Prodigy Performance 3.6 Turbo DIY Install

[UselessPickles]

The centrifugal supercharger essentially the compressor side of a turbo, but driven by the crankshaft rather than an exhaust turbine. The mechanics by which they compress air and maintain manifold pressure on a running engine is the same.

Yes, there will be differences in characteristics of efficiency because of the differences in what drives the compressor (one system may get a different amount of net power with the same amount of boost), but the differences cannot possibly be so much that the supercharger is able to produce 40% gains with less than 1 psi, while the turbo does not produce any significantly noticeable gain at the same amount of boost. In general, I would expect the turbo to be more efficient at creating net gains from boost pressure, because it uses some "free" heat/expansion energy from the exhaust.

Your example of the Whipple producing 50% gains at low rpm... that's with more than 5 times the amount of boost at which RIPP claims 40% gains! With a similar boostower-gain efficiency, the RIPP would make less than 10% gains at the rpm/boost in question. That seems a lot more believable.

[gbaumann]

I agree with KaiserBill. It's a complex recipe. I've often wondered what type of hp/torque gains you'd get with just the larger injectors that come with these forced induction kits together with premium gas and an aggressive calibration. Let's put that on the dyno and pull without boost. People seem to focus on boost and PSI. But, as we all agree, the compressor is merely a means to an end. The end being a desired air/fuel charge. Again, I'm no expert but having built my fair share of naturally aspirated engines I know there are plenty of gains to be found in just helping the motor breathe better. The vacuum of the piston dropping on intake is not always met with an efficient air/fuel charge. Port size, runner design, valve size, cam degree, lift, duration and so on all affect whether the air/fuel charge snaps into the cylinder or slugs into it. If you've ever set cam degree then you know you can get a better air/fuel charge by delaying the opening of the intake valve a bit and causing the piston drop to create vacuum. When the valve opens the "rush" generates velocity and fills the cylinder better than if intake valve were to open right at TDC and the charge were just drawn into the cylinder. But don't wait too long or the vacuum can draw the intake valve open and cause havoc. Also, don't create too much vacuum and encourage power loss. And, of course, one cam degree doesn't serve all RPMs well. Nor does one anything. And so we have Variable Valve Timing, four valves per cylinder in some engines, unequal length intake runners, dual plane manifolds and so on. We have myriad options to play with.

The point here is unless you know how each calibration table is set up at a given RPM you just can't know what's going on inside the cylinder and what the HP/torque numbers will (or should) be. I'd approach it by defining what I want to achieve. Max torque at 2,800 rpm. Max HP at 5,500 rpm. Killer low end torque. Screamer peaking near redline. Build to your definition and don't worry about what others are saying they can do.

Of course, all that said (rambled) I think RIPP could be "a bit off" in their claim unless, of course, the thing is tuned just perfectly and you wouldn't really need any boost to get the gain with the larger injectors, cams timed right, ignition spot on and high octane fuel.

[UselessPickles]

The point here is unless you know how each calibration table is set up at a given RPM you just can't know what's going on inside the cylinder and what the HP/torque numbers will (or should) be.

And my point is that if the difference is not primarily the type of forced induction (which I don't think it is, because both are a centrifugal compressor, and the turbo should theoretically be more efficient anyway), then there must be some combination of RIPP exaggerating their claim, or a difference in the calibration (tune) causing the difference in low RPM gains. It's the same engine on the same vehicle, so there's no sense trying to get into details of how port size, runner design, etc. can affect the results. All those details are exactly the same between the two vehicles being compared here, so it's irrelevant.

Of course, all that said (rambled) I think RIPP could be "a bit off" in their claim unless, of course, the thing is tuned just perfectly and you wouldn't really need any boost to get the gain with the larger injectors, cams timed right, ignition spot on and high octane fuel.

And if that's the case, then a dialed-in tune with the turbo should get similar results at those low RPMs where boost is similar to RIPP. I heard a rumor that a new tune for the turbo may have some low rpm improvements, so maybe Prodigy and RIPP won't be so far away from each other at low rpms after all.

Still no response from RIPP. Maybe they don't check their PMs on that forum.

