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pekkerwood

I am thinking of getting a K&N

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I am thinking of getting a K&N marine air filter/spark arrestor for my boat. I have had good experience with these on my cars/trucks over the years.

What does the forum think? Anybody using one know? Pros/Cons?

Here is a think for the filter for a 7.4L MPI

http://store.knfilters.com/search/product.aspx?Prod=59-5004

I have one in my truck and I love it. My only concern for the boat would be clearance. Your engine hatch might not close with this filter.

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Yes - you basically have NO air filtration. just a few metal fins to re-direct the air. Probably catches 15% of the junk your car air filter catches.

can't be good for your engine in the long run.

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Agree with Fred for your particular engine.

Only issue I have heard reps from MerCruiser say is the K&N lets in too much air. An automotive style EFI system uses a wire that heats up/cools down up as more or less air flows past the throttle body, (whatever) thus letting the computer know how much fuel to add for a proper air/fuel ratio in conjuction with present load, rpm, temp, etc. info.

A MerCruiser system apparently doesn't use this wire system, but has the cubic inch capacity stored in the computers memory, and adds fuel based on load, rpm, temp, etc. MerCruiser guys are afraid of the air/fuel ratio being too lean, and detonating the engine. Have never heard of this condition happening, and apparently the K&N filtercharger even quiets down the whistling in the 7.4L MPI (L29 aka the 'whistling gopher') engine; this being a good thing.

NOTE: It has been my experience that MerCruiser always has had the EFI/MPI air/fuel ratio too rich anyway. I foresee no problems.

p.s. If you look on current model MerCruiser engines, I'd swear that the filter/flame arrestor material bears more than a strong resemblence to the K&N material. Sure looks like a K&N unit on the factory MerCruiser 525 Race engine too.

Chris

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Chris - are you saying the "current" as in 2008 Merc 5.7's have more of a filter than the usual metal finned flash arrestor? My 2004 Merc 5.7 had only this metal fin flash arrestor.

My 2005 manufactured (2006 model year boat) Volvo 5.7s have the same style arrestor as the older Merc. No air filtration whatsover - I always wondered about this but did not know K&N had a marine filter.

Merc and Volvo 5.7 is K&N part number 59-3364. You can add a bigger one - but it would vary by clearance.

They also mention to use a "Z-stud" part number 08009. Any idea what this is? It does not come up on the parts site for K&N.

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Chris - are you saying the "current" as in 2008 Merc 5.7's have more of a filter than the usual metal finned flash arrestor? My 2004 Merc 5.7 had only this metal fin flash arrestor.

My 2005 manufactured (2006 model year boat) Volvo 5.7s have the same style arrestor as the older Merc. No air filtration whatsover - I always wondered about this but did not know K&N had a marine filter.

Merc and Volvo 5.7 is K&N part number 59-3364. You can add a bigger one - but it would vary by clearance.

They also mention to use a "Z-stud" part number 08009. Any idea what this is? It does not come up on the parts site for K&N.

Yeah Fred, the new model MerCruiser's use a different flame arrestor/filter. Real recent, maybe the last 2 model years? I have no idea what a 'z stud' is. French Canadian Stud perhaps? :P "Did Mademoiselle call for zee Stud?"

Chris

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Yeah Fred, the new model MerCruiser's use a different flame arrestor/filter. Real recent, maybe the last 2 model years? I have no idea what a 'z stud' is. French Canadian Stud perhaps? :P "Did Mademoiselle call for zee Stud?"

Chris

Wow, knowlegable, and with a sense of humor...what a guy :tofunny:

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Yeah Fred, the new model MerCruiser's use a different flame arrestor/filter. Real recent, maybe the last 2 model years? I have no idea what a 'z stud' is. French Canadian Stud perhaps? :P "Did Mademoiselle call for zee Stud?"

Chris

another name for JB

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Not Hardly... LOL

SOOO - sounds like I'm gonna have to add an air filter to my boat. Looks like the K&N is the only available part - unless Volvo has added a filter to their 2008 engines that fits a 2005 5.7.

The deer is a little high - but think about it - at the moment whatever debris is in your bilge can enter your engine - seems a no brainer to add one. Or just wrap a bunch of gauze around your current flash arrestor - LOL.

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Not Hardly... LOL

SOOO - sounds like I'm gonna have to add an air filter to my boat. Looks like the K&N is the only available part - unless Volvo has added a filter to their 2008 engines that fits a 2005 5.7.

The deer is a little high - but think about it - at the moment whatever debris is in your bilge can enter your engine - seems a no brainer to add one. Or just wrap a bunch of gauze around your current flash arrestor - LOL.

check with NAPA - I think they have suitable filter for a lot less money. K and N makes a good filter but half the price is marketing costs- you are paying for name

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Well, I honestly think a K&N filter on a boat is a waste of $$.......

Granted, the air "filter" we use now really doesn't stop much of anything smaller than a dead cat, but then again, how much dust and dirt do we hit on the WATER.....

And as far as dirt under the engine cowl, I keep mine pretty clean....

I may be sounding a little negative about K&N filters but I have a good reason to be this way.

I put a K&N filter on my "03 ford Dually that has a 7.3 powerstroke, and within 15,000, the turbo compressor fins were starting to get "dusted".... they were losing their edges off the fins. Another 15,000 miles and the turbo would have failed.

I went back to a stock air cleaner and no more damage has been noticed, also noticed no difference in power or mileage with the K&N.

Maybe for an all out race car or where every small percentage of power gain is needed, a K&N may be worth it, but for anything else, I'll pass.

wncrjb

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Well, I honestly think a K&N filter on a boat is a waste of $$.......

Granted, the air "filter" we use now really doesn't stop much of anything smaller than a dead cat, but then again, how much dust and dirt do we hit on the WATER.....

And as far as dirt under the engine cowl, I keep mine pretty clean....

I may be sounding a little negative about K&N filters but I have a good reason to be this way.

I put a K&N filter on my "03 ford Dually that has a 7.3 powerstroke, and within 15,000, the turbo compressor fins were starting to get "dusted".... they were losing their edges off the fins. Another 15,000 miles and the turbo would have failed.

I went back to a stock air cleaner and no more damage has been noticed, also noticed no difference in power or mileage with the K&N.

Maybe for an all out race car or where every small percentage of power gain is needed, a K&N may be worth it, but for anything else, I'll pass.

wncrjb

I did not want to rain on the K and N parade but a lot of "rodders" feel the same way. K and N is like Amsoil. 1/4 product and 3/4 's marketing. The cost to benefit ratio is upside down .

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i'll have to see what else is available - but it seems like a good idea to add some sort of filter.

and there is a lot more dirt in the air on the water than you would think... my boat is COVERED in dust/pollen/stuff after a month or two of being on the water. all of that stuff is airborne and does get sucked through your engine.

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I have that same filter on my 7.4L. I have been running it for two seasons and have had no problems. I haven't notice any performance gains, however I wanted to replace the stock one because it just looked old and dirty.

Jaysled

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