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  #31  
Old 09-02-2015, 02:19 AM
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Quote:
Originally Posted by Diesel911 View Post
I guess you don't believe that when the Guy installed the Turbo Kit on his formally NA 300D that he got better peformance as he said he did?

I have tried to back my opinion with some facts. But, today the learning curve is too steep and it is hard to find specifics on Diesels.

There was at least 2 threads on gasoline engines where they said raising the compression in the Cylinder increased gas expansion during combustion reguarless of the extra Fuel or if there is a turbocharger.

So perhaps that increased gas expansion compensates for that extra work compressing the Extra Air supplied by the Turbo.

Also energy is used up creating the low pressure in the cylinder as the Piston is going down due to the fact the Intake port with Intake Valve is a restriction.
When the Turbo is boosting the energy that is needed to create the low pressure in the cylinder is not needed. So there is an energy savings there.

The Turbo itself is not a parisite on the Engine after it starts boosting.

So when Turbo is boosting compression goes up causing increased exhaust gas expansion pushing down on the Pistons and the Engine does not have to work at creating a low pressure to intake Air.
Apparently that is enough to give the engine some extra power it did not have before the Turbo was added.

Also if you are on level ground the Turbo is not going to start Boosting right off and you won't get that extra low end torque you speak of.

However, when the Car starts going up the a Hill that changes because the pressure in the cylinders goes up wich increase the velocity of the Exhaust Gasses which turns the Turbo faster and sooner. So I could see the low rpm torque in that situation.
I'm sure that the guy got better performance as you say he did.

i guess i'm trying to bring some clarity to the discussion by separating two notions: power and torque.

The engine would have more POWER if the car's max speed increased after the upgrade. Or was able to pull heavier loads at the same speed. No matter how much time it'd take to get to said speed.

The engine would produce more TORQUE if the car was able to accelerate to a given speed in a shorter amount of time.

What i'm saying is that with the turbo upgrade one can expect better acceleration because there would be more air available to burn fuel in lower rpms, BUT the increase in maximum speed of the car would be marginal if any if the fuel delivery remained the same.

The engine would feel more 'powerful' but not because of increase what is usually understood as (horse)power.

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  #32  
Old 09-02-2015, 08:30 AM
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Lol. You guys are missing my point. Im not doing it for a high power. I would like to run very low boost just to add a bit more power for everyday driving. Probably max it out at 5lbs. I dont want a lot of power i have my track car for that. Im planning on turning the injection pump up to compensate for the added air. Im going to run a wide band to check the afrs and mechanically adjust accordingly. I will not be smashing the gas every chance i get.
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  #33  
Old 09-02-2015, 08:36 AM
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Driving a 40whp car in modern day traffic is almost dangerous.
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  #34  
Old 09-02-2015, 09:16 AM
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Fascinating discussion here .

I'm old and have been hearing about wonderous projects my whole life (I began working as a Mechanic before age 8 Y.O.) and 90 + % of them either die or get killed off , as a Yankee Farmer born & bred I hate waste so I'm always skeptical .

However , my Son , the Die Hard (and competitive !) racer , took the brandy new low compression engine out of my old VW Panel truck and put it into his dune buggy then cobbled up a turbo charger ~ it now handily beats new Chargers and Mustangs etc. on the drag strip , he said ' well of COURSE Pop ~ you're in love with low compression engines you can beat the crap out of , that made it a natural for turbocharging ' .

We'll see how long it lasts , right ? .

For sure , this 240D turbo project won't be like my '81 240D parked out side , 234,XXX miles , leaks and has about 200 # compression in # 1 cylinder but no smoke and runs like a top .

I'm collecting $ and bits and bobs as I want all my ducks in a row before I overhaul the engine and rebuild the tranny (also never done yet) , hopefully this year .

In the end , short lived projects are worthless to me .
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  #35  
Old 09-02-2015, 09:17 AM
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Unhappy OM616 Output ?

Quote:
Originally Posted by soates4 View Post
Driving a 40whp car in modern day traffic is almost dangerous.
Is that really how little it makes stock ? .

