To turbo or not to turbo?

[Bruce B]

OK,
I'll begin this.
It appears that we have proponents of turbochargers and we have people who dislike the very thought of their existence!
Where do you stand and why?
Having begun my career in automobile repair back in the early 1980's working as a Saab mechanic I had some fun exposure to those early Garrett T3 units bolted to the 1978 and later Saab Turbo. I maintained them and I repaired them including more than a few bench rebuilds.
They are pretty simple things really. Good oil changes and proper use went a long way to making them nearly bulletproof. I've also worked on a pile of VW 4, 5 and 6 cylinder turbo Diesel engines.
I found that like most mechanical systems, turbo engine lifespan comes down to use and maintenance first. The same things that lead to turbo engine demise will hasten any engine towards its end of life.
I've seen people who could destroy a Toyota Corolla in just a few years and I've seen people who could milk 200,000 out of a 1970's GM/Olds diesel.
I vote that turbos are fine.
What say you?

 

[MurrayM]

I'm a slope foreheaded, uni-browed, knuckle dragging lout when it comes to mechanical things, so I read the manual for our Yanmar 4JH2-UTE engine.

It gives instruction on how, if running at a fast idle for a prolonged period, to run it at a faster rpm for a certain length of time...I'm assuming this is to clean the turbo, among other things...

Would idleing for prolonged periods, such as battery charging or trolling for salmon, be a major reason why turbos fail?

Looking forward to more in depth answers.

 

[Bruce B]

I'm a slope foreheaded, uni-browed, knuckle dragging lout when it comes to mechanical things, so I read the manual for our Yanmar 4JH2-UTE engine.

It gives instruction on how, if running at a fast idle for a prolonged period, to run it at a faster rpm for a certain length of time...I'm assuming this is to clean the turbo, among other things...

Would idleing for prolonged periods, such as battery charging or trolling for salmon, be a major reason why turbos fail?

Looking forward to more in depth answers.

Running any Diesel engine for long periods without "proper" load is bad for the engine, turbo or no turbo. We used to have to charge batteries on our sailboat (40 hp Yanmar) and I hated doing it! I finally found a way to install a proper 4 kW generator for charging and air conditioning duties...

By the way, the manual for our 40 hp naturally aspirated Yanmar used the same language about running at higher speeds after extended no load operation.
My answer was to run it hard when we were actually using it for propulsion.
Bruce

 

[DavidM]

Well, the question is becoming moot, as you can't buy a non turbo engine today from a major manufacturer unless it is under 100 hp.

And I guess the beef if any with turbo engines is that they produce too much horsepower for the size. An older Ford Lehman or Perkins 6.354 is limited to 135 hp from its 5.8 liter engine with no turbo.

Today you can get 450 hp or so out of the same dispacement with a turbo and sea water cooled after cooler.

It isn't the turbo per se that is the problem with these engines, it is the high horsepower output and the associated after cooler failures that breaks them.

But if you keep the horsepower down to reasonable levels, turbos are no problem. One of the best medium horsepower engines available is the Cummins 210 hp 6BT with no after cooler.

Another factor that gives turbos a bad rep is salt water. I see lots and lots of reports of the owner replacing his turbo and assuming that this is something you just have to do. Well you don't usually replace turbos on auto or truck engines even after 10,000 hours. But owners do it all of the time on marine engines, usually because a lousy exhaust system allowed sea water to back up into them.

So, turbos are fine. It is all the baggage that goes with them that isn't so good.

David

 

[Bruce B]

David,
The exhaust system is the subject of much verbiage on the Seaboard Marine website. Apparently, many, many boats are built with flawed exhaust systems.
It is actually interesting reading material.
I am a maintenance kind of guy so I will be keeping an eye on the aftercoolers in our new Cummins QSB and I will surely disassemble them and lubricate seals the minute it gets home!

I've said it before, so many boat owners keep their equipment in such poor shape that I am amazed that boats run at all!
Maintenance is key! Then most other failures should come down to acceptable levels.
Bruce

 

[Bruce B]

On the subject of maintenance, my last marine diesel, pictured here at 10 years of age and at about 1800 hours, saw the following annual maintenance...

Replace engine oil and filter.
Replace fuel filters.
Replace alternator drive belt.
Replace raw water pump impeller.
Adjust valves.
Remove and inspect exhaust riser.
Check all raw water hoses and clamps.
Disassemble and clean engine heat exchanger.
Replace thermostat (every second or third year)
Drain antifreeze and replace.
Inspect all electrical connections in engine harness.
Wash engine with Roll-Off and water.
Run engine until dry and then spray entire engine down with WD-40. Wipe down
engine surfaces of excess WD-40.

