In defense of the 2.7 ecoboost
01-28-2019, 09:15 AM
#71
Senior Member
I'm not certain this the case. Almost all real world reports I've seen (on here and on Fuelly) indicate that the 2.7EB does provide better mileage on the highway than either the 3.5EB or 5.0.
How would it take the 2.7 more power to pass on the highway? Power output is based on demand, so identical acceleration in a near identical truck (same drag coefficient, similar weights) should require the same amount of power, with fuel consumption being based on BSFC. BSFC is generally lower (more efficient) at higher cylinder pressures and lower engine speed, so a 2.7 under boost to develop higher power at a lower speed would most likely be more efficient than the 5.0. As for the 2.7 being more efficient than the 3.5, I can only guess it's due to a number of factors including additional rotating and reciprocating mass.
I don't think the 2.7 needs much defending since the feedback for that engine is overwhelmingly good. In fact, if there were an identical truck to mine on the lot except with a 2.7, then I may have very well gone that route.
How would it take the 2.7 more power to pass on the highway? Power output is based on demand, so identical acceleration in a near identical truck (same drag coefficient, similar weights) should require the same amount of power, with fuel consumption being based on BSFC. BSFC is generally lower (more efficient) at higher cylinder pressures and lower engine speed, so a 2.7 under boost to develop higher power at a lower speed would most likely be more efficient than the 5.0. As for the 2.7 being more efficient than the 3.5, I can only guess it's due to a number of factors including additional rotating and reciprocating mass.
I don't think the 2.7 needs much defending since the feedback for that engine is overwhelmingly good. In fact, if there were an identical truck to mine on the lot except with a 2.7, then I may have very well gone that route.
01-28-2019, 12:27 PM
#72
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Summers22 (01-28-2019)
01-28-2019, 01:46 PM
#74
Senior Member
The 2.7L kinda has to be heavier per liter. The relation between liters and strength is not linear, so the heads, cams, chains, etc. in the 2.7 are not significantly lighter than the 3.5.
Indy car is 300+hp/ltr. Ford GT? 185hp/ltr
Ability to remove heat is determined by engine design, not displacement. Ford could have designed the 2.7 to remove a lot more heat had they felt the need. If you're watching the temp gauge, it's not because of the hp/liter number.
Common mod for tracked street cars is a smaller water pump pulley matched to a larger radiator. The smaller pully spins the pump faster, larger radiator gives the coolant more time to dump heat. A well thought out coolant mod decreases coolant time in a hotter block so it leaves the block at a similar temp as the oem design, with the larger radiator sized so the faster moving coolant spends the same amount of time in the larger radiator as the oem unit, in essence a FASTER heat pump.
This is every 2.7L owner's answer to it's lower (Vs 3.5eco) heat capability. The only questions that exist are 1) Is the oem pump maxed out, so that faster speeds cause too much cavitation, 2) is the design of the 2.7 block such that more pump pressure won't result in more significant flow, or will disrupt the flow pattern through the block that results in eddies that cause hot spots, and 3) is the thermostat a pressure bottleneck?
There is a lower limit where the available cylinder surface area will force transition to coolants that can absorb heat at a faster rate, or new types of cooling, maybe cylinders with aluminum cores that are drilled to flow coolant within the cylinder as well, but we are not there yet.
Ability to remove heat is determined by engine design, not displacement. Ford could have designed the 2.7 to remove a lot more heat had they felt the need. If you're watching the temp gauge, it's not because of the hp/liter number.
Common mod for tracked street cars is a smaller water pump pulley matched to a larger radiator. The smaller pully spins the pump faster, larger radiator gives the coolant more time to dump heat. A well thought out coolant mod decreases coolant time in a hotter block so it leaves the block at a similar temp as the oem design, with the larger radiator sized so the faster moving coolant spends the same amount of time in the larger radiator as the oem unit, in essence a FASTER heat pump.