[KaiserBill]

I agree with KaiserBill. It's a complex recipe. I've often wondered what type of hp/torque gains you'd get with just the larger injectors that come with these forced induction kits together with premium gas and an aggressive calibration. Let's put that on the dyno and pull without boost. People seem to focus on boost and PSI. But, as we all agree, the compressor is merely a means to an end. The end being a desired air/fuel charge. Again, I'm no expert but having built my fair share of naturally aspirated engines I know there are plenty of gains to be found in just helping the motor breathe better. The vacuum of the piston dropping on intake is not always met with an efficient air/fuel charge. Port size, runner design, valve size, cam degree, lift, duration and so on all affect whether the air/fuel charge snaps into the cylinder or slugs into it. If you've ever set cam degree then you know you can get a better air/fuel charge by delaying the opening of the intake valve a bit and causing the piston drop to create vacuum. When the valve opens the "rush" generates velocity and fills the cylinder better than if intake valve were to open right at TDC and the charge were just drawn into the cylinder. But don't wait too long or the vacuum can draw the intake valve open and cause havoc. Also, don't create too much vacuum and encourage power loss. And, of course, one cam degree doesn't serve all RPMs well. Nor does one anything. And so we have Variable Valve Timing, four valves per cylinder in some engines, unequal length intake runners, dual plane manifolds and so on. We have myriad options to play with.

The point here is unless you know how each calibration table is set up at a given RPM you just can't know what's going on inside the cylinder and what the HP/torque numbers will (or should) be. I'd approach it by defining what I want to achieve. Max torque at 2,800 rpm. Max HP at 5,500 rpm. Killer low end torque. Screamer peaking near redline. Build to your definition and don't worry about what others are saying they can do.

Of course, all that said (rambled) I think RIPP could be "a bit off" in their claim unless, of course, the thing is tuned just perfectly and you wouldn't really need any boost to get the gain with the larger injectors, cams timed right, ignition spot on and high octane fuel.

Now, I would like to see your 6.4 on pair of turbos! Nelson Racing Engines from CA makes a Hemi they say gets 2000hp...

https://www.youtube.com/watch?v=wHmx6KvL69U

or more for your application a mere 700hp.
https://www.youtube.com/watch?v=cnBbofUhCdE

These are like 50K or more but hey if you want to play you've got to pay.


But getting back on point. It is so hard to compare bolt on kits true performance values because most of the time these units are designed for street driving applications. So they tend to make sure that the vehicle has a pretty broad power range and sacrifice a lot performance for reliability and drive-ability. But, usually what they get customers hung up on is manifold pressure. Yes, there is a relationship between manifold pressure and volume of air reaching the cylinder heads but it isn't a linear relationship if you are comparing two different units. I don't think Useless Pickles wants to accept the fact that you really need to know the volumetric efficiency of each unit at a specific rpm range. That is what is really going to tell you how much power you are going to get at specific boost setting.

For all we know the Ripp unit could be flowing twice as much air into the cylinder head as his Prodigy's Garrett turbo does at 1800rpm which could result in a 40% increase in power at that rpm range over the stock engine. It isn't impossible that unit could turn say 75hp into 105hp at 1800rpm. However, the fact is they might have really played around with this engine as well.

At the end of the day you are correct we need more information about how they've setup the systems and what their goals were.

[KaiserBill]

And my point is that if the difference is not primarily the type of forced induction (which I don't think it is, because both are a centrifugal compressor, and the turbo should theoretically be more efficient anyway), then there must be some combination of RIPP exaggerating their claim, or a difference in the calibration (tune) causing the difference in low RPM gains. It's the same engine on the same vehicle, so there's no sense trying to get into details of how port size, runner design, etc. can affect the results. All those details are exactly the same between the two vehicles being compared here, so it's irrelevant.



And if that's the case, then a dialed-in tune with the turbo should get similar results at those low RPMs where boost is similar to RIPP. I heard a rumor that a new tune for the turbo may have some low rpm improvements, so maybe Prodigy and RIPP won't be so far away from each other at low rpms after all.

Still no response from RIPP. Maybe they don't check their PMs on that forum.

Well, actually Turbos tend actually rob you of power when they aren't producing boost. They create back pressure on the manifold and that resistance has to be over come before you start to see a gain in power. The severity of this issue is based on the turbo size and the engine's size. Which is why when you sequentially turbocharger and engine you will notice the first turbo is small and it operates almost immediately producing boost. Then you have a bigger unit for higher RPM and higher power where the turbo's exhaust back pressure is more than over come by the immense HP and Torque gains.

And since centrifugal superchargers have the same basic deign they also have the same issues with lag. However, if you gear them correctly, you can reduce this lag at low rpm. Another plus is that your average centrifugal unit can run at much higher rpm ranges than the positive displacement model superchargers.

