Na->Turbo - Page 4 - PeachParts Mercedes-Benz Forum

leathermang · #46 09-02-2015, 08:58 PM

Quote:

Originally Posted by Diesel911

....However, the book also lists the cautions to adding a Turbo Kit to a Vehicle that was not made for one.

Instead of just listing the pro statements in that Chilton's... why don't you post that caution list ?

interzonearts · #47 09-02-2015, 11:08 PM

Quote:

Originally Posted by leathermang

Diesel911,

To get more power or torque you need both more fuel and more air... not just the air.

You would be right if stock IP was capable of delivering only as much fuel as the NA engine was able to burn efficiently at any point.

Any black smoke as the engine is accelerating is potentially more energy that can be claimed with addition of extra air.

Myself i never saw a diesel engine that wouldn't smoke when you first step on it.

leathermang · #48 09-02-2015, 11:17 PM

Quote:

Originally Posted by interzonearts

You would be right if stock IP was capable of delivering only as much fuel as the NA engine was able to burn efficiently.

Any black smoke as the engine is accelerating is potentially more energy that can be claimed with addition of extra air.

Myself i never saw a diesel engine that wouldn't smoke when you first step on it.

By ' capable' you are implying it can be modified or set to provide more fuel per stroke of the piston ? If yes, that is true... but we have been saying that from the first of this thread... and that getting that variable relationship correct for an intermediate pressure restricted hybrid is not possible for most people.

As IS it appears to be a mechanically set relationship determined by the controls inside the Injector Pump which is not affected by an increase in airflow...
a carbed gasoline engine would automatically respond to more airflow...

interzonearts · #49 09-02-2015, 11:32 PM

Quote:

Originally Posted by leathermang

By ' capable' you are implying it can be modified or set to provide more fuel per stroke of the piston ? If yes, that is true... but we have been saying that from the first of this thread... and that getting that variable relationship correct for an intermediate pressure restricted hybrid is not possible for most people.

As IS it appears to be a mechanically set relationship determined by the controls inside the Injector Pump which is not affected by an increase in airflow...
a carbed gasoline engine would automatically respond to more airflow...

I can see your point and frankly you might be right but what i'm saying is that stock, unmodified IP will make black smoke if you floor it and that unburned fuel can be utilized by increased airflow.

leathermang · #50 09-02-2015, 11:52 PM

[QUOTE=interzonearts;3515648]I can see your point and frankly you might be right but what i'm saying is that stock, unmodified IP will make black smoke if you floor it and that unburned fuel can be utilized by increased airflow.[/QUOTE

Yes, perhaps, but do you not think that the MB Engineers did not know of that situation and IF some straight forward ( meaning it would not mess up some more important criteria ) they would not have already incorporated the fix into our cars ?
Given that it happens when ' floored'.... the question is how much less fast than ' floored' will cause that symptom to be eliminated ? That may be the key to the reason that still happens as a result of that fast movement of the pedal. That to address that typically unnecessarily fast action might cause
detriment to the normally excellent mileage under normal conditions.
And some seem to be arguing that adding a pressure limited turbo would correct this situation... which I would argue is NOT the case due to TURBO LAG...
If ' flooring it' was creating black smoke before the limited turbo... it will do it with the turbo also.

interzonearts · #51 09-03-2015, 12:27 AM

[QUOTE=leathermang;3515651]

Quote:

Originally Posted by interzonearts

I can see your point and frankly you might be right but what i'm saying is that stock, unmodified IP will make black smoke if you floor it and that unburned fuel can be utilized by increased airflow.[/QUOTE

Yes, perhaps, but do you not think that the MB Engineers did not know of that situation and IF some straight forward ( meaning it would not mess up some more important criteria ) they would not have already incorporated the fix into our cars ?
Given that it happens when ' floored'.... the question is how much less fast than ' floored' will cause that symptom to be eliminated ? That may be the key to the reason that still happens as a result of that fast movement of the pedal. That to address that typically unnecessarily fast action might cause
detriment to the normally excellent mileage under normal conditions.
And some seem to be arguing that adding a pressure limited turbo would correct this situation... which I would argue is NOT the case due to TURBO LAG...
If ' flooring it' was creating black smoke before the limited turbo... it will do it with the turbo also.

I have no personal experience with installing a turbo an a NA engine but i did replace the stock turbo i had with a fast spooling turbo and a LOT of the lag i had experienced with the stock turbo has been eliminated. I did not touch the IP but the engine seems to pul a lot stronger in low rpms now also.

A buddy of mine is driving a jeep (gasser) with an electric fan inside the air intake that gives him some boost at a touch of a button. That could be a way of getting moderate boost without lag

leathermang · #52 09-03-2015, 12:48 AM

Quote:

Originally Posted by interzonearts

...A buddy of mine is driving a jeep (gasser) with an electric fan inside the air intake that gives him some boost at a touch of a button. That could be a way of getting moderate boost without lag

If you do the math on how much air an engine requires just to run normally... and then how much it takes to INcrease the amount entering the engine...and how much that fan puts out.... I promise you that is all in his imagination... which is not a bad thing... but it is not supported by the physics of fluid flow and pressure gradients...

Here is what is probably happening..... he has restricted the normal flow of air into the engine by placing that fan in the air stream .... so when he turns it ON... then he has less restriction from when it is off ... and feels the "boost"... but it is an imaginary improvement not an actual one from stock.

