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Do cats rob power?

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Old 09-24-2010, 03:06 PM
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496's don't have cats. You can put headers on them.b
Just the new 502's have cats.
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.
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Old 09-24-2010, 03:14 PM
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Any form of restriction however small robs power.

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


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Old 09-24-2010, 03:18 PM
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[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

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.
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Old 09-24-2010, 03:24 PM
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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.



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Old 09-24-2010, 04:35 PM
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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
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!!!
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Old 09-24-2010, 04:35 PM
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[/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
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Old 09-24-2010, 04:39 PM
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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!!!!
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Old 09-25-2010, 12:51 AM
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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 [/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.

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