mac21 or novarossi

[AndyBrown]

I think it is a nearly an even trade off with the slight advantage to the Drum engine.

While the crank induction has less drag, the very important flow through the crank is limited compared to the drum. The I.D of the drum is lager than the ID of the crank. We are also able to move the timing window closer to the center of the engine. Something we can't do with the crank because the big bearing is in the way. We have moved this window deeper into the engine since the early versions of the MAC and the torque and power have greatly increased.

With the Drum engine we can use a crank bearing that has less rotating mass, lower ball speed for a givin rpm and yet is stronger. Cheaper too when it needs replacing which is not often.

My main reason for building the crank induction MAC for inboard use is because there are a number of boaters who have existing installations or boat designs that will not easily except the MAC drum engine. For instance, the MAC drum engine will not fit in a Dumas Hawk rigger without major modification and upsetting the center of gravity.

 

[TomMoorehouse]

So if you had the choice..... you would use the regular mac before the rear exhaust?

I'm glad to hear they have more torque now. I had an early one (1st or second batch i believe) and it really didnt like to spin up my 1450. will the newer ones do this better?

what is the price for the new 21's when they come in? errr uhhh hey Andy..... what's my price for one

oh yea..... what's this plugged rotor thing I keep hearing about? are the new ones plugged?

 

[AndyBrown]

The last batch was plugged. and had several other improvments.

 

[Paul Pachmayer]

Hello Guys,

I've been keeping a close eye on this thread since I'm in the market for a .21 for sport hydro. Sounds like the Mac is the way to go so Andy tell me, which motor would be best suited to my task? Keep in mind I'm a "newbie" to nitro but I do want the best for my boat.

Paul.