Limitations of F series engines
February-25th-2002, 08:15 PM
#16
Protege Enthusiast
Join Date: Feb 2002
Location: Gainesville, FL
Posts: 87
As for ATS/TKT/Geoff/Thomas Knight Turbos...he has taken more than one person for a few grand in exchange for a shoddy product with ZERO responsibility for any workmanship issues.
As for how much boost a FSDE can hold w/o a stand alone; I suppose it really depends on fuel. I recall Bryan is selling his matched set of 550cc/min injectors and calibrated ProFlow MAF which would significantly increase how much air you can account for. If you're opposed to a stand alone, then get the SAFC, ITC, and try to do the same thing. Or if you wanna patch it, just get an FMU and some 550's and a BTM set to 2 deg/psi and call it a day. Depends what you want...
As for how much boost a FSDE can hold w/o a stand alone; I suppose it really depends on fuel. I recall Bryan is selling his matched set of 550cc/min injectors and calibrated ProFlow MAF which would significantly increase how much air you can account for. If you're opposed to a stand alone, then get the SAFC, ITC, and try to do the same thing. Or if you wanna patch it, just get an FMU and some 550's and a BTM set to 2 deg/psi and call it a day. Depends what you want...
February-25th-2002, 08:51 PM
#17
Jedi Master Yoda
Join Date: Jan 2002
Location: Asheville NC
Posts: 528
bryan is selling his MAF for 75 bucks i'm nto sure abotu the injectors though. I am going to use a FMU in my setup since i'm liimiting it to 6 PSI anyways no need for a high dollar stand alone. I agree about TKT's wrokmanship it is shotty from what I have seen but i don't use any of his product just his advise....he might not make the best product but he does know a thing or two about turbos and our engines.
February-26th-2002, 03:58 PM
#19
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Thread Starter
Join Date: Dec 2001
Location: Miami
Posts: 41
I also agree on TKT he is based in Miami, where I live and I have seen his facility and work first hand.......nothing spectacular. I am running a link ecu that controls fuel, ignition and boost. I will stay with 8 psi for now, even though I think I can extract a bit more with my setup but I am very paranoid and will wait for somebody else to grenade there motor so I can get a vague perception of the boost threshold of our motors.
April-5th-2002, 08:36 AM
#21
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Join Date: Apr 2002
Location: Houston, TX
Posts: 48
Originally posted by chdesign
I still go with Bryan Pendleton on this one.......you cannot have more air in the same space under teh same pressure in the same type of gas it defetes the laws of physics.....get a 6" diameter tube by 12" long and fill it with one pressure and try to put more air into it without increasing the pressure...and yes i have heard of compressor maps...i'm nto an idiot. I am saying you cannot put more air into the same space under the same pressure without raising the pressure.
I still go with Bryan Pendleton on this one.......you cannot have more air in the same space under teh same pressure in the same type of gas it defetes the laws of physics.....get a 6" diameter tube by 12" long and fill it with one pressure and try to put more air into it without increasing the pressure...and yes i have heard of compressor maps...i'm nto an idiot. I am saying you cannot put more air into the same space under the same pressure without raising the pressure.
Here is a little quote from a write up I just did on trying to explain turbo compressor effeciencies over at probetalk. Keep in mind that things are much more complicated, but this was to keep things simple and easy to understand.
What people need to understand is that just about any turbo will deliever about any boost you want. You can weld the wastegate shut and use a T25 to produce 30psi on the 2.5L. The thing that makes the T25 BAD for running 30psi, is that its effeciency at the volume of air flow and boost is probably 5% (exaggerating). Let me try and explain.
