Fast Lane Truck: Ecoboost vs i-Force vs Ecotec
#221
Senior Member
It really depends on how Fords engine management works, if it only allows so much pressure, and how much "extra" the turbos have in them. My turbo charged sled has quite a bit more power at 1000' @ 8 psi then it does at 8psi on top of a mountain. I usually need to crank it up to 11-12psi to get the same amount of "Go". That said the Eco-boost SHOULD loose a smaller percentage of power than an N/A engine but how much is anyone guess. I brought this up because I've seen it claimed a few times on a few forums that that Eco Boost will still make rated HP at 10,000 feet. It would be really neat if the would dyno a few of the trucks at sea level then again in Denver and really see how much altitude effects power on these.
#222
It really depends on how Fords engine management works, if it only allows so much pressure, and how much "extra" the turbos have in them. My turbo charged sled has quite a bit more power at 1000' @ 8 psi then it does at 8psi on top of a mountain. I usually need to crank it up to 11-12psi to get the same amount of "Go". \
8psi of boost is the same at sea level as it is at the top of the mountain. Now your turbo may have to spin more to build that 8lbs of boost but your engine does not know or care, if the manifold pressure is 8psi at the top of the mountain and the bottom of the mountain then you are making the same amount of power.
Now that being said you will have less NPSHA (net positive suction head available) at the top of the mountain, so it wont be as easy to make 8 psi of boost as it is at sea level. Your turbo will have to ingest more (less dense) air to make 8 psi. But like i said before, after the compressor (if the manifold is actually 8 psi) the engine does not know or care.
8 psi of air in a engine intake manifold is 8 psi, whether its at the top of a mountain or at sea level.
Sorry to burst your bubble.
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#224
Physics says other wise there bud. 8 psi of boost is just that 8 psi of boost. There is less pressure at altitude for a naturally aspirated engine so less oxygen is making it into the cylinder. If you have a turbo/Supercharger application though you will make the same power.
8psi of boost is the same at sea level as it is at the top of the mountain. Now your turbo may have to spin more to build that 8lbs of boost but your engine does not know or care, if the manifold pressure is 8psi at the top of the mountain and the bottom of the mountain then you are making the same amount of power.
Now that being said you will have less NPSHA (net positive suction head available) at the top of the mountain, so it wont be as easy to make 8 psi of boost as it is at sea level. Your turbo will have to ingest more (less dense) air to make 8 psi. But like i said before, after the compressor (if the manifold is actually 8 psi) the engine does not know or care.
8 psi of air in a engine intake manifold is 8 psi, whether its at the top of a mountain or at sea level.
Sorry to burst your bubble.
8psi of boost is the same at sea level as it is at the top of the mountain. Now your turbo may have to spin more to build that 8lbs of boost but your engine does not know or care, if the manifold pressure is 8psi at the top of the mountain and the bottom of the mountain then you are making the same amount of power.
Now that being said you will have less NPSHA (net positive suction head available) at the top of the mountain, so it wont be as easy to make 8 psi of boost as it is at sea level. Your turbo will have to ingest more (less dense) air to make 8 psi. But like i said before, after the compressor (if the manifold is actually 8 psi) the engine does not know or care.
8 psi of air in a engine intake manifold is 8 psi, whether its at the top of a mountain or at sea level.
Sorry to burst your bubble.
But to add, it depends on what you are measuring. I think that is where rancherlee's/xtralargetall comment comes from. When people talk about boost, they are not always referring to the same thing unless they are at the same elvation.
If your boost reading is coming from the manifold, 8psi is 8psi since it is an absolute pressure reading. If you have an analog gauge showing pressure relative to atmospheric 8psi at elevation is not the same volume of air as 8psi at sea level. At altitude the 12 psi gauge reading is probably what it takes to get you to the 8psi equivalent manifold pressure. If you are using the torque app, there is a setting to adjust the readings for atmospheric pressure at high altitudes and that can also account for different values you are seeing since torque uses MAP data but reports in relative numbers (I think, torque options are often not well explained).
A turbo engine definitely loses some power due to heat generation and loss of turbo efficiency. Just nowhere near as much as NA engines. Figure a few percentage points and only at extreme altitudes most of us won't experience..
Last edited by packplantpath; 08-29-2013 at 09:40 AM.
