Definition of forced induction

[TurboPuma]

Just been having a lively debate with some friends regarding whether Nitrous is classed as "forced induction" or not. VE got thrown into the equation along with BMEP, CFM etc etc.

Can anyone enlighten me ?

Is there a good definition for "forced induction" ?

VE uses "air" in its equation, but does not consider the composition of air hence the ability of nitrous in the "air" to break down give more oxygen per volume.

I feel this would make an interesting discussion

[Reed]

i would say that in the phrase "forced induction" the first word (Mechanical) is silent. so supercharging (including exhaust driven) and thats pretty much it. no ram air and no N2O.

[TurboPuma]

playing devils advocate...

you say "mechanical" is "slient", isn't Nitrous "chemical" based BUT also "silent" ? and both are forms of "forced induction" ?

[Zgringo]

One of the primary factors affecting engine performance as the ability to get as much of the air and fuel mixture into the engine as possible. It can be thought of as the engines ability to "inhale". In order to produce power, an engine requires a fuel and air mixture to be mixed together and then brought into the cycle. The concept of forced induction is essentially a method wherein we literally compress the air before we bring it into the process of combustion. So basically, think of an engine as a person who is gasping for air after a long run down the street. This person is gasping because they are trying to circulate as much air as possible through their lungs. Now imagine if you were able to force more air into their lungs then they would otherwise be able to suck in on their own. This would in turn help them out very much. In fact, it would help them so much that they would probably be able to run for allot longer without having to stop in order to "catch their breath". In turn, this would yield greater performance. So basically, you can pretty much parallel this idea to an engine. The more air you get into it, the more performance you'll get out of it. This is where the concept of forced induction was derived. While different systems have been designed to achieve the same result (e.g. Nitrous, Superchargers and Turbo Units) the Turbo unit seems to have dominated. In brief, the systems differ from one another in the means by which the process is powered. The turbo unit works by making use of exhaust gases in order to compress the intake while the supercharger mechanically translates the engines rotational power in order to do the same job.
Nitrous is a chemical process.
All 3 are a means of forced induction, 1 using exhaust gases, 1 using mechanical means and the other chemical, and all accomplish the same thing, providing more oxygen to the engine.

[Black Lotus]

Originally Posted by Schister66

only turboing and supercharging is forced induction....N20 is not

I believe Schister is right.
Also--Various auto racing rulesmaking bodies have classed nitrous as a substance that alters fuel and/or combustion chemistry--not as a form of supercharge or forced induction.

[Reed]

Correct me if im wrong but i dont think of chemical injection as forced induction. Now would nitrous be considered chemical as it is just a way to get more OXYGEN into the cylinders? i dont think that either. i think one of the major requisites of a system to be considered forced induction is that it must force air into the cyliders. nitrous doesnt do this because it uses the vacume created in the cylinders to suck the nitrous oxide into them. (or a supercharger pushes it into them)

[nissanfanatic]

Well a 50 shot theoretically makes 50 more HP. So it has the equivalent of 5lb/min of airflow. Somehow 5lb/min of airflow extra is being ingested by the engine.

We should just come to an agreement on classification on all of these tho. I say power-adders.

[beef_bourito]

I would say forced induction is when you force the engine to intake more oxygen. this isn't the same as facilitating the intake (higher flowing intake etc) but forcing the engine to intake it. now since i said oxygen, nitrous would fit into the category, you are forcing the engine to get more oxygen because you are injecting an oxygen rich chemical into the intake.

[Reed]

well you are injecting oxygen into the intake but not forcing it into the cylinder. the cylinder is still sucking it in instead of it being FORCED in.

[Zgringo]

Originally Posted by Reed

i would say that in the phrase "forced induction" the first word (Mechanical) is silent. so supercharging (including exhaust driven) and thats pretty much it. no ram air and no N2O.

Now your 1st statement says no ram air and no N2O

Originally Posted by Reed

Correct me if im wrong but i dont think of chemical injection as forced induction. Now would nitrous be considered chemical as it is just a way to get more OXYGEN into the cylinders? i dont think that either. i think one of the major requisites of a system to be considered forced induction is that it must force air into the cyliders. nitrous doesnt do this because it uses the vacume created in the cylinders to suck the nitrous oxide into them. (or a supercharger pushes it into them)

Your 2 post kills you 1st post. Doesn't ram air force air into the cylinders. You speak with a forked tongue white man.
Correction #2 if there was no vacume at all, nitrous would still be injected into the intake. What about blown (supercharged) cars with nitrous...Hmmmm, no vacuum.

Anytime you force a engine to take in more oxygen than available to a N/A engine be it with ram tuning or whatever you forcing the induction system of that engine to provide more oxygen bearing air to the cylinders.

[Reed]

on your first correction, yes ram air does force more air into the engine but not by mechanical means.

on your second correction, even on a blown nitrous engine it is not the nitrous that is forcing itself into the cylinders, it is the supercharger forcing it in there.

[Alastor187]

Originally Posted by Reed

on your first correction, yes ram air does force more air into the engine but not by mechanical means.

on your second correction, even on a blown nitrous engine it is not the nitrous that is forcing itself into the cylinders, it is the supercharger forcing it in there.

Although when I first started reading this thread I would have agreed with you, after more thought I believe Zgringo is right.

Firstly, I can see why you would think ram air is not a mechanical device (no moving parts etc.) but I think it is. Would you consider a pitot tube or even a venturi a mechanical device? I would.

Secondly, if the point of forced induction is to get more oxygen (as apposed to air) into the cylinder, than Nitrous Oxide would defiantly be classified as a form of forced induction. I think we would all agree that Nitrous Oxide is a chemical method not mechanical.

So why not seperate forced induction into two or more subcategories such as:

FORCE INDUCTION
- Mechanical Induction
- Chemical Induction


In this way all devices that create a more oxygen rich cylinder condition are covered?

[Reed]

i would be more likely to say that ram air is forced induction before i would say nitrous is, and after some thinking i was almost ready to consent that ram air was. But, i still think that to be considered forced induction there needs to be active mechanical compression of air, and i dont consider pitot tubes or venturies to be mechanical or active. they are passive and are entirely dependant on the speed of the air that is already moving through/around them.

[nissanfanatic]

6psi of boost is "condensed air". a 50shot of nitrous is "condensed oxygen".

[King Of Crunk]

good point...