Naturally aspirated, turboed, and intercooled

I have had a question that has been bugging me for several years, but never thought to pose the question to this group. What prompted me to ask this question stems from the fairly regular forum questions pertaining to engine transplants, then adding turbochargers, and even intercoolers. I have seen some 4450's with intercoolers added sitting in dealer's lots or listed on-line. For the sake of conversation, let's back down to a 4050 and it has a naturally aspirated diesel engine, and as I recall, that tractor was rated 105 horsepower at a stock rating. If one was to add a turbocharger to that tractor, but keep the engine at stock horsepower ratings, would that tractor likely see an improvement in fuel efficiency? How about adding an intercooler on top of the turbocharger? How about improvements or changes in how the engine performs with respect to torque? Just wanted to throw this "off the wall question" out to the group to gain some opinions from those who could speak from more in depth experience than I have ever had. Thank you to those who respond, as I look forward to your opinions! By the way................I am not trying to build a tractor such as this! It is just a question that has been in the back of my mind for 15 to 20 years since I first saw a 4450 with an intercooler added.

Here is what I think.

A turbo can increase the HP 1.4 times, less loss due to heating, for each atmosphere (14.7) PSI of boost

An intercooler will reduce the loss due to heating of the compressed air.

Please add or correct as needed.

Adding a turbo to a natural asperated engine (one that did not have a turbo) will increase the power some,,maybe 5-10%,,and help the fuel economy "some"..an "inter cooler" is like a heater core in the intake housing, where engine coolant 'cools' the turbo charged compressed air making it cooler and more dense as it goes into the engine,,I don't think they help all that much,,but some I am sure...the modern engines use a air to air inter cooler which is in front of the radiator,,they are much more eficient..The purpose of these 2 forms of compressed air coolers is to make the air denser,, the turbo charged air is very hot coming off the turbo,, and hot air is not as dense,, to compare think about when your in the top of the hay mow on a hot day and you can't get your breath in all that hot air,,,,then think about a cold December day and you walk out side and take a deep breath and it hurts your throat,, that is sort of a comperison...more air can be packed into the mix of fuel when it's cooler, thus helping to make power.. others can add to this to help you understand..

To the OP, I think for your scenario to be realized may take more, earlier intervention. Yes, you could make 105 horsepower with a turbocharged engine with or with out an aftercooler . Adding the turbo to the stock, naturally aspirated engine without raising power output would require you to turn down the fuel since the turbo would pack more air into the cylinder- I'm not sure you could back off by 40% as David G suggests without an injector or pump change. In fact, you may actually be able to make that 105 hp with the same fuel setting and turbo from just 5 cylinders or even 4, requiring an even earlier, more drastic engineering adjustment.

That's one of the reasons turbos are so common, the manufacturers can build one or two basic engines and fill the power spaces by adding a turbo: 3cyl, 3cylT, 4cyl, 4 cylT etc. It seems at first blush to be pushing the turbo engines that much harder, but my experience (admittedly limited) is that they still hold up well in the long run.

What kind of boost do the JD engines run?

My truck typically runs about 5-10 PSI, with the most I have seen is 30 PSI for a moment.

Near every thing has a turbo now days,, My Hot Rod Lincoln has 2 of them, one on each bank of a 3.8 6 cylinder,,all stock, like the Eco-boost 150's,,and it is a power house..

The HP gains have to have fuel to back up the air, thing to remember, if it smokes it is not converting all the fuel into HP.

Yes all things need to be in harmony as you increase the power systems,,and like the old guys would say "Faster horses need better Wagons"

Your question if adding a turbo but maintaining the same power level would improve efficiency depends on how much un-burned fuel was being blown out in the exhaust of the naturally aspirated engine. If at a given fueling rate ALL the fuel is getting burned than increasing the boost or cooling the incoming air won't increase efficiency; you'd just be expending energy to compress air that isn't needed for combustion. Typically this isn't the case, however, and the black smoke you see out of many diesels is the product of incomplete combustion meaning not all the energy is being extracted from the fuel. More boost and more dense air from aftercooling allows more of the fuel to be burned to produce more power and/or increase efficiency. The side effect of too much air relative to fuel, though, is increased NOX emissions since the surplus oxygen not used for combustion readily combines with the air's nitrogen under the high combustion temperatures. This is where exhaust gas recirculation (EGR) comes in which dilutes the air with exhaust gas which is lower in oxygen levels. And, as Tim S said, the air out of a high-boost turbo is incredibly hot (350 F or more) and aftercooling gets rid of this heat before it can compound the NOX problem in the combustion chamber.

