To turbo or not to turbo?

[smitty477]

"As far as burning cleaner or more efficiency, the turbo would not necessarily do that. Clean burning and not wasting extra full is just having the correct stoichiometric mixture in the cylinder for burning. Also affecting that is timing. In some cases a variable timing device is used, but I don't know that there's any timing at all in a diesel, suspect it's built into the engine and not adjustable"


This is a good book that will likely sway your view after you read it and it helps describe the turbo on a diesel....
"Marine diesel engines" - Nigel Calder ISBN #0-87742-313-X
It is more than just a basic book as it has some very good charts and troubleshooting guides for those with diesels.
In general the more turbulence and larger intake charge you can supply the more efficient they will run.

 

[Lepke]

I been running marine diesels since about 1960. At least dozens of engines that I maintained and overhauled most. Primarily heavy duty engines like Cat and Detroit. Both turbo and non-turbo. The point of a turbo is to get more hp in a smaller space. Manufacturers start with a basic engine , sometimes change pistons to a lower compression, bigger injectors and maybe a different cam. The turbo pushes in more air causing a bigger bang and releasing much higher temp exhaust gases. The EGTs are the real drawback to turbos in the hands of a hot rod captain. Often turbo engines go half or less time/distance between overhauls. The extra hot gases eat away at the metal in the valves and rings and cause more wear on the sleeves/cylinder walls. At 70-80% of hp you get less wear, but then if you run like that you might as well have a non-turbo.
Often in my life in the military and tugs, I ran the same boat and engines as other captains. I always got longer life and better economy out of my engines. I did that by keeping the power under 80% and keeping the oil clean. When I needed full power I did it sparingly and cooled down the engine before shutting down. MY dad was a chief engineer and it's how I was taught.
I've owned more boats than I can accurately remember, maybe old age, but when I bought a new engine, I would weigh the size, weight and hp needed and usually pick a non turbo. Many had roots style blowers like a Detroit, but a turbo would be in addition. Turbos themselves are not any less reliable than other parts, but effected by high EGTs like other parts. I usually change the bearings and seals at 1/2 life and don't remember a turbo failure. Just because the coolant doesn't overheat doesn't mean parts of the engine aren't too hot.
Small yacht light duty engines are more effected by turbo use than bigger engines. But a responsible captain can get long life out of them considering the hours typically used in recreation.
My current Detroit Diesel mains can burn from 3 to 35 gallons an hour each depending on the configuration and hp used. The basic block produces from 165hp (early non-turbo) to about 485hp (twin turbos).

 

[Seevee]

"As far as burning cleaner or more efficiency, the turbo would not necessarily do that. Clean burning and not wasting extra full is just having the correct stoichiometric mixture in the cylinder for burning. Also affecting that is timing. In some cases a variable timing device is used, but I don't know that there's any timing at all in a diesel, suspect it's built into the engine and not adjustable"


This is a good book that will likely sway your view after you read it and it helps describe the turbo on a diesel....
"Marine diesel engines" - Nigel Calder ISBN #0-87742-313-X
It is more than just a basic book as it has some very good charts and troubleshooting guides for those with diesels.
In general the more turbulence and larger intake charge you can supply the more efficient they will run.

Thx much, will see if it's available on IPad. I generally don't read books (too time consuming), but this one could be an exception.

...Found it, 2007 edition on Kindle... good enough.

 

[Seevee]

