Engine: Cat vs Non-Cat

[pridekit]

So I have heard about a Cat engine and well, not a Cat engine. I don't really understand what Cat engines are. I gather they are Catalyst engines from Indmar, but what does that mean?

Could someone explain (or provide links) what the Cat engines are, the differences between those and normal engines, and how to identify a Cat engine?

Thanks in advance!

[MJHKnox]

The cat is the catalytic converter. Used to deal with heat. I think the term used is ETX/CAT (Extreme Tuned Exhaust with Catalyst).

Try this: http://www.moomba.com/msgboard/showt...mpi-325-or-340

Mark

[cadunkle]

Emissions. Thank your government for driving up the price of your new boat and wear items on your boat. There is nothing extreme, tuned, or performance about catalytic converters. It's smog equipment robbing you of power and increasing fuel consumption. Though in fairness the performance difference is likely minimal for typical low flowing cast manifolds on a ski boat.

As for identifying... Look for manifolds or risers that are bulky or don't look normal and are not performance parts.

[MJHKnox]

Thanks cadunkle. I guess I should read my post before I hit the Post Button - catalytic converter = emission scrubber.
Some local guys were talking about that motor running at lower temps. I do not know about the motor internals that would cause that.
The Cat started with the emission standards in California 2007/8, the followed by the EPA.

I recall my buddy's 350 MAG MPI/Mercruiser and the two O2 sensors on the exhaust manifold to measure the fuel/air mix in the exhaust.

Yes on the prices, the B.O.A.T. (bust out another thousand) would be multiplied by 2 or 3 on engines back then.

M-

[pridekit]

Thanks guys! I am pricing out manifolds/risers so I can start putting money aside for them.