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Old 08-17-2009, 03:21 PM   #1
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Default Ports question.

Ok so this is probably a stupid question but is the difference between a 4 and 5 port motor just the number of ports? and the more ports the better right?
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Old 08-17-2009, 03:28 PM   #2
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yeah its number of ports..

more isnt necessarily better
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Old 08-17-2009, 03:31 PM   #3
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There's not hard and fast rule to the relation of number of ports and power output, nor is there an accepted standard for how to count them. A 3-port engine actually has 4-ports including the exahust port. The OS V-spec has long been one of the most powerful engines available from bottom to top-end and it's a 3-port. Novarossi's newest engines (+4) are a 4-port which I believe is what we usually call a 3-port (they are probably counting the exhaust port). One reason higher port count engines are usually in the higher end of the price spectrum is that it costs more to make them, also the engine maker has a higher thing to count and use in their marketing.

The new Novarossi's, Orion Alpha, and Reedy engines are all 3/4 port engines so OS must've been onto something.
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Old 08-17-2009, 04:18 PM   #4
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Another thing to consider is that a general rule (with exceptions) is that the more ports an engine has the better top end it has, and the bottom end lacks..that is why you see people matching bottom end pipes to top end engines and vica versa...Large tracks with wide open long straight aways would be better suited for high end (more port) engines so you can utilize the top end speed and performance, the opposite is true with small tight technical tracks...Nowadays it seems that the 3-5 port engines are taking over the market. They have gobs of low end and enough top end (speed) to compete on any track...High port engines are basically getting pushed to On-road only as they dont need the low end as much as the instant top speeds that you need, and are required for on-road
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Old 08-17-2009, 04:25 PM   #5
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Good post above. Usually the more ports you have the worse the fuel mileage also..not huge amounts but noticable
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Old 08-17-2009, 04:26 PM   #6
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Default fuel

You get better fuel mileage with the 3 port motors over the 7 port motors also. I have 3+1 motors and 5+2 motors and I like the 3 port motors even on big tracks.
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Old 08-17-2009, 04:38 PM   #7
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alright thanks for clearin that up for me guys!
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Old 08-17-2009, 04:46 PM   #8
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Just FYI the +4 has 4 intake, 1 exhaust. Some would call it a 5 port, there is no hard and fast rule.
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