On Wed, 22 Aug 2007 21:05:57 +0700, wrote:

On Wed, 22 Aug 2007 12:27:55 GMT, "Pete C."
wrote:

Eisboch wrote:

"JohnM" wrote in message
m...


All two-stroke Detroits have a blower. It's necessary to the operation of
the engine, does the job that crankcase pressure does in a little
two-stroke. On the inline motors it mounts on the side of the block.

John

If a "blower" is defined by you as a turbo (i.e. .., device to increase air
flow into the cylinders), then you are in error. I know several people with
2 stroke DD 6-71's. Some are naturally aspirated, some have turbos
(blowers).

Eisboch

A "blower" generally refers to a direct driven super charger, not an
exhaust driven turbo charger.

The Detroit Diesel is a two stroke, diesel. The piston goes down on
the power stroke and comes up on the compression stroke. Without the
mechanical driven "blower" which simply blows air in through the
cylinder ports and through the exhaust ports at the beginning of the
compression stroke there would be no way to get a charge of air into
the engine.

If you wanted to increase the pressure and volume of this air flow you
could add a exhaust driven compressor before the "blower", But you
must have the "blower" for the engine to run.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Neither being a two-stroke nor using diesel oil (nor indeed the
combination) requires a blower/turbo for such an engine to operate. It is
true that engines can be designed so that, were the blower/turbo with which
they are normally equipped to be removed they would not run, that would be
due to other design decisions, not to the choice of fuel, method of
ignition, and/or two/four-stroke operation.

On Wed, 22 Aug 2007 07:30:16 -0700, UglyDan®©™ penned the following
well considered thoughts to the readers of rec.boats:

Eisboch wrote
If a "blower" is defined by you as a turbo (i.e. .., device to increase
air flow into the cylinders), then you are in error. I know several
people with 2 stroke DD 6-71's. Some are naturally aspirated, some have
turbos (blowers).
Eisboch

Richard,
All 2 stroke DD series whether inline or V configuration 71- 53's- 92's
even the old 110's etc.. have blowers, Naturally aspirated (NA) or
turbocharged (TI) . The 6v53 in my boat is a NA with a blower. UD

An engine is, by definition, either naturally aspirated or not. If it
has a blower (supercharger) or turbocharger it is not naturally
aspirated.

http://en.wikipedia.org/wiki/Naturally-aspirated_engine

--

Grady-White Gulfstream, out of Oak Island, NC.

Homepage
http://pamandgene.idleplay.net/

Rec.boats at Lee Yeaton's Bayguide
http://www.thebayguide.com/rec.boats
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wrote in message
...
On Wed, 22 Aug 2007 12:27:55 GMT, "Pete C."
wrote:

Eisboch wrote:

"JohnM" wrote in message
m...


All two-stroke Detroits have a blower. It's necessary to the operation
of
the engine, does the job that crankcase pressure does in a little
two-stroke. On the inline motors it mounts on the side of the block.

John

If a "blower" is defined by you as a turbo (i.e. .., device to increase
air
flow into the cylinders), then you are in error. I know several people
with
2 stroke DD 6-71's. Some are naturally aspirated, some have turbos
(blowers).

Eisboch

A "blower" generally refers to a direct driven super charger, not an
exhaust driven turbo charger.

The Detroit Diesel is a two stroke, diesel. The piston goes down on
the power stroke and comes up on the compression stroke. Without the
mechanical driven "blower" which simply blows air in through the
cylinder ports and through the exhaust ports at the beginning of the
compression stroke there would be no way to get a charge of air into
the engine.

If you wanted to increase the pressure and volume of this air flow you
could add a exhaust driven compressor before the "blower", But you
must have the "blower" for the engine to run.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

On large stationary diesel generators using Detroit diesels, there a often
both shaft driven " blowers" and turbochargers.
The blowers are used to start the engine and get it up to speed.
Afterwards, the blowers are cut off by damper valves and the turbochargers
take over the air supply job. This is done because the overall engine
efficiency is better using the turbochargers.

Randy

On Wed, 22 Aug 2007 11:18:57 -0400, Gene Kearns penned the following
well considered thoughts to the readers of rec.boats:

On Wed, 22 Aug 2007 07:30:16 -0700, UglyDan®©™ penned the following
well considered thoughts to the readers of rec.boats:

Eisboch wrote
If a "blower" is defined by you as a turbo (i.e. .., device to increase
air flow into the cylinders), then you are in error. I know several
people with 2 stroke DD 6-71's. Some are naturally aspirated, some have
turbos (blowers).
Eisboch

Richard,
All 2 stroke DD series whether inline or V configuration 71- 53's- 92's
even the old 110's etc.. have blowers, Naturally aspirated (NA) or
turbocharged (TI) . The 6v53 in my boat is a NA with a blower. UD

An engine is, by definition, either naturally aspirated or not. If it
has a blower (supercharger) or turbocharger it is not naturally
aspirated.

http://en.wikipedia.org/wiki/Naturally-aspirated_engine

Hmmmm.... are you saying that this is an "altitude" engine and is
equipped with a "sea level" boost? It might make some sense if you are
boating at 10,000 feet, otherwise I don't get it.