I been running marine diesels since about 1960. At least dozens of engines that I maintained and overhauled most. Primarily heavy duty engines like Cat and Detroit. Both turbo and non-turbo. The point of a turbo is to get more hp in a smaller space. Manufacturers start with a basic engine , sometimes change pistons to a lower compression, bigger injectors and maybe a different cam. The turbo pushes in more air causing a bigger bang and releasing much higher temp exhaust gases. The EGTs are the real drawback to turbos in the hands of a hot rod captain. Often turbo engines go half or less time/distance between overhauls. The extra hot gases eat away at the metal in the valves and rings and cause more wear on the sleeves/cylinder walls. At 70-80% of hp you get less wear, but then if you run like that you might as well have a non-turbo.
Often in my life in the military and tugs, I ran the same boat and engines as other captains. I always got longer life and better economy out of my engines. I did that by keeping the power under 80% and keeping the oil clean. When I needed full power I did it sparingly and cooled down the engine before shutting down. MY dad was a chief engineer and it's how I was taught.
I've owned more boats than I can accurately remember, maybe old age, but when I bought a new engine, I would weigh the size, weight and hp needed and usually pick a non turbo. Many had roots style blowers like a Detroit, but a turbo would be in addition. Turbos themselves are not any less reliable than other parts, but effected by high EGTs like other parts. I usually change the bearings and seals at 1/2 life and don't remember a turbo failure. Just because the coolant doesn't overheat doesn't mean parts of the engine aren't too hot.
Small yacht light duty engines are more effected by turbo use than bigger engines. But a responsible captain can get long life out of them considering the hours typically used in recreation.
My current Detroit Diesel mains can burn from 3 to 35 gallons an hour each depending on the configuration and hp used. The basic block produces from 165hp (early non-turbo) to about 485hp (twin turbos).

Lepke,

Good points and I need to orient my turbo knowledge from planes to boats. However the EGT is significant. It's actually the cylinder head temperature that's the killer, but the EGT give instant indication of heat that will cause the CHTs to be an issue. Do boats typically have EGT and CHT indications like planes do? Or is it really valuable? Suspect that just the water temp would give a good indication of damaging temps.


Your post is very logical.

 

[Lou_tribal]

I also disagree with Lou_Tribal, sorry Lou. You're out of touch there. I'm still driving a 1990 GT4

You're just a cheap disturber but cannot argue with a guy driving a GT4 - respect

Can't even agree with you there Lou. In 1983 I bout a Mitsubishi Cordia automatic. Remember them..?.

Now all the aussies are chasing me
In 1983 I was just young enough to try to find how women work and was not in north america neither, so no don't know what this mitsu was.

 

[Ski in NC]

No analog on boat engines for CHT. Having water jackets, the temp is controlled in a close band unless there is sloppy maintenance. Actual fire deck temps can be out of spec, but due to water jacket those are not easily measured.

EGT, GPH and manifold pressure are the running indicators for boat engines. EGT is an add-on, if gph and manifold pressure are on target, so will EGT.

 

[Xsbank]

Did you ever find out (how women work)? If so, we're waiting...

 

[Xsbank]

Run your engines how they are rated (mine is M1 - continuous, so I can run mine at rated power 24 hours per day). I don't, though, the noise and the fuel burn prevent that. Cool the turbo down a bit (most of us don't roar into the dock and switch off anyway, idling while we tie up) and change the oil and all the filters as required in the book then go boating and stop fussing.

 

[Ski in NC]

Did you ever find out (how women work)? If so, we're waiting...

Answer: No. I'm good with machinery and I can build things. Women throw me ass over head. Baffle me completely. Machinery is EASY.

 

[Lou_tribal]

No never really find my answer. I tried many, but never found one with an owner manual. Finally I found one who was working better than the other, five years ago I married her. She is still working so I apply the old rule... If it is not broken don't try to repair her

 

[gaston]

No never really find my answer. I tried many, but never found one with an owner manual. Finally I found one who was working better than the other, five years ago I married her. She is still working so I apply the old rule... If it is not broken don't try to repair her

Guys, we are going far from the subject of this thread. Let s keep it focused on To turbo or not to turbo?

 

[Peter B]

Guys, we are going far from the subject of this thread. Let s keep it focused on To turbo or not to turbo?

This amount of thread drift suggests we are about turbo'd out, and I suspect the OP had his answer many posts ago..?

 

[Bruce B]

This amount of thread drift suggests we are about turbo'd out, and I suspect the OP had his answer many posts ago..?

I only began this post as a result of multiple suggestions in another thread.
I have no issue with turbos, especially in diesels.
Like many of these threads the thread drift is often as interesting as the original subject.
Bruce

 

[Seevee]

This amount of thread drift suggests we are about turbo'd out, and I suspect the OP had his answer many posts ago..?

