Efficiency increase through turbocharger?

Hi.
I've somehow ended up with a diesel car (like the Virgin Mary with the child).
For me, as someone who is sensitive to gas, it's not exactly the real thing. But somehow, filling up the tank is fun.
The car is a 1988 Polo diesel with a 1.3-liter engine. It consumes 5 liters per 100 kilometers when driven in a smooth and anticipatory manner.
Well, there has to be more or less room for improvement.
I would like to achieve the same performance with even lower fuel consumption. I was thinking about a turbocharger. What would a turbocharger achieve without increasing the amount of diesel fuel injected?


As a loader, I would like to use a modern system with VTG (if it makes sense). Which types are suitable for that?
I was thinking about getting a 3L Lupo 1.4 PD or an A-class. Are there any models where the exhaust manifold isn't directly connected to the turbo?
and how can one implement a boost pressure control system?


Well, I would be grateful if you could answer some or all of the questions.
and please don't tell me that something can't be included or is forbidden, or anything like that.
I know that myself. It's just an experiment.

What would a turbocharger achieve without an increase in fuel injection volume?

The turbocharger is designed to force more oxygen into the cylinders than a naturally aspirated engine, allowing for the combustion of MORE diesel fuel. A turbo alone, therefore, doesn't really achieve much.

Not quite. Cord is talking about an increase in efficiency. In many operational situations, efficiency improves, and consequently, consumption decreases, similar to how "chiptuned" vehicles often consume less rather than more.
However, I would like to point out that installing a turbocharger can be just as expensive as buying a used Golf TDI.
You need the turbo, including components like the exhaust manifold, a modified exhaust system, and altered air intake from the air filter onwards, including the air mass sensor, engine control unit, wiring harness, and all sensors. All of this has to be fitted to an engine for which these parts were never originally designed, and then the whole thing has to actually work...
In the past, it was more common to find turbocharger kits for retrofitting on standard passenger cars in the United States. I remember installing a turbocharger on a Honda CRX myself in the 80s. However, I don't think your car is suitable for that. There are other areas where you might be able to save money, such as the diesel-specific wear parts (e.g.,). to replace the injectors or to optimize the injection timing.


Best regards,
Uwe

However, I would like to point out that installing a turbocharger can be just as expensive as buying a used Golf TDI.


I also suspect that this would be a very complex and time-consuming operation.
Simply bolting on a turbocharger is probably not going to work. I also doubt that the engine itself is designed to handle the increased power (if it even works, assuming the 'god of mechanics' allows it). Imagine this: after a year of tinkering, the car might run, but then, after another year, it could be scrap metal due to overload. It wouldn't be as fun.

hi,

Retrofitting a naturally aspirated engine with a turbocharger presents a completely different set of challenges.
The compression!
Turbocharged engines have a lower compression ratio than naturally aspirated engines because the gas is already being forced into the cylinders under pressure. A significant reduction in interest rates, regardless of the cause, is likely the first hurdle to overcome.

The conversion kits from the USA often included an adapter plate that was installed between the cylinder head and the block to reduce compression. However, some simply involved installing a second cylinder head gasket. Good turbo tuners replace the pistons and combustion chambers (which is very expensive).

Hello Bertil,

Quote:

Retrofitting a naturally aspirated engine with a turbocharger initially presents a completely different problem: The compression!

For diesel engines, it's not quite the same. You were probably thinking of gasoline turbo engines.
The reason for this is the knocking limit, which does not exist in diesel engines.
In diesel engines, the compression ratio is primarily set so that the engine can still start reasonably well in cold weather. A pre-combustion chamber engine definitely wouldn't achieve that with reduced compression.

Best regards,
Albrecht.

@ Uwe: My statement was more related to the topic of increased performance.
'However, I don't see any fuel savings, because whether the turbocharger is attached or not, the amount of fuel injected remains the same. It's possible that the higher oxygen content in the cylinders could, in some situations, lead to better combustion.' Is it not also the case that a vacuum cleaner is designed in such a way that there is always a certain...
Is there an excess of oxygen?

Hi,

"I'm going to risk saying this, but..."
What about a G40? That's also a 1.3-liter engine, and it's likely that the two engines are very similar, except for the cylinder head.

Perhaps it would be a good idea to look for parts there.

Or maybe a G40 diesel .

Greetings.
Thomas.

Albrecht wrote:

With diesel, it's not quite the same. You were probably thinking of gasoline turbo engines. The reason for this is the knocking limit, which does not exist in diesel engines. In diesel engines, the compression ratio is primarily set so that the engine can still start reasonably well in cold weather. A pre-combustion chamber engine definitely wouldn't achieve that with reduced compression.

Hello Albrecht,

Unfortunately, the same applies to diesel engines! The problem with diesel engines isn't the knocking limit, but rather the operating pressures, which you can't increase indefinitely.
Okay, I understand. Please provide the German text you want me to translate into English. I will only provide the translation.