It is the same thing as the feeling that your car runs better after you just washed it.... a natural tendency towards optimism which is conducive to the progress of the human species.

vwnate1 · #53 09-03-2015, 08:17 AM

...Because I was asked .

My Son's VW Dune Buggy is running a Solex 34PICT-3 carby with a # 180 main jet and he's upped it to 24 # boost ~ wow that sounds like a lot to me .

It has *very* good street manners when driven .

I am reading all the detailed Technical discussion here and learning as I go...

Diesel911 · #54 09-03-2015, 10:02 AM

Quote:

Originally Posted by leathermang

Instead of just listing the pro statements in that Chilton's... why don't you post that caution list ?

This is part of what the OP said "I know what you all are going to say. i know that its a terrible idea. i know the stock 240d internals cant handle it, i know i dont have oil squirters. Don't care."

That means the OP already is aware of the cautions. And that means the thread already started off with an admitted applied warning.

leathermang · #55 09-03-2015, 10:12 AM

Diesel911,
Perhaps you missed my post early on saying that I do not care what he does with his engine... that these posts will be in the archives and are for the benefit of those who read them later and might get excited by some OP's unmitigated enthusiasm for a project with spurious chance of satisfactory results... forums have a wide variety of experience represented in their readership.... I think that there is a responsibility to the least experienced readers to have legit warnings explained as clearly as possible... or at least to know there are red flags which should be investigated before committing money and or labor....

I think you meant ' implied ' instead of ' applied' warning...
but interesting that you would type out all those possibly unsupported positive statements... and not the actual list of the warnings from that Chiltons manual ... perhaps a bias on your part ? Perhaps you lost the bookmark ?

Diesel911 · #56 09-03-2015, 10:14 AM

Quote:

Originally Posted by interzonearts

You would be right if stock IP was capable of delivering only as much fuel as the NA engine was able to burn efficiently at any point.

Any black smoke as the engine is accelerating is potentially more energy that can be claimed with addition of extra air.

Myself i never saw a diesel engine that wouldn't smoke when you first step on it.

You are right.

Not picking an other argument. That guy that was speaking of the air to fuel ratios of gas and diesls engines. I did not read it closely but I am really sure that in order to accelerate you need to go into wan is briefly excess fuel concerning that air to fuel ratio.

Also back to the Mercedes Manual after you get off idle you also go off of the Governor until you get way up close to the max rpms where the Goernor again take over. So while there is no accelerator pump your Foot is what is determing how much Fuel is going to be injected most of the time.
So if you tromp on the accelreator pedal there is no Governor control that is going to limit the Fuel until the rpms get way up thier.

Diesel911 · #57 09-03-2015, 10:24 AM

vvvvvvvvvvv

leathermang · #58 09-03-2015, 10:31 AM

Quote:

Originally Posted by Diesel911

...... So while there is no accelerator pump your Foot is what is determing how much Fuel is going to be injected most of the time.
So if you tromp on the accelreator pedal there is no Governor control that is going to limit the Fuel until the rpms get way up thier.

Just to keep as many people up with the elements of the descriptions here...
The mention of the accelerator pump for a gas engine... as it compares to what our diesel engines deal with...
A carb on a gas engine has a set relationship between the air entering the venturi , a smaller section of the air path, which due to physics laws causes an increase in the speed of that air AND a decrease in the air pressure.... that is where the little tube of a specific size has its end located and as an interaction with the gas in the float bowl this lower pressure causes fuel to come out and mix with the air heading towards to cylinder.
The ACCELERATOR PUMP is an ADDITIONAL gas pump which is needed to offset the lag between the wide open throttle of the gas carb and the reaction by the lower pressure to pull gas out of the float bowl.
This has the potential to waste a lot of gas when the driver has a heavy foot...
Diesels do not have that...

Diesel911 · #59 09-03-2015, 10:32 AM

If the OP had a NA Engine he likely has an M type Fuel Injection Pump. It has a different Governor then the MW does. But, I am assuming that though it is different it functions the same.

The below pictured description from the Mercedes Manual is a short description of some of the operation of the Governor that is on the MW Fuel Injection Pumps. Notice that in the mid range there is no Governor regulation of the Fuel Delivery.

That means you Foot is going to determing if you get more or less Fuel (in the mid range). That means if you depress the accelerator pedal down fast you can easily give the Engine more Fuel then it can burn is going to be period of time where you are going to smoke till the Engine catches up.
If you have a new Engine that time catch up time period is going to be shorter then if your Engine was badly worn.

To me that means if you added a Turbo to your NA Engine when you tromp on the accelerator pedan the Turbo is going to help you burn that excess Fuel that would normally exit the tail pipe as smoke.

leathermang · #60 09-03-2015, 10:40 AM

Quote:

Originally Posted by Diesel911

......To me that means if you added a Turbo to your NA Engine when you tromp on the accelerator pedan the Turbo is going to help you burn that excess Fuel that would normally exit the tail pipe as smoke.

All the rest of your statement is true....
but here is the defining question which shows the last statement is not true..

Do tubo'ed MB Diesel engines also produce black smoke under the ' flooring ' it situation you are describing ?

It all has to do with turbo lag ... the feedback of the pressure to the engine from the spinning of the EXhaust propelled turbo can not be INSTANTANEOUS . Just not physically possible .... thus the addition of a turbo to an NA engine to supposedly fix a non existent ' problem ' suffers the same physics restriction that even a properly designed from the factory Turbo engine does.