As for performance-- of course tuning a car for better performance at low rpm or high rpm will trump a car designed for daily driving under those conditions. But you just don't have enough information about each system to really say for example that if my turbo makes .75 PSI at 1800rpm I'm getting 800CFM and the Ripp unit is making 1100CFM at .75PSI Boost with 1800rpm. Then you could say oh, I see why my system isn't producing %40 percent more power at that rpm range because they have 300CFM more air in the engine than I do. And that is all we're telling you Useless Pickles you just need more technical information about the units to really do the analysis you want to do.

But, I agree that %40 increase in power at that rpm range seems hard to believe but it is possible to do.

[UselessPickles]

For all we know the Ripp unit could be flowing twice as much air into the cylinder head as his Prodigy's Garrett turbo does at 1800rpm which could result in a 40% increase in power at that rpm range over the stock engine.

No.

Each cylinder has a capacity: 3.6L / 6 = 0.6L

The cylinder fills with 0.6L of air at close to the manifold pressure. Yes, it's more complex than that due to valve overlap, timing, etc., etc., that can affect how efficiently the cylinder fills, but let's simplify it and just say it fills with 0.6L of air at the same pressure as the manifold pressure. It doesn't matter for the sake of this discussion because we are not comparing different engines with different cylinder fill efficiencies.

If the manifold pressure is 15.7 psia (1 psi boost above atmospheric pressure at sea level), then the cylinder will fill with 0.6L of air at 15.7 psia. It is 100% irrelevant what the supercharger/turbo is *capable* of flowing. If it is producing 1 psi boost, then there is 0.6L of air at 15.7 psia going into the cylinder. The only difference is going to be the efficiency of the turbo/supercharger and the intercooler, leading to differences in air temperature, which will affect the actual amount of air molecules in the cylinder. I can assure you that intake temps at full throttle at low RPMs with the turbo are pretty close to ambient temperature. There's no way that the RIPP could have intake temps at that RPM so much cooler that it could explain a much larger gain.

At 1800 rpm, the RIPP is making about 0.6 psi. So at sea level, standard temp, pressure, etc, that would be about 14.7 + 0.6 = 15.3 psi.
At 1800 rpm, the Prodigy is making about 0.3 psi, so same conditions, that's about 14.7 + 0.3 = 15.0 psi.

Ideal gas law, PV = nRT. Given the same volume (1 cylinder), temperature (already established IATs must be very close) and type of gas (atmosphere), pressure is DIRECTLY PROPORTIONAL to number of molecules of gas. That means that at 1800 rpm, the RIPP is only putting about 100 x (15.3 - 15.0) / 15.0 = 2% more air into the cylinder than the Prodigy.

The RIPP also only puts 100 x (15.3 - 14.7) / 14.7 = 4% more air in than stock. Add to that that the RIPP is DIRECTLY driven by the engine itself, it just does not make sense at all that the RIPP supercharger itself could be responsible for a 40% gain in net power output at that RPM.

Exhaust back pressure with the turbo would not explain a much smaller gain from the turbo compared to RIPP at the same RPM where boost is very similar. The exhaust pressure is much more indirect than the RIPP being powered by the crankshaft. That exhaust pressure is what is driving the turbo. I also happen to know that the exhaust:boost pressure ratio with the Prodigy setup is less than 1:1. That means the boost filling the cylinder is stronger than the exhaust back-pressure during valve overlap, so there won't be an issue of exhaust back pressure causing some exhaust to remain in the cylinder. The boost will actually help push the exhaust out of the cylinder.

It has to be either a much improved calibration over stock that favors power rather than whatever Chrysler sacrificed power for at that RPM (emissions? fuel efficiency? dumbing down power for "driveability"?), or the 40% gain claim is B.S., or a mix of both.

If such a large gain in power is possible at 1800 rpm with the RIPP, then a respectable gain should also be possible with the turbo down in that rpm range if tuned similarly. A 40% gain from RIPP vs a perceived zero gain from Prodigy at the same RPM (we unfortunately do not have any good stock vs Prodigy dyno charts yet to see for sure) simply cannot be primarily explained by differences between the supercharger and turbo themselves.

Well, actually Turbos tend actually rob you of power when they aren't producing boost.

The turbo is producing boost in the situation being discussed here.

[KaiserBill]

No.

Each cylinder has a capacity: 3.6L / 6 = 0.6L

The cylinder fills with 0.6L of air at close to the manifold pressure. Yes, it's more complex than that due to valve overlap, timing, etc., etc., that can affect how efficiently the cylinder fills, but let's simplify it and just say it fills with 0.6L of air at the same pressure as the manifold pressure. It doesn't matter for the sake of this discussion because we are not comparing different engines with different cylinder fill efficiencies.

