Prodigy Performance 3.6 Turbo DIY Install

[UselessPickles]

What do you say to letting me take the post and start a new thread. I only hesitate because you specifically state "not worth its own thread".

If anyone could chart it out pickles, its you. What do you say? Everyone loooooves to O.D. on charts and graphs.

I just didn't feel like committing to fleshing out the beginnings of a complete FI comparison post at the time. Next time I'm looking to kill some time in the evening, I'll start a new thread with the intent to continue to update the first post as a basic comparison guide.

Maybe this is a dumb question, but if RIPP and Mag indicate they are producing 8 PSI of boost with std pulley, and 11 PSI of boost with High Elevation pulley, why does your chart (or their data) only show Magnuson with a max of 6 PSI?

I took the boost data straight from Magnuson's own dyno chart (link in my post above was incorrect, but is now fixed). This is a chart that Ross posted on the wrangler forum, identifying it as a dyno chart from Magnuson:




If you know of any more recent data about that supersedes that chart, please point me to it so I can update my data.

BTW, this is from Magnuson's web site:

In testing, this kit demonstrated between an 80 - 100 HP and 60-70 lb-ft increase at the wheels at just 6 psi.

[UselessPickles]

to obtain an increase in CFM at the same pressure would require an increase in the diameter of the garden hose!!!

Since water is incompressible (in practicality, at least), but air IS compressible, the garden hose is a bit oversimplified.

With water, there IS a direct relationship between volumetric flow rate (e.g., CFM) and mass flow rate (e.g., lbs/ft^3).

With air, the relationship between volumetric flow rate and mass flow rate depends on density, which depends on temperature, pressure and volume.

To make things more confusing, in the world of engine dynamics, they speak of the volumetric efficiency of the engine. It is often explained as the percentage of "volume" of the cylinder that gets filled with air. As I discussed before, the volume of the displacement of the cylinder never changes. So volumetric efficiency is a bit of a misnomer (but not entirely incorrect, either, as I'll explain later). It's really a ratio of the AMOUNT (mass) of air that gets into the cylinder compared to the AMOUNT of air that *would* fill the cylinder *if* it were allowed to reach full equilibrium with the intake manifold.

At 50% volumetric efficiency (number chosen arbitrarily to make my later example easier to comprehend), it doesn't mean that the cylinder is only filled 50% of the of the way with air. That's impossible, because whatever AMOUNT of air enters the cylinder will expand to fill the entire volume.

But if you think of it from the perspective of the intake manifold, the term "volumetric efficiency" actually makes sense: 50% efficiency means that 50% of the cylinder's volume worth of air in the manifold has filled the cylinder. For the Pentastar, a cylinder is 3.6L / 6 = 0.6L. Let's say the manifold pressure is 10 psi (easy number to work with). At 50% volumetric efficiency, that means 50% of 0.6L = 0.3L worth of the manifold's 10 psi air enters the cylinder. That AMOUNT of air will fill the entire 0.6L in the cylinder (when the piston is at the bottom of the stroke). Volume are inversely proportional. That means when that 0.3L of the 10 psi air expands by double to fill the 0.6L cylinder, the pressure will be cut in half to 5 psi* (see disclaimer below). The air in the cylinder now has 50% the pressure of the manifold, AND 50% the amount (mass) of air that would have filled the cylinder if it were allowed to completely "fill" with air from the manifold.

So because of the relationships between volume, pressure, density and mass of air, it can really be thought of as either volumetric efficiency (from the perspective of the manifold) OR mass filling efficiency. It all works out mathematically the same, and will produce the same result in the calculation to determine the amount of air in the cylinder.

*Disclaimer: I simplified a bit for the explanation. When that 0.3L of 10 psi air expands into the 0.6L cylinder, the pressure may not become exactly half, because I believe the temperature of the expanding gas will decrease as well. This gets into some complications that I don't understand. So some of my previous statements in earlier posts may be incorrect about the relationship of how much pressure gets into the cylinder, but the concepts would be correct if you worked in terms of mass rather than pressure.

[KaiserBill]

Good explanation Pickles! I kept scratching my head with what was being written in the other posts regarding CFM... As an example... The idea that you could push 1000 CFM @ 1 PSI vs. 1500 CFM @ 1 PSI through the same pipe, what the!?! Did someone not play with a garden hose as a kid enough to know that to obtain an increase in CFM at the same pressure would require an increase in the diameter of the garden hose!!!

