LS Engines Maybe the future of I/O's
02-12-2024, 08:56 PM
#81
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I never said Sterling was doing anything wrong. Its more about the efficiency of the cylinder head and no parasitic loss.
And those Sterlings were $65K for the pair from Dave. I have way more than that in my LS engines. I’m simply sharing performance data I have measured. I’m not saying one is better than other.
The PSI engines are cooler IMO. They were so obnoxious they knocked the lights down in the dyno. They looked cool, sounded cool, and screamed power boat.
And those Sterlings were $65K for the pair from Dave. I have way more than that in my LS engines. I’m simply sharing performance data I have measured. I’m not saying one is better than other.
The PSI engines are cooler IMO. They were so obnoxious they knocked the lights down in the dyno. They looked cool, sounded cool, and screamed power boat.
Last edited by ICDEDPPL; 02-12-2024 at 09:01 PM.
02-12-2024, 09:05 PM
#82
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You can turn a big block into a giant LS with 20* heads, and a bigger cam core and lifter bores.
https://brodix.com/heads-2/big-block.../br-x-series20
It’s not cheap but at 600” it’s going to crush any 366” motor setup similarly.
A poster here put 1000hp NA 600” SR20 head motors in a skater 32B and went 160. Another guy ran a 41 Apache with NA big blocks that went in the 1teens.
Just too hard to overcome a 50% displacement advantage. And why bother when a BBC can be modified to have the LSs inherent head and cam advantages.
https://brodix.com/heads-2/big-block.../br-x-series20
It’s not cheap but at 600” it’s going to crush any 366” motor setup similarly.
A poster here put 1000hp NA 600” SR20 head motors in a skater 32B and went 160. Another guy ran a 41 Apache with NA big blocks that went in the 1teens.
Just too hard to overcome a 50% displacement advantage. And why bother when a BBC can be modified to have the LSs inherent head and cam advantages.
02-12-2024, 09:07 PM
#83
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Correct me if I`m wrong but at the end of the day an engine is a pump, you can make a more efficient pump but the basic principle is the same. Expansion of air and fuel is what creates the force to move that piston down.
It`s cylinder pressure that makes power. The more cylinder pressure the more chances of detonation and pre ignition . Generally a smaller displacement engine needs to operate at higher cylinder pressures to produce the same power as a larger displacement engine since it needs to extract more energy from each combustion event to compensate for its smaller size. Larger displacement engines will have higher tq (important in boats) at lower rpms and they do not need to make as much cylinder pressure to make the same power and the octane requirements are lower .
There is no replacement for displacement, thats not a slogan that`s just physics.
You better have some high octane to make 1350hp in an endurance engine especially if it`s a small block.
The LS is not some magic engine that defies physics.
It`s cylinder pressure that makes power. The more cylinder pressure the more chances of detonation and pre ignition . Generally a smaller displacement engine needs to operate at higher cylinder pressures to produce the same power as a larger displacement engine since it needs to extract more energy from each combustion event to compensate for its smaller size. Larger displacement engines will have higher tq (important in boats) at lower rpms and they do not need to make as much cylinder pressure to make the same power and the octane requirements are lower .
There is no replacement for displacement, thats not a slogan that`s just physics.
You better have some high octane to make 1350hp in an endurance engine especially if it`s a small block.
The LS is not some magic engine that defies physics.
TQ X RPM / 5252.
The engine the Ken and his team built makes a lot of power, but is turning quite a few RPM to do it. The stress or load from TQ is less but now we have to contend with piston speed and valvetrain wear.
Where a big cubic inch engine would cruise a boat at let’s say 4,000 RPM this engine would have to do it at a higher RPM do create the same power output and the same speed.
The only difference here is the LS engine would extract a little more power out of the fuel mixture per combustion cycle than the big block. But, that little bit of power won’t make a big difference in a heavy vee.
02-12-2024, 09:13 PM
#84
Registered
Last edited by hogie roll; 02-12-2024 at 09:16 PM.
02-12-2024, 09:18 PM
#85
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BSAC and drive vs compressor pressures are the most important data points I can collect when we are testing compressor and turbine designs.
The starting point of all of this is NA testing to determine what combinations we should start with.
Edit:
The LS testing I have done to date has been mostly LS7 12* heads. And the BBC testing has been Mercury 525 (Edelbrock Performer RPM).
I have yet to test the Big Chief stuff I’m working on currently.
Last edited by Precision; 02-12-2024 at 09:25 PM.
02-12-2024, 09:46 PM
#87
Registered
That’s a genuine possibility, but since the 525 turbo kit is what I’ve been working on that’s where my experience is at.
02-13-2024, 01:48 AM
#89
Registered
Correct me if I`m wrong but at the end of the day an engine is a pump, you can make a more efficient pump but the basic principle is the same. Expansion of air and fuel is what creates the force to move that piston down.
It`s cylinder pressure that makes power. The more cylinder pressure the more chances of detonation and pre ignition . Generally a smaller displacement engine needs to operate at higher cylinder pressures to produce the same power as a larger displacement engine since it needs to extract more energy from each combustion event to compensate for its smaller size. Larger displacement engines will have higher tq (important in boats) at lower rpms and they do not need to make as much cylinder pressure to make the same power and the octane requirements are lower .
There is no replacement for displacement, thats not a slogan that`s just physics.
You better have some high octane to make 1350hp in an endurance engine especially if it`s a small block.
The LS is not some magic engine that defies physics.
It`s cylinder pressure that makes power. The more cylinder pressure the more chances of detonation and pre ignition . Generally a smaller displacement engine needs to operate at higher cylinder pressures to produce the same power as a larger displacement engine since it needs to extract more energy from each combustion event to compensate for its smaller size. Larger displacement engines will have higher tq (important in boats) at lower rpms and they do not need to make as much cylinder pressure to make the same power and the octane requirements are lower .
There is no replacement for displacement, thats not a slogan that`s just physics.
You better have some high octane to make 1350hp in an endurance engine especially if it`s a small block.
The LS is not some magic engine that defies physics.
Reliability as a factor: more likely higher if an engine isn't working working as hard.
Part weights on a high rpm scenario dictate 'working hard' more than power output.
It really comes down to what makes an LS engine, an LS?
Cam base circle bigger
Valve angle is shallower
Intake port better geometry
Bearing size (main/rod)
Anything else that couln't be found on a BBC aftermarket?
As in, FI, coil/cyl, modern heads/chambers etc
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articfriends (02-19-2024)
02-13-2024, 02:00 AM
#90
Registered
The BBC also has a wider bore, making combustion less efficient.
BBC is under valved. An LS would have an advantage, that would translate to a SC LS.
Smaller bearing size.
GM engineers did a great job on the LS.engine. But it was always a small.block.