Lets pretend for a moment that you are the compressor on a turbo. In the simipliest terms, how you operate is based on two parameters. One is the boost pressure you are trying to achieve and two is the volume of air you are trying to move/pump. Keep in mind that volume of air needed increases with rpm of the motor. Now in order for you, as the compressor, to do any work you must have an energy source. For you to do work (ie. pumping air) you must have work done to you. You, as the compressor get your energy (or work done to you) from the turbo shaft, which is driven by the turbine section of the turbo. So you are given so much energy to work with from the turbo shaft. If the world was a perfect place you would be able to utilize 100% of that work or energy to move/flow/pump air into your motor. Unfortunately that is not the case. Well what happens to the wasted energy that is not used? It is converted to heat energy, which a good percentage of the heat energy is then passed off to your intake air charge, the very air you are pumping. Based on the series of Compressor you choose, peak effeciencies may range from around 60% to 75%. At 75% effeciency, that mean that 75% of the energy given to it is used to pump air while the remaining 25% is converter to heat. Based on how big you are or how small, as a compressor, you flow certain volumes of air better than and at any given volume of air, you flow better (more effeciently) at certain pump pressures (boost pressure).
Now with our newfound understand lets look at the T25. We don't have a compressor map handy, but I know its small for the PGT, so we will assume its too small. The T25 is going to be effecient at lower boost pressures and lower air flow rates. You are consider low boost pressure, so you match up there, BUT if you consider air flow rates you will most likely find the following. The T25 will be operating very effeciently around 1500-3000 rpm, but as your rpms increase the T25's effeciency drops, and drops and drops. By the time you reach 7000 rpm the effeciency may have drop to 25%. If you recall, this means 75% of the turbo shaft energy is being converted to heat, which is heating up your intake charge. (Keep in mind that the numbers in this example are hypothetical)
That is the basic life of a compressor. Stay tuned next week for the life of a turbine.
Lets pretend for a moment that you are the compressor on a turbo. In the simipliest terms, how you operate is based on two parameters. One is the boost pressure you are trying to achieve and two is the volume of air you are trying to move/pump. Keep in mind that volume of air needed increases with rpm of the motor. Now in order for you, as the compressor, to do any work you must have an energy source. For you to do work (ie. pumping air) you must have work done to you. You, as the compressor get your energy (or work done to you) from the turbo shaft, which is driven by the turbine section of the turbo. So you are given so much energy to work with from the turbo shaft. If the world was a perfect place you would be able to utilize 100% of that work or energy to move/flow/pump air into your motor. Unfortunately that is not the case. Well what happens to the wasted energy that is not used? It is converted to heat energy, which a good percentage of the heat energy is then passed off to your intake air charge, the very air you are pumping. Based on the series of Compressor you choose, peak effeciencies may range from around 60% to 75%. At 75% effeciency, that mean that 75% of the energy given to it is used to pump air while the remaining 25% is converter to heat. Based on how big you are or how small, as a compressor, you flow certain volumes of air better than and at any given volume of air, you flow better (more effeciently) at certain pump pressures (boost pressure).
Now with our newfound understand lets look at the T25. We don't have a compressor map handy, but I know its small for the PGT, so we will assume its too small. The T25 is going to be effecient at lower boost pressures and lower air flow rates. You are consider low boost pressure, so you match up there, BUT if you consider air flow rates you will most likely find the following. The T25 will be operating very effeciently around 1500-3000 rpm, but as your rpms increase the T25's effeciency drops, and drops and drops. By the time you reach 7000 rpm the effeciency may have drop to 25%. If you recall, this means 75% of the turbo shaft energy is being converted to heat, which is heating up your intake charge. (Keep in mind that the numbers in this example are hypothetical)
That is the basic life of a compressor. Stay tuned next week for the life of a turbine.
April-5th-2002, 02:46 PM
#23
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Join Date: Nov 2001
Location: Hamilton, ON
Posts: 323
Originally posted by BryanPendleton
Craig, the key to clearing the confusion is understanding the difference between CFM (volumetric flowrate) and Mass Flow Rate. A T25 on an FS at 6500 rpm may be operating at 60% effeciency, but a T04E compressor on the same motor at the same rpm may operate at 72% effeciency. If both cases are running the same boost pressure the CFM will be the same, but the the more effecient T04E will be flowing more mass, and as already mentioned, mass is what counts, not volume.