Peter,
I sure learned a bit, but there's tons more.... sure wouldn't mine continuing.

 

[smitty477]

"Do boats typically have EGT and CHT indications like planes do? Or is it really valuable? Suspect that just the water temp would give a good indication of damaging temps."


Really really good questions.....
Boats typically do not have EGT gages.
Water temps are not good indicators of EGT , not at all
It is very inexpensive to add EGT gages which will supply the data real time
EGT is affected by many factors or loading including too much prop/boat weight/trim/ambient temps and humidity and bottom and running gear growth.


I'lll find a pic of the last EGT gages I installed on my last boat for like $200 total.

 

[smitty477]

IMO - Pyro and boost gages are extremely valuable and cost very little if you install them yourself. Valuable to keep your engine out of trouble and they can be a great help diagnosing many issues even when your props/shafts have been fouled too much.


To the far right are two boost gages on the top - cost for both was about $150.
Below them is a dual sweep EGT gage reading two engines - both with senders and extensions cost about $250.

 

[sunchaser]

Diesel engines have a much greater exhaust volume that gasoline engines. As was discovered in the 30s recapturing this large volume and using it for spinning a wheel was simply accomplished via a turbocharger, already on the market for use in aircraft engines. Much simpler than on a gasoline engine with relatively low volumes of exhaust in comparison.

A century ago the very smart engineers of the time were well used to designing pumps, hydroelectric turbines and sophisticated windmills. Utilizing this liquid, wind or hot exhaust was deemed a freebie with early versions of companies like Garrett Air Research coming to life. For sure GE and Westinghouse from the hydro and steam turbine side. Then along came screw compressors. So much was going way back then for recapture of energy.

In the late 40s the science exploded with nuclear power generation (no pun intended) whether land or ship based. Again using rotating devices being driven by a source of energy.

Gas vs diesel engine turbos are not quite the same though as far as recapturing of energy. Because of the high vs low exhaust volume difference the amount the gains from diesel exhaust recirculation via a turbo are greater. There have been some attempts at suicide in a garage by a diesel VW, it takes a very long time with the attemptee getting so sick that they'd rather live.

For many years I worked in UG mines. No gasoline engines allowed but diesels and the much lower CO and other noxious contents acceptable for mammals. Ventilation requirement are quite manageable with diesel in this environment.

Since the 30s turbos have been extensively used on diesels, especially in genset and continuous duty applications where BSFC is important with resultant optimum fuel efficiency. My boat diesel engines were specifically designed for genset duty at 1800 RPM, most diesel are the same. That is one reason why running most heavy duty diesels at this RPM is pretty much in its fuel and mechanical efficiency sweet spot and where turbos shine.

For some of us, detailed diesel engine books, research and use histories have been a working way of life. Fortunately much of this data and design logic (usually simplified) is available on the internet. One could read very well researched and documented treatises on the subject. All it takes is desire, comprehensive ability and curiosity. Good stuff abounds.

 

[rwidman]

.................. Not many of us get to decide whether the engine has a turbo or not. We buy what we want, and if it has a turbo, then it has a turbo. ...........

I think that pretty well sums it up.

 

[Baker]

Peter,
I sure learned a bit, but there's tons more.... sure wouldn't mine continuing.

One of the things that might be confusing you is "turbo normalizing" used in aviation. The biggest reason aircraft engines are turbocharged is NOT to boost power. It is to maintain sea level power while at altitude. Is more work being done producing sea level power at altitude? Is more heat generated? I think there is but am not totally sure as to why. I might need to meditate on that for awhile. I just know I have flown a turbo 310 at night and could see the turbos(or related hardware) glowing thru the cowling vents.
Anyway, don't get too caught up on the aviation deal. Aircraft engines aren't turbocharged for the same reasons. At least not totally. So it is not necessarily apples to apples.

