Exhaust / Intake upgrades?!?
#1
02-22-2009, 12:34 PM
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Exhaust / Intake upgrades?!?
Does anyone have some good data (MPG gains, HP gains, etc) on the Gibson exhaust for the 2008 escape hybrid, or know someone that has it. I hear a lot of talk about less restriction = more power/FE but with less back pressure wouldn’t you lose some of the gasses on the compression stroke with less pressure to keep it in? This is important to me because I am about 6 months away from driving from CT to CA and I want to get the best MPG I can.
Now for intake: is there anything out there other than air filters and will these really even do anything for FE.
How about a chip? Anyone make one, and do they do anything? or an optima deep cycle batt?
Would any of this require reprogramming the computer?
Thank you for your time.
Now for intake: is there anything out there other than air filters and will these really even do anything for FE.
How about a chip? Anyone make one, and do they do anything? or an optima deep cycle batt?
Would any of this require reprogramming the computer?
Thank you for your time.
Last edited by GRIMM; 02-22-2009 at 12:48 PM.
#2
02-22-2009, 02:56 PM
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Location: Southwestern Pa
Posts: 1,747
Re: Exhaust / Intake upgrades?!?
Does anyone have some good data (MPG gains, HP gains, etc) on the Gibson exhaust for the 2008 escape hybrid, or know someone that has it. I hear a lot of talk about less restriction = more power/FE but with less back pressure wouldn’t you lose some of the gasses on the compression stroke with less pressure to keep it in? This is important to me because I am about 6 months away from driving from CT to CA and I want to get the best MPG I can.
Now for intake: is there anything out there other than air filters and will these really even do anything for FE.
How about a chip? Anyone make one, and do they do anything? or an optima deep cycle batt?
Would any of this require reprogramming the computer?
Thank you for your time.
Now for intake: is there anything out there other than air filters and will these really even do anything for FE.
How about a chip? Anyone make one, and do they do anything? or an optima deep cycle batt?
Would any of this require reprogramming the computer?
Thank you for your time.
Use of different exhaust system may result in a "louder" vehicle without any real world performance change.
#3
02-22-2009, 05:59 PM
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Join Date: Jan 2009
Posts: 863
Re: Exhaust / Intake upgrades?!?
Exhaust side: a lower restriction system will usually result in slightly better fuel mileage. Basically some energy is needed to move the exhaust out of the cylinder & down the pipe. That comes from the fuel consumed by the engine. Just make sure it is from a reputable company.
Intake Side: I'd be careful. This system is tuned and is particularly susceptible to changes that will actually increase fuel burned. Basically there is a long tube system, anyone remember the old Chrysler slant six? The basis of the design was to allow independent operation of each cylinder.
The FEH intake is a folded version of this. But with the addition of the pseudo-Atkinson cycle feature of delayed closing of the intake valve to push some intake charge back into the manifold. This effectively provides a compression stroke that is smaller than the power stroke. This allows more energy to be removed from a fuel charge than an Otto cycle engine.
So I would say don't mess with the tuning of the intake side without serious design work.
Intake Side: I'd be careful. This system is tuned and is particularly susceptible to changes that will actually increase fuel burned. Basically there is a long tube system, anyone remember the old Chrysler slant six? The basis of the design was to allow independent operation of each cylinder.
The FEH intake is a folded version of this. But with the addition of the pseudo-Atkinson cycle feature of delayed closing of the intake valve to push some intake charge back into the manifold. This effectively provides a compression stroke that is smaller than the power stroke. This allows more energy to be removed from a fuel charge than an Otto cycle engine.
So I would say don't mess with the tuning of the intake side without serious design work.
#4
02-23-2009, 10:26 AM
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Join Date: Sep 2006
Location: Beautiful Pacific NW
Posts: 1,678
Re: Exhaust / Intake upgrades?!?