This was my normal engine to-do-list, every year.
The picture of our engine was taken midway through a 6 week trip to Maine. This is the way it looks all of the time. No rust, no leaks no issues. Most people say it looks better at 11 years of age than a typical 1 year old boat.
I like leaving nothing to chance but I do not believe that a turbo would have made any difference in this engines reliability.
Bruce

 

[eyschulman]

David,
The exhaust system is the subject of much verbiage on the Seaboard Marine website. Apparently, many, many boats are built with flawed exhaust systems.
It is actually interesting reading material.
I am a maintenance kind of guy so I will be keeping an eye on the aftercoolers in our new Cummins QSB and I will surely disassemble them and lubricate seals the minute it gets home!

I've said it before, so many boat owners keep their equipment in such poor shape that I am amazed that boats run at all!
Maintenance is key! Then most other failures should come down to acceptable levels.
Bruce

The exhaust SX issue hits the nail square on. The other issue is not allowing a turbo a cool down at lower rpm after hard running. All other issues are pretty much routine engine maintenance. Most trawlers which invariably are equipped with bigger engines than needed and are running below hull speed may not even engage the turbos which are usually designed to kick in at higher load. SD hulls that can travel faster will benefit from the larger turbo engines where the turbo will kick in and give extra boost at the higher speeds.For ecology and power output reasons new motors have or will soon have turbos unless you go low hp and that may also change soon. Best to learn what you need to know about the units because like computers it will be hard to avoid them.

 

[Lou_tribal]

As you ask for opinion I will give!
About cars first... No turbo,never, ever! The problem with turbo is the rpm. When you are low rpm you don't have any power at all. If you drive a turbocharged car you need to be sure to always be high rpm as if you go low you loose all the power. I am not professional driver at all but sport car lover. I love the flat 6 in my car, it kicks your ass at any rpm, no need for a turbo. Not a general rule but usually turbocharger are used for emission rules and try to compensate underpowered engines.
On trawler now. Don't think the same apply as the need for power is really not the same. Turbocharged marine engine are a way to have smaller engine delivering the needed power and meet emission regulations. However for me it is also introducing a failure point in the equation. Is it really needed, I do not think so. Do you really need 500 hp on a trawler? It depends on the boat but for mine my straight old naturally aspirated 6 is doing a great job and far enough for the need. I saw some trawler running on 60hp or 70hp and they were going nice and slow like it should be.

 

[Bay Pelican]

Turbo or non-turbo. Like everything else on a boat it depends on what you are going to use it for. A turbo when you are running the ICW on the east coast of the US, or daytripping out of any harbor is one thing. A single engine turbo crossing an ocean is one more thing that can break.

My preference is simplicity when crossing oceans. I have a Yanmar wing engine that can be started with a hand crank.

 

[Bruce B]

Turbo or non-turbo. Like everything else on a boat it depends on what you are going to use it for. A turbo when you are running the ICW on the east coast of the US, or daytripping out of any harbor is one thing. A single engine turbo crossing an ocean is one more thing that can break.

My preference is simplicity when crossing oceans. I have a Yanmar wing engine that can be started with a hand crank.

So here is an argument for simplicity.
I've started Yanmar QM series with a hand crank and although it started, it wasn't easy and I'm not sure that with my damaged rotator cuff I could do it today...

I do understand the argument for simplicity though as if it isn't there it can't break can it?
Bruce

 

[psneeld]

While I am not worried about turbos..having run many thousands of hours with and without them....

I have had one failure on a brand new Cat where it threw a blade on a a trip to the fuel dock for a delivery to the new owner the next day.

I also had a Cat Aftercooler that leaked into the 5 and 6 cylinders and it needed a rebuild, that was on a delivery. CAT had a class action lawsuit for those after coolers and made good...but the engine still needed rebuilding and delayed the delivery for a month.

So I do agree that more pieces equal more chances of failure, I see these failures being the equivalent to being hit by lightning.

I know some here like to risk manage to the point of nearly not getting underway...but turbos and their systems if maintained are not a likely source of being stopped dead in your tracks.

 

[BandB]

Turbo. For me, it's very simple.

I've never owned a diesel that wasn't turbo. I've never had any issues with a turbo engine. They only manufacture turbo engines in the size and for the boats I want. Simplicity.

 

[Seevee]

Bruce,

Thx for starting this thread.

As for me, I'm in the camp where I don't want one on most any engine. It's just one more failure point and does need maintenance.

Most of my turbo experience is on aircraft, and my Marine experience is minimal. In the aviation world turbos offer a LOT of performance that you just don't get without one. A lot better climb and altitude capability, and once higher up, more speed. They typically last about 1500 hours and you rebuild them for perhaps $3 to $4K, so they are not horribly expensive.

