Fuel Economy: LS1 swap vs. EFI kit?
09-20-2014, 12:03 AM
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Fuel Economy: LS1 swap vs. EFI kit? Salutations, people of the internets. I have a question I was hoping you people more knowledgable than I could answer; from a fuel economy perspective, is swapping an LS series engine into a car, for the sake of the question, let's say a 1969 Firebird with a 350 Cubic Inch Chevy motor, better (read more efficient) than adding a fuel injection kit to that 350 Chevy? I know a lot of your milage has to do with how heavy your right foot is 
and if you have a manual or an automatic transmission, but, disregarding those, or assuming they are the same regardless of engine, which offers better mpg's?
Sorry if this is the wrong section, I'm new here.
and if you have a manual or an automatic transmission, but, disregarding those, or assuming they are the same regardless of engine, which offers better mpg's?Sorry if this is the wrong section, I'm new here.
09-21-2014, 10:58 PM
#2
Modern technology(LS) really is that much better. If you want MPG, go LS. Heck, an LS motor will make more power while getting better MPG. The fuel injection only accounts for some of the improvement. Even carbureted the LS just makes more power with less fuel and BS because it is the true evolution of the Chevy small block.
Even the smallest LS, the 4.8(about 290 cubic inches) would make more power and get better mileage than that 350(5.7L)
Even the smallest LS, the 4.8(about 290 cubic inches) would make more power and get better mileage than that 350(5.7L)
09-21-2014, 11:50 PM
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Modern technology(LS) really is that much better. If you want MPG, go LS. Heck, an LS motor will make more power while getting better MPG. The fuel injection only accounts for some of the improvement. Even carbureted the LS just makes more power with less fuel and BS because it is the true evolution of the Chevy small block.
Even the smallest LS, the 4.8(about 290 cubic inches) would make more power and get better mileage than that 350(5.7L)
Even the smallest LS, the 4.8(about 290 cubic inches) would make more power and get better mileage than that 350(5.7L)
Thank you for taking the time to reply. I'm curious though, as to something you mentioned. Would a carbureted LS really be noticeably more fuel efficient then an older 350, assuming they have the same carb? Why is this?
09-22-2014, 12:07 AM
#4
Roller cam(and lifters), superior factory aluminum head design, better cylinder sealing, better machining on everything..plus when maintained and treated well, they are designed to run well for over 250K miles.
A carb, if really tuned well and not oversized, will get very good mileage with a stock to mild LS1 IMO. If you throw a Dominator on there though MPG would be out the window. It's not the same as putting big injectors..if you want over 500HP and MPG then I would say you are probably better off with fuel injection and paying a good tuner.
That being said, LS fuel injection has been easy and kind to me and is cheap and reliable/predictable. It's worth it even putting MPG and power aside.
A carb, if really tuned well and not oversized, will get very good mileage with a stock to mild LS1 IMO. If you throw a Dominator on there though MPG would be out the window. It's not the same as putting big injectors..if you want over 500HP and MPG then I would say you are probably better off with fuel injection and paying a good tuner.
That being said, LS fuel injection has been easy and kind to me and is cheap and reliable/predictable. It's worth it even putting MPG and power aside.
Last edited by Mercier; 09-22-2014 at 11:02 AM.
