'96 252 454 Magnum performance benchmark

[akorcovelos]

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Great pics for the site Akor...thank you!
Btw, I was going to mention how dirty your engine compartment was in an earlier thread but held off. Now I'm glad I did. You are all over it brutha!

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Haha, yeah the bilge was pretty nasty when we bought the boat, and each year my detailer gets it a little better. This year he got it maybe 80% of what I want, so next spring it should be where I want it.

Side question A7, can you change the name of this thread to say 454 instead of 7.4? I can’t seem to do it myself.

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Roger that....and thread title changed. Technically it bothered me too.

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Thanks A7! Honestly, I tried to change it the day I started this thread and it’s bugged me ever since.

[xlint89]

Just thinking out loud here. What flame arrestor do you have? The large SS mesh one that says EFI, or is it the flat/flush one that looks like a car radiator?

Only reason I ask is the large mesh one (gen 5 I believe) is the best flowing FA available from the test I saw. The newer style FA (flat/flush radiator looking) was a bit restrictive. Not going to get more top end if she can't breathe.

Just throwing out ideas.

Yeah, I saw the Hardon marine setup, and the AS&M kit came with MSD ignition and a K&N FA.. This is what mine has, plan is to give it a real good clean when I do the TB. If it’s too nasty I’ll get the adapter to run the K&N, though I’ve never been a K&N fan there doesn’t seem to be many other options out there.

As for the idle issue, it did it with both ECUs so I’m not calling the Whipple tune bad yet.

Stay tuned, heading out to service the lower unit and pull the TB off for inspection. Pics to follow.

This is absolutely awesome you're doing this. I will be doing the exact same thing very soon. We can help each other out along the way I believe.

First off, you have THE best flowing flame arrestor available. Clean it up, do NOT buy the K&N filter with the adapter. You will lose air flow. There was a guy on another board that was flow testing FA's and was losing performance when trying different brands, and even removed a layer of the SS mesh from the one you have and lost performance from that too. He found yours to be the BEST available period. (up to 500-600 HP or something like that) Obviously it's too small for really big number engines. The Merc 525 EFI uses a larger monoblade TB with a different FA mounted to the front.

The vacuum fitting on the bottom of the air plenum, (I think is your completely clogged hose) is for the fuel pressure regulator. It is at least on mine. I have the cool fuel system though, not the VSP.

Can you do me a favor? The valve cover on the starboard side has that 1/2" I.D. hose usually for a PCV valve. Where does that go on yours?

I have the newer/restrictive FA on mine and will be switching to your style. However, mine has that hose going into the FA for emissions reasons.

[xlint89]

If you want to clean the injectors, I got a guy in TX. I'm considering sending down mine out of the 496's in the 360. He does tons of ECM repairs as well.

Boats Unlimited
John Mosetti
817-658-7721
jmboatsunlimited@yahoo.com

Does he go by the screen name BUP on the OSO website?

If so, he's highly recommended.

[xlint89]

Just thinking out loud here. What flame arrestor do you have? The large SS mesh one that says EFI, or is it the flat/flush one that looks like a car radiator?

Only reason I ask is the large mesh one (gen 5 I believe) is the best flowing FA available from the test I saw. The newer style FA (flat/flush radiator looking) was a bit restrictive. Not going to get more top end if she can't breathe.

Just throwing out ideas.

Yeah, I saw the Hardon marine setup, and the AS&M kit came with MSD ignition and a K&N FA.. This is what mine has, plan is to give it a real good clean when I do the TB. If it’s too nasty I’ll get the adapter to run the K&N, though I’ve never been a K&N fan there doesn’t seem to be many other options out there.

As for the idle issue, it did it with both ECUs so I’m not calling the Whipple tune bad yet.

Stay tuned, heading out to service the lower unit and pull the TB off for inspection. Pics to follow.

Sorry to be the pain in your arse. This pic reminded me of something.

Your bilge vent hoses. Where is the second on on the starboard side going to? Mine has 2 hose. Port goes all the way to bottom of bilge. And the one starboard is attached to the blower sitting atop the "box". Where's the other one going?