Take a look at the specifications for the 1.6 D and 1.6 TD engines; you'll see that the TD has a lower compression ratio.

hello Bertil,

Why do you think that my thesis is being severely limited? I tend to think they will be confirmed.
The TURBO-diesel engine became popular precisely because of its resilience to overcharging (and this despite its high compression ratio).
Otto-Turbo: approximately 9.5:1; TDI: approximately 18:1.
While a low compression ratio is generally desirable in diesel engines due to the peak pressure involved, naturally aspirated diesel engines often have their components excessively oversized. In the specific case mentioned above, I see the compression ratio as the least problematic aspect. That's why I wrote it!

Best regards,
Albrecht.

Albrecht wrote:

TDI approximately 18:1.

Attention, we are talking about a WK engine, not a TDI!
WK-Diesel --- ~22-24:1

I know a club member who, before the 1.6 TD was released, converted a 1.6 D engine to a TD and used it with two ZKD head gaskets (which was likely not a coincidence).
The part constantly has its pressure-retaining ribs/seals blown out.

Hi everyone,

The Volkswagen Golf 2 also had two very similar diesel engines: a naturally aspirated diesel with 55 hp, and a turbocharged diesel with a catalytic converter and 60 hp. Apparently, the turbocharger in the latter was only intended to provide the catalytic converter with the necessary excess oxygen. To the best of my knowledge, the fuel injection pump (quantity) was the same.

Is it possible to infer a potential advantage of turbocharging without increasing the fuel injection amount? If the turbocharger increases power by approximately 10%, it suggests an improvement in efficiency. And then, with the same performance, the consumption should decrease.
There are probably a few experienced mechanics here who know the difference between the two old G2 engines...

Regards,

Eike.

Quote:

"I'm going to risk saying this, but..." What about a G40? That's also a 1.3-liter engine, and it's likely that the two engines are very similar, except for the cylinder head. Perhaps it would be a good idea to look for parts there. Or just a G40 diesel.

I think the G-charger doesn't have as good an efficiency as a turbocharger. This is because the G-charger draws power from the crankshaft and is always running, which also contributes to increased fuel consumption.
However, there are turbo conversion kits available for the G40 engine. And, coincidentally, I'm also working on a 1.3 turbo Polo in my garage, but it's supposed to run on gasoline.
The most difficult part is actually installing the turbocharger into the exhaust system. The rest can be done relatively easily.

Okay, let's go back to my diesel. I think the problem with its high fuel consumption is that the engine is designed to operate at too high of an RPM. It produces its 45 horsepower at 4900 RPM, and consequently, the gearbox has a very short ratio. At those 4900 RPM, it only goes 140 km/h.
I've been thinking about increasing the torque from 75 Nm by a small amount, and then using it in conjunction with a longer gearbox.

Okay, so let's adjust the turbo pump to deliver a bit more fuel, and to compensate, we'll use a longer gear ratio.

I'm not worried about the compression for now; if it falls apart, then I'm just out of luck.

@Marco!

I didn't necessarily mean the efficiency under absolutely identical driving conditions (same gear, same driving style), but rather the more favorable driving style that is possible due to the increased torque.
"A naturally aspirated diesel engine doesn't have much power (no offense, Cord!). To make decent progress, you often have to drive in the lower gears, which significantly reduces fuel efficiency. With more torque available, you can spend much more time in 5th gear." Driving in a convoy can save fuel.
The engine is likely running at its maximum fuel injection capacity and close to its soot limit. I think that forced induction could actually improve combustion. However, these are all just theories. I believe enough arguments have been presented against installing a turbocharger. And 5 liters per 100 kilometers is okay, right?

Best regards,
Uwe

Cord wrote:

So, adjust the turbo pump to be a bit richer, and then use a longer gear ratio.

@Cord!

Our contributions overlapped.
As I mentioned above, the engine is already operating near its soot limit. Without forced induction, it will be difficult to achieve significantly higher torque. You can slightly increase the soot output, but that's about it. I would advise against a longer gear ratio. With even a slight headwind, you'll slow down, won't reach the top speed, and will have to use the lower gears more often. The consumption will likely increase rather than decrease as a result.
Keep us updated on your progress.

Best regards,
Uwe

I only meant that the pump should be greased under the assumption that the engine is turbocharged.
Okay, I'll see if I can find a cheap turbocharger somewhere that's suitable for such small engines.

Do you have any other ideas about which cars might have small turbos that don't have an exhaust manifold attached?
Otherwise, I might be able to get a turbocharger from a T3 with a 1.6L JX engine, but that's probably not the real deal. It probably doesn't have a variable geometry turbo (VTG) and is likely too large.

And how could one build a boost pressure control system that works with a VTG turbocharger?