As Tim said, you won't gain much by adding a turbo to a Naturally Aspirated engine in stock form. If you add the turbo and then turn on the fuel screw, you'll have more fuel AND air in the combustion chamber and it will net you more power.

Turbochargers create heat when they pressurize the air. the more pressure, the more heat. When you start getting over 15 psi, it's best to run the charge air through a jacket water aftercooler or even better an air to air aftercooler.

Tractors that run turbochargers are generally more efficient, because they burn every last bit of fuel that is being introduced into the engine. Putting a turbo on an engine that's going to stay with stock fuel settings won't net you much more efficiency or power.

Another thing to consider is when the factory started adding goodies and upping the power they always made changes you can't see inside of the engine too. Things like larger piston pins and piston oil coolers and maybe different compression ratios come to mind.

Yes Mike that was part of the mix as they made little things a bit stronger to deal with the extra power. Most tractors back then had stronger conponents than needed,,they were a bit "over built"..and could deal with a lot more power than they came with...

study the Carnot efficiency of the Brayton heat engine with the common examples of the gas turbine , Otto gasoline engine or the Diesel engine .
Generally It's all about heat and heat's ability to make trapped gasses build pressure and want to expand back to atmosphic pressure .
A partly loaded diesel, gas turbine or firebox heating a boiler/heat exchanger. If the air fuel mixture is too lean , which is due to excess "air". Flowing full power airflow with part throttle fuel flow is a waste of heat. as the energy used to make the heat is lost up the stack.
Take a look at the Nebraska tractor tests of any diesel tractor at 75% power vs 100% power. Far greater thermal efficiency at 100% power.
Not nearly as pronounced on throttled engines such as spark ignition engines . There are on occasion throttled diesel designs out there . Also some throttled gas turbine engines operating power generating plants.
Throttled engines are for variable speeds , variable loads , idling and part loads. The gas turbine , boiler and diesel have the highest thermal efficiency at continuous full rated power .
turbo boost on a diesel operating at a part load is a waste. Adds exhaust system back pressure and flows even more wasted extra air through the combustion chamber.
The "power" of a diesel or gas turbine for that matter . Is the difference in the mean pressure of the compression stroke. And the mean pressure of the expansion stroke .
The same diesel or gas turbine burning the same amount of fuel , at the same rpm but having intake air entering the engine at 100F instead of 500F. The gasses in the combustion chamber will have a greater mean pressure difference between the compression stroke and the expansion/power stroke .in the engine with the 100F intake air vs the lower efficiency engines with 500F intake air.
Hence the use of intercoolers for thermal Efficiency gains. Intercoolers also tend to limit max combustion chamber temperatures . This reduces metal thermal failure and production of NOX in the exhaust.

The 4050 also offered the 359T which was very fuel efficient.Turbo charged engines are quieter and are more efficient.Engines that are designed for more H.P.are usually built with that in mind.

The smaller engine has less combustion chamber wall area to loose heat through .
The same HP small turbo engine will have superior part load efficiency vs the same HP NA engine at part load.

Didnt the 4050 come with two different engines , the one with the 466 non turbo, used a lot of fuel, my cousin had one, it was a good tractor, but later on they came with a smaller cubic inch engine and was more fuel effecient.

You'r right on the money Tim, Agree totally.

Thanks

Early 4050 had non-turboed 466. Later ones had turboed 359 I believe. Was the same engine as European 4040.
I don't know how efficient it was in a 4050 but it surely wasn't in the 4040. Then again it could have been
running 120 HP instead of the lower HP 404 on the US 4040. The earlier 4050 seems to be more desirable
and in higher demand.
Turbo won't increase power significantly w/o increasing fuel delivery. Deere hot water intercooler would not
be as efficient as an air to air cooler and of no value unless running high HP if then.
I know a guy who has two 4240 which were the non-turboed 466 who has experimented with inline pumps and turboes.
He now runs them w/inline pumps and no turboes at 130 HP and no smoke.

Maybe not especially relevant here, but I added an intercooler to my 7.3 powerstroke to reduce the combustion chamber temp...allowing more fuel without overheating the pistons