What's wrong with AFR's exhaust port?
03-01-2015, 09:10 AM
#61
I think a lot off the problems with pro comp come from lack of material ...thin deck.. A good quality head is 3/4" or so at mating surface .I don't think pro comps are near that thick........
Last edited by motor; 03-01-2015 at 09:12 AM.
03-01-2015, 10:59 AM
#62
Amen, Unfortunetly the flow bench is the only reletively enexpensive tool that I know of for testing before it goes to dyno. I heard of some equipment that can measure combustion pressure but not export pressure in front of the valve. If there is a question on the dyno I will put extra lash on the exhaust valve to see if theres a loss or gain. My opinion there needs to be a buttload more r/d for marine engines starting with exhaust valve size and port size.To say it again, there are four or five options for intake runner volume with only one choice for exports. I cringe when I see a 310ish volume intake runner 2.250 valve with a 1.880 export. If someone wants to fund it I'd like to start with a 1.750 valve with a port size to fit and increase combination including looking at a stepped header design, primary tube diameter and an up to date collector. I did find a better flowing export dosen't need as much duration on the cam lobe. I'll bet theres enough talent on this board to bring the technology forward.
We will have to agree to dissagree on the importance of flowing exports no hate here. Thanks, Jim
The steady, low pressure airflow testing described for intake valves often fails to adequately predict the performance of exhaust valves/ports. Inconsistences frequently occur where enhanced flow bench performance leads to decreased engine performance. This is a result of the considerably different exhaust port flow environment, which includes higher pressures, compressible flow, and products of combustion. Early gas exiting occurs under high pressure as critical, or choked, flow then transitions to sub- critical flow under lower pressure ratios. Normal practices are to ensure the exhaust port flow capabilities are at a minimum of 60-80% of the intake. This however does not ensure the most efficient geometry and can lead to larger than required valves/ports or a restrictive exhaust. Excessively large diameter exhaust valves leave less room in the cylinder head for the intake valves, while a restriction can significantly lower the capabilities of the engine regardless of intake flow improvements. Other general findings include maintaining a minimum area throughout the port or increasing exhaust port volume can often increase engine performance. It would be desirable to have improved methods of analysis specifically designed for exhaust ports during critical flow to understand these findings and produce more efficient port geometry. This would be of particular interest to high performance engine designers within the motorsports industry.
Copied from a research study Unniversity of Miami. And the main reason why I began the thread the way I did. The flow bench is a poor piece of equipment to be using on the exhaust port. My question is was the flow bench the final test done with the exhaust port? Was there and kind of dyno testing before and after? Track, water whatever kind of testing before and after the work was done to the port?
With page upon page of combinations putting up big numbers AFR's port with the cheater pipe seems like it has done very well. I'd really like to see some more real world testing cause as stated the flow bench testing doesn't really mean anything. Maybe the port wasn't fixed and instead broken.[/QUOTE]
We will have to agree to dissagree on the importance of flowing exports no hate here. Thanks, Jim
The steady, low pressure airflow testing described for intake valves often fails to adequately predict the performance of exhaust valves/ports. Inconsistences frequently occur where enhanced flow bench performance leads to decreased engine performance. This is a result of the considerably different exhaust port flow environment, which includes higher pressures, compressible flow, and products of combustion. Early gas exiting occurs under high pressure as critical, or choked, flow then transitions to sub- critical flow under lower pressure ratios. Normal practices are to ensure the exhaust port flow capabilities are at a minimum of 60-80% of the intake. This however does not ensure the most efficient geometry and can lead to larger than required valves/ports or a restrictive exhaust. Excessively large diameter exhaust valves leave less room in the cylinder head for the intake valves, while a restriction can significantly lower the capabilities of the engine regardless of intake flow improvements. Other general findings include maintaining a minimum area throughout the port or increasing exhaust port volume can often increase engine performance. It would be desirable to have improved methods of analysis specifically designed for exhaust ports during critical flow to understand these findings and produce more efficient port geometry. This would be of particular interest to high performance engine designers within the motorsports industry.
Copied from a research study Unniversity of Miami. And the main reason why I began the thread the way I did. The flow bench is a poor piece of equipment to be using on the exhaust port. My question is was the flow bench the final test done with the exhaust port? Was there and kind of dyno testing before and after? Track, water whatever kind of testing before and after the work was done to the port?