Does anyone have some good data (MPG gains, HP gains, etc) on the Gibson exhaust for the 2008 escape hybrid, or know someone that has it. I hear a lot of talk about less restriction = more power/FE but with less back pressure wouldn’t you lose some of the gasses on the compression stroke with less pressure to keep it in? This is important to me because I am about 6 months away from driving from CT to CA and I want to get the best MPG I can.
Now for intake: is there anything out there other than air filters and will these really even do anything for FE.
How about a chip? Anyone make one, and do they do anything? or an optima deep cycle batt?
Would any of this require reprogramming the computer?
Thank you for your time.
Now for intake: is there anything out there other than air filters and will these really even do anything for FE.
How about a chip? Anyone make one, and do they do anything? or an optima deep cycle batt?
Would any of this require reprogramming the computer?
Thank you for your time.
Keep in mind that the Atkinson cycle results in a more thorough "burn" within the cylinder itself during the power stroke, so there is less "pressure" and HEAT in the exhaust manifold. You may have also noticed the EXTREMES the design engineers have had to go to with these hybrid vehicles to keep the catalyst HEATED to full operational temperature.
Add any form of a freer flowing exhaust and you may very well be compromising their work.
Intake:
Here again, its important to remember the Atkinson cycle and the fact that this is a hybrid engine we're discussing. The Atkinson cycle results in derating/detuning of the engine displacement volume by something in the range of 20-30%
While the Atkinson cycle engine is highly fuel efficient it does so by sacrificing POWER. So at near WOT or WOT it is moreso the battery/electric systems, especially at low speeds, that you are relying on for TORQUE.
Lastly since the throttle plate itself is the PRIMARY restriction to intake airflow except at WOT just how often would a more "open" intake be of help..??
And don't forget that it would be very easy for an aftermarket intake system to screw up the factory calibration for the MAF/IAT and throw the A/F mixture off just enough that you might need to replace the catalyst or even an engine overhaul in as little as 60-70,000 miles.
And let's not even discuss the uselessness and high potential for detrimental effects of one of these "oiled" K&N filters.
#5
02-23-2009, 12:06 PM
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Join Date: Jan 2009
Posts: 863
Re: Exhaust / Intake upgrades?!?
Be careful of the previous post.
First: a true Atkinson Cycle (which the FEH is not) uses a different crankshaft arrangement to achieve a smaller compression volume and a larger expansion volume than the common Otto Cycle engine which has equal volumes. Thus, nothing is "derated," rather the engine design simply is not capable of producing the same power as compared to an engine displacement as is in common usage today (Otto cycle).
The manner by which Ford achieves the effect of the Atkinson cycle (& why I called it a pseudo Atkinson Cycle) is by delaying the closing of the intake valve and allowing the piston to push back out a fraction of the intake charge. This achieves a measure of reduction of the compression volume relative to the power stroke volume. This is not a more thorough burn of any kind, it is simply a larger expansion of a given amount of combustion gas.
The effect of the long branches of the intake (as has been done on some previous engines) is to enable each cylinder intake to be unaffected by an adjacent cylinder (envision a setup where two cylinder intake valves are adjacent and operation of one can affect the other).
Since this engine relies on the pushback of some intake charge back into the intake piping to achieve the Atkinson effect, the tuning of the intake lines is important to the design. You tamper with that feature at your peril.
The issue raised of throwing off the A/F ratio is not accurate. So long as all air ingested by the engine passes the Mass Air Flow unit, the engine's computer will meter the right amount of fuel via the fuel injectors. The real issue is tuning of the inlet air flow system (or detuning if you mess with it).
Regarding low speed operation: all gasoline engines are low torque at lower rpm. Thus the marriage of electric machines, which produce higher torque at lower rpms, with a gasoline engine is a good one.
First: a true Atkinson Cycle (which the FEH is not) uses a different crankshaft arrangement to achieve a smaller compression volume and a larger expansion volume than the common Otto Cycle engine which has equal volumes. Thus, nothing is "derated," rather the engine design simply is not capable of producing the same power as compared to an engine displacement as is in common usage today (Otto cycle).
