Does anyone know, if there is any difference in the power the merc's with cat's put out, compared to the ones without cat's?

Any hp gains, if removed?

Thanks

I doubt there is any way to test it right now since the new 502engines coming out will still be under warranty for at least a year. Probably would have to recalibrate the ecm's as well.

I can tell you this much, they make the engine compartment EXTREMELY HOT!

cats when new and everything 100% should rob little or no power..
Its when it gets older or if stuff changes like a/f that they will start clogging and robbing power.
I think catalytic convertors on a boat are a really stupid idea..

This was my fear when I heard they were going to try it, can't wait till someone drives through the first misfire sequence and the cats go cherry red, couple thousand degrees inside a small fiberglass box...yeah, that sounds like a good idea

Any form of restriction however small robs power.

My new motorcycle has converters. Talk about hot pipes!

Thanks guys.

Are they not waterjacketed? That would be the most insane thing I've heard. I wonder if the insurance companies will like that.

Is it then not possible to install CMI sport tubes on something like a 496HO? Just a thought.

Lets hope all the good engine builders out there find a way to get lots of power with cleaner motors, so our hobby and passion won't suffer too much

496's don't have cats. You can put headers on them.
Just the new 502's have cats.

Well, you can tune around most restrictions and still make good power, but if it is more restricted than it was specced for then you lose power. I bet your little German toy makes all kinds of power with cats on it

They are water jacketed but they still have to generate a ton of heat even when they are running right, if they run too rich like a misfire they get really hot.

The funny thing is that a high performance fuel injected engine like an HP525 is so efficient already that a catalyst isn't even needed to get good emissions from them, except at idle and when cold.