Engine swaps for economy
08-14-2018 | 11:05 PM
#12
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Joined: Dec 2013
Posts: 358
Likes: 2
From: Minneapolis, Mn
I can tell you the LS sip fuel compared to a BBC there combustion champers are just that much more efficient. That being fuel still contains X amount of BTU whether its in a BBC or LS or briggs motor. Those BTU are what drive your piston down and spin the crankshaft.
Something you can do with a LS that aren't as easy as todo with say a MPI motor is set your fuel burn at cruise to pretty lean. Due to the efficiency of the cylinder heads, the port fuel injection and your abilty with cam sensor to control end of injection events you can get the most out of each gallon of gas.
I know on my boat at 3k rpms is pretty close to 30mph and roughly 30 percent throttle, so what I did in my ECU is set my lamda to be 1 (afr 14.7) and my timing up there(each motor is different) I have a full function knock detection on the boat so I don't have to worry as much about part throttle detonation. I can actually go as lean as 15.0 and timing up 4 degree before I see any kinds of knock showing up. Plenty safe.
From the caculations I have done I burn roughly the same fuel at cruise that my boat did when it had a 4cly mecruiser motor in it.
What does all this mean, pretty much nothing. The cost and TIME you spend changing this over and hell even just dyno tuning the motor to peak performance will never pay off compared to what those BBC drink for fuel. If you think boat gas is expensive don't look at air planes.
Something you can do with a LS that aren't as easy as todo with say a MPI motor is set your fuel burn at cruise to pretty lean. Due to the efficiency of the cylinder heads, the port fuel injection and your abilty with cam sensor to control end of injection events you can get the most out of each gallon of gas.
I know on my boat at 3k rpms is pretty close to 30mph and roughly 30 percent throttle, so what I did in my ECU is set my lamda to be 1 (afr 14.7) and my timing up there(each motor is different) I have a full function knock detection on the boat so I don't have to worry as much about part throttle detonation. I can actually go as lean as 15.0 and timing up 4 degree before I see any kinds of knock showing up. Plenty safe.
From the caculations I have done I burn roughly the same fuel at cruise that my boat did when it had a 4cly mecruiser motor in it.
What does all this mean, pretty much nothing. The cost and TIME you spend changing this over and hell even just dyno tuning the motor to peak performance will never pay off compared to what those BBC drink for fuel. If you think boat gas is expensive don't look at air planes.
08-15-2018 | 09:23 AM
#14
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Joined: Jun 2012
Posts: 428
Likes: 3
Great points. I like the idea of:
Tuning what I have to be more efficient at cruise. I bought a LM-2 and MEFIBurn. Can anyone spend a few minutes to start me off in the right direction with this.
Alum LS engine would be efficent due to the weight and modern design.
And yes I know boating is EXPENSIVE this is my 6th boat!!! Too much fun!!
Tuning what I have to be more efficient at cruise. I bought a LM-2 and MEFIBurn. Can anyone spend a few minutes to start me off in the right direction with this.
Alum LS engine would be efficent due to the weight and modern design.
And yes I know boating is EXPENSIVE this is my 6th boat!!! Too much fun!!
08-15-2018 | 11:38 AM
#16
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Joined: Oct 2013
Posts: 2,888
Likes: 148
From: SF Bay Area
A buddy and I both bought similar Tundas but he got the V6 and I got the V8 but my mileage was nearly identical because he was wfo all the time to go the same speed I cruised at. It takes X amount of HP to go Y speed. The smaller engine just has to work harder for the same result.
08-15-2018 | 07:56 PM
#19
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Joined: Oct 2012
Posts: 2,235
Likes: 538
I can tell you the LS sip fuel compared to a BBC there combustion champers are just that much more efficient. That being fuel still contains X amount of BTU whether its in a BBC or LS or briggs motor. Those BTU are what drive your piston down and spin the crankshaft.
Something you can do with a LS that aren't as easy as todo with say a MPI motor is set your fuel burn at cruise to pretty lean. Due to the efficiency of the cylinder heads, the port fuel injection and your abilty with cam sensor to control end of injection events you can get the most out of each gallon of gas.
I know on my boat at 3k rpms is pretty close to 30mph and roughly 30 percent throttle, so what I did in my ECU is set my lamda to be 1 (afr 14.7) and my timing up there(each motor is different) I have a full function knock detection on the boat so I don't have to worry as much about part throttle detonation. I can actually go as lean as 15.0 and timing up 4 degree before I see any kinds of knock showing up. Plenty safe.
From the caculations I have done I burn roughly the same fuel at cruise that my boat did when it had a 4cly mecruiser motor in it.
What does all this mean, pretty much nothing. The cost and TIME you spend changing this over and hell even just dyno tuning the motor to peak performance will never pay off compared to what those BBC drink for fuel. If you think boat gas is expensive don't look at air planes.
Something you can do with a LS that aren't as easy as todo with say a MPI motor is set your fuel burn at cruise to pretty lean. Due to the efficiency of the cylinder heads, the port fuel injection and your abilty with cam sensor to control end of injection events you can get the most out of each gallon of gas.
I know on my boat at 3k rpms is pretty close to 30mph and roughly 30 percent throttle, so what I did in my ECU is set my lamda to be 1 (afr 14.7) and my timing up there(each motor is different) I have a full function knock detection on the boat so I don't have to worry as much about part throttle detonation. I can actually go as lean as 15.0 and timing up 4 degree before I see any kinds of knock showing up. Plenty safe.
From the caculations I have done I burn roughly the same fuel at cruise that my boat did when it had a 4cly mecruiser motor in it.
What does all this mean, pretty much nothing. The cost and TIME you spend changing this over and hell even just dyno tuning the motor to peak performance will never pay off compared to what those BBC drink for fuel. If you think boat gas is expensive don't look at air planes.
Just curious what the load is at your 3000rpm cruise speed?