 

[North Baltic sea]

93 years experience in turbo diesel ships. materials and will continue to develop, but it is certain Turbo is here to stay. if the turbo fails the cause is almost always a bad service or stupid captain, maybe the same thing. Boating is always a risk, but the goblins is useless to worry about. when you look at the last vibration damper? If the damage it can break the crankshaft ...

 

[Peter B]

"Do boats typically have EGT and CHT indications like planes do? Or is it really valuable? Suspect that just the water temp would give a good indication of damaging temps."

Really really good questions.....
Boats typically do not have EGT gages.
Water temps are not good indicators of EGT , not at all
It is very inexpensive to add EGT gages which will supply the data real time
EGT is affected by many factors or loading including too much prop/boat weight/trim/ambient temps and humidity and bottom and running gear growth.

I'lll find a pic of the last EGT gages I installed on my last boat for like $200 total.

Ok, ok, I'll bite. What the heck are EGT and CHT gauges. Boost I understand, my car has one, but please exchange these abbreviations, and what they are measuring.

However, one other thing worth ventilating, if we go on with this turbo thing, is that folk are really wasting their time worrying about under-loading turbo engines. Think about it. Most of the time a car turbo is just spinning but not boosting - Unless you're a real lead-foot or racing - doesn't hurt them. My car has done 300,000 km, original turbo. Same with boats. If you use the boost to get on the plane, you might find they are still boosting to stay up there, but not much, and if you drop off the plane, or are not a planing hull, then once up to cruising speed the turbo won't be boosting unless pushing into a huge headway. Again...I suspect it doesn't matter, as they are just spinning slower in the exhaust stream , and if tuned properly, carbon build-up will be more theoretical than real, and nothing the odd burst at a fuller throttle won't clear off. So, again....not something to lose sleep over.

However, as Baker has pointed out, in the case of aircraft, the turbo is more useful at overcoming the less dense air issue up high, rather than for increased low level performance, although no doubt does add some extra oomph at take-off.

 

[Baker]

Ok, ok, I'll bite. What the heck are EGT and CHT gauges. Boost I understand, my car has one, but please exchange these abbreviations, and what they are measuring.

However, one other thing worth ventilating, if we go on with this turbo thing, is that folk are really wasting their time worrying about under-loading turbo engines. Think about it. Most of the time a car turbo is just spinning but not boosting - Unless you're a real lead-foot or racing - doesn't hurt them. My car has done 300,000 km, original turbo. Same with boats. If you use the boost to get on the plane, you might find they are still boosting to stay up there, but not much, and if you drop off the plane, or are not a planing hull, then once up to cruising speed the turbo won't be boosting unless pushing into a huge headway. Again...I suspect it doesn't matter, as they are just spinning slower in the exhaust stream , and if tuned properly, carbon build-up will be more theoretical than real, and nothing the odd burst at a fuller throttle won't clear off. So, again....not something to lose sleep over.

However, as Baker has pointed out, in the case of aircraft, the turbo is more useful at overcoming the less dense air issue up high, rather than for increased low level performance, although no doubt does add some extra oomph at take-off.

EGT=Exhaust Gas Temperature
CHT=Cylinder Head Temperature

You will also hear EGT gauges referred to as Pyro gauges. EGT is a fairly useful measure of work being done. The hotter it is, the more work is being done. EGT gauges do different things in airplanes. THey obviously measure the same thing, but in an airplane, you have control of the mixture. As you climb, one needs to adjust the mixture as the air gets thinner. There are ways to do that as it relates to EGT. As you lean the mixture, EGTs rise...to a point and then fall off. So engine manufactures will recommend "20 degrees lean of peak"...IOW, you lean the mixture to the peak EGT and then continue to lean it until the EGT falls 20 degrees on the lean side of the peak EGT. Or maybe they want 20 degrees on the rich side of peak...whatever. Add turbocharged engines to the mix and this becomes even more important since you have more air and can burn more fuel.