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SultanGris (08-29-2013)
#225
Retired and loving it!
I understand that at higher altitudes, there is no longer 14.7 psi of air that the engine is able to inhale, so for an NA engine, less available oxygen = less HP.
Let's see if I can ask what I am thinking about --- if a turbo engine is capable of producing 16 psi of total boost, and at sea level it has to use 8 psi of that to tow a defined weight up a hill.....wouldn't the turbos produce MORE boost --- even up to the 16 max to compensate for the altitude when asked to tow that same weight up the same size hill?
Wouldn't the capability to produce MORE boost than needed at sea level make the turbo'd engine much more capable at altitude (?), comparatively speaking to an NA engine of course. I realize that the turbo engine is working harder than at sea level, but the added boost wold still enable it to make HP (and torque) that was unavailable to the NA engine at that altitude, right?
What is the PSI of the air at 9,000 feet?
Let's see if I can ask what I am thinking about --- if a turbo engine is capable of producing 16 psi of total boost, and at sea level it has to use 8 psi of that to tow a defined weight up a hill.....wouldn't the turbos produce MORE boost --- even up to the 16 max to compensate for the altitude when asked to tow that same weight up the same size hill?
Wouldn't the capability to produce MORE boost than needed at sea level make the turbo'd engine much more capable at altitude (?), comparatively speaking to an NA engine of course. I realize that the turbo engine is working harder than at sea level, but the added boost wold still enable it to make HP (and torque) that was unavailable to the NA engine at that altitude, right?
What is the PSI of the air at 9,000 feet?
#226
Interesting write up on the Ecoboost engine and turbo performance at elevation
http://www.ask.com/explore/effects-a...-ecoboost-5040
http://www.ask.com/explore/effects-a...-ecoboost-5040
Last edited by frieed; 08-29-2013 at 10:24 AM.
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MadocHandyman (08-29-2013)
#227
I understand that at higher altitudes, there is no longer 14.7 psi of air that the engine is able to inhale, so for an NA engine, less available oxygen = less HP.
Let's see if I can ask what I am thinking about --- if a turbo engine is capable of producing 16 psi of total boost, and at sea level it has to use 8 psi of that to tow a defined weight up a hill.....wouldn't the turbos produce MORE boost --- even up to the 16 max to compensate for the altitude when asked to tow that same weight up the same size hill?
Wouldn't the capability to produce MORE boost than needed at sea level make the turbo'd engine much more capable at altitude (?), comparatively speaking to an NA engine of course. I realize that the turbo engine is working harder than at sea level, but the added boost wold still enable it to make HP (and torque) that was unavailable to the NA engine at that altitude, right?
What is the PSI of the air at 9,000 feet?
Let's see if I can ask what I am thinking about --- if a turbo engine is capable of producing 16 psi of total boost, and at sea level it has to use 8 psi of that to tow a defined weight up a hill.....wouldn't the turbos produce MORE boost --- even up to the 16 max to compensate for the altitude when asked to tow that same weight up the same size hill?
Wouldn't the capability to produce MORE boost than needed at sea level make the turbo'd engine much more capable at altitude (?), comparatively speaking to an NA engine of course. I realize that the turbo engine is working harder than at sea level, but the added boost wold still enable it to make HP (and torque) that was unavailable to the NA engine at that altitude, right?
What is the PSI of the air at 9,000 feet?
Turbo engines are the unmistakable king of altitude towing for this reason. There is a reason the eco won the shootout.
#228
According to the article I posted above, the Ecoboost should maintain full HP to about 22,500 feet
I will add, I have towed my trailer and full load of stuff (I'd guess 8000+ lbs) through Bald Mt. pass at 10,759 ft with no apparent difference in power vs 4640 ft in my driveway. As measured by my butt dyno.
I will add, I have towed my trailer and full load of stuff (I'd guess 8000+ lbs) through Bald Mt. pass at 10,759 ft with no apparent difference in power vs 4640 ft in my driveway. As measured by my butt dyno.
Last edited by frieed; 08-29-2013 at 11:11 AM.
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rdkev (08-29-2013)
#229
Senior Member
Physics says other wise there bud. 8 psi of boost is just that 8 psi of boost. There is less pressure at altitude for a naturally aspirated engine so less oxygen is making it into the cylinder. If you have a turbo/Supercharger application though you will make the same power.
