Backpressure ???
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From: Drexel Hill, Pa, 19026
Backpressure ???
This topic has been goin over and over but I keep hearing different things. Is backpressure a good thing on an NA setup? or does it matter on how much power ur putting out ? Or does less backpressure just mean less low end but better top end ?
Joined: Sep 2002
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From: Oxnard, CA, USA
Re: Backpressure ??? (lude98SH)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lude98SH »</TD></TR><TR><TD CLASS="quote">This topic has been goin over and over but I keep hearing different things. Is backpressure a good thing on an NA setup? or does it matter on how much power ur putting out ? Or does less backpressure just mean less low end but better top end ? </TD></TR></TABLE>
You want NO BACKPRESSURE.
So why do you lose power if your piping is too big? It is because there is an OPTIMAL EXHAUST VELOCITY to make power at a certain range. This velocity is 300 feet per minute.
Lets say you have a header with 2" primaries, 2.5" secondaries, and 3" collector on an N/A car with little mods. Because the pipes are so big, the velocity of the gasses are SLOWER. Hence you lose power.
Now lets say you have a header with 1" primaries, 1.5" secondaries, and a 1.75" collector on an N/A car with little mods. Becuase are too small, you have a restriction, which makes you lose power. However, at lower RPMs, somewhere along the power curve, you will be at 300 fpm, which is why you feel better low-end power, but worser top-end power.
So bascially, the main factors that determin fpm is displacement and rpm. Bigger displacement = more fpm throughout the rpm band. Higher rpm = more fpm (directly proportional).
You want NO BACKPRESSURE.
So why do you lose power if your piping is too big? It is because there is an OPTIMAL EXHAUST VELOCITY to make power at a certain range. This velocity is 300 feet per minute.
Lets say you have a header with 2" primaries, 2.5" secondaries, and 3" collector on an N/A car with little mods. Because the pipes are so big, the velocity of the gasses are SLOWER. Hence you lose power.
Now lets say you have a header with 1" primaries, 1.5" secondaries, and a 1.75" collector on an N/A car with little mods. Becuase are too small, you have a restriction, which makes you lose power. However, at lower RPMs, somewhere along the power curve, you will be at 300 fpm, which is why you feel better low-end power, but worser top-end power.
So bascially, the main factors that determin fpm is displacement and rpm. Bigger displacement = more fpm throughout the rpm band. Higher rpm = more fpm (directly proportional).
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