[akorcovelos]

Just thinking out loud here. What flame arrestor do you have? The large SS mesh one that says EFI, or is it the flat/flush one that looks like a car radiator?

Only reason I ask is the large mesh one (gen 5 I believe) is the best flowing FA available from the test I saw. The newer style FA (flat/flush radiator looking) was a bit restrictive. Not going to get more top end if she can't breathe.

Just throwing out ideas.

Yeah, I saw the Hardon marine setup, and the AS&M kit came with MSD ignition and a K&N FA.. This is what mine has, plan is to give it a real good clean when I do the TB. If it’s too nasty I’ll get the adapter to run the K&N, though I’ve never been a K&N fan there doesn’t seem to be many other options out there.

As for the idle issue, it did it with both ECUs so I’m not calling the Whipple tune bad yet.

Stay tuned, heading out to service the lower unit and pull the TB off for inspection. Pics to follow.

This is absolutely awesome you're doing this. I will be doing the exact same thing very soon. We can help each other out along the way I believe.

First off, you have THE best flowing flame arrestor available. Clean it up, do NOT buy the K&N filter with the adapter. You will lose air flow. There was a guy on another board that was flow testing FA's and was losing performance when trying different brands, and even removed a layer of the SS mesh from the one you have and lost performance from that too. He found yours to be the BEST available period. (up to 500-600 HP or something like that) Obviously it's too small for really big number engines. The Merc 525 EFI uses a larger monoblade TB with a different FA mounted to the front.

The vacuum fitting on the bottom of the air plenum, (I think is your completely clogged hose) is for the fuel pressure regulator. It is at least on mine. I have the cool fuel system though, not the VSP.

Can you do me a favor? The valve cover on the starboard side has that 1/2" I.D. hose usually for a PCV valve. Where does that go on yours?

I have the newer/restrictive FA on mine and will be switching to your style. However, mine has that hose going into the FA for emissions reasons.

Hard to believe, but that crank case vent hose actually just sits against the flame arrestor screen, which is why the bottom of the flame arrestor is black. I just ordered a remote catch can w/ a breather so that tube will no longer pollute my intake air charge.

EVIL ENERGY Polish Baffled Universal Oi ... PEbHP0H9MA

Your bilge vent hoses. Where is the second on on the starboard side going to? Mine has 2 hose. Port goes all the way to bottom of bilge. And the one starboard is attached to the blower sitting atop the "box". Where's the other one going?

I’ll have to check, never really looked.

[cmattj]

Just an idea I used in my 502efi.

What was Merc thinking with a dangling pcv hose under the flame arrestor??

Since I wanted some source of pull ventilation and to keep the splatter occurring after hard runs I first used the K&N but the linkage rubbed the media. Removed it.

E383DC39-E291-43CE-AB1E-D7EC8AEC7600.jpeg

My last one was this with a fitting on the back plate that left zero splatter and mimics a true Pcv source to truly direct crankcase pressure.
Pretty slick.

[Holy Smokes]

If you want to clean the injectors, I got a guy in TX. I'm considering sending down mine out of the 496's in the 360. He does tons of ECM repairs as well.

Boats Unlimited
John Mosetti
817-658-7721
jmboatsunlimited@yahoo.com

Does he go by the screen name BUP on the OSO website?

If so, he's highly recommended.

Yes, that's the same guy. I had him complete a mechanical inspection on a boat I was going to buy out of TX last year. Very thorough and found some things that definitely would have been significant cost and headaches. Passed on the boat, but the inspection fee was money well spent.

[akorcovelos]

Just an idea I used in my 502efi.

What was Merc thinking with a dangling pcv hose under the flame arrestor??

Since I wanted some source of pull ventilation and to keep the splatter occurring after hard runs I first used the K&N but the linkage rubbed the media. Removed it.
E383DC39-E291-43CE-AB1E-D7EC8AEC7600.jpeg

My last one was this with a fitting on the back plate that left zero splatter and mimics a true Pcv source to truly direct crankcase pressure.
Pretty slick.

