Prodigy Performance 3.6 Turbo DIY Install

[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?