Even if turbonormalized, the engine is not NA......

--

Grady-White Gulfstream, out of Oak Island, NC.

Homepage
http://pamandgene.idleplay.net/

Rec.boats at Lee Yeaton's Bayguide
http://www.thebayguide.com/rec.boats
-----------------
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Access your favorite newsgroups from home or on the road
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On Aug 22, 8:18 am, Gene Kearns
wrote:
On Wed, 22 Aug 2007 07:30:16 -0700, UglyDan®©™ penned the following
well considered thoughts to the readers of rec.boats:

Eisboch wrote
If a "blower" is defined by you as a turbo (i.e. .., device to increase
air flow into the cylinders), then you are in error. I know several
people with 2 stroke DD 6-71's. Some are naturally aspirated, some have
turbos (blowers).
Eisboch

Richard,
All 2 stroke DD series whether inline or V configuration 71- 53's- 92's
even the old 110's etc.. have blowers, Naturally aspirated (NA) or
turbocharged (TI) . The 6v53 in my boat is a NA with a blower. UD

An engine is, by definition, either naturally aspirated or not. If it
has a blower (supercharger) or turbocharger it is not naturally
aspirated.

http://en.wikipedia.org/wiki/Naturally-aspirated_engine

--

Grady-White Gulfstream, out of Oak Island, NC.

Technically, you are correct, but since ALL Detroit Diesel (and their
precursors, the "Jimmies") 2-strokes have crankcase blowers by design,
the convention has always been to call an otherwise unenhanced engine
"naturally aspirated" (NA), and add the appropriate moniker if also
turbo-charged with or without cooling (T, TI, TIA).

By design, without the crankcase blower, a DD won't run.

Regards,

Bob

Homepagehttp://pamandgene.idleplay.net/

Rec.boats at Lee Yeaton's Bayguidehttp://www.thebayguide.com/rec.boats
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Is anyone at rec.crafts.metalworking reading this thread??
If not, I suggest we (at rec.boats) stop further crossposting there.

On Wed, 22 Aug 07, jtay wrote:
Neither being a two-stroke nor using diesel oil (nor indeed the
combination) requires a blower/turbo for such an engine to operate.

Running a Detroit 4-53 without a blower (and maybe all Detroit 2
strokes -shrug- I dunno) would indeed take a complete and major league
re-design. Not just a few bolt on changes for sure.

Rick

On Wed, 22 Aug 2007 11:29:44 -0500, lid wrote:

On Wed, 22 Aug 07, jtay wrote:
Neither being a two-stroke nor using diesel oil (nor indeed the
combination) requires a blower/turbo for such an engine to operate.

Running a Detroit 4-53 without a blower (and maybe all Detroit 2
strokes -shrug- I dunno) would indeed take a complete and major league
re-design. Not just a few bolt on changes for sure.

Absolutely right. The Detroit 2 stroke design requires a blower to
move new air into the piston and purge the ehaust gases. It will not
run without it, and little or no increase in volumetric efficiency is
achieved. A turbo charger on the other hand is designed to increase
the air charge to the piston above atmospheric pressure, and therefore
horsepower is increased as the effective cylinder volume is increased.

The confusion arises from the fact that a Detroit blower can also be
used on a gasoline engine as a supercharger. Same basic device but a
different purpose and result.

On Wed, 22 Aug 2007 11:18:57 -0400, Gene Kearns
wrote:

An engine is, by definition, either naturally aspirated or not. If it
has a blower (supercharger) or turbocharger it is not naturally
aspirated.

http://en.wikipedia.org/wiki/Naturally-aspirated_engine

That may be true in a strictly technical sense, and true for all gas
engines and 4 stroke diesels, but "naturally aspirated" 2 stroke
Detroit Diesels are commonly understood to be without a turbocharger
since all DDs have a blower just to move air into the cylinders.

Gene Kearns:
If it
has a blower (supercharger) or turbocharger it is not naturally
aspirated.

Wayne.B:
but "naturally aspirated" 2 stroke
Detroit Diesels are commonly understood to be without a turbocharger
since all DDs have a blower just to move air into the cylinders.

Okay, I think I'm gettin' it now. I was thinking the DD "blower" was
just another term for "supercharger" but it's not.
The "blower" just provides the normal air pressure required to run the
engine (other 2 stroke designs do the same thing with crankcase
vacuum/pressure). But a "supercharger" would provide more than that.
An extra (super) boost so to speak. Thus the use of separate
terminology. Izat about right?

Rick

On Wed, 22 Aug 2007 14:01:49 -0500, lid wrote:

The "blower" just provides the normal air pressure required to run the
engine (other 2 stroke designs do the same thing with crankcase
vacuum/pressure). But a "supercharger" would provide more than that.
An extra (super) boost so to speak. Thus the use of separate
terminology. Izat about right?

Almost. Superchargers and turbochargers both generate boost pressure,
the difference is in how they are driven. Superchargers are direct
drive (belts, gears, etc), turbos are driven by exhaust pressure.