If the manifold pressure is 15.7 psia (1 psi boost above atmospheric pressure at sea level), then the cylinder will fill with 0.6L of air at 15.7 psia. It is 100% irrelevant what the supercharger/turbo is *capable* of flowing. If it is producing 1 psi boost, then there is 0.6L of air at 15.7 psia going into the cylinder. The only difference is going to be the efficiency of the turbo/supercharger and the intercooler, leading to differences in air temperature, which will affect the actual amount of air molecules in the cylinder. I can assure you that intake temps at full throttle at low RPMs with the turbo are pretty close to ambient temperature. There's no way that the RIPP could have intake temps at that RPM so much cooler that it could explain a much larger gain.

At 1800 rpm, the RIPP is making about 0.6 psi. So at sea level, standard temp, pressure, etc, that would be about 14.7 + 0.6 = 15.3 psi.
At 1800 rpm, the Prodigy is making about 0.3 psi, so same conditions, that's about 14.7 + 0.3 = 15.0 psi.

Ideal gas law, PV = nRT. Given the same volume (1 cylinder), temperature (already established IATs must be very close) and type of gas (atmosphere), pressure is DIRECTLY PROPORTIONAL to number of molecules of gas. That means that at 1800 rpm, the RIPP is only putting about 100 x (15.3 - 15.0) / 15.0 = 2% more air into the cylinder than the Prodigy.

The RIPP also only puts 100 x (15.3 - 14.7) / 14.7 = 4% more air in than stock. Add to that that the RIPP is DIRECTLY driven by the engine itself, it just does not make sense at all that the RIPP supercharger itself could be responsible for a 40% gain in net power output at that RPM.

Exhaust back pressure with the turbo would not explain a much smaller gain from the turbo compared to RIPP at the same RPM where boost is very similar. The exhaust pressure is much more indirect than the RIPP being powered by the crankshaft. That exhaust pressure is what is driving the turbo. I also happen to know that the exhaust:boost pressure ratio with the Prodigy setup is less than 1:1. That means the boost filling the cylinder is stronger than the exhaust back-pressure during valve overlap, so there won't be an issue of exhaust back pressure causing some exhaust to remain in the cylinder. The boost will actually help push the exhaust out of the cylinder.

It has to be either a much improved calibration over stock that favors power rather than whatever Chrysler sacrificed power for at that RPM (emissions? fuel efficiency? dumbing down power for "driveability"?), or the 40% gain claim is B.S., or a mix of both.

If such a large gain in power is possible at 1800 rpm with the RIPP, then a respectable gain should also be possible with the turbo down in that rpm range if tuned similarly. A 40% gain from RIPP vs a perceived zero gain from Prodigy at the same RPM (we unfortunately do not have any good stock vs Prodigy dyno charts yet to see for sure) simply cannot be primarily explained by differences between the supercharger and turbo themselves.



The turbo is producing boost in the situation being discussed here.

Some of your formulas need to be tweaked... The guage pressure is different than absolute pressures and you will have to adjust your gauge pressure.

But here you go: Vortech makes two models of the V-2 Supercharger: The V-2SCI which runs at 17PSI and 1050CFM max making 725HP and the V-2E which runs at 17PSI and 1150CFM creating 775Hp max--

http://www.vortechsuperchargers.com/page.php?id=30157
http://www.vortechsuperchargers.com/page.php?id=30008

So, you know do you still want to go with CFM factor doesn't matter???? All we've been saying is that you don't have enough information to say anything meaningful about your Turbo running at .3 PSI and Ripp's unit operating at .6 PSI. You need more data points. Also you don't exactly know how Ripp has tuned this vehicle or the differences between the kits to really say anything at all about why your system seems to make less power at the same hp range.

Oh, and depending on your turbo's size and requirements .3 psi of boost might not over come the back pressure on the cylinder head.

Yes, your right you can figure out how much theoretical power the engine can create. However, to do that you really need to know all the specs for each unit you comparing. You don't have enough of the picture to really be able to see the differences in Ripp's setup and Prodigy's setup.

I applaud what you are doing actually. However, you just need more data. I would get a friend with a Ripp Unit and Your Truck to a Dyno place-- pop out the engines and really put all the gauges on them. Find out the flow from the supercharger/turbochargers, find out the programing points for the fuel air management system, check to see if maybe the Ripp system has a better flowing intake system, maybe they have a better aftercooler system, and then you can really say okay-- this is what we found and this what they claim and here is why it does whatever it does. It is expensive.