Craig, the key to clearing the confusion is understanding the difference between CFM (volumetric flowrate) and Mass Flow Rate. A T25 on an FS at 6500 rpm may be operating at 60% effeciency, but a T04E compressor on the same motor at the same rpm may operate at 72% effeciency. If both cases are running the same boost pressure the CFM will be the same, but the the more effecient T04E will be flowing more mass, and as already mentioned, mass is what counts, not volume.
Wow that had to be the longest explanation of PV=nRT I have ever seen.
If volume (V) and Pressure (P)is kept constant, more mass (n) can(must) be introduced into the system if the temperature (T) is reduced. Therefore more efficient turbo=less heat=more mass (or O2 to burn in this case)
I know the gas isn't ideal, but it serves to explain the idea.
Stocker
Last edited by stocker; April-5th-2002 at 02:51 PM.
April-7th-2002, 12:32 AM
#24
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There is one thing I haven't seen discussed here and that's the engines' ability to flow air. If all you are doing is stacking up boost pressure in the intake behind a flow restriction, you won't make power. Since an engine is nothing but an air pump, you need to reduce the restrictions to make power. If you are boosting a stock engine to 15 psi and are using an efficient turbo, you still won't make as much power as an engine with that has been properly set up to take advantage of the turbo.
Example: Engine with stock cams, stock ports, stock intake and exhaust. Runs at 14 psi of boost and makes 230 HP. Using the same engine with a free flowing exhaust, higher lift cams, ported cylinder head, reworked intake and air meter, you might only make 10 psi with the same turbo. BUT, you are moving a lot more air and not stacking it up so you will probably make closer to 280 HP. I've seen this demonstrated to great effect on mechanical superchargers especially. I've seen guys run a 9 psi pulley on their stock small block chevy and make less HP than the guy that is running headers, ported heads and 5-6 psi.
It's not really a question of how much psi an FS engine will take but how much air it will move and power it will make before parts break. I've spoken with Bell (BEGI) a few days ago and they are making a turbo kit for the 2.0L right now. Figure 8-9 weeks to release or so. Pre-orders are $2950 for the first 10 people to pre-order no matter what the final cost of the kit is. Expect the regular kit to be around $3200-3300 after the 1st ten.
They have taken the engine apart and are saying that the pistons and rods should be good for quite a bit of power. The engine uses oil squirters to cool the bottoms of the pistons, the top ring land is fairly thick and should hold up well under boost, and the piston tops are fairly thick. They are initially planning on 6-8 psi for the early kits and will continue to develop them further after the initial release. They think that the engine may take well over 10 but will test it fairly extensively before they uprate the kit.
These are the same people that have been building the Flying Miata kits for a long time now. They have some of those up to 14 psi on a stock block motor so they know how to milk a Mazda.
Example: Engine with stock cams, stock ports, stock intake and exhaust. Runs at 14 psi of boost and makes 230 HP. Using the same engine with a free flowing exhaust, higher lift cams, ported cylinder head, reworked intake and air meter, you might only make 10 psi with the same turbo. BUT, you are moving a lot more air and not stacking it up so you will probably make closer to 280 HP. I've seen this demonstrated to great effect on mechanical superchargers especially. I've seen guys run a 9 psi pulley on their stock small block chevy and make less HP than the guy that is running headers, ported heads and 5-6 psi.
It's not really a question of how much psi an FS engine will take but how much air it will move and power it will make before parts break. I've spoken with Bell (BEGI) a few days ago and they are making a turbo kit for the 2.0L right now. Figure 8-9 weeks to release or so. Pre-orders are $2950 for the first 10 people to pre-order no matter what the final cost of the kit is. Expect the regular kit to be around $3200-3300 after the 1st ten.
They have taken the engine apart and are saying that the pistons and rods should be good for quite a bit of power. The engine uses oil squirters to cool the bottoms of the pistons, the top ring land is fairly thick and should hold up well under boost, and the piston tops are fairly thick. They are initially planning on 6-8 psi for the early kits and will continue to develop them further after the initial release. They think that the engine may take well over 10 but will test it fairly extensively before they uprate the kit.
These are the same people that have been building the Flying Miata kits for a long time now. They have some of those up to 14 psi on a stock block motor so they know how to milk a Mazda.