For those who didn't get to play with a garden hose as a kid, here's the real formula.

cfm = area of pipe * sqrt (2*Pressure/density)

The idea that one turbo could deliver higher CFM at the same pressure, on the same engine, at the same RPM versus another turbo is just silly. That goes against the laws of physics (as previously stated by said poster named Pickles.)

No, genius air expands when it enters the cylinder head!!!! This why Roots Lobe Units are called Blowers-- because they develop very very low pressure all the time! So, since no engine runs at 100% volume metric efficiency throughout its entire rpm range-- you can squeeze in more air into the cylinders just by increasing the volume metric flow of the air reaching engine. Remember as the air expands to fill in the open space it will slightly cool. This is where Roots Lobe units really have problems because of the way they create pressure and volume they actually tend to heat the air up more at low rpm then they do at high rpm. But when it comes to volume metric efficiency across a broad RPM range the RL system is hard to beat. Now, with a more air friendly system like the Centrifugal unit Vortech uses the air at low pressures is relatively cold and dense-- the the more you add the greater air density in the cylinder head (up to a point). The point is this at .6 PSI there is a good bet that the Vortech unit can move enough air into the cylinder head to achieve a noticeable increase in the volume metric efficiency of the engine without requiring the engine to need extra manifold pressure to compress more air into the cylinder head. So basically, you might go form say 91% volume metric efficiency to 95% efficiency thus allowing you to burn more fuel creating a mere 30-40hp extra. Physics is just fine... All the fun laws of Boyle's, Charles', and the kinetic theory of heat are intact and happily loving each other.

What, I said was Manifold Pressure doesn't necessarily have a linear relationship between CFM and Boost Pressure! You can very well have two different turbos running at the same engine speed, on similar engines developing two radically different CFM outputs. Why do you think they make so many different units that fit essentially the same size displacement engines??? Is it because they just want to sell people two different turbos for no reason at all? No, it is because different sorts of performance goals require different types of units and peak CFM outputs for specific manifold pressures.

Then I proved to you people with a link to two Vortech V-2 mode Units that outwardly look identical with only minor differences in specifications that have 100CFM difference in peak output. And this translates to 50HP extra at peak performance all while maintaining a maximum boost of 17PSI. So, yeah, would like to try to stating again how wrong I am.

http://www.vortechsuperchargers.com/page.php?id=30157

http://www.vortechsuperchargers.com/page.php?id=30008



My entire point since day one is that if you look a boost graph and decide that some company is misrepresenting their claims on this data alone-- you will probably look foolish. There are just so many more factors that come into play with adding forced induction to an engine. If you don't know how the engines are setup and what goals each kit has-- then it is hard to say that one claim is preposterous because I've got Prodigy's turbo kit and it cannot do it. It might not be designed to do it. And that is just bummer for you. Personally, I think they put out boost graphs because they know most people buying kits aren't well enough versed in forced induction theory to really know what they are looking at.. So yeah you see 10PSI or 11PSI or 22PSI and think wow that is going to be so awesome in my car, truck, or jeep. And not knowing what exactly your engine is doing to start with gives you almost no way of knowing how effective that kit will be on your engine in the long run.

[KaiserBill]

Since water is incompressible (in practicality, at least), but air IS compressible, the garden hose is a bit oversimplified.

With water, there IS a direct relationship between volumetric flow rate (e.g., CFM) and mass flow rate (e.g., lbs/ft^3).

With air, the relationship between volumetric flow rate and mass flow rate depends on density, which depends on temperature, pressure and volume.

To make things more confusing, in the world of engine dynamics, they speak of the volumetric efficiency of the engine. It is often explained as the percentage of "volume" of the cylinder that gets filled with air. As I discussed before, the volume of the displacement of the cylinder never changes. So volumetric efficiency is a bit of a misnomer (but not entirely incorrect, either, as I'll explain later). It's really a ratio of the AMOUNT (mass) of air that gets into the cylinder compared to the AMOUNT of air that *would* fill the cylinder *if* it were allowed to reach full equilibrium with the intake manifold.

