Small Diesel Engines - Natural Aspiration vs Turbo Charged?

[welyell]

I'm not looking at a specific manufacturer, just seeking general information on aspects of Naturally Aspirated vs Turbo Charged diesel engines in the 45 to 65 HP range. I understand that turbo chargers increase horsepower and "think" I understand that turbo charging also increases engine efficiency at high altitudes (not an issue for me, I'm close to sea level), so my current questions are:

Question #1 - Does turbo charging decrease the service life of the engine?
Question #2 - Which engine (of the same HP) gets better fuel efficiency?
Question #3 - Are there any significant differences in engine maintenance requirements between the two types?
Question #4 - Are there any significant differences on how well the DPF functions perform between the two types

Thanks in Advance

 

[ericm979]

Turbos can be harder on oil due to the high temps in the turbo. I use synthetic and change the oil more frequently on my gas turbo cars. The turbo takes heat out of the exhaust. Some smaller turbo CUTs like the Kubota B3350 can have more difficulties getting the DPF up to temp for regens. It's probably not an issue in the HP range you're looking at. Turbos go well with diesel. There's a reason that there's no NA road diesels.

I love turbo cars but I bought a NA tractor. The main advantage of a turbo is a higher power/weight ratio and for a CUT weight is good, not bad. The turbo is not a big issue in my opionion- if the CUT I'd wanted had a turbo it would not have discouraged me.

 

[welyell]

Turbos can be harder on oil due to the high temps in the turbo. I use synthetic and change the oil more frequently on my gas turbo cars. The turbo takes heat out of the exhaust. Some smaller turbo CUTs like the Kubota B3350 can have more difficulties getting the DPF up to temp for regens. It's probably not an issue in the HP range you're looking at. Turbos go well with diesel. There's a reason that there's no NA road diesels.

I love turbo cars but I bought a NA tractor. The main advantage of a turbo is a higher power/weight ratio and for a CUT weight is good, not bad. The turbo is not a big issue in my opionion- if the CUT I'd wanted had a turbo it would not have discouraged me.

Thanks - I hadn't considered the weight factor and from all my reading on the forums here, everyone says more weight is a good thing

 

[Agvg]

A lot of non turbo tractors can be very lazy, very few want to drive a diesel car without turbo, it's the same with tractors. Compare torque and rpm.

 

[Industrial Toys]

I have quite a bunch of Diesels. Only my Duramax and JD 6200 are turbo. I'm glad I don't have more, given my stuff is old, and turbo repair is expensive. Plus, I have never felt any of my other stuff lacked power or performance.

To me, the best is a low hour, non computerized, non turbo diesel. Oh, and preferably Japanese.

It's really becoming apparent to me, that the more stuff I have, this is bullet proof and reliable and doesn't make me have to count on (or pay) someone else, the absolute better.

 

[DieselBound]

I have four turbo diesel cars, one turbo diesel truck and one turbo diesel tractor. Two of my cars (I picked up a "newer" car [2003] and it'll replace an older one [2000]) have about 220k miles, one has just under 180k and the other about 161k. Not a single turbo issue. Truck I just got recently, a 94 12v Cummins; about 192k miles and no concerns here either.

My cars, VW TDIS, are 15 and 18 years old. Not a single computer issue. These cars are solid. The ALH engine is as good a diesel as has ever been made. VW spec'd oil change intervals, with conventional oil being the oil-of-the-day at the time, at 10k miles. I go by that interval, but have luxury of newer/better oils (CJ-4 works great in everything I have).

I have three non-turbo diesels: my B7800, my Polaris Brutus (UTV) and my generator. Generator doesn't need a turbo. The B7800 is OK. UTV manages: the HST makes it feel even more piggish, but it don't need to be a rocket anyway. I DO love those Kubota engines. The Yanmar engine i(Polaris) s noisy as heck.

My generator was manufactured in 1994. The engine, a Kubota, is totally mechanical: now has 670 hours on it (they're known to go 20k hours). BUT, there's all the electrical generation and control bits: had to retrofit a replacement voltage regulator as the original one failed. This is emergency stuff, which SHOULD be as robust as possible.

Turbos get you a good bump in torque: my cars (with some mild performance mods) put out more torque per liter than a new Dodge Cummins.