[UselessPickles]

Some of your formulas need to be tweaked... The guage pressure is different than absolute pressures and you will have to adjust your gauge pressure.

Please explain what was wrong with my calculations. I did my calculations in terms of absolute pressure (psia): atmospheric pressure + boost (aka guage pressure, psig).

But here you go: Vortech makes two models of the V-2 Supercharger: The V-2SCI which runs at 17PSI and 1050CFM max making 725HP and the V-2E which runs at 17PSI and 1150CFM creating 775Hp max--

http://www.vortechsuperchargers.com/page.php?id=30157
http://www.vortechsuperchargers.com/page.php?id=30008

So, you know do you still want to go with CFM factor doesn't matter????

Yes, for the context of what I'm talking about, CFM *capability* is irrelevant. The specs you linked to only show that a supercharger that is *capable* of flowing more air at a given pressure is *capable* of producing more power (because more total air per unit time = more power; I did not need to be convinced of this) than a supercharger that can maintain the same boost, but at a lower flow rate... IF... BIG IF... it is paired up with an engine that is capable of CONSUMING air at that flow rate. The flow rating of a supercharger/turbo is important in choosing the correct size for the engine that you are installing it on. A higher CFM supercharger cannot magically force more air through an engine at a higher flow rate, but at the same pressure. To push more air through the engine requires higher pressure (which would actually still be the same lower CFM, but at a higher pressure, because CFM is just volume per rate of time, regardless of pressure).

Two different things that are pushing air into the same engine with the same pressure cannot possibly be pushing different amounts of air into the cylinder (which I already fully explained in my previous post).

Oh, and depending on your turbo's size and requirements .3 psi of boost might not over come the back pressure on the cylinder head.

Did you miss the part where I mentioned that the exhaust:boost pressure ratio of the turbo system is less than 1:1? And therefore the boost pressure is stronger than exhaust back-pressure?

[UselessPickles]

One last attempt to explain from a different direction why CFM capability of the supercharger/turbo is completely irrelevant to my analysis of RIPP's claim of 40% gains at 1800 rpm. Please actually read through this and put some effort into understanding it before responding.


CFM = Cubic Feet Per Minute

That's a rate of flow of a volume of air per unit time. A volumetric flow rate. That's it. Volume/time. Pressure, mass of air, or number of molecules is completely independent of flow rate.

What is the flow rate of the Pentastar engine at 1800 rpm? For simplicity, we will ignore extra volume in the ceiling of the combustion chamber, valve overlap, etc. Let's just go by the displacement.

3.6 L total displacement, but each cylinder requires 2 rotations of the engine to intake and exhaust 1 cylinder full of air.

So (3.6 L) * (1800 rpm) / 2 = 3240 L/minute

Again... this is just volume of air. Pressure, temperature, etc., are all unspecified. It does not specify the AMOUNT of air flowing through the engine. Just the VOLUME. The AMOUNT of air depends on the volume, pressure and temperature.

So what's the volumetric flow rate of the engine at 1800 rpm with 0.3 psi boost? At 0.6 psi boost? At 37 psi boost? The answer is always 3240 L/minute. The difference is the pressure and temperature of the air, which results in a different AMOUNT of air, but the same VOLUME.

Even if there's some inefficiency with cylinder filling (intake valve isn't open long enough to equalize pressure between cylinder and manifold, for example), the end result will still be the same VOLUME of air, but at a slightly lower pressure than manifold pressure (the ECU has lookup tables of volumetric efficiency multipliers to deal with this).

What if you have a supercharger capable of flowing up to 98,000 L/min at 58 psi, and it's producing 23 psi at 1800 rpm? What's the volumetric flow rate through the engine now? Still 3240 L/minute! The supercharger does not change the volume of the cylinders. And it does not change the engine speed. Therefore it cannot possibly change the volumetric flow rate of air through the engine. It only compresses air, changing its pressure and temperature.

Therefore, two different forced induction systems producing the same boost pressures and intake air temperatures on the same engine at the same engine speed cannot possibly be operating at different volumetric flow rates (CFM, or whatever units you care to use), no matter what their peak boost or peak CFM ratings are.

[KaiserBill]

One last attempt to explain from a different direction why CFM capability of the supercharger/turbo is completely irrelevant to my analysis of RIPP's claim of 40% gains at 1800 rpm. Please actually read through this and put some effort into understanding it before responding.