But they do have a higher failure rate. Wheel failures, oil line failure, oil pressure failure, and occasionally the failure can be exciting with fire in the engine compartment. These things are HOT, and a oil line bursting over a hot turbo is not fun. I've had 4 turbo chargers on planes and only one failure which was an oil line breakage, but a non event. (aviation mechanic and pilot).

For cars I've had one, inherited it, from mother in law, immaculate but pricey. Son in law destroyed it in a month, burned up the turbo.

My boat experience was with friends 450 Sundancer, with cats. I spend a lot of time on it and helped with the maintenance. The turbos needed TLC and one had to watch them. Caught a clamp loosening up a bit, but no major issue. I couldn't imagine operating one without an intercooler.... that compresses air is awful hot.

Overall, I'd MUCH rather have a bigger engine instead of a small/turbo'd one. Seems like operating the turbo at slows speeds has more issues that a larger engine, do I get that right?

However, seems like an awful lot of marine diesels do have turbos. I don't understand how the turbo allows for a better EPA profile, can someone explain that?

 

[kmacdonald]

It depends on a lot of factors and the answer will be yes sometimes and no in other situations. It comes down to application.

 

[MurrayM]

Running any Diesel engine for long periods without "proper" load is bad for the engine, turbo or no turbo. We used to have to charge batteries on our sailboat (40 hp Yanmar) and I hated doing it! I finally found a way to install a proper 4 kW generator for charging and air conditioning duties...

By the way, the manual for our 40 hp naturally aspirated Yanmar used the same language about running at higher speeds after extended no load operation.
My answer was to run it hard when we were actually using it for propulsion.
Bruce

We don't charge at idle either, or troll for salmon. Our electrical needs at anchor are small, and battery charging is much faster now while underway after getting a larger alternator and cables.

Engine is nowhere as squeaky clean as yours, but is running great.

 

[Bruce B]

Turbo. For me, it's very simple.

I've never owned a diesel that wasn't turbo. I've never had any issues with a turbo engine. They only manufacture turbo engines in the size and for the boats I want. Simplicity.

That is simple!
We are in the same boat, so to speak, at least as we look forward.
Plus, I kind of like the whistle of a turbo under boost.
Bruce

 

[Fletcher500]

If turbo's were a reliability issue, they wouldn't use them on these.

 

[Bruce B]

We don't charge at idle either, or troll for salmon. Our electrical needs at anchor are small, and battery charging is much faster now while underway after getting a larger alternator and cables.

Engine is nowhere as squeaky clean as yours, but is running great.

The Cummins in our new boat is white. I'm going to have to up my game! That Yanmar is "squeaky clean" though...
It makes me happy!
Bruce

 

[BruceK]

As you ask for opinion I will give!
About cars first... No turbo,never, ever! The problem with turbo is the rpm. When you are low rpm you don't have any power at all. If you drive a turbocharged car you need to be sure to always be high rpm as if you go low you loose all the power....
On trawler now. Don't think the same apply as the need for power is really not the same....
Do you really need 500 hp on a trawler? It depends on the boat but for mine my straight old naturally aspirated 6 is doing a great job and far enough for the need. I saw some trawler running on 60hp or 70hp and they were going nice and slow like it should be.

As to turbo cars, disagree, my turbo diesel car has heaps of torque and power and response down low. Plenty of (non exotic)performance cars have a diesel option.
As to boats, agree. I`d rather a big slow revving naturally aspirated diesel than a high rpm turbo diesel, it`s just another layer of maintenance and potential for trouble. But, as said above, for new engines, no non turbo option.

 

[BandB]

As to turbo cars, disagree, my turbo diesel car has heaps of torque and power and response down low. Plenty of (non exotic)performance cars have a diesel option.
As to boats, agree. I`d rather a big slow revving naturally aspirated diesel than a high rpm turbo diesel, it`s just another layer of maintenance and potential for trouble. But, as said above, for new engines, no non turbo option.

Wifey B: My turbo car has power at all rpm's. 530 hp or so, 0 to 60 in 3 seconds.

 

[Bruce B]

So, one observation... There is a difference in engines that modern design practices bring to the table. Once upon a time, engineers made things strong by adding material. Today, with CAD design, this is no longer as necessary. Even engines designed in the days before modern CAD that are still in production benefit from constant upgrades driven by newer technologies. Certainly the Cummins QSB6.7 is much different from its predecessors...and it appears to be very reliable in its current form.
So, the question of "turbo or not" might change depending on the age of the engine in question...
Bruce

 

[Bruce B]

Wifey B: My turbo car has power at all rpm's. 530 hp or so, 0 to 60 in 3 seconds.

That must be one hell f a grocery getter!
Forgive me, that was sexist wasn't it?!?!
Bruce

 

[BruceK]

Wifey B: My turbo car has power at all rpm's. 530 hp or so, 0 to 60 in 3 seconds.

But is it a diesel? And not "exotic"?

