers on them. While it is true that the basic purpose of the blower is to scavenge the cylinder of exhaust gases, the addition of a turbo just increases this available pressure in the intake tract just as it does on a 4 cycle. The engine's cylinders just get more air into them whether through valves in a 4 cycle or through cylinder wall ports on the 2 cycle.

There are many Detroits set up with dual or even quad turbos.

:) :) :)
 
alt

A farm I worked on had a '78 Chevy C-70 with a factory installed turbocharged 4-53 Detroit:) I understand the gear driven superchargers, I have a 2-71 and a 6V-71 (non turbo'd) disassembled in the shed;) :) The roots type Detroit superchargers were never engineered to pressurize the intake tract (they are relatively short lived and inefficient when used as a compressor in automotive performance and racing applications), a turbocharger is a much more efficient compressor. I think Detroit found it easier, cheaper and more efficient to use a turbocharger than to redesign the supercharger. As others have said the turbo is used to deliver a pre-pressurized charge to the supercharger.

Jared
 
Try and find some info on class 8 trucks that hold the land speed record on the Bonneville Salt Flats. They had 12V71 or 16V71 and had a turbo for every 3 or 4 cylinders.
 
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