April-7th-2002, 10:52 AM
#25
Jedi Master Yoda
Join Date: Jan 2002
Location: Asheville NC
Posts: 528
Hey Bryan welcome to the forum. I do understand about the density of the air and all that I didn't really protray myself that well. I just built my setup with the daily driver in mind. I know a couple of my friends running T3/T04E hybrids in B18 swap hondas have alot of lag. I have full boost right at 2300 RPM so I'm very pleased with that. I just don't see the point of putting such a large turbo on our engines when 90% of us will be using them for daily drivers.
April-8th-2002, 09:36 AM
#26
Registered User
Join Date: Apr 2002
Location: Houston, TX
Posts: 48
Aaah yes. . . Volumetric Effeciency. Thats what its all about.
For the benefit of those who do not understand VE:
This is a term that measure how effeciently your motor injests air through the intake and expells the exhaust gases out the exhaust side. This is a very important term to understand, because most engine modifications effectively change the VE of your motor, and hince why you decreases or increases in torque and power at various rpms. Mathimatically, VE is the percentage of air that the motor injests and expells vs the total volume of air the motor could potentially injest and expell. First the easy part. How much can your motor injest. Lets use the 2.0L FS motor as an example. Its total displacement is 2.0L's, and it has four cylinders, so each cylinder displaces approximately 0.5L's. Now if the motor were 100% effecient at all rpms it would injest 0.5L's of fresh air each cycle then expell it. Unfortunately, a 100% effecient motor is impossible. How effecient your motor actually is unknown, but as a general rule of thumb most dual overhead cam engines have maximum VE's around 80-90%. The actual numbers are not important though. What is important is the VE curve, or a "map" of VE vs RPM. Your VE curve will have the same basic trend as your torque curve, as measured on an engine dyno or a wheel dyno. So your peak VE will occur around peak torque. Without changing the displacement of the motor you cannot injest any more air, but you can change the VE of the existing motor. This takes on infinate degrees of modifications, from something as simply as changing the air filter or as complex as reworking the cylinder head with larger valves and ported runners. So we want to change the VE of the motor? Almost all performance modicafications will increase high rpm VE while sacrificing some low rpm VE. Recalling earlier statements, this means that the high rpm torque will increase and low rpm torque will decrease, and where torque increase, so does power. Learn this and understand it, as high VE is your friend.
For the benefit of those who do not understand VE:
This is a term that measure how effeciently your motor injests air through the intake and expells the exhaust gases out the exhaust side. This is a very important term to understand, because most engine modifications effectively change the VE of your motor, and hince why you decreases or increases in torque and power at various rpms. Mathimatically, VE is the percentage of air that the motor injests and expells vs the total volume of air the motor could potentially injest and expell. First the easy part. How much can your motor injest. Lets use the 2.0L FS motor as an example. Its total displacement is 2.0L's, and it has four cylinders, so each cylinder displaces approximately 0.5L's. Now if the motor were 100% effecient at all rpms it would injest 0.5L's of fresh air each cycle then expell it. Unfortunately, a 100% effecient motor is impossible. How effecient your motor actually is unknown, but as a general rule of thumb most dual overhead cam engines have maximum VE's around 80-90%. The actual numbers are not important though. What is important is the VE curve, or a "map" of VE vs RPM. Your VE curve will have the same basic trend as your torque curve, as measured on an engine dyno or a wheel dyno. So your peak VE will occur around peak torque. Without changing the displacement of the motor you cannot injest any more air, but you can change the VE of the existing motor. This takes on infinate degrees of modifications, from something as simply as changing the air filter or as complex as reworking the cylinder head with larger valves and ported runners. So we want to change the VE of the motor? Almost all performance modicafications will increase high rpm VE while sacrificing some low rpm VE. Recalling earlier statements, this means that the high rpm torque will increase and low rpm torque will decrease, and where torque increase, so does power. Learn this and understand it, as high VE is your friend.
