ProCharger on Nitro?

[Chili]

Interesting article on the possibility of replacing the blower with a procharger.

Running A ProCharger On A Top Fuel Nitromethane Engine

What would happen if Top Fuel engines switched from the traditional Roots blowers to a modern ProCharger F-4X supercharger?

www.dragzine.com

 

[flapjack]

How hot does the compressed air get coming out of a procharger versus a roots blower?
I know on a roots blower the injection of nitro in the hat helps cool the air flowing through
the blower, but what would they do for a procharger? Or do they just run that much cooler?

 

[Chili]

How hot does the compressed air get coming out of a procharger versus a roots blower?
I know on a roots blower the injection of nitro in the hat helps cool the air flowing through
the blower, but what would they do for a procharger? Or do they just run that much cooler?

I don’t know much about the technical side of them. They are definitely lower maintenance than a roots blower.

 

[Ramjet]

Not sure it would ever happen, but the temperature could be reduced with an intercooler. The advantage of a centrifugal supercharger over a Blower is in the way the air is delivered and its effieincy. The Supercharger has constant even flow vs the Blower which is positive displacement with two rotors with three blades on each side. The Blower basically discharges air into the engine by pulses and is not evenly discharged as designed. Thats why they are kind of turned into compressors by changing the shape of the discharge side. Even so about a zillion nozzles are needed to make everybody (all cylinders) even. This also helps the uneven stress on the crankshaft as well as the cylinders. NHRA does not allow the third option which is the Screw Supercharger because of the RPM (overdrive) they have to turn. The Procharger (Gear driven Supercharger) has the same situation but only more so. You can think of the Compressor side of a Turbocharger pretty much as the same as the "Procharger" Compressor but just gets its spinning a different way. The both are ultra high RPM compared to the Blower. The Blower is pretty basic - A 1471 Blower pumps almost 1000 cubic inches (71X14) of air per revolution into the engine @ 1 to 1 ratio. Multiply that by the overdrive to get how much air goes into the engine. To get that much air from the "Procharger" or Screw (PSI) you have to spin it to numbers that are crazy. The bottom line on this is pretty soon the only people that once you allow this stuff you will probably have is a very few who can afford it. The 4 car show would be Elon Musk - Warren Buffett - Jeff Bezos & Bill Gates. My money is on Musk .

 

[none]

Roger,

A Screw supercharger is not allowed in the Nitro classes mainly because when they were coming into the Alcohol classes the Nitro racers all agreed that they should be banned from use with Nitro. The expense involved in sorting out the new combination would be prohibitive. And if it turned out that it was actually better, then the expense for every team to switch as well as making their current blower inventory worthless would not be a good thing for anybody.

Alan

 

[Ramjet]

Roger,

A Screw supercharger is not allowed in the Nitro classes mainly because when they were coming into the Alcohol classes the Nitro racers all agreed that they should be banned from use with Nitro. The expense involved in sorting out the new combination would be prohibitive. And if it turned out that it was actually better, then the expense for every team to switch as well as making their current blower inventory worthless would not be a good thing for anybody.

Alan

Agree - From above - The bottom line on this is pretty soon the only people that once you allow this stuff you will probably have is a very few who can afford it. The 4 car show would be Elon Musk - Warren Buffett - Jeff Bezos & Bill Gates. My money is on Musk .

 

[handsome]

the manifold temps are very high on procharged engines so I'm not sure how that will work with nitro.

 

[Ponyhntr]

the manifold temps are very high on procharged engines so I'm not sure how that will work with nitro.

ProChargers are much more efficient (i.e. cooler air charge) than a roots blower at the same boost pressure. The fuel volume is what is cooling the charge air, so theoretically, the air entering the engine from a ProCharger combo will be the same, if not cooler, than that of a roots blown combo.

 

[handsome]

I've raced with both. some pro mods see intake temps of 400 degrees. even with injection I saw 200 degree temps on my procharged dragster. I went back to a roots and the intake temp is an average of 130 degrees.

 

[Ramjet]

Temperature of a gas (Air) is directly proportional to the pressure given the same volume. If you squeeze more air together to raise the pressure given the same volume the temperature goes up proportionaly. What can affect this is the efficency of the pump (Blower vs Supercharger). Fuel does the same thing. In what we call Fuel Injection (It's Fuel Induction unless its a Diesel) the temperature drops when the fuel looses pressure for instance when it exits through an orifice (nozzle) and expands. It actually does not reach the Atomic state but we call it Atomizing. It's kind of like calling an Engine a Motor. Blown Alcohol engines usually put as much Alcohol as they can in the Top because it cools the charge. The guage pressure in the manifold is lower but the efficency is higer and the result is better.