Ideas for increasing power in a pair of Merc 454 L29s
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Ideas for increasing power in a pair of Merc 454 L29s
Just to be up front about this, I'm just toying with the idea of how much it would cost and what would be the best increase for the money/work required.
The boat:
'99 Formula 330 SS
Dual Merc 454 L29 engines (SN: 0L34xxxx) w/ about 400hrs/ea (stock AFAIK)
Bravo 3 outdrives, rebuilt by the previous owner two years ago (at the insane cost of $14k!!!)
26P props
What I've done so far or is in the works (all done after winterizing):
As of last year I could get to maybe 46-48mph on a smooth day, but, well, I like SPEED! I was hoping I could get it to 60mph+ safely, but I don't actually have a target speed. Currently the holeshot is VERY good (in my very limited experience) unless I have it seriously loaded down with people and gear. I haven't yet seen how much of an increase the work listed above will get me, I don't expect much...
So now with Spring finally hitting us in the DC/VA/MD area, I'm getting curious about some REAL upgrades I could do, here are a few of the things I've looked into: (listed by level of sanity)
Is there anything I haven't considered? Which of these would be the most nag for the buck? Every time I look at prices I remember that I have two engines, so the price and work doubles...
The boat:
'99 Formula 330 SS
Dual Merc 454 L29 engines (SN: 0L34xxxx) w/ about 400hrs/ea (stock AFAIK)
Bravo 3 outdrives, rebuilt by the previous owner two years ago (at the insane cost of $14k!!!)
26P props
What I've done so far or is in the works (all done after winterizing):
- New NGK BPR6EFS spark plugs, the old ones were Champion RS12PYP and look WELL past their service life.
- New MSD ignition wires
- New fuel filters
- New Sierra distributors and caps
- New K&N Air Filters/Flame arrestors (don't worry, I don't expect miracles from these)
- fuel/water separators changed
- Oil/filers changed
- Drive fluid changed
- All ethanol fuel should be out by now, replaced with ethanol free
- Replaced a thermostat including the gasket that was totally missing!
As of last year I could get to maybe 46-48mph on a smooth day, but, well, I like SPEED! I was hoping I could get it to 60mph+ safely, but I don't actually have a target speed. Currently the holeshot is VERY good (in my very limited experience) unless I have it seriously loaded down with people and gear. I haven't yet seen how much of an increase the work listed above will get me, I don't expect much...
So now with Spring finally hitting us in the DC/VA/MD area, I'm getting curious about some REAL upgrades I could do, here are a few of the things I've looked into: (listed by level of sanity)
- Bottom paint (needs to be done soon regardless)
- New props
- New intake manifolds
- New exhaust headers or more?
- New MSD ignition system.
- New heads
- New cams
- New forged (mine are cast) cranks/pistons/arms
- New complete engines
- Superchargers (quickly realized how bad of an idea this would be on my old engines and the price)
Is there anything I haven't considered? Which of these would be the most nag for the buck? Every time I look at prices I remember that I have two engines, so the price and work doubles...
#2
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Bottom paint will scrub speed . Two 500 to 600 hp engines and bravo I's would make you smile . Only question is , is doing this to the boat you have worth it to you ? It's a waste of time to try and soup up those 330's unless you want to invest lots o money . A simple tune up will gain you nothing in speed . Little tweaks that you can feel in a car do nothing for a boat .
#3
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Short of bigger motors with a lot more HP, there is nothing you are going to do to realize any significant gain in speed with your current setup. If you like speed, you need a different boat. With that said:
Bottom paint - costing you some speed. If you can get a lift or trailer the boat, remove the bottom paint.
Weight - gear that is rarely used or not needed adds up quick. Lighten the boat as much as you can.
Props - make sure you are hitting 4,600 RPM at WOT. Brett at BBlades can lab your propsets for a little extra speed but you will most likely give up cruise efficiency.
Exhaust manifolds - if you boat in salt or brackish water and the manifolds need replaced, you might consider Stainless Marine or other aftermarket aluminum manifolds. You might realize some slight gains due to the reduction in weight and slightly better breathing. Headers would be a waste of money on those motors.
Do note that some K&N marine filters are more restrictive than the flame arrestors they replace.
Bottom paint - costing you some speed. If you can get a lift or trailer the boat, remove the bottom paint.
Weight - gear that is rarely used or not needed adds up quick. Lighten the boat as much as you can.