8psi of boost is the same at sea level as it is at the top of the mountain. Now your turbo may have to spin more to build that 8lbs of boost but your engine does not know or care, if the manifold pressure is 8psi at the top of the mountain and the bottom of the mountain then you are making the same amount of power.
Now that being said you will have less NPSHA (net positive suction head available) at the top of the mountain, so it wont be as easy to make 8 psi of boost as it is at sea level. Your turbo will have to ingest more (less dense) air to make 8 psi. But like i said before, after the compressor (if the manifold is actually 8 psi) the engine does not know or care.
8 psi of air in a engine intake manifold is 8 psi, whether its at the top of a mountain or at sea level.
Sorry to burst your bubble.
8psi of boost is the same at sea level as it is at the top of the mountain. Now your turbo may have to spin more to build that 8lbs of boost but your engine does not know or care, if the manifold pressure is 8psi at the top of the mountain and the bottom of the mountain then you are making the same amount of power.
Now that being said you will have less NPSHA (net positive suction head available) at the top of the mountain, so it wont be as easy to make 8 psi of boost as it is at sea level. Your turbo will have to ingest more (less dense) air to make 8 psi. But like i said before, after the compressor (if the manifold is actually 8 psi) the engine does not know or care.
8 psi of air in a engine intake manifold is 8 psi, whether its at the top of a mountain or at sea level.
Sorry to burst your bubble.
Last edited by Ssls6; 08-29-2013 at 11:24 AM.
#230
Senior Member
Rancherlee is part right.
On a snowmobile it is a little different than our eco trucks. On a sled you set it to run a set amount of boost at WOT, most don't run the fancy systems such as vipecs, boost-its, or the new bullydog ECU's. You set up the amount of boost you want to run and then adjust your fuel maps to run it, usually a dobec or power comander or a boondocker box, its an add on to the fuel system to add or subtract from the original fuel map on the sled, basically.
When you go up in elevation you can obvisouly run the same amount of boost, but the "quality" in that "boosted air" still comes down to not having the same amount of oxygen in it to burn, also one of the reasons you could run the same fuel mapping on 91 octane at elevation and sea level you might have to splash some AV or race gas in the tank, less oxygen at elevation on the same amount of boost but its still different air. The cool thing about two stroke engine at elevation on boost is that you can crank the hell out of the boost at elevation compared to low elevation and really let it rip, higher elevation is easier to tune for and ultimately makes it more forgiving.
Enter our trucks, we are spoiled by having some very sophisticated electronics that even though we aren't getting the same air quiality, they can manipulate that small bit by giving us more boost on the fly or other variables to factor out that small loss.
On a truck it is still prevelant and even though it is small enough that our computer can compensate for it without most of us knowing, Rancherlee and his sled will show the same losses that our truck sees only it is a lot more obvious and he has to tune for it where our trucks do the work for us.
On a snowmobile it is a little different than our eco trucks. On a sled you set it to run a set amount of boost at WOT, most don't run the fancy systems such as vipecs, boost-its, or the new bullydog ECU's. You set up the amount of boost you want to run and then adjust your fuel maps to run it, usually a dobec or power comander or a boondocker box, its an add on to the fuel system to add or subtract from the original fuel map on the sled, basically.
When you go up in elevation you can obvisouly run the same amount of boost, but the "quality" in that "boosted air" still comes down to not having the same amount of oxygen in it to burn, also one of the reasons you could run the same fuel mapping on 91 octane at elevation and sea level you might have to splash some AV or race gas in the tank, less oxygen at elevation on the same amount of boost but its still different air. The cool thing about two stroke engine at elevation on boost is that you can crank the hell out of the boost at elevation compared to low elevation and really let it rip, higher elevation is easier to tune for and ultimately makes it more forgiving.
Enter our trucks, we are spoiled by having some very sophisticated electronics that even though we aren't getting the same air quiality, they can manipulate that small bit by giving us more boost on the fly or other variables to factor out that small loss.
On a truck it is still prevelant and even though it is small enough that our computer can compensate for it without most of us knowing, Rancherlee and his sled will show the same losses that our truck sees only it is a lot more obvious and he has to tune for it where our trucks do the work for us.