With page upon page of combinations putting up big numbers AFR's port with the cheater pipe seems like it has done very well. I'd really like to see some more real world testing cause as stated the flow bench testing doesn't really mean anything. Maybe the port wasn't fixed and instead broken.[/QUOTE]
03-01-2015, 12:05 PM
#63
AFR stands behind all of our advertised flow numbers (to account for production tolerances, we guarantee our numbers within 2% of advertised). While some of our competitors seem to take some liberties in that department, we try our best to meet or exceed all our published data. In fact, a handful of our products actually flow notably higher than we claim. Read More A lot of engine builders rely on our heads to deliver the power they guarantee. It is important we provide them with a head that delivers and flows as promised every time. It’s also important to note that some manufacturer’s flow their heads on different types of equipment and conveniently don’t include that information in their test results. Cylinder head flow testing equipment is no different than dyno’s; some read higher than others and a few types of equipment tend to read a lot higher. All of our heads are tested on an accurately calibrated SF600, what most still consider to be the industry standard although the SF1020 has gained a lot of popularity in recent years as well. The newer 1020 benches read very close to an SF600 model while some of the older 1020 units were a little stingier. Note all our intake data is obtained using a proper fitting radius plate with the appropriate corner radius’s (clay is not consistent), and all our exhaust data is flowed thru a curved pipe that directly simulates a typical header installed in a production vehicle (a pipe about 10” long that has an immediate curve off the exhaust flange and straightens out).
That was copied from there website for those that think they use the cheater pipe just to market/ sell heads.
That was copied from there website for those that think they use the cheater pipe just to market/ sell heads.
03-01-2015, 12:10 PM
#65
Amen, Unfortunetly the flow bench is the only reletively enexpensive tool that I know of for testing before it goes to dyno. I heard of some equipment that can measure combustion pressure but not export pressure in front of the valve. If there is a question on the dyno I will put extra lash on the exhaust valve to see if theres a loss or gain. My opinion there needs to be a buttload more r/d for marine engines starting with exhaust valve size and port size.To say it again, there are four or five options for intake runner volume with only one choice for exports. I cringe when I see a 310ish volume intake runner 2.250 valve with a 1.880 export. If someone wants to fund it I'd like to start with a 1.750 valve with a port size to fit and increase combination including looking at a stepped header design, primary tube diameter and an up to date collector. I did find a better flowing export dosen't need as much duration on the cam lobe. I'll bet theres enough talent on this board to bring the technology forward.
We will have to agree to dissagree on the importance of flowing exports no hate here. Thanks, Jim
The steady, low pressure airflow testing described for intake valves often fails to adequately predict the performance of exhaust valves/ports. Inconsistences frequently occur where enhanced flow bench performance leads to decreased engine performance. This is a result of the considerably different exhaust port flow environment, which includes higher pressures, compressible flow, and products of combustion. Early gas exiting occurs under high pressure as critical, or choked, flow then transitions to sub- critical flow under lower pressure ratios. Normal practices are to ensure the exhaust port flow capabilities are at a minimum of 60-80% of the intake. This however does not ensure the most efficient geometry and can lead to larger than required valves/ports or a restrictive exhaust. Excessively large diameter exhaust valves leave less room in the cylinder head for the intake valves, while a restriction can significantly lower the capabilities of the engine regardless of intake flow improvements. Other general findings include maintaining a minimum area throughout the port or increasing exhaust port volume can often increase engine performance. It would be desirable to have improved methods of analysis specifically designed for exhaust ports during critical flow to understand these findings and produce more efficient port geometry. This would be of particular interest to high performance engine designers within the motorsports industry.
Copied from a research study Unniversity of Miami. And the main reason why I began the thread the way I did. The flow bench is a poor piece of equipment to be using on the exhaust port. My question is was the flow bench the final test done with the exhaust port? Was there and kind of dyno testing before and after? Track, water whatever kind of testing before and after the work was done to the port?
With page upon page of combinations putting up big numbers AFR's port with the cheater pipe seems like it has done very well. I'd really like to see some more real world testing cause as stated the flow bench testing doesn't really mean anything. Maybe the port wasn't fixed and instead broken.