Originally posted by Traveler
There is one thing I haven't seen discussed here and that's the engines' ability to flow air. If all you are doing is stacking up boost pressure in the intake behind a flow restriction, you won't make power. Since an engine is nothing but an air pump, you need to reduce the restrictions to make power. If you are boosting a stock engine to 15 psi and are using an efficient turbo, you still won't make as much power as an engine with that has been properly set up to take advantage of the turbo.
Example: Engine with stock cams, stock ports, stock intake and exhaust. Runs at 14 psi of boost and makes 230 HP. Using the same engine with a free flowing exhaust, higher lift cams, ported cylinder head, reworked intake and air meter, you might only make 10 psi with the same turbo. BUT, you are moving a lot more air and not stacking it up so you will probably make closer to 280 HP. I've seen this demonstrated to great effect on mechanical superchargers especially. I've seen guys run a 9 psi pulley on their stock small block chevy and make less HP than the guy that is running headers, ported heads and 5-6 psi.
It's not really a question of how much psi an FS engine will take but how much air it will move and power it will make before parts break. I've spoken with Bell (BEGI) a few days ago and they are making a turbo kit for the 2.0L right now. Figure 8-9 weeks to release or so. Pre-orders are $2950 for the first 10 people to pre-order no matter what the final cost of the kit is. Expect the regular kit to be around $3200-3300 after the 1st ten.
They have taken the engine apart and are saying that the pistons and rods should be good for quite a bit of power. The engine uses oil squirters to cool the bottoms of the pistons, the top ring land is fairly thick and should hold up well under boost, and the piston tops are fairly thick. They are initially planning on 6-8 psi for the early kits and will continue to develop them further after the initial release. They think that the engine may take well over 10 but will test it fairly extensively before they uprate the kit.
These are the same people that have been building the Flying Miata kits for a long time now. They have some of those up to 14 psi on a stock block motor so they know how to milk a Mazda.
There is one thing I haven't seen discussed here and that's the engines' ability to flow air. If all you are doing is stacking up boost pressure in the intake behind a flow restriction, you won't make power. Since an engine is nothing but an air pump, you need to reduce the restrictions to make power. If you are boosting a stock engine to 15 psi and are using an efficient turbo, you still won't make as much power as an engine with that has been properly set up to take advantage of the turbo.
Example: Engine with stock cams, stock ports, stock intake and exhaust. Runs at 14 psi of boost and makes 230 HP. Using the same engine with a free flowing exhaust, higher lift cams, ported cylinder head, reworked intake and air meter, you might only make 10 psi with the same turbo. BUT, you are moving a lot more air and not stacking it up so you will probably make closer to 280 HP. I've seen this demonstrated to great effect on mechanical superchargers especially. I've seen guys run a 9 psi pulley on their stock small block chevy and make less HP than the guy that is running headers, ported heads and 5-6 psi.
It's not really a question of how much psi an FS engine will take but how much air it will move and power it will make before parts break. I've spoken with Bell (BEGI) a few days ago and they are making a turbo kit for the 2.0L right now. Figure 8-9 weeks to release or so. Pre-orders are $2950 for the first 10 people to pre-order no matter what the final cost of the kit is. Expect the regular kit to be around $3200-3300 after the 1st ten.
They have taken the engine apart and are saying that the pistons and rods should be good for quite a bit of power. The engine uses oil squirters to cool the bottoms of the pistons, the top ring land is fairly thick and should hold up well under boost, and the piston tops are fairly thick. They are initially planning on 6-8 psi for the early kits and will continue to develop them further after the initial release. They think that the engine may take well over 10 but will test it fairly extensively before they uprate the kit.
These are the same people that have been building the Flying Miata kits for a long time now. They have some of those up to 14 psi on a stock block motor so they know how to milk a Mazda.
April-8th-2002, 05:16 PM
#27
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Join Date: Mar 2002
Location: Spokane WA
Posts: 453
Originally posted by PseudoRealityX
14 lbs on a stock block miata isnt too great at all. Most of the EGT guys are around this number and its all with homebuilt kits and piggybacks.
14 lbs on a stock block miata isnt too great at all. Most of the EGT guys are around this number and its all with homebuilt kits and piggybacks.
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