Not a fan of K&N in general, but that second one you posted looks NICE, but AS&M shows it as a HP500 part, and last I talked to them the adapter for the 454/502 was NLA...I’m fine with a catch can that vents to atmosphere.

C6FE1ECE-0236-4A9F-873C-B690FE509B92.png

[akorcovelos]

The flame arrestor cleaned up pretty good. Looks nicer but doubt it will make a difference.

14B988DE-7ADA-41F6-B918-414E44007CBA.jpeg

94C59E96-EE58-4749-94D7-0F51043D6D60.jpeg

95FF0B48-A90B-4FF4-BBE0-8B2CB1D31A9B.jpeg

D26520A1-125F-4FA4-87DD-307DE11B8326.jpeg

31D4D57B-759A-4A27-8312-7969A988B78F.jpeg

8BC21711-2BF0-47B5-82A5-124327705BB4.jpeg

[akorcovelos]

Touched up the paint to pass some time.

4FE146A8-7DCE-4F7E-8F87-D47D8F5E372E.jpeg

6B749CC2-84B0-4671-A993-E7D89A9D1E19.jpeg

E4210A61-3DAA-4462-AA88-96CC86F135C5.jpeg

Hard to tell in the pics, but whatever Merc used to paint/powder coat these parts shines up like new after 24 years.

[akorcovelos]

The gear oil tank on the other hand...there is no way this system was working as designed. The tank was so clogged it held half a tank of electronic cleaner for a good 3 minutes before the stuff worked its way through the barb fitting. It’s not perfect, but it’s functional again.

58848C41-5924-4B96-9F41-564CF0020165.jpeg

124F8D13-7B46-487B-934C-EF64C52E4E9B.jpeg

My new ICV should be here tomorrow, so I’ll break the throttle body down and clean it.

[xlint89]

Yeah, I saw the Hardon marine setup, and the AS&M kit came with MSD ignition and a K&N FA.. This is what mine has, plan is to give it a real good clean when I do the TB. If it’s too nasty I’ll get the adapter to run the K&N, though I’ve never been a K&N fan there doesn’t seem to be many other options out there.

As for the idle issue, it did it with both ECUs so I’m not calling the Whipple tune bad yet.

Stay tuned, heading out to service the lower unit and pull the TB off for inspection. Pics to follow.

This is absolutely awesome you're doing this. I will be doing the exact same thing very soon. We can help each other out along the way I believe.

First off, you have THE best flowing flame arrestor available. Clean it up, do NOT buy the K&N filter with the adapter. You will lose air flow. There was a guy on another board that was flow testing FA's and was losing performance when trying different brands, and even removed a layer of the SS mesh from the one you have and lost performance from that too. He found yours to be the BEST available period. (up to 500-600 HP or something like that) Obviously it's too small for really big number engines. The Merc 525 EFI uses a larger monoblade TB with a different FA mounted to the front.

The vacuum fitting on the bottom of the air plenum, (I think is your completely clogged hose) is for the fuel pressure regulator. It is at least on mine. I have the cool fuel system though, not the VSP.

Can you do me a favor? The valve cover on the starboard side has that 1/2" I.D. hose usually for a PCV valve. Where does that go on yours?

I have the newer/restrictive FA on mine and will be switching to your style. However, mine has that hose going into the FA for emissions reasons.

Hard to believe, but that crank case vent hose actually just sits against the flame arrestor screen, which is why the bottom of the flame arrestor is black. I just ordered a remote catch can w/ a breather so that tube will no longer pollute my intake air charge.

EVIL ENERGY Polish Baffled Universal Oi ... PEbHP0H9MA

Your bilge vent hoses. Where is the second on on the starboard side going to? Mine has 2 hose. Port goes all the way to bottom of bilge. And the one starboard is attached to the blower sitting atop the "box". Where's the other one going?

I’ll have to check, never really looked.