The manner by which Ford achieves the effect of the Atkinson cycle (& why I called it a pseudo Atkinson Cycle) is by delaying the closing of the intake valve and allowing the piston to push back out a fraction of the intake charge. This achieves a measure of reduction of the compression volume relative to the power stroke volume. This is not a more thorough burn of any kind, it is simply a larger expansion of a given amount of combustion gas.
The effect of the long branches of the intake (as has been done on some previous engines) is to enable each cylinder intake to be unaffected by an adjacent cylinder (envision a setup where two cylinder intake valves are adjacent and operation of one can affect the other).
Since this engine relies on the pushback of some intake charge back into the intake piping to achieve the Atkinson effect, the tuning of the intake lines is important to the design. You tamper with that feature at your peril.
The issue raised of throwing off the A/F ratio is not accurate. So long as all air ingested by the engine passes the Mass Air Flow unit, the engine's computer will meter the right amount of fuel via the fuel injectors. The real issue is tuning of the inlet air flow system (or detuning if you mess with it).
Regarding low speed operation: all gasoline engines are low torque at lower rpm. Thus the marriage of electric machines, which produce higher torque at lower rpms, with a gasoline engine is a good one.
#6
02-26-2009, 09:44 AM
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Join Date: Sep 2006
Location: Beautiful Pacific NW
Posts: 1,678
Re: Exhaust / Intake upgrades?!?
Be careful of the previous post.
First: a true Atkinson Cycle (which the FEH is not) uses a different crankshaft arrangement to achieve a smaller compression volume and a larger expansion volume than the common Otto Cycle engine which has equal volumes. Thus, nothing is "derated," rather the engine design simply is not capable of producing the same power as compared to an engine displacement as is in common usage today (Otto cycle).
In other words an "Otto" engine of 2.0L will produce substantially more power than an Atkinson engine of the same displacement. A ~30% loss in power in return for a comparable increase in FE.
The manner by which Ford achieves the effect of the Atkinson cycle (& why I called it a pseudo Atkinson Cycle) is by delaying the closing of the intake valve and allowing the piston to push back out a fraction of the intake charge. This achieves a measure of reduction of the compression volume relative to the power stroke volume. This is not a more thorough burn of any kind, it is simply a larger expansion of a given amount of combustion gas.
Okay, if an Otto engine is operating at WOT throttle and presuming the cylinders are being fully filled with A/F mixture charge, what happens when I suddenly go to 1/2 throttle (RPM remains constant briefly), doesn't the resulting lower charge still have the same time to burn and therefore a more complete burn..??
If the Atkinson cycle were to allow a full charge to enter/remain in the cylinder bore you would be correct. But in reality the Atkinson cylinder charge is only ~70% of maximum based on the engine displacement.
The effect of the long branches of the intake (as has been done on some previous engines) is to enable each cylinder intake to be unaffected by an adjacent cylinder (envision a setup where two cylinder intake valves are adjacent and operation of one can affect the other).
Since this engine relies on the pushback of some intake charge back into the intake piping to achieve the Atkinson effect, the tuning of the intake lines is important to the design. You tamper with that feature at your peril.
Not exactly true, fully true, when dealing with a 4 cylinder engine. With 4 cylinders an intake cycle on one cylinder is in PERFECT balance with an "opposite" cylinder insofar as intake airflow or outflow is concerned. As one cylinder's charge is being forced back into the intake manifold due to delayed intake valve closing its opposite cylinder is drawing air, EXACTLY equal in rate and volume, in from the intake manifold.
The issue raised of throwing off the A/F ratio is not accurate. So long as all air ingested by the engine passes the Mass Air Flow unit, the engine's computer will meter the right amount of fuel via the fuel injectors. The real issue is tuning of the inlet air flow system (or detuning if you mess with it).
