Explain to me "tube motor"

[f8f1]

Title says it all.

[Lon Moer]

It's a matter of removing the intercooler on the Merlin and replacing it with a tube that runs directly from the supercharger to the motor. The interecooler is the big boxy thing that sits at the rear of the engine, and is a liquid cooled heat exchanger that cools and controls the teperature of the compressed air/fuel mixture from becoming too hot.

Dwight Thorn developed the 'tube' motor back in the 1960's and was used as early as Chuck Lyford's Bardahl Special and on the Bardahl Hydroplanes. Since then, the trend for stuff like Dwight Thorn's "Mouse Motors", and copies like Mike Barrow and Mike Nixon have made, utilize the tube specifically to GET the air/fuel mixture hotter...hopefully for more horsepower.

Rick Shanholzer is a protige' of the late Dave Zeuschel. Big Z 'didn't believe' in using the tube...so all of his motors had the intercooler. Rick builds his the same way. They're still very good engines. And Rick has improved on Z's designs from back in the 80's.

Again, not digging on him...just a philosophical way of building the engines. But it's been shown that the tube motors can typically handle higher MAP than the intercooler engines.

[RichH]

It's a matter of removing the intercooler on the Merlin and replacing it with a tube that runs directly from the supercharger to the motor. The interecooler is the big boxy thing that sits at the rear of the engine, and is a liquid cooled heat exchanger that cools and controls the teperature of the compressed air/fuel mixture from becoming too hot.

Dwight Thorn developed the 'tube' motor back in the 1960's and was used as early as Chuck Lyford's Bardahl Special and on the Bardahl Hydroplanes. Since then, the trend for stuff like Dwight Thorn's "Mouse Motors", and copies like Mike Barrow and Mike Nixon have made, utilize the tube specifically to GET the air/fuel mixture hotter...hopefully for more horsepower.

Rick Shanholzer is a protige' of the late Dave Zeuschel. Big Z 'didn't believe' in using the tube...so all of his motors had the intercooler. Rick builds his the same way. They're still very good engines. And Rick has improved on Z's designs from back in the 80's.

Again, not digging on him...just a philosophical way of building the engines. But it's been shown that the tube motors can typically handle higher MAP than the intercooler engines.

You left out the ADI part... rather than an intercooler that is prone to cracking at high MAP, ADI injection is used to cool the charge. Incidentally, early Merlins before intercoolers were employed were actually "tube" motors... they just didn't have ADI. So the tube itself is not a novel idea...

[Smee Again]

As has been stated, the “tube” is just that - an approximately 5” diameter tube connecting the outlet from the blower to the intake manifold of the Merlin. As for the aftercooler (or intercooler), it works as a heat exchanger to cool the compressed fuel/air charge from the blower, which is heated as it’s compressed. On a stock Mustang, 1/3 of the radiator is used for the aftercooler, the remaining 2/3 for the engine coolant. But even with an aftercooler in place, any power setting above about 70” MAP will still require ADI to provide additional cooling for the fuel/air charge and prevent high induction temps (go BOOM!). With a tube motor, the flow of the fuel/air to the intake manifold is much cleaner and more efficient, but requires a TON of ADI, as there is no help from an aftercooler of any kind. We used to do regular checks of our ADI regulator on both RR III and Dago Red, and the amount of ADI flow at race power on a tube motor looks like a damn fire hose!

SA

[MRE]

I like your explanation Smee, see you in Reno..