Now, as it relates to my particular boat and boost and the way I run my boat. I have a planing boat and I operate on plane. And trust me, the turbos are pumped up and running. I run 2400RPM on a 2800RPM engine. There is work being done!!! Now my boat is fairly underpropped so it is not working as hard as a boat that was propped dead on or even overpropped. Again, if you had an EGT gauge you get a good idea of the work being done. An overpropped boat running the same RPM as an underpropped boat would have a much higher EGT because the load is higher and more work is being done.

Comparing a turbo car to a planing turbodiesel boat is totally apples to oranges because a car is not nearly as loaded up as a boat. Water is a much denser medium than air and it has to continue to push thru that medium.

ANd an airplane that has a turbonormalized engine produces no more power at sea level than a naturally aspirated engine of the same horsepower. I have flown a C310 with IO520s and one with TIO520s. Both engines are rated at 300hp. So no extra oomph on takeoff. The only difference is the TIO520 will maintain that power to a much higher altitude. The NA engine is losing power the minute you leave the ground.

And let us not forget....not all airports are at sea level. Turbocharged airplanes provide greater "lift capability" at higher density altitude airports.

PS...nomenclature for piston aircraft engines IO520 means (fuel)Injected and Opposed(flat horizontally opposed cylinders) The "T" in TIO just means Turbocharged. The 520 is cubic inch displacement.

 

[Bruce B]

Peter B
EGT is an abbreviation for exhaust gas temperature.
CHT is cylinder head temperature.
I am a little surprised that someone is monitoring cylinder head temperature in a water cooled diesel engine as I tend to equate the importance of that measurement with air cooled engines.
Exhaust temperature as measured before the turbo is a useful indicator of effeciancy along with a way of monitoring for engine damaging levels of heat in the exhaust system.

As for boost pressure and turbo compressor speed, I think you are sort of correct. On a turbocharged Diesel engine, the turbo begins actually spinning the second the engine is running, just not at a very high speed. So yes, the turbo is always spinning on these engines (at least on any diesel I have ever worked on...). They do however develop boost more easily than you think. Even the Cummins ISB 6.7 in my Ram 2500 develops boost any time I press the throttle.
It has a boost gauge built into the display and I like to watch it sometimes.
When the truck is not loaded, just driving along at say 30 miles per hour, a slight press of the pedal creates boost. We all know that an unloaded road vehicle at 30 mph has far less load on it than any boat moving through the water...
When we had the opportunity to go on the 100 mile mini delivery of the Cummins powered American Tug, I watched boost levels and that engine saw boost even at non planing speeds. I didn't record numbers though, kind of wish I did...
I think that the common rail injected engines do run much cleaner over a greater range of conditions than mechanically injected engines though. This likely leads to less need of boost pressure to keep the engine and turbo turbine clean.

Bruce

 

[Seevee]

One of the things that might be confusing you is "turbo normalizing" used in aviation. The biggest reason aircraft engines are turbocharged is NOT to boost power. It is to maintain sea level power while at altitude. Is more work being done producing sea level power at altitude? Is more heat generated? I think there is but am not totally sure as to why. I might need to meditate on that for awhile. I just know I have flown a turbo 310 at night and could see the turbos(or related hardware) glowing thru the cowling vents.
Anyway, don't get too caught up on the aviation deal. Aircraft engines aren't turbocharged for the same reasons. At least not totally. So it is not necessarily apples to apples.

Baker, Sounds like you have an aviation background, too... Also fun and expensive as boats but not sure which is worse. When we meet sometime, this is a good subject for cocktail hour......can beat it to death.

Agreed the turbo in aviation has a bit different goal than in marine or auto... primarily to give the plane altitude (and provide for pressurization, maybe).

And also agree, they ALL produce heat. You can't compress air like a turbo does without heat, which can be an issue. That's where intercoolers help. Turbo normalizing is the vast minority of planes out there but I like the concept better.... less stress, can use a high compression engine, no "over boost" issues (for the most part) and generally is more economical that a regular turbod engine. Yes the "normalized" turbo maintains sea level pressure but does not increase it, while a regular turbo charger may increase it up to 45 inches or more, which does give more take off power.