I'd thought at least 50 hp .
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  #36  
Old 09-02-2015, 09:34 AM
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Nate, Your son boosted a gas engine or a diesel ?
Did he increase the fuel to go along with the increased air flow ?
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  #37  
Old 09-02-2015, 09:35 AM
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Stock they make 60 engine hp. Between drivetrain loss and lower compression of a 41 year old car.
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  #38  
Old 09-02-2015, 09:41 AM
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Quote:
Originally Posted by soates4 View Post
Stock they make 60 engine hp. Between drivetrain loss and lower compression of a 41 year old car.
There are at least three different power versions of the engine due to changes in the precombustion chamber and possibly the cam shafts.
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  #39  
Old 09-02-2015, 09:50 AM
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https://en.wikipedia.org/wiki/Mercedes-Benz_OM616
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  #40  
Old 09-02-2015, 01:24 PM
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In six months and 3500 miles, the k26 that I put on my mom's(formerly granny's) 78 300D has been great in combination with backing the Ada out 1.5 turns. 8-9psi is what it runs as I softened the wastegate preload. It was noticeably quicker in any gear according to my mom. I intend to put the newer head on it eventually and turn up the full load screw one turn it I ever get around to fixing the oil filter housing gasket leak. It has been much more enjoyable to drive and less sluggish and more efficient.
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  #41  
Old 09-02-2015, 01:40 PM
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Thanx for the various links & info ! .

My Son's Dune Buggy (NOT a Manx , there were many others) is a 1600 C.C. VW Air Cooled engine , it has a modified carby on it , I taught him how to do that when he was a child as I ran VW's for decades and don't like them to last less than 150,000 miles .

Every time I get on here , I learn something new , I like this aspect of Tech Talk *very* much ! .
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  #42  
Old 09-02-2015, 08:31 PM
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[QUOTE=interzonearts;3515230]I'm sure that the guy got better performance as you say he did.

i guess i'm trying to bring some clarity to the discussion by separating two notions: power and torque.

The engine would have more POWER if the car's max speed increased after the upgrade. Or was able to pull heavier loads at the same speed. No matter how much time it'd take to get to said speed.

The engine would produce more TORQUE if the car was able to accelerate to a given speed in a shorter amount of time.

What i'm saying is that with the turbo upgrade one can expect better acceleration because there would be more air available to burn fuel in lower rpms, BUT the increase in maximum speed of the car would be marginal if any if the fuel delivery remained the same.

The engine would feel more 'powerful' but not because of increase what is usually understood as (horse)power.[/QUOT

Concerning the Guy that installed the Turbo Kit he is speaking of seat of the pants better performance. Be that more torque or more HP he cannot tell wich. He just means that the Car is moving forward better at a better speed then the past.

These are just some notes I have from research. Unfotunatly most of it in volves gassers.

Google Search =Do higher compression put the Fuel Molecules closer to the oxygen molecules?
Compression
http://www.ankn.uaf.edu/publications/vs/compression.html
“The same principle is applied in a cylinder. The air (oxygen) and fuel (gasoline) are well mixed in the carburetor. They enter the cylinder, but fuel particles and oxygen are far apart. When the piston comes up in the cylinder, the air molecules and fuel particles are forced close together. When one or two droplets are ignited by the spark plug, the chain reaction is set off.”
Combustion is thorough and quick. When a gas is compressed, as in a cylinder, heat is generated as the molecules collide much more in tighter space. This gets the fuel/air mixture close to the burning point even before the spark ignites them.”
“Conclusion
Compression brings fuel particles together in an engine, heating them, and giving them the opportunity to burn more rapidly. The principle of compression is easy to understand, but is worth mentioning as there is considerable power loss and inefficiency resulting from decreased compression from bad piston rings or head gasket leakage.”
 
This one is interesting and helps expalin another reason why not all of the Fuel burns. So beside Fuel that is not exposed to Oxygen there is parts of the Fuel that just don't want to burn as easily as the rest of the Fuel.

http://www.nobugs.org/bike/engine.html Pushing Molecules together
Hydrocarbons are either saturated (only contain single bonds) or unsaturated (contains at least one double bond). Saturated hydrocarbons tend to burn cleanly, whereas unsaturated hydrocarbons burn smokily and are unstable.
Now, you want to get the biggest possible bang out of your fuel/air mixture, and you can do this by compressing it before igniting it. This pushes all of the fuel and air molecules closer together. A compression ratio of 6:1 gives 25% efficiency, whereas raising it to 12:1 gives 35% efficiency.”
 
Google search = What are the benefits of increasing engine compression?