The factory calibration of the MAF/IAT module is a function of the CSA, Cross Sectional Area, surrounding the sensor. the sensor only measures the speed of the airflow passing over it, the "mass" calculation must expand this measure to the entire CSA. Change the CSA or to a lessor extent the before and/or after airflow restriction coefficient and the factory calibration no longer has true meaning.
Regarding low speed operation: all gasoline engines are low torque at lower rpm. Thus the marriage of electric machines, which produce higher torque at lower rpms, with a gasoline engine is a good one.
First, as you can now see, a 2L Atkinson cycle engine is derated/detuned by something like 20-30% in comparison to its 2L Otto engine counterpart. In addition the effect of allowing a longer "burn" in the power stroke in order to extract more of the burn energy results in a substantial loss of torque during the late part of the power cycle.
This is one of the main reasons you will likely NEVER see a turbocharged Atkinson cycle engine, or even a turbocharged MILLER cycle engine. Due to the more complete burn within the cylinder there is NEVER enough energy in the exhaust to spin the turbine.
First: a true Atkinson Cycle (which the FEH is not) uses a different crankshaft arrangement to achieve a smaller compression volume and a larger expansion volume than the common Otto Cycle engine which has equal volumes. Thus, nothing is "derated," rather the engine design simply is not capable of producing the same power as compared to an engine displacement as is in common usage today (Otto cycle).
In other words an "Otto" engine of 2.0L will produce substantially more power than an Atkinson engine of the same displacement. A ~30% loss in power in return for a comparable increase in FE.
The manner by which Ford achieves the effect of the Atkinson cycle (& why I called it a pseudo Atkinson Cycle) is by delaying the closing of the intake valve and allowing the piston to push back out a fraction of the intake charge. This achieves a measure of reduction of the compression volume relative to the power stroke volume. This is not a more thorough burn of any kind, it is simply a larger expansion of a given amount of combustion gas.
Okay, if an Otto engine is operating at WOT throttle and presuming the cylinders are being fully filled with A/F mixture charge, what happens when I suddenly go to 1/2 throttle (RPM remains constant briefly), doesn't the resulting lower charge still have the same time to burn and therefore a more complete burn..??
If the Atkinson cycle were to allow a full charge to enter/remain in the cylinder bore you would be correct. But in reality the Atkinson cylinder charge is only ~70% of maximum based on the engine displacement.
The effect of the long branches of the intake (as has been done on some previous engines) is to enable each cylinder intake to be unaffected by an adjacent cylinder (envision a setup where two cylinder intake valves are adjacent and operation of one can affect the other).
Since this engine relies on the pushback of some intake charge back into the intake piping to achieve the Atkinson effect, the tuning of the intake lines is important to the design. You tamper with that feature at your peril.
Not exactly true, fully true, when dealing with a 4 cylinder engine. With 4 cylinders an intake cycle on one cylinder is in PERFECT balance with an "opposite" cylinder insofar as intake airflow or outflow is concerned. As one cylinder's charge is being forced back into the intake manifold due to delayed intake valve closing its opposite cylinder is drawing air, EXACTLY equal in rate and volume, in from the intake manifold.
The issue raised of throwing off the A/F ratio is not accurate. So long as all air ingested by the engine passes the Mass Air Flow unit, the engine's computer will meter the right amount of fuel via the fuel injectors. The real issue is tuning of the inlet air flow system (or detuning if you mess with it).
The factory calibration of the MAF/IAT module is a function of the CSA, Cross Sectional Area, surrounding the sensor. the sensor only measures the speed of the airflow passing over it, the "mass" calculation must expand this measure to the entire CSA. Change the CSA or to a lessor extent the before and/or after airflow restriction coefficient and the factory calibration no longer has true meaning.
Regarding low speed operation: all gasoline engines are low torque at lower rpm. Thus the marriage of electric machines, which produce higher torque at lower rpms, with a gasoline engine is a good one.
