Do cats rob power?
 

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:lolhit::lolhit::lolhit:

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 :evilb:

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.

Griff

Last I looked at mercs web site, I'm pretty sure I saw them with cat's. I think they offered them from 2009, but I could be wrong.

I'm right there with ya. Having seen dyno runs of Highflow cats VS test pipes, the test pipes won out every time.


Darrell.

[QUOTE=Ted G;3216155]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 :evilb:

A friend of mine who is a mechanic, told me that, when they tried to remove cat's on modern cars, to increase performance, it would work the other way, and they could not tune it to perform better. This was on Audi's, so not really boat related, so therefore my uncertanty, about the same issue on the V8's from merc.

A friend of mine who is a mechanic, told me that, when they tried to remove cat's on modern cars, to increase performance, it would work the other way, and they could not tune it to perform better. This was on Audi's, so not really boat related, so therefore my uncertanty, about the same issue on the V8's from merc.[/QUOTE]



If they were unable to make more power, it was because they were unable to get the tune correct (F/AR ) That's a separate issue from the cats reducing flow.



Darrell.

Your right but my guess is instead of 520 those Audi krauts would of gotten 650 out of that Italian skirted kraut car if the cats did not need to be there!!!

[/QUOTE]If they were unable to make more power, it was because they were unable to get the tune correct (F/AR ) That's a separate issue from the cats reducing flow.



Darrell.[/QUOTE]

I know what your saying. But from what I understood, it was rather complicated. I think the thing is, that the entire engine is build to work with the cat's, and because of that, it can't work right without. So unless you make internal mods, and then do the removal and dyno tuning, it's no good.
I'm not a mechanic, but I'm allways eager to learn about this stuff.
Keep it coming :ernaehrung004:

A-farkin-men!

This damn plane better take off. I am in need of booze soon!!!!!

Fog at 436 pm.... Only in this sh!tpit.... JFK!!!!

Wow number 27 for departure!!!!

If they were unable to make more power, it was because they were unable to get the tune correct (F/AR ) That's a separate issue from the cats reducing flow.



Darrell.[/QUOTE]

I know what your saying. But from what I understood, it was rather complicated. I think the thing is, that the entire engine is build to work with the cat's, and because of that, it can't work right without. So unless you make internal mods, and then do the removal and dyno tuning, it's no good.
I'm not a mechanic, but I'm allways eager to learn about this stuff.
Keep it coming :ernaehrung004:[/QUOTE]


I'd agree. A modern high performance engine is certainly tuned for the cats. They don't leave much on the table in street trim. If ya take a look at some of the one make sports car races(Porsche Cup for instance) those guys are able to get quite a few extra ponies by a simple de cat, and efi tuning. It all comes down to the EFI system being able to make enough adjustment to take advantage of the extra exhaust flow.

Darrell.