CFM = Cubic Feet Per Minute

That's a rate of flow of a volume of air per unit time. A volumetric flow rate. That's it. Volume/time. Pressure, mass of air, or number of molecules is completely independent of flow rate.

What is the flow rate of the Pentastar engine at 1800 rpm? For simplicity, we will ignore extra volume in the ceiling of the combustion chamber, valve overlap, etc. Let's just go by the displacement.

3.6 L total displacement, but each cylinder requires 2 rotations of the engine to intake and exhaust 1 cylinder full of air.

So (3.6 L) * (1800 rpm) / 2 = 3240 L/minute

Again... this is just volume of air. Pressure, temperature, etc., are all unspecified. It does not specify the AMOUNT of air flowing through the engine. Just the VOLUME. The AMOUNT of air depends on the volume, pressure and temperature.

So what's the volumetric flow rate of the engine at 1800 rpm with 0.3 psi boost? At 0.6 psi boost? At 37 psi boost? The answer is always 3240 L/minute. The difference is the pressure and temperature of the air, which results in a different AMOUNT of air, but the same VOLUME.

Even if there's some inefficiency with cylinder filling (intake valve isn't open long enough to equalize pressure between cylinder and manifold, for example), the end result will still be the same VOLUME of air, but at a slightly lower pressure than manifold pressure (the ECU has lookup tables of volumetric efficiency multipliers to deal with this).

What if you have a supercharger capable of flowing up to 98,000 L/min at 58 psi, and it's producing 23 psi at 1800 rpm? What's the volumetric flow rate through the engine now? Still 3240 L/minute! The supercharger does not change the volume of the cylinders. And it does not change the engine speed. Therefore it cannot possibly change the volumetric flow rate of air through the engine. It only compresses air, changing its pressure and temperature.

Therefore, two different forced induction systems producing the same boost pressures and intake air temperatures on the same engine at the same engine speed cannot possibly be operating at different volumetric flow rates (CFM, or whatever units you care to use), no matter what their peak boost or peak CFM ratings are.

Whatever, you want to believe is fine with me. However, your first formula is wrong-- your volume at 1800rpm is always 3.6L at 5400 rpm the engine still is 3.6L at 150,000rpm still 3.6L! Now CFM is also directly related to the more important number--- lbs/Ft3 measuring air-density. That formula looks like this take CFM x .076Lbs/ft3 and poof that is the magic number. I tend to use CFM because it, well, works just as long as you remember to change it over to Lbs/ft3 and then remember that is per minute. Thusly, even a compressor running at .6 PSI operating at X Lbs/ft3 will create less power than a similar unit doing .6PSI with X+2 Lbs/ft3.

Hence my Vortech examples-- at any given Manifold pressure the V-2E has the potential to produce more horsepower than its similar brother the V-2SCI unit. That little 100CFM difference if it is constant across the entire units performance band produces an extra 7.6Lbs/Ft3 of air mass per minute!!! which if you say rough equates to about 30-50hp at any rpm range for any given boost. If that is a constant 100CFM increase. Now it might not be, but it could be. Which would make your analysis totally meaningless if you didn't take that extra air-mass into account for each given boost level.

So here is the general rule of thumb!!!! And it isn't supper accurate, but if you are making 125 HP at flywheel/ by 10.5 = 12.5hp per Lb/min. So if you are at 1800 rpm and you are pulling in an extra 2.2lbs/min of air (which can then be converted over to CFM, LFM, KG/CM3 or ML/CM or whatever you like) you roughly get a 27.5 hp which is pretty damn close to a 40% increase in power if go from 75HP at 1800 rpm to about 102.5HP: So what it is about a 37 percent increase in power? And it only required an addition 2.2lbs/min of air mass to reach the cylinders.

Until you know exactly how much air/mass is reaching the cylinders for a given boost pressure will not tell you anything of importance. Because guess what moving more air at any pressure means the potential for more air-molecules to be found in that specific volume of gas. Damn that air density.

Also on a side not I think you are misunderstanding Pressure Ratio on the Turbo chart. It doesn't measure the ratio of boost produced for a given volume of exhaust- it measures the ratio of compressione from absolute pressure at the inlet of the turbo to the outlet of the turbo. So lets say you have a 1.25:1 Pressure Ratio at 55,000rpm (impeller speed) means that you out pressure is 1.25 times that of the absolute pressure reading of the inlet side. Most turbos never get much more than 3.0 to 3.5 to 1 ratios. But that is pretty damn impressive. That's why staging turbos can get really insane pressures rapidly.