LS Engines Maybe the future of I/O's
02-20-2024, 10:50 AM
#121
Registered
Where did you find the HP/TQ for the Mercury 450?
The LS3/480 has 475 lbft torque and 490 hp on flywheel, let's say it has a gear ratio of 1.56.
The Mercury 450R has 450 hp on the propeller shaft, so it's very comparable in power to the LS3/480, but it has only 439 LBFT of torque or less and it has a 1.6 gear ratio.
The LS3/480 has equal or greater torque from 3,000 rpm to 6,000 rpm.
https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAE
Where is the reason the 450R "pulls like an airplane" while the LS3/480 doesn't have enough torque for marine use?
The Mercury 450R has 450 hp on the propeller shaft, so it's very comparable in power to the LS3/480, but it has only 439 LBFT of torque or less and it has a 1.6 gear ratio.
The LS3/480 has equal or greater torque from 3,000 rpm to 6,000 rpm.
https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAE
Where is the reason the 450R "pulls like an airplane" while the LS3/480 doesn't have enough torque for marine use?
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Twin O/B Sonic (02-21-2024)
02-20-2024, 11:39 AM
#122
Platinum Member
Platinum Member
The LS3/480 has 475 lbft torque and 490 hp on flywheel, let's say it has a gear ratio of 1.56.
The Mercury 450R has 450 hp on the propeller shaft, so it's very comparable in power to the LS3/480, but it has only 439 LBFT of torque or less and it has a 1.6 gear ratio.
The LS3/480 has equal or greater torque from 3,000 rpm to 6,000 rpm.
https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAE
Where is the reason the 450R "pulls like an airplane" while the LS3/480 doesn't have enough torque for marine use?
The Mercury 450R has 450 hp on the propeller shaft, so it's very comparable in power to the LS3/480, but it has only 439 LBFT of torque or less and it has a 1.6 gear ratio.
The LS3/480 has equal or greater torque from 3,000 rpm to 6,000 rpm.
https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAE
Where is the reason the 450R "pulls like an airplane" while the LS3/480 doesn't have enough torque for marine use?
figure 10,000 for the engine
15,000 for cmi headers/accesories and rest of parts you need
then the struggle begins to get the boat to balance out and drive right IF it was originally a bbc powered twin.
if you had a 18, 20 ft single with a 260 hp merc that was junk, it would be a rocket ship going to a 480 hp ls3
if you had a twin that was built for bbc's, say hp 500s or 500 efis, youd spend 50k to outfit it with 2 ls3 480 hp engines.
then youd have to gut the cabin or add ballast to back to get it to not plow the nose and ride right.
going from 580 ft lbs of tq at 3800/4000 to 450 in that area, youd have to regear the drives or go from typical 28s to 25's or 24s to get it to drive close to the same.
ive easily made 600/600 from modded 502s that I went thru for around 15 k each assuming they at least had entry level performance manifolds and block/accesories were usable.
A NA Ls is very efficient for its size and puts out substantial power for its size . IF you spend enough money on one, it could compare to a typical bbc but wont be cheap.
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02-20-2024, 12:40 PM
#123
Registered
@ Wildman_grafix;
Google, for example https://www.boatingmag.com/mercury-r...tboard-review/
@ Articfriends;
I have almost ready LS3/480 to put it in the 4.200 lbs boat (Boat have pad keel and notched transom it is made for light engine.) Peak torque is at 4500 rpm, which in my case translates to a cruising speed of around 55 mph, which is just right for my taste.
According to the data, it is a good engine with good fuel consumption, which I like because I will stop at the gas station less. The complete dry engine with the ZF63A weighs 663 lbs and reading about the lack of torque makes me fear that "I threw money out the window". I can't do the first test before May 1, because that's when they open the season on a nearby lake. Until then...
Google, for example https://www.boatingmag.com/mercury-r...tboard-review/
@ Articfriends;
I have almost ready LS3/480 to put it in the 4.200 lbs boat (Boat have pad keel and notched transom it is made for light engine.) Peak torque is at 4500 rpm, which in my case translates to a cruising speed of around 55 mph, which is just right for my taste.