But, as to the marine version.... because boats don't fly very high, the turbo is mainly to get more power out of a smaller engine, and there's some merit to that. So, there's no need for a turbo normalized engine in a boat... only on that is boosted above sea level pressure.

But in all turbos, there is an extra part and extra maintenance, so one has to decide if that's a value in his operation. And the percentage of turbo diesels in boats is WAY higher than piston airplanes... so they are VERY popular..... or at least the manufacturers think so.

I'm still not totally sold, but seems like a well maintained turbo diesel isn't an awful bad idea. I'm still leaned on having a bigger engine that's non turbo'd, just like I prefer in aviation. Simple. I'm still waiting to be convinced the turbo is a better deal.

 

[Seevee]

Peter B
EGT is an abbreviation for exhaust gas temperature.
CHT is cylinder head temperature.
I am a little surprised that someone is monitoring cylinder head temperature in a water cooled diesel engine as I tend to equate the importance of that measurement with air cooled engines.
Exhaust temperature as measured before the turbo is a useful indicator of efficiency along with a way of monitoring for engine damaging levels of heat in the exhaust system.

As for boost pressure and turbo compressor speed, I think you are sort of correct. On a turbocharged Diesel engine, the turbo begins actually spinning the second the engine is running, just not at a very high speed. So yes, the turbo is always spinning on these engines (at least on any diesel I have ever worked on...). They do however develop boost more easily than you think. Even the Cummins ISB 6.7 in my Ram 2500 develops boost any time I press the throttle.
It has a boost gauge built into the display and I like to watch it sometimes.
When the truck is not loaded, just driving along at say 30 miles per hour, a slight press of the pedal creates boost. We all know that an unloaded road vehicle at 30 mph has far less load on it than any boat moving through the water...
When we had the opportunity to go on the 100 mile mini delivery of the Cummins powered American Tug, I watched boost levels and that engine saw boost even at non planing speeds. I didn't record numbers though, kind of wish I did...
I think that the common rail injected engines do run much cleaner over a greater range of conditions than mechanically injected engines though. This likely leads to less need of boost pressure to keep the engine and turbo turbine clean.

Bruce

Bruce,
One doesn't need to monitor CHT in a boat, as they can monitor water temp, but need to know the engine is the right temp.

As for EGT, perhaps a measurement that may or may not be needed. However, it's more of a "relative" measurement whereas the CHT or water temps are absolute. But EGT temps are almost instant for giving information and the water or CHT are slower to respond.

Just FWIW.... my plane monitors the EGT and CHT on every cylinder and I can tell if an issue is developing instantly, and often diagnose it before ever landing. And can later download the info to a computer (with a lot of other data) for diagnosis and trend analysis. I'd like to have that kind of info on a boat.... but not sure if it's that common... or necessary. Perhaps someone can clue me in.

I don't see where the EGT has anything to do with efficiency. Efficiency is measure with fuel consumption and performance.

As for the turbo spinning, I don't know of a turbo engine where the turbo is not spinning, even as the engine is starting. The "control" of a turbo is down stream of the turbo unit with a waste gate that will direct the compressed air into the engine, or overboard depending on the power needed. If it were uncontrolled it would power the engine up to destruction... maybe.

There are a lot different designs of turbo systems, it's hard to explain all of them, other than just the basics. However, they all have the same function... to get more power out of an engine.

 

[jleonard]

I like turbo charged diesels. Had a couple in boats, had them in pickup trucks where they are really fun.
As long as you let them cool a bit, they last a very long time. in a boat make sure the exhaust is designed and built properly to keep the salt water out and they will last a long time.

 

[North Baltic sea]

Baker, Sounds like you have an aviation background, too... Also fun and expensive as boats but not sure which is worse. When we meet sometime, this is a good subject for cocktail hour......can beat it to death.

Agreed the turbo in aviation has a bit different goal than in marine or auto... primarily to give the plane altitude (and provide for pressurization, maybe).