 

[BandB]

But is it a diesel? And not "exotic"?

Wifey B: It won't hold many groceries, but then I don't do much grocery shopping. Not a diesel. Define exotic It's a production car, not a custom build.

 

[Lou_tribal]

As to turbo cars, disagree, my turbo diesel car has heaps of torque and power and response down low. Plenty of (non exotic)performance cars have a diesel option.
As to boats, agree. I`d rather a big slow revving naturally aspirated diesel than a high rpm turbo diesel, it`s just another layer of maintenance and potential for trouble. But, as said above, for new engines, no non turbo option.

Of course not talking about high end sportcar where a turbo is not there to be able to have a smaller engine but there to increase power output from an already hyper powerful engine. But most of the case, the goal of adding turbo to a car engine is not to get a diabolic engine, it is only to be able to get more from a smaller, lighter engine and increase fuel efficiency.

Do a test, take a production car, outside any supercar, start than put immediately your car in 4th or 5th gear, and try to accelerate to 100km/h, with a turbo charged engine you will need an eternity, and it is totally normal as you will fall in low rpm when shifting to 5th and the turbo won't be able to kickin and the engine will loose all power. Do the same with non turbocharged. You will see the difference.
Diesel have more torque than gas engine for sure. But generally speaking take two diesel engines of same hp, the one without turbo will have far more torque at low rpm than the other.
Where you can notice this difference is driving in mountain road. If going up in a pass in the Alps, and did it plenty of times with and without turbocharged car, with turbo charged one, you take a turn and miss a shift you are screwed.

But again, everything is depending on the base engine that is turbocharged and the goal to it. Some are good some are not.

 

[Ski in NC]

Turbocharged is the way to go with marine diesels. If you want say 100hp at cruise, you could do it with a 4 liter with a turbo, or a 6 liter without. More parasitic losses with the bigger non-turbo engine. The turbo engine will do the job for less fuel. Pretty much all engines on the market now over 100hp are turbo.

Problem with trawlers is that many engines are spec'd for planing out, and if you are not going to run like that, the turbo and extra engine size is rather pointless. But most of the time you pick a boat and deal with the engine someone else spec'd.

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.

When I built my boat I estimated that it would need 250hp to cruise 20kts. I picked an engine rated at 450hp, turbo of course, figuring it would have a happy life at 250hp. So far, so good. Turns out the boat is a little more slippery than estimated, 20kts is about 220hp which I could safely have done with a six liter engine. But it is fun to go fast some times!!

At slow speed the turbo does nothing. The engine there at 8.3 liter is not much different than a 6.6 liter Ford natural.

Whether an engine is turbo or not is WAY down on my list of things to worry about.

 

[smitty477]

Mostly found that turbo's add efficiency and power when needed in both cars and trucks in various makes both gas and diesel. Similarly in boats I generally favor the turbo versions as they have always been clean runners and ran great for us.

 

[smitty477]

"Do a test, take a production car, outside any supercar, start than put immediately your car in 4th or 5th gear, and try to accelerate to 100km/h, with a turbo charged engine you will need an eternity, and it is totally normal as you will fall in low rpm when shifting to 5th and the turbo won't be able to kickin and the engine will loose all power. Do the same with non turbocharged. You will see the difference"


You could do the same test with various sizes/hp of regular non-turbo gas engine options in the same vehicle. When comparing this test in say a Checy pickup one with a base 6 cyl vs another with a 502 V-8 the same results would happen. Your just seeing the results of power available and the gearing you are forcing onto the experiment.

 

[Nomad Willy]

My turbo Jetta had plenty of torque but there was a lag and it was midrange. It was an issue but a very monor one. The midrange power was really strong. My present 5cyl Jetta is 600cc bigger, same power but absolutely flat power curve. Very precictable. Of the two engines In a boat I'd opt for the turbo. For my car definitely the 5cyl non turbo.

In Alaska I was an operator in a powerhouse w a new (almost) 1500hp eight cyl Enterprise engine. This was 1960 and it had a turbo and the big E ran at about 75% load 25% of the time. Very little turbo noise.

 

[Baker]

Wifey B: My turbo car has power at all rpm's. 530 hp or so, 0 to 60 in 3 seconds.

I was about to say....most modern day turbocharged cars have no turbo lag.

To answer the OP, it is all a matter of application...as someone has already said. If you need "power density" there is no better choice than to turbocharge.

My choice in a car would be V8 NA. I just love the roar of an American made V8....like the modern Chevy small blocks. Turbochargers inherently muffle that exhaust note. Some people like that whoosh noise of a turbocharged car. I like the roar.

As it applies to boats...I would prefer NA if I am going slow. Nothing wrong with something like a Lehman 135. But if you want to go on plane in a larger powerboat, you don't have a choice than to go with boost.