Seriously, the hose just ran up to the bottom of the FA? Thank you for that.

I too was thinking of using the catch can. Real performance cannot be achieved by introducing oil mist into the air fuel mixture.

Please let me know about that 3rd vent hose. Slightly baffled by it.

[xlint89]

If you want to clean the injectors, I got a guy in TX. I'm considering sending down mine out of the 496's in the 360. He does tons of ECM repairs as well.

Boats Unlimited
John Mosetti
817-658-7721
jmboatsunlimited@yahoo.com

Does he go by the screen name BUP on the OSO website?

If so, he's highly recommended.

Yes, that's the same guy. I had him complete a mechanical inspection on a boat I was going to buy out of TX last year. Very thorough and found some things that definitely would have been significant cost and headaches. Passed on the boat, but the inspection fee was money well spent.

Thought so. Just spoke to him this evening and will be using his injector cleaning service. Did seem to be quite knowledgeable. I can see him being a good surveyor.

[akorcovelos]

This is absolutely awesome you're doing this. I will be doing the exact same thing very soon. We can help each other out along the way I believe.

First off, you have THE best flowing flame arrestor available. Clean it up, do NOT buy the K&N filter with the adapter. You will lose air flow. There was a guy on another board that was flow testing FA's and was losing performance when trying different brands, and even removed a layer of the SS mesh from the one you have and lost performance from that too. He found yours to be the BEST available period. (up to 500-600 HP or something like that) Obviously it's too small for really big number engines. The Merc 525 EFI uses a larger monoblade TB with a different FA mounted to the front.

The vacuum fitting on the bottom of the air plenum, (I think is your completely clogged hose) is for the fuel pressure regulator. It is at least on mine. I have the cool fuel system though, not the VSP.

Can you do me a favor? The valve cover on the starboard side has that 1/2" I.D. hose usually for a PCV valve. Where does that go on yours?

I have the newer/restrictive FA on mine and will be switching to your style. However, mine has that hose going into the FA for emissions reasons.

Hard to believe, but that crank case vent hose actually just sits against the flame arrestor screen, which is why the bottom of the flame arrestor is black. I just ordered a remote catch can w/ a breather so that tube will no longer pollute my intake air charge.

EVIL ENERGY Polish Baffled Universal Oi ... PEbHP0H9MA

Your bilge vent hoses. Where is the second on on the starboard side going to? Mine has 2 hose. Port goes all the way to bottom of bilge. And the one starboard is attached to the blower sitting atop the "box". Where's the other one going?

I’ll have to check, never really looked.

Seriously, the hose just ran up to the bottom of the FA? Thank you for that.

I too was thinking of using the catch can. Real performance cannot be achieved by introducing oil mist into the air fuel mixture.

Please let me know about that 3rd vent hose. Slightly baffled by it.

I’ll snap a couple pics this weekend.

[cmattj]

I too was thinking of using the catch can. Real performance cannot be achieved by introducing oil mist into the air fuel mixture.

It’s not a great set up but having a Partial PCV system is better than it expelling pressure from the crank case right?

Marine engines of those eras have had some weird hose to the flame arrester, as opposed to a direct intake port fitting. So I agree on the funky.

Remember these engines don’t use an open valve cover breather on the other side.

Pcv systems direct crank case pressure to a exit source and actually improve power.

We’ve tested belt driven vacuum pumps that a - 12 inches add 15 hp.

It’s not a big number but it tells you that reducing crankcase pressure allows improving the resistance in the crankcase as certain blow by , and rotation of crank can build up this working pressure.

Dry sump systems on our vehicles today ,and in the performance world also create a relief of crankcase pressure in the design .

So in short don’t think of it as a oil mixture that is hindering performance ( it wouldn’t be noticed like a straw sucking out oil).
Look at it as a direction of crankcase pressure to reduce internal resistance.

Puke tanks and catch cans?
That why they call them puke tanks , and catch cans.

My .03 cents is attempt getting your pcv system working in some basic form.

You won’t regret it.