Props - make sure you are hitting 4,600 RPM at WOT. Brett at BBlades can lab your propsets for a little extra speed but you will most likely give up cruise efficiency.
Exhaust manifolds - if you boat in salt or brackish water and the manifolds need replaced, you might consider Stainless Marine or other aftermarket aluminum manifolds. You might realize some slight gains due to the reduction in weight and slightly better breathing. Headers would be a waste of money on those motors.
Do note that some K&N marine filters are more restrictive than the flame arrestors they replace.
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Short of bigger motors with a lot more HP, there is nothing you are going to do to realize any significant gain in speed with your current setup. If you like speed, you need a different boat. With that said:
Bottom paint - costing you some speed. If you can get a lift or trailer the boat, remove the bottom paint.
Weight - gear that is rarely used or not needed adds up quick. Lighten the boat as much as you can.
Props - make sure you are hitting 4,600 RPM at WOT. Brett at BBlades can lab your propsets for a little extra speed but you will most likely give up cruise efficiency.
Exhaust manifolds - if you boat in salt or brackish water and the manifolds need replaced, you might consider Stainless Marine or other aftermarket aluminum manifolds. You might realize some slight gains due to the reduction in weight and slightly better breathing. Headers would be a waste of money on those motors.
Do note that some K&N marine filters are more restrictive than the flame arrestors they replace.
Bottom paint - costing you some speed. If you can get a lift or trailer the boat, remove the bottom paint.
Weight - gear that is rarely used or not needed adds up quick. Lighten the boat as much as you can.
Props - make sure you are hitting 4,600 RPM at WOT. Brett at BBlades can lab your propsets for a little extra speed but you will most likely give up cruise efficiency.
Exhaust manifolds - if you boat in salt or brackish water and the manifolds need replaced, you might consider Stainless Marine or other aftermarket aluminum manifolds. You might realize some slight gains due to the reduction in weight and slightly better breathing. Headers would be a waste of money on those motors.
Do note that some K&N marine filters are more restrictive than the flame arrestors they replace.
I was told when I bought the boat last year that the bottom paint was on it's last leg, I planned to do that very soon. Unfortunately I can't trailer the boat though, I have no lift at my marina and no trailer or truck (that's big enough). I assume you meant remove the bottom paint and reapply it?
Very good point about weight, I think I'll be taking a lot of stuff out of it very soon... I'm also probably dragging around a lot more water than I should, since it only gets used for the toilet.
My understanding was that I should be getting 4800 WOT, which I'm getting on one engine while the other seems to hit a wall at like 4200. That was before I replaced the thermostat seal on that engine though, which was preventing it from getting to the correct temperature. Before I started investigating this further I wanted to rule out all preventive maintenance problems. The props were checked during the survey last year and I was told they were in very good shape. The seller claimed they were replaced the year before when the outdrives were rebuilt.
Nope, she stays 100% in fresh water. I've looked at exhaust before but I wasn't sure how much it would help...
I did some very simple breathing test for the flame arrestors where I held them to my face and tried to breathe, the K&N clearly let through substantially more air, but the stock filter looked NASTY!
What about the intake manifold? I've had a few people tell me that they made a significant difference on these engines.
Thanks for the reply,
Dan
#5
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You would be better off upgrading to 496 HO's. 425HP or even a 502 Mag EFI 415HP. Will give you some added pop without breaking the bank. Would definately put you in the mid to upper 50's.
#7
If one motor is turning 4800 and the other only 4200,you do realize a strong one will kind of drag a weak one along .Are you sure drives are same ratio?. Same props ? . Tachs right? if they are, start figuring out what is wrong with 4200rpm motor. Fuel pressure? bad hole? You may just need what you have to run right to get 50'ish.Just food for thought
#8
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the one thing to try if you can bum a pair is installing Bravo 1 lowers. of course the hole shot suffers a little but a B3 is built for comfort...and then you have prop options...
#9
In op's second post he states one motor turns 4800 and the other hits a wall at 4200.Shouldn't we make sure we have two healthy soldiers , before we start spending money on more motors, drives..etc.
#10
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If you wanna go faster, I'd sell the engines you have in stock form, and replace with either 496HO's, 502 Mag MPI's, or something like that. As for the Holeshots, go easy, bravo drives don't like to be hammered on out of the gate. Good luck.
But, before anything, I'd find out why the one engine is down 600RPM. It could be either a engine issue, prop issue, or hopefully, when they rebuilt the drives, they didn't install a different ratio gearset in one drive. .