And also agree, they ALL produce heat. You can't compress air like a turbo does without heat, which can be an issue. That's where intercoolers help. Turbo normalizing is the vast minority of planes out there but I like the concept better.... less stress, can use a high compression engine, no "over boost" issues (for the most part) and generally is more economical that a regular turbod engine. Yes the "normalized" turbo maintains sea level pressure but does not increase it, while a regular turbo charger may increase it up to 45 inches or more, which does give more take off power.

But, as to the marine version.... because boats don't fly very high, the turbo is mainly to get more power out of a smaller engine, and there's some merit to that. So, there's no need for a turbo normalized engine in a boat... only on that is boosted above sea level pressure.

But in all turbos, there is an extra part and extra maintenance, so one has to decide if that's a value in his operation. And the percentage of turbo diesels in boats is WAY higher than piston airplanes... so they are VERY popular..... or at least the manufacturers think so.

I'm still not totally sold, but seems like a well maintained turbo diesel isn't an awful bad idea. I'm still leaned on having a bigger engine that's non turbo'd, just like I prefer in aviation. Simple. I'm still waiting to be convinced the turbo is a better deal.

I think that you think fairly narrowly turbo. From the outset intended to improve efficiency and provide more power.

here is a good example. Dald diesel engine 18-22. 33 liter, 220Hp turbo + intercooler, + 5000kg mass. RMP 400-800.

this machine has a 28m trawler vessel weight 110000kg, at a speed of 8 knots consumption of 4-5 gal / hour. 160 g / kwh. I think that the volume of the machine 33 liters vs power 220Hp is quite small. the question why the machine is equipped with a turbo even modestly power? 18-22 The figures come from the cylinder diameter - stroke in centimeters.


Video this diesel.
https://youtu.be/wYm6a6GK82Y

 

[sunchaser]

There are a lot different designs of turbo systems, it's hard to explain all of them, other than just the basics. However, they all have the same function... to get more power out of an engine.

Power in a diesel is only part of the turbos reason for being there. Today, turbos are an essential part of meeting Tier XYZ emissions. The diesel engine manufacturers found out decades ago that by recirculating hot exhaust power gains were achieved and some unwanted pollutants were lowered.

When stricter emission requirements were introduced it became apparent that a combination of off gas measurement, more precise fuel metering, inlet pressure etc all were tied together via on engine chips not only monitoring but changing these variables hundreds of times per second. Without these controls and related hardware (including turbos) today's diesels could not achieve compliance.

You have no choice, buying a new diesel involves buying a turbo. For those few on TF that have FD older vessels, keeping the old NAs diesels going seems a logical choice.

BTW, ever seen a SeaRay with an NA? Me neither.

 

[Seevee]

Power in a diesel is only part of the turbos reason for being there. Today, turbos are an essential part of meeting Tier XYZ emissions. The diesel engine manufacturers found out decades ago that by recirculating hot exhaust power gains were achieved and some unwanted pollutants were lowered.

When stricter emission requirements were introduced it became apparent that a combination of off gas measurement, more precise fuel metering, inlet pressure etc all were tied together via on engine chips not only monitoring but changing these variables hundreds of times per second. Without these controls and related hardware (including turbos) today's diesels could not achieve compliance.

You have no choice, buying a new diesel involves buying a turbo. For those few on TF that have FD older vessels, keeping the old NAs diesels going seems a logical choice.

BTW, ever seen a SeaRay with an NA? Me neither.

Sunchaser,

Good points, didn't know that it was easier with emissions control with a turbo... don't understand why it couldn't be done with a NA engine... they both have exhaust.

SeaRay with an NA (normally aspirated)?? Thousands of them.

Merry Christmas

 

[Baker]

Sunchaser,

Good points, didn't know that it was easier with emissions control with a turbo... don't understand why it couldn't be done with a NA engine... they both have exhaust.

SeaRay with an NA (normally aspirated)?? Thousands of them.

Merry Christmas

The turbo burns more cleanly and therefore less exhaust pollutants.

And his reference to Sea Rays are diesel powered Sea Rays. Have you ever seen a NA diesel powered Sea Ray???