Turbo Charged Engines - Avoid or Buy?

[megaboz]

As I understand it, the whole reason for introducing the turbos was to meet the EPA standards, NOT to improve tractor performance.

They only add ONE horsepower to the Kubota specs. Not worth it, IMO. More cost and you have the hassle of the "waiting to shut it down". If I had my choice, I'd go non turbo. Not saying it's a big deal, but why add complications and more contraptions to go wrong?

Ken

1 HP? I think there is something else going on there. Maybe it is a smaller engine, thus less HP when the turbo was added. I'm no engineer and thus do not know how HP affects tractors, but I know in my pick up as a genreal rule of thumb, 1 HP is 2 FT LBS of torque (not always the case, but a genreal guess about torque numbers, accurate enough.)

Turbo's are nothing to be scared of, yes more parts, and costs more to replace/fix. Keep the oil changed, don't over heat and all should be fine.

Also, and maybe I am wrong here, but I don't think there is much turbo lag on a tractor, afterall you rev the throttle to a paticular RPM, and it stays there. The exhaust pressure is the same while you are driving or not. Might be a slight delay if you hammer the throttle and then the go pedal, but after that it should be constant power.

Also, as long as the tractor is at normal operating temps when it is shut down, there shouldn't be an issue with turbo.

 

[crazyal]

If I'm not mistaken the gl 4749, 5040, and 5240 all have the same size engines. The 4740 is the only non-turbo of the three and also the lowest in HP. The other two, the 5040 has 1 more HP and the 5240 has 3 more but HP is misleading since torque is the real number.

As far as turbo lag, that's mainly a gas engine problem due to the fact gas engines have a much wider rpm range. I had a toyota with a turbo that red lined at 8,000 rpm. A correctly designed turbo will need to provide the correct CFM. An engine turning high RPM requires a lot of air and a bigger turbo. The exhaust flow at low RPMs is just not powerful enough produce any boost. Some manufactorers have been installing two turbos on gas engines, a small turbo to provide boost at near idle engine speeds and a main turbo to provide the CFM needed at higher RPMs.

 

[ecoslik]

:thumbsup:
My wife is having a little laugh ... I have been so enthusiastic all weekend about every reply that each of you has taken the time to share. Thank you!

I am the type that reads all directions before starting anything. Yes, I could wing it, but why not just do it right the first time. I appreciate all the advice.

 

[Redneck in training]

If I'm not mistaken the gl 4749, 5040, and 5240 all have the same size engines. The 4740 is the only non-turbo of the three and also the lowest in HP. The other two, the 5040 has 1 more HP and the 5240 has 3 more but HP is misleading since torque is the real number.

As far as turbo lag, that's mainly a gas engine problem due to the fact gas engines have a much wider rpm range. I had a toyota with a turbo that red lined at 8,000 rpm. A correctly designed turbo will need to provide the correct CFM. An engine turning high RPM requires a lot of air and a bigger turbo. The exhaust flow at low RPMs is just not powerful enough produce any boost. Some manufactorers have been installing two turbos on gas engines, a small turbo to provide boost at near idle engine speeds and a main turbo to provide the CFM needed at higher RPMs.

The small power gain has nothing to do with the turbo. It is a design decision. Diesel engine power depends on fuel delivery (up certain limit) and I can guarantee you that, if given the fuel, turbocharged and even NA engine can deliver enough power to self-destruct. The designer decided to limit the power due to mechanical limits of the engine. Look at specs of some tractors they use the same engine displacement but the power of different models range from 67 to 95 HP. Typical tractor engine has 20 HP/Liter. That is why they last forever. It doesn't matter if they are NA or TC.
The TC engines are running cleaner and that is the primary reason for TC installation. To meet TIER II standards the engine is usually just turbocharged. To meet TIER III emission standard the engine will also have intercooler.
Speaking about reliability. Turbos are very simple devices that only rotate and put very small stress on the bearings. If properly designed (to keep the bearings cool) they will outlast the engine.
Typical industrial turbo compressor has at least 40,000 hours between overhauls and usually at least twice as much.

 

[texasjohn]

Welcome to TBN, I agree with you, consider a used tractor with lowish hours and purchase more attachments with the $ difference from new. It's the attachments that actually do the work. I have a 50ish hp Grand L and it's been great for me (no turbo) on 200+ acres...I think this size would be good for your needs. Many on TBN would advise you to purchase now all the tractor you will need in the future. I agree.

 

[firefighter jim]

That seems strange. What kind of trucks/engines do you have?

Had. American La France, Maxim, Pierce. Detroit Diesel. I believe every one of them had 6-71 or 8-71 blowers.

 

[Ken45101]

If you look at the specs on the Kubota M series (M5040, M9540 for example), the DT1 models (turbo charged) have 1 hp more than the DT models (non turbo). Kubota did not otherwise change the engines.

Ken

 

[megaboz]

If you look at the specs on the Kubota M series (M5040, M9540 for example), the DT1 models (turbo charged) have 1 hp more than the DT models (non turbo). Kubota did not otherwise change the engines.

Ken

It might be the same engine, however without seeing the parts list for the two engines with the turbo and without it is hard to say.

It is possbile to change HP by using different pistions, connecting rods, heads, or a combination of the above.

I never said I was right a 100%, but I imagine that something was done. But a turbo could have been added that only provides a mild (or weak in this case boost). The lack of real specs of Turbo boost pressure and engine displacement makes it hard to really see what the turbo is doing for the engine in this case.

 

[Smokin Diesel]

Had. American La France, Maxim, Pierce. Detroit Diesel. I believe every one of them had 6-71 or 8-71 blowers.

The two-stroke Detroits (like the the 6v-71 and the 8v-71) needed superchargers to keep the airflow going in the correct direction through the engine. Not so much of a power adder, just a required component. There were versions that had turborchargers as well, with the turbocharger feeding the supercharger.

When you reference a "6-71" or an "8-71" blower, that name comes from its original application on the ol' Detroits.

 

[firefighter jim]

6-71 (6 cylinder, 71 cubic inches per cylinder). 8-71 (8 cylinder, 71 cubic inches per cylinder). Early drag racers also used them hence the term blown as in blown, injected, nitro burning, etc. etc.!