This is every 2.7L owner's answer to it's lower (Vs 3.5eco) heat capability. The only questions that exist are 1) Is the oem pump maxed out, so that faster speeds cause too much cavitation, 2) is the design of the 2.7 block such that more pump pressure won't result in more significant flow, or will disrupt the flow pattern through the block that results in eddies that cause hot spots, and 3) is the thermostat a pressure bottleneck?
There is a lower limit where the available cylinder surface area will force transition to coolants that can absorb heat at a faster rate, or new types of cooling, maybe cylinders with aluminum cores that are drilled to flow coolant within the cylinder as well, but we are not there yet.
01-28-2019, 06:53 PM
#75
Senior Member
Thread Starter
The 2.7L kinda has to be heavier per liter. The relation between liters and strength is not linear, so the heads, cams, chains, etc. in the 2.7 are not significantly lighter than the 3.5.
Indy car is 300+hp/ltr. Ford GT? 185hp/ltr
Ability to remove heat is determined by engine design, not displacement. Ford could have designed the 2.7 to remove a lot more heat had they felt the need. If you're watching the temp gauge, it's not because of the hp/liter number.
Common mod for tracked street cars is a smaller water pump pulley matched to a larger radiator. The smaller pully spins the pump faster, larger radiator gives the coolant more time to dump heat. A well thought out coolant mod decreases coolant time in a hotter block so it leaves the block at a similar temp as the oem design, with the larger radiator sized so the faster moving coolant spends the same amount of time in the larger radiator as the oem unit, in essence a FASTER heat pump.
This is every 2.7L owner's answer to it's lower (Vs 3.5eco) heat capability. The only questions that exist are 1) Is the oem pump maxed out, so that faster speeds cause too much cavitation, 2) is the design of the 2.7 block such that more pump pressure won't result in more significant flow, or will disrupt the flow pattern through the block that results in eddies that cause hot spots, and 3) is the thermostat a pressure bottleneck?
There is a lower limit where the available cylinder surface area will force transition to coolants that can absorb heat at a faster rate, or new types of cooling, maybe cylinders with aluminum cores that are drilled to flow coolant within the cylinder as well, but we are not there yet.
Indy car is 300+hp/ltr. Ford GT? 185hp/ltr
Ability to remove heat is determined by engine design, not displacement. Ford could have designed the 2.7 to remove a lot more heat had they felt the need. If you're watching the temp gauge, it's not because of the hp/liter number.
Common mod for tracked street cars is a smaller water pump pulley matched to a larger radiator. The smaller pully spins the pump faster, larger radiator gives the coolant more time to dump heat. A well thought out coolant mod decreases coolant time in a hotter block so it leaves the block at a similar temp as the oem design, with the larger radiator sized so the faster moving coolant spends the same amount of time in the larger radiator as the oem unit, in essence a FASTER heat pump.
This is every 2.7L owner's answer to it's lower (Vs 3.5eco) heat capability. The only questions that exist are 1) Is the oem pump maxed out, so that faster speeds cause too much cavitation, 2) is the design of the 2.7 block such that more pump pressure won't result in more significant flow, or will disrupt the flow pattern through the block that results in eddies that cause hot spots, and 3) is the thermostat a pressure bottleneck?
There is a lower limit where the available cylinder surface area will force transition to coolants that can absorb heat at a faster rate, or new types of cooling, maybe cylinders with aluminum cores that are drilled to flow coolant within the cylinder as well, but we are not there yet.
01-28-2019, 07:27 PM
#76
And the winner of the most BS comment of the thread goes to yooper39! If he was going on and on about his 5.0 i could see him being a fanboy but he didnt mention it once lol Also hate to break it to you but these are trucks people are buying, the 5.0 might have felt like a slug on your 10 min test drive(that you went in already hating because you were buying a 2.7) but i can guarantee its got the 2.7 beat where it counts......
Last edited by Yooper39; 01-28-2019 at 07:45 PM. Reason: I stink at typing on an iPad
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