At 50% volumetric efficiency (number chosen arbitrarily to make my later example easier to comprehend), it doesn't mean that the cylinder is only filled 50% of the of the way with air. That's impossible, because whatever AMOUNT of air enters the cylinder will expand to fill the entire volume.

But if you think of it from the perspective of the intake manifold, the term "volumetric efficiency" actually makes sense: 50% efficiency means that 50% of the cylinder's volume worth of air in the manifold has filled the cylinder. For the Pentastar, a cylinder is 3.6L / 6 = 0.6L. Let's say the manifold pressure is 10 psi (easy number to work with). At 50% volumetric efficiency, that means 50% of 0.6L = 0.3L worth of the manifold's 10 psi air enters the cylinder. That AMOUNT of air will fill the entire 0.6L in the cylinder (when the piston is at the bottom of the stroke). Volume are inversely proportional. That means when that 0.3L of the 10 psi air expands by double to fill the 0.6L cylinder, the pressure will be cut in half to 5 psi* (see disclaimer below). The air in the cylinder now has 50% the pressure of the manifold, AND 50% the amount (mass) of air that would have filled the cylinder if it were allowed to completely "fill" with air from the manifold.

So because of the relationships between volume, pressure, density and mass of air, it can really be thought of as either volumetric efficiency (from the perspective of the manifold) OR mass filling efficiency. It all works out mathematically the same, and will produce the same result in the calculation to determine the amount of air in the cylinder.

*Disclaimer: I simplified a bit for the explanation. When that 0.3L of 10 psi air expands into the 0.6L cylinder, the pressure may not become exactly half, because I believe the temperature of the expanding gas will decrease as well. This gets into some complications that I don't understand. So some of my previous statements in earlier posts may be incorrect about the relationship of how much pressure gets into the cylinder, but the concepts would be correct if you worked in terms of mass rather than pressure.

It is not a misnomer. What it is saying is that the distance between the molecules of air is now 50% greater. So let's say you have .6L of air in a 1.2L bottle that means the gas has twice the volume to fill-- now I can fill this same space with 50% more stuff before I start to need extra pressure to get air into the same space. That is all it means. It have this 1.2L bottle completely filled at 14.7PSI and I try to fill it up with 50% more air I will need roughly 50% more more pressure to do so. So, to get to 150% Volumetric efficiency I will need roughly 22.05PSI of pressure in the bottle which is the original 14.7 PSI to keep the air in and then addition 7.35PSI to compress it enough to get 50% extra volume in.

So, as I said before more air in the chamber means what??? More molecules which means greater density!

[UselessPickles]

It's over. Stop. Please.

[UselessPickles]

I do need to correct myself on one detail, though. The reference for "volumetric efficiency" is atmosphere, rather than the intake manifold, as I incorrectly stated early. This does not invalidate any of the concepts or relationships I described, though. So volumetric efficiency is the percentage of a cylinder's volume worth of ambient atmosphere air (the amount of air, number of molecules, in that volume of atmosphere) that actually gets into the cylinder. Boost causes a volumetric efficiency of over 100%.

[KaiserBill]

I do need to correct myself on one detail, though. The reference for "volumetric efficiency" is atmosphere, rather than the intake manifold, as I incorrectly stated early. This does not invalidate any of the concepts or relationships I described, though. So volumetric efficiency is the percentage of a cylinder's volume worth of ambient atmosphere air (the amount of air, number of molecules, in that volume of atmosphere) that actually gets into the cylinder. Boost causes a volumetric efficiency of over 100%.

What happens when we increase our volumetric efficiency from say 80% to 90%??? I'll give you a clue--- AIR DENSITY INCREASES!

[UselessPickles]

I don't know why you are shouting the obvious at me and think you need to give it to me as a clue. Your "clue" is not inconsistent with anything I have said. Please stop. Your lack of comprehension is hanging out and it's embarrassing.

[KaiserBill]

It's over. Stop. Please.

Why Pickles... What did the Ideal Gas law leave you cold this morning? Or have you finally realized that, yes, you need more data to make any intelligible analysis of the Ripp v. Prodigy systems?

[Yoinkers]

Why Pickles... What did the Ideal Gas law leave you cold this morning? Or have you finally realized that, yes, you need more data to make any intelligible analysis of the Ripp v. Prodigy systems?

This thread is off the rails. Spiraling out of control. The tech discussion here makes my head spin.