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Remove Mercruiser catalyst

Old 05-08-2012, 12:50 PM
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Drivehard-
I agree. The pre sensor is still driving the fueling via running in closed loop control at the slower speeds. The stock system on cars and boats go rich when you go to WOT. And yes, the post sensor is now gone, but the pre sensor has to stay in the system. That is why you can now buy headers with a sensor hole in them. And that is for both sides of the engine.

All four sensors are identical and they are 4 wire sensors.
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Old 05-08-2012, 12:54 PM
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Originally Posted by Drivehard
If this is the case (which I totally believe is possible)...how could they possible have three different settings that would change the power output of the engine? I'm sure the main ECM would not change fueling or spark timing based on what the "cat computer" was telling it...so I would for sure call "BS" on this little box making any difference other than to keep that little dash light from popping on.
They are not saying there are three settings, they are saying you can use it in three different applications: headers without cats, stock exhaust without cats, stock exhaust with cats but without the post sensor.

I have heard that there are a lot of post sensor failures with the stock setup.
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Old 06-10-2012, 04:07 PM
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I haven't spent the money yet, but I did speak with a few different people at CP. They said they have sold some kits, but they would not tell me who or what engines they went on. They said they have not had issues with this system.

So, who out there has tried this system? Someone has!
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Old 06-10-2012, 06:40 PM
  #24  
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The issue is that this device is recognized by the Coast Guard as an electronic device specifically designed to illegally modify a complient engine in many areas. It's a fine or impounding waiting to happen. They have bulletins infroming them to look for these units. If you install them you must hide them and then the issue of the cat being missing. There may be an after market device that looks like a cat but is a thru pipe of sorts.

If the cats are missing and the Coast Guard asks some will answer the engine is modified and makes over 500 HP. A cat is not required. They will look for a blower sometimes.

If the light is on after pulling a cat off and the Coast Guard now is checking for this. You get friend.

I know a couple guys who just got their boats factory new and ordered the boats without cats and stated intended use in areas outside the US. No questions asked.

A paralegal said that if the vessal is retitled (aka straw deal) it slides through where autos or trucks would not.

Next boat I get will simply have 525's in them as the engines have headers and no cats.
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Old 06-10-2012, 09:56 PM
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The Coast Guard has no jurisdiction regarding emissions, so I don't know where this device is "recognized" by them. Do you have a copy of one of these bulletins you speak of?

If a stock Merc exhaust system is used, but the cats are removed, there is no way to tell by looking at the system from the outside other than the Check Engine light being on; it would have to be disassembled. This device is suppose to keep the light off.

Only the Federal EPA and CARB have emissions jurisdiction. The EPA and CARB are so broke they hardly check cars anymore, never mind boats! I have had the Coast Guard check for safety gear like an anchor and life jackets. I have heard of them doing noise testing on small lakes. I have never heard of them checking for emissions. Other than pulling an engine and putting it on an emissions bench, I don't see how they can replicate the 5 mode emissions test in a boat.
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Old 06-11-2012, 02:46 AM
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Originally Posted by Engineer
The Coast Guard has no jurisdiction regarding emissions, so I don't know where this device is "recognized" by them. Do you have a copy of one of these bulletins you speak of?

If a stock Merc exhaust system is used, but the cats are removed, there is no way to tell by looking at the system from the outside other than the Check Engine light being on; it would have to be disassembled. This device is suppose to keep the light off.

Only the Federal EPA and CARB have emissions jurisdiction. The EPA and CARB are so broke they hardly check cars anymore, never mind boats! I have had the Coast Guard check for safety gear like an anchor and life jackets. I have heard of them doing noise testing on small lakes. I have never heard of them checking for emissions. Other than pulling an engine and putting it on an emissions bench, I don't see how they can replicate the 5 mode emissions test in a boat.
What make/model of boat are you wanting to try this on?
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Old 06-11-2012, 08:48 AM
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I would like to see it tried on any marine catalyst engine, but preferably a V8 Merc.
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Old 06-11-2012, 11:47 AM
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Engineer:

This is your thread and you're the "engineer", so why don't you buy this system, put it on your boat and report back to all us interested parties if it works properly and you have good results.
My personal opinion is that it is not the cats on the new engines that are keeping you stock power down, but the special camshaft profiles, fuel mapping and tuning that must be run to keep the engines in the emissions compliance numbers the EPA is requiring on these engines.

If you reaaly want and need more power you will have to change the camshafts, remove the cats for a better power producing exhaust and completely re-ECM the engine for the proper fuel and spark mapping that will support and work correctly with these power adding modifications. If you get somehow nailed for these illegal modifications then that's your issue to deal with. If you choose to do it and have great results and never have compliance issue then you're the ultimate winner!

In other words, just eliminating the cats from your stock engines is not going to add squat to your available power from those engines! Unless you are prepared to go into the engine and do the real power increase upgrades, why even bother with the cats!?

Best Regards,
Ray @ Raylar
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Old 06-11-2012, 12:13 PM
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Originally Posted by Raylar
Engineer:

This is your thread and you're the "engineer", so why don't you buy this system, put it on your boat and report back to all us interested parties if it works properly and you have good results.
My personal opinion is that it is not the cats on the new engines that are keeping you stock power down, but the special camshaft profiles, fuel mapping and tuning that must be run to keep the engines in the emissions compliance numbers the EPA is requiring on these engines.

If you reaaly want and need more power you will have to change the camshafts, remove the cats for a better power producing exhaust and completely re-ECM the engine for the proper fuel and spark mapping that will support and work correctly with these power adding modifications. If you get somehow nailed for these illegal modifications then that's your issue to deal with. If you choose to do it and have great results and never have compliance issue then you're the ultimate winner!

In other words, just eliminating the cats from your stock engines is not going to add squat to your available power from those engines! Unless you are prepared to go into the engine and do the real power increase upgrades, why even bother with the cats!?

Best Regards,
Ray @ Raylar
WOW! Why the hostility?

As a marine engine builder, I am surprised that you didn't know that the camshafts are the same between the cat and non-cat engines. Also, if you look at the fuel flow (or injector pulse width) and ignition advance at WOT, you will see they are almost identical between the cat and non-cat engine.

Lastly, my issue has to do less about power and more about the way the engine looks. If dumping the cast gets me a few extra horsepower, then great.

It may be my thread, but I am just looking for info before my warranty runs out. I am sorry if my questions annoy you.
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Old 06-11-2012, 02:42 PM
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No Hostility on my part here, just a little head scratching trying to understand if you already know all the information, have already done all the research to identify the same camshafts, same injector pulse width, same timing advance, you must already have some pretty sophisticated equipment becuse there are few if any companies or individuals outside Mercury and their owned ECM company that can read this newer ECM family,those pulse widths and timing with standard industry scan tools. So it sounds like you are way ahead of anyone on this forum on this cat-versus non-cat information, data and knowledge and from your own research, what the hell are you waiting for!
No that's not hostility its just wondering why you are on a budget technical forum asking for confirmation of your already gleened knowledge and expertise in this matter.
I know what you really want I think in my opinion is someone else to be your guinea pig, buy the expensive parts avaiable and tell you whether it works or not so you don't have to put yourself out to do it or spend the money if it does not work. If this opinion makes me seem hostile I am sorry but that's just the way I feel after reading your previous posts and discussion. If you really have done your homework, you know it will work and you really want to see if you will get more power and you like the look of taking them off and adding an aftermarket exhaust, then by all means get busy and do it. We would all like to know of your success and improvements.
Not hostile, just waiting to hear of your success with this project.

Best Regards,
Ray @ Raylar
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