First, as you can now see, a 2L Atkinson cycle engine is derated/detuned by something like 20-30% in comparison to its 2L Otto engine counterpart. In addition the effect of allowing a longer "burn" in the power stroke in order to extract more of the burn energy results in a substantial loss of torque during the late part of the power cycle.
This is one of the main reasons you will likely NEVER see a turbocharged Atkinson cycle engine, or even a turbocharged MILLER cycle engine. Due to the more complete burn within the cylinder there is NEVER enough energy in the exhaust to spin the turbine.
Last edited by wwest; 02-26-2009 at 11:51 AM.
#9
02-26-2009, 02:22 PM
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Join Date: Sep 2006
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Re: Exhaust / Intake upgrades?!?
Be careful of the previous post.
First: a true Atkinson Cycle (which the FEH is not) uses a different crankshaft arrangement to achieve a smaller compression volume and a larger expansion volume than the common Otto Cycle engine which has equal volumes. Thus, nothing is "derated," rather the engine design simply is not capable of producing the same power as compared to an engine displacement as is in common usage today (Otto cycle).
The manner by which Ford achieves the effect of the Atkinson cycle (& why I called it a pseudo Atkinson Cycle) is by delaying the closing of the intake valve and allowing the piston to push back out a fraction of the intake charge. This achieves a measure of reduction of the compression volume relative to the power stroke volume. This is not a more thorough burn of any kind, it is simply a larger expansion of a given amount of combustion gas.
The effect of the long branches of the intake (as has been done on some previous engines) is to enable each cylinder intake to be unaffected by an adjacent cylinder (envision a setup where two cylinder intake valves are adjacent and operation of one can affect the other).
Since this engine relies on the pushback of some intake charge back into the intake piping to achieve the Atkinson effect, the tuning of the intake lines is important to the design. You tamper with that feature at your peril.
The only case that I know of wherein this might be the situation is that Lexus has announced that the new 2010 hybrid RX's V6 takes advantage of the Atkinson cycle. I'm still awaiting the details of this V6 implemention as I would have thought the complexity, "tuning" of the intake system would make the cost too prohibitive.
I have always presumed that the only way to Atkinsonize a V6 is the way Mazda did it already, use a positive displacement SuperCharger to prevent reverse intake flow. But then you have a Miller cycle engine.
Other than a very complex intake tuning technique the only way I could think of to Atkinsonize a V6 would be with the type of "reed" valve, reverse airflow prevention/blocking valve used in a 2-cycle engine.
The only other
The issue raised of throwing off the A/F ratio is not accurate. So long as all air ingested by the engine passes the Mass Air Flow unit, the engine's computer will meter the right amount of fuel via the fuel injectors. The real issue is tuning of the inlet air flow system (or detuning if you mess with it).
Regarding low speed operation: all gasoline engines are low torque at lower rpm. Thus the marriage of electric machines, which produce higher torque at lower rpms, with a gasoline engine is a good one.
First: a true Atkinson Cycle (which the FEH is not) uses a different crankshaft arrangement to achieve a smaller compression volume and a larger expansion volume than the common Otto Cycle engine which has equal volumes. Thus, nothing is "derated," rather the engine design simply is not capable of producing the same power as compared to an engine displacement as is in common usage today (Otto cycle).
The manner by which Ford achieves the effect of the Atkinson cycle (& why I called it a pseudo Atkinson Cycle) is by delaying the closing of the intake valve and allowing the piston to push back out a fraction of the intake charge. This achieves a measure of reduction of the compression volume relative to the power stroke volume. This is not a more thorough burn of any kind, it is simply a larger expansion of a given amount of combustion gas.
The effect of the long branches of the intake (as has been done on some previous engines) is to enable each cylinder intake to be unaffected by an adjacent cylinder (envision a setup where two cylinder intake valves are adjacent and operation of one can affect the other).
