whats the best manifold set up for the f20c?
02-03-2006, 04:57 AM
#1
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whats the best manifold set up for the f20c?
we're currently in the process of building s2k powered kit car.
once the engine is in we will be faced with what to do with the exhaust. all i know at the moment is that it will be a side exit running down the drivers side and custom made.
the engine will be n/a and have work done to the head with polished valves, polished inlet mani with 70mm spoon t/b, fuel pressure regulator and hondata ecu
should i keep the standard size bore pipe or upgrade? and should the design follow a 4into1 or a 4 into 2 in one
cheers
once the engine is in we will be faced with what to do with the exhaust. all i know at the moment is that it will be a side exit running down the drivers side and custom made.
the engine will be n/a and have work done to the head with polished valves, polished inlet mani with 70mm spoon t/b, fuel pressure regulator and hondata ecu
should i keep the standard size bore pipe or upgrade? and should the design follow a 4into1 or a 4 into 2 in one
cheers
02-03-2006, 09:51 AM
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Header design is relatively complex. Common speculation is that a 4-2-1 makes more midrange power at the sacrifice of peak hp and 4-1 makes more peak power but sacrifices midrange. This convention is not necessarily true.. both styles can be designed to produce torque where and how you want it.
Four contributing factors:
Diameter: bigger diameter shifts peak torque to a higher rpm and creates higher peak torque. This is because the exhaust takes longer to reach its max speed. But since the pipe is larger, it should be able to reach a higher speed, at a higher rpm compared to a smaller diameter pipe.
Length of primary tubes: longer tubes will create more torque at rpms before the peak torque rpm. Longer tubes speed up the velocity of air flow so you reach max velocity faster (faster accel), so more power before peak torque, and peak torque reached at a lower rpm than shorter tubes.
Collectors: these are the joints where the individual tubes merge. large diameter and shorter collectors have more peak power. Longer and smaller diameter collectors produce more midrange power. Also, you want to angles the tubes meet to be as shallow as possible to not upset the flow of the gas.
Orientation: You can hook the tubes up sequentially such as tubes from cyl 1 to 3, 2 to 4, or 1 to 2, 3 to 4. These setups are identical since both will see back to back exhaust pulses if the engine fires 1-3-4-2 (I'm assuming thats what the F20C does). You can also pair the tubes non sequentially i.e. 1 to 4, 2 to 3. Here the pulses will always alternate. The choice has to do with the energy imparted to the exhaust charge. sequential pulsing gives you more energy to work with. The energy from one tube will have larger impact on its cylinder, and the combined energy will have a much greater effect on the tube it merges with. Sequential setup will give you a broader power band and better accelleration.
Now as far as how you want to design your exhaust, the diamater, lenght, etc.. I can't give you anyhelp
Four contributing factors:
Diameter: bigger diameter shifts peak torque to a higher rpm and creates higher peak torque. This is because the exhaust takes longer to reach its max speed. But since the pipe is larger, it should be able to reach a higher speed, at a higher rpm compared to a smaller diameter pipe.
Length of primary tubes: longer tubes will create more torque at rpms before the peak torque rpm. Longer tubes speed up the velocity of air flow so you reach max velocity faster (faster accel), so more power before peak torque, and peak torque reached at a lower rpm than shorter tubes.
Collectors: these are the joints where the individual tubes merge. large diameter and shorter collectors have more peak power. Longer and smaller diameter collectors produce more midrange power. Also, you want to angles the tubes meet to be as shallow as possible to not upset the flow of the gas.
Orientation: You can hook the tubes up sequentially such as tubes from cyl 1 to 3, 2 to 4, or 1 to 2, 3 to 4. These setups are identical since both will see back to back exhaust pulses if the engine fires 1-3-4-2 (I'm assuming thats what the F20C does). You can also pair the tubes non sequentially i.e. 1 to 4, 2 to 3. Here the pulses will always alternate. The choice has to do with the energy imparted to the exhaust charge. sequential pulsing gives you more energy to work with. The energy from one tube will have larger impact on its cylinder, and the combined energy will have a much greater effect on the tube it merges with. Sequential setup will give you a broader power band and better accelleration.
Now as far as how you want to design your exhaust, the diamater, lenght, etc.. I can't give you anyhelp
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02-04-2006, 10:53 AM
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great that what i wanted to know thanks for that!!
for example. say i go for the 1 to 4, 2 to 3 should i run 4 long pipes before they join or relitively short, and then the same again one i have 2 pipes left
cheers vtec9 this rly helps
for example. say i go for the 1 to 4, 2 to 3 should i run 4 long pipes before they join or relitively short, and then the same again one i have 2 pipes left
cheers vtec9 this rly helps
02-04-2006, 03:44 PM
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Be carefull what intake an exhaust you use. In some magazine the did an s2k swap in a miata and had some POS exhaust/intake and lost 40 horsepower compared to stock set up. Some thing to think about...