Maximizing the compression ratio delivers more bang for the buck than you may imagine.
http://www.hotrod.com/events/coverage/0311em-power-squeeze/
“Understanding how the CR affects your street or race engine can easily net as much as a 50hp benefit.”
“Increasing the CR produces an increase in output throughout the rpm range.”
“Cylinder pressures and output will increase as the CR is raised, but what is less obvious is that the increase in compression also increases the engines thermal efficiency. Thermal efficiency is a measure of how effectively the engine converts heat into mechanical power. To appreciate this it is better to consider the engines expansion ratio (ER). This is the opposite side of the coin to the CR and describes what is occurring as the piston moves down on the power stroke rather than what happens as it moves up on the compression stroke.”
The site goes on to explain more how the above works.
“From this you can see why a high-compression cylinder produces better power and fuel economy. It is not just because the charge is squeezed harder and the resulting combustion pressure goes up, but also because the higher expansion ratio allows more energy to be extracted from the original high-pressure charge.”
Google Search = How does a Turbocharger help the engine breathe?

Google search = Diesel stoichiometric
http://designingsound.org/2014/07/turbocharging-and-its-effect-on-our-soundscape/
“However, gasoline works best at a very specific ratio of fuel to air, which is roughly 14:1. So, if you want to make a bigger bang, you need 14 times more air than your increase in fuel to get it.”
“However, this so-called “natural aspiration” or NA for short, has a limitation in air pressure. Just like a straw, the inhale of an engine works by creating low pressure, which atmospheric pressure then fills in. So, another way to get more air into an engine is to pressurize it, or use “forced induction.”
 
I could not get this site to open for me on my dial up internet.
http://www.brighthubengineering.com/machine-design/15235-the-stoichiometric-air-fuel-ratio/
.
Google search = How does a Turbocharger help the engine breathe?
http://www.knowyourparts.com/technical-articles/the-benefits-of-forced-induction/
“A forced induction system overcomes the limitations of atmospheric pressure by pushing more air into the cylinders. Consequently, the engine’s power output becomes a function of how much boost it gets. What’s more, dialing up the boost pressure overcomes a lot of deficiencies in the induction system and cylinder heads that would otherwise limit air flow and the engine’s volumetric efficiency.
After all, it is much easier to push air into an engine with a turbo or blower than to suck it in with intake vacuum alone.”

 
 Read more: http://www.hotrod.com/events/coverage/0311em-power-squeeze/#ixzz3kav6UpX0
Follow us: @HotRodMagazine on Twitter | HotRodMag on Facebook
 
Engine compression ratio how does it effect performance?
http://forums.anandtech.com/showthread.php?t=198458
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  #43  
Old 09-02-2015, 08:46 PM
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Also in the Chiltons book (older book Copyright 1983) on Diesel it said that the Turbo Kits for NA Engies are sold and that they do work. Even if the reason for the kit working is elusive.

From the Book:
"Nevertheless, some excellent turbo kits are available…” “Many who have " kitted" their naturally aspirated diesels, and now revel in their vehicle’s new performance, swear they would never again drive unturbochartged, in spite of the warranty risk."

So apparently the Kits do increase performance without having an ALDA to change amount of Fuel injected during boost; even if pinpointing the reason for the better performance is elusive.

However, the book also lists the cautions to adding a Turbo Kit to a Vehicle that was not made for one.
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  #44  
Old 09-02-2015, 08:55 PM
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Quote:
Originally Posted by soates4 View Post
Lol. You guys are missing my point. Im not doing it for a high power. I would like to run very low boost just to add a bit more power for everyday driving. Probably max it out at 5lbs. I dont want a lot of power i have my track car for that. Im planning on turning the injection pump up to compensate for the added air. Im going to run a wide band to check the afrs and mechanically adjust accordingly. I will not be smashing the gas every chance i get.
Everything I have read indicates that you will get some better performance. But, after you are done be sure to come back to this thread or start another thread giving the results of what you did as that will help others.
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  #45  
Old 09-02-2015, 08:55 PM
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Diesel911,
You are leaving out major basics with almost everyone of your statements.
It is not legit to use increased speed ( read RPM ) for a diesel engine without a change in gearing. That is because due to the valve train limitations with regard to overlap , as compared to a gas engine, and added stroke distance.... the diesel simply has physics limitations to the rpms.
To get more power or torque you need both more fuel and more air... not just the air.
In imagining that a normally working 21 to 1 diesel is suffering from lack of oxygen to burn fuel is just not in line with the physics of our engines.
The same with imagining that nitrogen is getting in the way of the oxygen and fuel getting together... you are visualizing a much faster burn than happens in a diesel engine.
It is REALLY not legit to use gasoline engines for trying to prove diesel concepts... they do not have the valve overlap restriction that diesels do... thus they CAN increase their rpms with a result in more horsepower and torque...

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