It's more how the fueling is done that makes the difference. In IDI (Indirect Injection) engines a turbo can only make a small increase in power. Id DI (Direct Injection) engines it's a different story. Someone put a turbo on a UTV like mine and he spent a LOT of money doing so and it only got him a bit more power.

Had an IDI Ford truck. It was a pig. I'd always wanted more power but I knew it would cost a lot for only a small gain. Had a head gasket go on it and decided that that was that: bought a 12v Cummins- far superior engine, DI a and with turbo (when I get a proper clutch in it I'm going to bump power [with no concerns for longevity]).

 

[big bubba]

i've seen recommendations to let the engine idle for a few minutes to cool down turbo after working it. i've also heard it said that to prevent pinwheeling of the turbo in transporting tractor, block off the stack. not an issue for me, the tractor stays put.

 

[Nick359]

I have a few turbo and NA diesels. It depends what you want to do. Turbo diesels seem to accelerate faster and not bog as much with less foot pedal. It isn't just how much pedal is towards the floor. They put more fuel as boost pressure increases. My John Deere 955 and Mustang 940 were fine NA. My 755 was a little slow on the hills, so I put a turbo on it. After I added the turbo, I also turned up the fuel pressure. If your diesel is blowing smoke you are wasting fuel. Turbos put more are in, so they can burn the fuel. I have a few old military trucks. They are slow and under powered with and with out turbos. The turbo trucks sound mean though. The government put turbos on those for emission reasons not performance.
A turbo or supercharger uses more fuel with boost. To make a long story short it gives a smaller cubic inch engine more cubes. They force more air in. You are burning more fuel under boost. If you properly size an engine they will have similar fuel usage. My wife's twin turbo Caddy gets great mileage when you are easy on it. When it sees 15 psi of boost you are burning fuel. It is a 3.6 v6 that gets 26 to 28 highway, but can still muster 12s in the quarter.

 

[DieselBound]

If you're running an engine hard it's always a good idea to idle down for a bit. Yeah, turbos build up a lot of heat, but modern designs and oils do a very good job of mitigating that heat. On my cars I don't bother letting them idle-down unless I've just had them spooled up hard.

I'd be interested in hearing whether any manufacture discusses the transport issue. Wouldn't think that enough pressure could be built up to cause excessive/damaging forces to the turbo (the turbo's shaft will, unless it's been run dry, in which case it's likely been killed!, cook off residual oil).

 

[DieselBound]

I have a few turbo and NA diesels. It depends what you want to do. Turbo diesels seem to accelerate faster and not bog as much with less foot pedal. It isn't just how much pedal is towards the floor. They put more fuel as boost pressure increases. My John Deere 955 and Mustang 940 were fine NA. My 755 was a little slow on the hills, so I put a turbo on it. After I added the turbo, I also turned up the fuel pressure. If your diesel is blowing smoke you are wasting fuel. Turbos put more are in, so they can burn the fuel. I have a few old military trucks. They are slow and under powered with and with out turbos. The turbo trucks sound mean though. The government put turbos on those for emission reasons not performance.
A turbo or supercharger uses more fuel with boost. To make a long story short it gives a smaller cubic inch engine more cubes. They force more air in. You are burning more fuel under boost. If you properly size an engine they will have similar fuel usage. My wife's twin turbo Caddy gets great mileage when you are easy on it. When it sees 15 psi of boost you are burning fuel. It is a 3.6 v6 that gets 26 to 28 highway, but can still muster 12s in the quarter.

As I mentioned, what matters most is how the fuel is delivered. IDI engines are outright pigs. Adding turbos is mostly just a waste of money: the fuel pathways just cannot take advantage of the extra air like direct injection can. DI plus turbo MAKE diesels diesels! One can have an DI NA w/o a turbo.

My VWs won't run 12s in the 1/4 mile (though folks over in the UK run a 2.0 literr PD engine and are running in the 9s bracket), but they do average over 50mpg (my car has averaged 50.6 mpg over the course of 60k+ miles since I've owned it- and it's got performance mods that I don't hesitate to use- IMO getting a big torque rush is far easier and fun than doing a long, fast high speed run (there's always someone out there faster, but very few vehicles out there that can get the mileage I get when on the highways [I'd pull out my 6spd ALH for a real challenge 60+mpg at 70 mph].