We will have to agree to dissagree on the importance of flowing exports no hate here. Thanks, Jim
The steady, low pressure airflow testing described for intake valves often fails to adequately predict the performance of exhaust valves/ports. Inconsistences frequently occur where enhanced flow bench performance leads to decreased engine performance. This is a result of the considerably different exhaust port flow environment, which includes higher pressures, compressible flow, and products of combustion. Early gas exiting occurs under high pressure as critical, or choked, flow then transitions to sub- critical flow under lower pressure ratios. Normal practices are to ensure the exhaust port flow capabilities are at a minimum of 60-80% of the intake. This however does not ensure the most efficient geometry and can lead to larger than required valves/ports or a restrictive exhaust. Excessively large diameter exhaust valves leave less room in the cylinder head for the intake valves, while a restriction can significantly lower the capabilities of the engine regardless of intake flow improvements. Other general findings include maintaining a minimum area throughout the port or increasing exhaust port volume can often increase engine performance. It would be desirable to have improved methods of analysis specifically designed for exhaust ports during critical flow to understand these findings and produce more efficient port geometry. This would be of particular interest to high performance engine designers within the motorsports industry.
Copied from a research study Unniversity of Miami. And the main reason why I began the thread the way I did. The flow bench is a poor piece of equipment to be using on the exhaust port. My question is was the flow bench the final test done with the exhaust port? Was there and kind of dyno testing before and after? Track, water whatever kind of testing before and after the work was done to the port?
With page upon page of combinations putting up big numbers AFR's port with the cheater pipe seems like it has done very well. I'd really like to see some more real world testing cause as stated the flow bench testing doesn't really mean anything. Maybe the port wasn't fixed and instead broken.
The Technology is there for improved exhaust port testing I don't understand why it's not mainstream yet. For a high volume/ production based company a piece of equipment thAt could simulate combustion and measure it's flow out of the chamber/ port in my eyes would be priceless.
03-01-2015, 02:01 PM
#67
AFR stands behind all of our advertised flow numbers (to account for production tolerances, we guarantee our numbers within 2% of advertised). While some of our competitors seem to take some liberties in that department, we try our best to meet or exceed all our published data. In fact, a handful of our products actually flow notably higher than we claim. Read More A lot of engine builders rely on our heads to deliver the power they guarantee. It is important we provide them with a head that delivers and flows as promised every time. It’s also important to note that some manufacturer’s flow their heads on different types of equipment and conveniently don’t include that information in their test results. Cylinder head flow testing equipment is no different than dyno’s; some read higher than others and a few types of equipment tend to read a lot higher. All of our heads are tested on an accurately calibrated SF600, what most still consider to be the industry standard although the SF1020 has gained a lot of popularity in recent years as well. The newer 1020 benches read very close to an SF600 model while some of the older 1020 units were a little stingier. Note all our intake data is obtained using a proper fitting radius plate with the appropriate corner radius’s (clay is not consistent), and all our exhaust data is flowed thru a curved pipe that directly simulates a typical header installed in a production vehicle (a pipe about 10” long that has an immediate curve off the exhaust flange and straightens out).
That was copied from there website for those that think they use the cheater pipe just to market/ sell heads.
That was copied from there website for those that think they use the cheater pipe just to market/ sell heads.
The AFR intake ports flow very close to there claims on my 600superflow the exhaust dont on all heads that I tested. All the exhaust ports were very consistant. Without the pipe and with. My bench is in good working order.
03-01-2015, 02:51 PM
#68
Registered
ok jim. what IS wrong with the AFR exports? i am not calling you out. i am at best a backyard a$$hole who just started playing with port work. apparently lingenfelter might have known a little more than you about cyl heads-but not much. what IS it about the ports that could be done better and can it be corrected with a die grinder? or does the casting need to be redesigned?
03-01-2015, 03:09 PM
#69
Registered
"apparently lingenfelter might have known a little more than you about cyl heads"
really,,I know my friends vette's heads were port so much that water pressure blew right into the port and Hydro-locked the motor.Good news is Lingenfelter replaced his engine w/ a 427sb,twin turboed it too(at owners expense) 760hp to the ground.yahoo.car still runs perfectly after 9yrs now.
really,,I know my friends vette's heads were port so much that water pressure blew right into the port and Hydro-locked the motor.Good news is Lingenfelter replaced his engine w/ a 427sb,twin turboed it too(at owners expense) 760hp to the ground.yahoo.car still runs perfectly after 9yrs now.
03-01-2015, 04:09 PM
#70
Registered
iTrader: (4)
ok jim. what IS wrong with the AFR exports? i am not calling you out. i am at best a backyard a$$hole who just started playing with port work. apparently lingenfelter might have known a little more than you about cyl heads-but not much. what IS it about the ports that could be done better and can it be corrected with a die grinder? or does the casting need to be redesigned?
