turbo 3 vs. natural 4 cylinder price/performance?

[MessickFarmEqu]

</font><font color="blue" class="small">(
As far as maintenance goes, how many people on TBN even wait for the recommended service interval?
)</font>

You can probably make this statement about TBN, however the VAST majority of people do a horrific job of keeping up with the maintance, especialy those who own CUT's as they tend to be people who are not super experienced with machinery.

In my opinion, the whole turbo thing is a marking ploy. Its too early to make some of the judgments people are trying to come to. We need to see more about the product to know and more importantly the pricing. I think a better idea would be to make a bolt on turbo completly optional. That way you can buy a non-turbo version and add it on if you feel you need the power.

 

[milkman]

Even the KISS. rule fails sometime /forums/images/graemlins/blush.gif but gotta admit, never seen one of these eat a turbo, or throw a rod.

 

[BillyP]

Here's a few specs on the JD 4710 vs the 4720.

4710
Engine (4 cylinder)-Yanmar 4TNE88
Displacement-133 cu. in.
Rated Engine Speed-2600
Gross Horsepower-46.3
Gross PTO Horsepower (w/hydro)-38.5
Engine Torque At Rated Speed-86 lb-ft
Maximum Torque @1,700 rpm-108 lb-ft

4720
Engine (4 cylinder)-John Deere 4024T (Turbo)
Displacement-149 cu. in.
Rated Engine Speed-2400
Gross Horsepower-58.1
Gross PTO Horsepower (w/hydro)-50
Engine Torque At Rated Speed-124 lb-ft
Maximum Torque @1440 rpm-155 lb-ft

The 4024T has a 12% larger engine but delivers 30% more gross PTO HP and 44% more torque. All of this increase in HP and torque is acheived at a lower RPM.

This doesn't really tell the story but it may give some information. What would be nice is to have 2 identical engines, one turbo and one without.

 

[ZJ_HR]

<font color="blue"> This doesn't really tell the story but it may give some information. What would be nice is to have 2 identical engines, one turbo and one without. </font>

Billy,
I have information about what you asked, and I guess that it will be interesting.
Data are about compact ag tractors, but relation is similar to any other engine.
As you can see from my logo, I'm SAME fan, so it was easiest for me to collect data about them (I don't want to bother anybody with tractors from other brand) /forums/images/graemlins/wink.gif

Engines mentioned are SAME DIESEL, direct injected, air or water cooled.

 

[BillyP]

From what I see you get a 27% more torque @ 1400 rpm and 15% more @ 2350 rpm, yet use 10% less fuel. On top of that you get a 13% better torque rise. Not a bad deal.

 

[yellowsocks93]

I can't imagine not having the turbo on our JD 5320 with cab. Too heavy and not enough pulling power without. I don't think a 5220 basically same motor minus the turbo would cut it, for the thick grass the flail mower chews up and other farm chores. Our motor seems to be a little snapper than the non turbos on the 5000 series I drive at work. I can go without a turbo on the 990 for now.

 

[kybota]

I'd like to admit a mistake I made when I started this thread, even though the query is still relevant to my buying decision.

The turbo I had driven earlier that day was a 4 cylinder turbo Kioti DK50. Several weeks earlier the dealer had given me one of those comparison guides that line up their models with Kubota, JD and NH. Given my fading memory, I had confused it with their turbo 3 cylinder model, the DK65 producing 64.4 gross hp. The DK50 is a 4 cylinder turbo producing 49 horsepower (the DK50 has much smaller displacement, 2000cc vs. 2700cc).

Since the turbo appeared to be the most distinquishing feature between the models I was considering, the non-turbo 45hp DK45 and the 49 hp DK50 I wondered what the performance/price issues would be between those two models.

 

[Evasive1]

</font><font color="blue" class="small">( <font color="blue"> This doesn't really tell the story but it may give some information. What would be nice is to have 2 identical engines, one turbo and one without. </font> . )</font>

The Century 3035 and 3040 or Branson 3520 and 4020 both use the Kukje 3T90L diesel engine. The 35 hp model is normally aspirated and the 40 hp model is turbo. They are both listed as 110 cu.in displacement with the same bore/stroke. I do not know the torque ratings for these engines for comparison but I bet someone in TBN land does.

One really interesting thing is the fuel economy. The aspirated engine has a capable working hour rating under maximum load of 4.1 hours. The turbo model has a working hour rating under maximum load of 3.6 hours per tank of fuel.

When you jump to the 45 hp Century/Branson (Yanmar engine model) it uses the Yanmar 4TNE88 engine like the John Deer 4710 and its hour rating per tank of fuel is 4.1 hours. This is a 4 cylinder engine 133 cu. in. displacement with 5 more horsepower than the turbo, yet gets 12% better fuel economy.

Is this relavent? Doubt it, but thought it was interesting when it came to fuel economy.

 

[bam747]

I too have been considering the advantages and disadvantages of turbo versus naturally aspirated engines but with the specific concern of horse power loss versus altitude. Since I live at 7000 ft in Colorado, this altitude loss of HP is a significant concern.

A rule of thumb I seem to remember is that naturally aspirated engines loose 3% of their rated HP per 1000 feet of elevation gain while turbo charged engines loose only 1% per 1000 feet.

If this is correct, then a nominal 50 PTO HP naturally aspirated tractor as specified at sea level will only produce 39.5 PTO HP at 7000 feet (3% per 1000 feet times 7000 feet or a 21% loss) while the same 50 PTO HP turbo charged tractor will produce 46.5 HP at the same 7000 feet (1% per 1000 feet times 7000 feet or a 7% loss).

Does anyone know if my altitude loss numbers are grossly incorrect? With these kind of HP losses, it would seem that a turbo charged motor with the same HP rating as a naturally aspirated motor has a significant advantage at altitude regardless of any reliability concerns associated with the turbo charger.

 

[SkyPup]

You are correct about the high altitude power loss in direct relation to the decrease in barometric pressure.

All diesel engines are basically simple air compressors. At sea level, a 100 cubic inch naturally aspirated diesel engine is able to intake only so much air and correspondingly fuel.

Adding a turbocharger and another full atomsphere of pressure to the intake effectively turns the 100 c.i. chugger into a 200 cubic inch powerhouse due to the 100% increase in air charge and more fuel, resulting in more horsepower but much more effective lower rpm higher torque.

Generally, a turbocharger effectively doubles the displacement of a diesel engine.