According to the data, it is a good engine with good fuel consumption, which I like because I will stop at the gas station less. The complete dry engine with the ZF63A weighs 663 lbs and reading about the lack of torque makes me fear that "I threw money out the window". I can't do the first test before May 1, because that's when they open the season on a nearby lake. Until then...
Last edited by plavutka; 02-20-2024 at 01:19 PM.
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Wildman_grafix (02-20-2024)
02-20-2024, 05:36 PM
#124
Registered
The LS3/480 has 475 lbft torque and 490 hp on flywheel, let's say it has a gear ratio of 1.56.
The Mercury 450R has 450 hp on the propeller shaft, so it's very comparable in power to the LS3/480, but it has only 439 LBFT of torque or less and it has a 1.6 gear ratio.
The LS3/480 has equal or greater torque from 3,000 rpm to 6,000 rpm.
https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAE
Where is the reason the 450R "pulls like an airplane" while the LS3/480 doesn't have enough torque for marine use?
The Mercury 450R has 450 hp on the propeller shaft, so it's very comparable in power to the LS3/480, but it has only 439 LBFT of torque or less and it has a 1.6 gear ratio.
The LS3/480 has equal or greater torque from 3,000 rpm to 6,000 rpm.
https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAE
Where is the reason the 450R "pulls like an airplane" while the LS3/480 doesn't have enough torque for marine use?
Brake HP vs accelerating HP are 2 diff animals. Not to say there us a diff with the outboard and inboard here.
The outboard has the advantage of only the output shaft and one 90° gear set to accelerate the prop.
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Twin O/B Sonic (02-21-2024)
02-21-2024, 04:59 AM
#126
Registered
I used to chuckle at the “readers rides” letters to Powerboat and Hot Boat mags.
Almost every issue had a letter stating:
”my buddy, who is a drag racer, and I built the motor and we don’t understand why it’s slower than the stock 454 version?
We used the best of everything including the heads w/the biggest ports, biggest valves, a cam w/the most lift/overlap, really pretty roller rockers, a 1050 Holley on the tallest single plane intake we could find.
It made 650 hp on the dyno at 6500!
It barely gets the boat on plane and only pulls the same 26” Bravo I to 4500!
What are we missing?
BTW, the boat is a ‘1992 Baja 270.
Looking forward to your reply”
Uhhhhhh, no you’re not 🤪
Boy do I miss those mags!
Almost every issue had a letter stating:
”my buddy, who is a drag racer, and I built the motor and we don’t understand why it’s slower than the stock 454 version?
We used the best of everything including the heads w/the biggest ports, biggest valves, a cam w/the most lift/overlap, really pretty roller rockers, a 1050 Holley on the tallest single plane intake we could find.
It made 650 hp on the dyno at 6500!
It barely gets the boat on plane and only pulls the same 26” Bravo I to 4500!
What are we missing?
BTW, the boat is a ‘1992 Baja 270.
Looking forward to your reply”
Uhhhhhh, no you’re not 🤪
Boy do I miss those mags!
If you take BOOST out of the equation and are simply comparing NA LS deals based on common production bore/.stroke LS stuff to average low hp NA 502 builds (550 to 600 hp), there's really NO comparison.
Yep, a 6.0 LS has great BSFCs because of all of its modern , low friction, efficient designed stuff
YES, you can take a production 6.0 with rect port heads, cam the **** out of it, do a trunnion/valve spring upgrade and BAM, you can make 575 hp (seen it/ done it on my dyno). Its also gonna be a gutless wonder from 1500 to 4800 with a tq peak at or over 5000 and hp peak at 6800
People get too wrapped up in that "easy" hp number with TOTAL disregard to tq, hotrods show up at my shop all the time too with these deals, total turds, owners totally got focused on that romantic hp number. We end up putting a **** TON of stall in and lower gears to make it actually drive GOOD.
You build a 575 hp 509 that makes tq from 2500/3000 up, its gonna pull alot more prop and feel MUCH better.
