Magnum performance cat delet?

Drnick

Cadet
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May 31, 2019
Messages
20
Has anyone removed cats and used what the above sells
to trick Ecu, so motor runs properly and no codes or
alarms?
 

Drnick

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May 31, 2019
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20
Removal of cats?

has anyone removed the cats in there manifolds on the newer engines?
 

HT32BSX115

Supreme Mariner
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Dec 8, 2005
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10,083
Howdy,

Aside from wondering how in the world does a cat get inside your manifold (did it have kittens inside?) .......:lol::lol:

You would just do it the way you do it with an automobile.

But beware, it won't be cheap (and although it's probably impossible to get caught.....it might be illegal)

You'll likely have to replace the manifolds and risers and possibly the Y-pipe if a V-8....with NON-cat models and there will likely be ECM issues since (someone please correct me if I am wrong, ) there's an oxygen sensor on the cat/EFI models.....

https://forums.iboats.com/forum/engi...ytic-converter (do not respond to this very old post btw)

So you could also add replacing the ECM along with (probably) the entire engine harness.

It would be MUCH cheaper to just swap the engine with a complete bob-tail NON-cat engine.(and then sell the cat engine complete)


One of the reasons I am quite happy with my 1987 boat and 1997 engine/drive.........

Cheers,


Rick
 
Last edited:

H20Rat

Vice Admiral
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Mar 8, 2009
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5,204
At least in the automotive world, getting rid of a cat almost always means you need to touch the computer programming and often the oxygen sensors. Just removing it without any other changes will hurt performance or really upset your engine.

Bigger question is why? Any performance increase in negligible at best.
 

Drnick

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May 31, 2019
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20
On the newer 4.5 cat is in the manifold,it’s a cartridge type about the size of a coffee can, and is easily removed,cost for these to replace is approximately $600 each! These cats add an enormous amount of heat to manifolds, and there is a slight performance increase, the only problem is there are 4 o2 sensor (upstream and downstream) they have to be eliminated
So ECU won’t throw a code and go on “limp” mode
 

Drnick

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May 31, 2019
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20
So, again, has anyone removed these expensive parts to make motor run cooler,better performance, and possibly better
fuel economy ?
 

Bondo

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71,291
So, again, has anyone removed these expensive parts to make motor run cooler,better performance, and possibly better
fuel economy ?

Nope,...... Welcome Aboard,......
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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51,243
you wont see a performance increase unless something catastrophic happened to the cat in the first place
removing emissions components is illegal
you do void your warranty

however it is your boat.
 

NHGuy

Captain
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May 21, 2009
Messages
3,631
You might get a little performance for a time. Or maybe use a different amount of fuel. But if the ecm is being "told" a lie by the cat-fake device it might send some wrong mixture or timing to the engine, which could over time cause troubles.
I'd need to understand what the cat delete system does before I made any choices for myself.
You might want to ask on THT (the Hull Truth) or Offshore Only. Some of the guys on there are very tech savvy.
 

bman440440

Petty Officer 1st Class
Joined
Apr 4, 2011
Messages
266
do a search on [h=1]Max Volt Catalyst Eliminator Computer[/h]
its for mercruiser engines... plug and play
 

HT32BSX115

Supreme Mariner
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Dec 8, 2005
Messages
10,083
So, again, has anyone removed these expensive parts to make motor run cooler,better performance, and possibly better
fuel economy ?

It is pretty doubtful that you'll see much difference in performance doing this to a 4.5L V-6

It might help to indicate what type of boat this is in. 1 or 2 engines? (Alpha, Bravo 1, 2, 3?) Salt or fresh water operation? Raw water cooling or closed etc?

Maybe your best choice might be to upgrade the engine(s)

I.E. pull the 4.5L engines and replace them with earlier 5.7 V-8's (EFI or carb depending on how much complexity you want in the swap)

Compare all this to replacing the cats (@$600 each) every 5 years or so and see if it's worth the difference......

I did a little search and there are indeed companies that have replacement ECM's that will allow removal of the cats. They of course will probably make all sorts of claims of fuel savings and performance increases. YMMV
 

Drnick

Cadet
Joined
May 31, 2019
Messages
20
Thanks Bman, already checked that out, will not work on the newer 6 pin sensors ( 4.5 has 4 pin downstream,and 6 pin
upstream.) PS I’m not considering this for performance, or fuel savings, I’m removing because cats create a lot of heat, are very expensive to replace, and create more problems then what there worth.
 
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