Since this engine relies on the pushback of some intake charge back into the intake piping to achieve the Atkinson effect, the tuning of the intake lines is important to the design. You tamper with that feature at your peril.
The only case that I know of wherein this might be the situation is that Lexus has announced that the new 2010 hybrid RX's V6 takes advantage of the Atkinson cycle. I'm still awaiting the details of this V6 implemention as I would have thought the complexity, "tuning" of the intake system would make the cost too prohibitive.
I have always presumed that the only way to Atkinsonize a V6 is the way Mazda did it already, use a positive displacement SuperCharger to prevent reverse intake flow. But then you have a Miller cycle engine.
Other than a very complex intake tuning technique the only way I could think of to Atkinsonize a V6 would be with the type of "reed" valve, reverse airflow prevention/blocking valve used in a 2-cycle engine.
The only other
The issue raised of throwing off the A/F ratio is not accurate. So long as all air ingested by the engine passes the Mass Air Flow unit, the engine's computer will meter the right amount of fuel via the fuel injectors. The real issue is tuning of the inlet air flow system (or detuning if you mess with it).
Regarding low speed operation: all gasoline engines are low torque at lower rpm. Thus the marriage of electric machines, which produce higher torque at lower rpms, with a gasoline engine is a good one.
#10
03-04-2009, 05:17 PM
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Location: All over the Central U.S.
Posts: 3,616
Re: Exhaust / Intake upgrades?!?
The deceptive part of all the "conventional wisdom" going around is, THIS IS NOT A CONVENTIONAL CAR!!!
With the Hybrid, and its eCVT, the gasoline engine operates at CLOSE TO WIDE OPEN THROTTLE as much as possible.
WOT does not equal "foot to the floor".
There is no physical link between your foot and the engine.
My 2005 operates at 90% wide open 90% of the time.
It does this on purpose, and by deliberate design.
Due to the generator motor controlling engine RPM, the FEH can, and does operate at near wide open, even at low RPM for increased efficiency.
The throttle intake can be wide open, and the engine RPM does not race due to the generator acting as a speed limiter.
How do I know? Watch the manifold absolute pressure with a scan tool.
My is at very low vacuum, nearly atmospheric pressure, most of the time.
Denver atmosphere is 12.4 psi. At true WOT I see 12.4 on the ScanGauge.
During normal "cruise" I see about 11.8 to 11.9 psi. Almost "wide open".
It's not broken. Foot off the pedal, I see 4.0 psi or 8.4 pounds of vacuum.
Try it in your car.
At Sea Level MAP = 14.7psi = Wide Open Throttle.
If you are even a little above sea level, you will see less than 14.7.
Use Denver to help you interpolate what WOT = for your sea level.
-John E
With the Hybrid, and its eCVT, the gasoline engine operates at CLOSE TO WIDE OPEN THROTTLE as much as possible.
WOT does not equal "foot to the floor".
There is no physical link between your foot and the engine.
My 2005 operates at 90% wide open 90% of the time.
It does this on purpose, and by deliberate design.
Due to the generator motor controlling engine RPM, the FEH can, and does operate at near wide open, even at low RPM for increased efficiency.
The throttle intake can be wide open, and the engine RPM does not race due to the generator acting as a speed limiter.
How do I know? Watch the manifold absolute pressure with a scan tool.
My is at very low vacuum, nearly atmospheric pressure, most of the time.
Denver atmosphere is 12.4 psi. At true WOT I see 12.4 on the ScanGauge.
During normal "cruise" I see about 11.8 to 11.9 psi. Almost "wide open".
It's not broken. Foot off the pedal, I see 4.0 psi or 8.4 pounds of vacuum.
Try it in your car.
At Sea Level MAP = 14.7psi = Wide Open Throttle.
If you are even a little above sea level, you will see less than 14.7.
Use Denver to help you interpolate what WOT = for your sea level.
-John E
Last edited by gpsman1; 03-04-2009 at 05:25 PM.