Your still comparing a 366 ci sb to 509 ci, no tq comparison,
Yep, do a 40,000$+ boosted LS with all kinds of cool goodies, or build one from scratch with a bunch of cubic inches ($$$), sure, it gets much better but that shuts out the dreamers who THINK their gonna shove a 2500$ used 6.0 in their boat with cam upgrade and set the world on fire.
Yep, a 6.0 LS has great BSFCs because of all of its modern , low friction, efficient designed stuff
YES, you can take a production 6.0 with rect port heads, cam the **** out of it, do a trunnion/valve spring upgrade and BAM, you can make 575 hp (seen it/ done it on my dyno). Its also gonna be a gutless wonder from 1500 to 4800 with a tq peak at or over 5000 and hp peak at 6800
People get too wrapped up in that "easy" hp number with TOTAL disregard to tq, hotrods show up at my shop all the time too with these deals, total turds, owners totally got focused on that romantic hp number. We end up putting a **** TON of stall in and lower gears to make it actually drive GOOD.
You build a 575 hp 509 that makes tq from 2500/3000 up, its gonna pull alot more prop and feel MUCH better.
Your still comparing a 366 ci sb to 509 ci, no tq comparison,
Yep, do a 40,000$+ boosted LS with all kinds of cool goodies, or build one from scratch with a bunch of cubic inches ($$$), sure, it gets much better but that shuts out the dreamers who THINK their gonna shove a 2500$ used 6.0 in their boat with cam upgrade and set the world on fire.
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02-21-2024, 05:11 AM
#127
Platinum Member
Platinum Member
@ Wildman_grafix;
Google, for example https://www.boatingmag.com/mercury-r...tboard-review/
@ Articfriends;
I have almost ready LS3/480 to put it in the 4.200 lbs boat (Boat have pad keel and notched transom it is made for light engine.) Peak torque is at 4500 rpm, which in my case translates to a cruising speed of around 55 mph, which is just right for my taste.
According to the data, it is a good engine with good fuel consumption, which I like because I will stop at the gas station less. The complete dry engine with the ZF63A weighs 663 lbs and reading about the lack of torque makes me fear that "I threw money out the window". I can't do the first test before May 1, because that's when they open the season on a nearby lake. Until then...
Google, for example https://www.boatingmag.com/mercury-r...tboard-review/
@ Articfriends;
I have almost ready LS3/480 to put it in the 4.200 lbs boat (Boat have pad keel and notched transom it is made for light engine.) Peak torque is at 4500 rpm, which in my case translates to a cruising speed of around 55 mph, which is just right for my taste.
According to the data, it is a good engine with good fuel consumption, which I like because I will stop at the gas station less. The complete dry engine with the ZF63A weighs 663 lbs and reading about the lack of torque makes me fear that "I threw money out the window". I can't do the first test before May 1, because that's when they open the season on a nearby lake. Until then...
02-21-2024, 05:28 AM
#128
Registered
We'll see. If it goes hard I will change the gear in ZF to 2. I have surface drive MSA Marine and it is work well with previous 300 hp, but slower like I want. The challenge is more important to me than the cost, and I hope I didn't make too bigg mistakes with my choice.
@Twin O/B Sonic;
Ilmor and Volvo Penta do worse than BB of the same power? Papers say otherwise, but what about practice?
@Twin O/B Sonic;
Ilmor and Volvo Penta do worse than BB of the same power? Papers say otherwise, but what about practice?
Last edited by plavutka; 02-21-2024 at 07:31 AM.
02-21-2024, 11:41 AM
#129
Registered
That's a very pretty motor! What are your plans for cooling that? I know CP makes the closed cooling setup but what are options other than the CP set up? Im sure it works great but im not a fan of how it looks hanging off the side like it does. Just curious what others are doing since its recomended it be a closed system.
02-21-2024, 11:56 AM
#130
Registered
That's a very pretty motor! What are your plans for cooling that? I know CP makes the closed cooling setup but what are options other than the CP set up? Im sure it works great but im not a fan of how it looks hanging off the side like it does. Just curious what others are doing since its recomended it be a closed system.
