Custom exhaust concern?
Nov 18, 2004, 05:57 AM
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Custom exhaust concern?
Recently my friends told me how fun it was to check out 2000 Civic Si on a dyno. S-AFC, Vtek controller, catback, headers, cai, clutch w/ pressure plate, and dyno showed 140whp!!??
It's not really better than stock when a lot of work was put into that car!
Two guys that were running the dyno told us that the problem is our custom catback.
It has a muffler and a straight 2.5 in pipe going from a downpipe.
They said the pipe is 2.5 allright but when it's bent in that place the diamater is only 1 in !!! So now we're going to buy a greddy exhaust for a civic to check whether it will make a difference.
CAn someone verify this? It would probably help a lot of people.
It's not really better than stock when a lot of work was put into that car!
Two guys that were running the dyno told us that the problem is our custom catback.
It has a muffler and a straight 2.5 in pipe going from a downpipe.
They said the pipe is 2.5 allright but when it's bent in that place the diamater is only 1 in !!! So now we're going to buy a greddy exhaust for a civic to check whether it will make a difference.
CAn someone verify this? It would probably help a lot of people.
Nov 18, 2004, 06:33 AM
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The car has 127hp stock at the crank. Problaby Like 110hp at the wheels. That is a 30hp gain. Pretty good if you ask me....expecially what you have described with that exhaust pipe.
IF he has rims (17") they will add unsprung weight to the car and take more inursha to get the car going and therefor give him a lower number.
If the exhaust wasnt bent using mandral bends then you are restricting it. 2 1/4 - 2 1/2 are optimum for an si. The muffler will not effect anything as long as it is a straight thrugh design and the piping size is not smaller then the rest of the exhaust.
To answer your question Yes a greddy exhaust would make a difference....or you could just go to an exhaust shop and get another custom one made this time use all stainless steel with mandral bends. Remember that air (exhaust gas) flows like water and will flow best in a design that has minimal bends and is a shorter distance from the start of the pipe to the end. Make sure you have a resignator (performance one) so that the exhaust gas can resignate properly.
This should be in the Other Cars forum.
IF he has rims (17") they will add unsprung weight to the car and take more inursha to get the car going and therefor give him a lower number.
If the exhaust wasnt bent using mandral bends then you are restricting it. 2 1/4 - 2 1/2 are optimum for an si. The muffler will not effect anything as long as it is a straight thrugh design and the piping size is not smaller then the rest of the exhaust.
To answer your question Yes a greddy exhaust would make a difference....or you could just go to an exhaust shop and get another custom one made this time use all stainless steel with mandral bends. Remember that air (exhaust gas) flows like water and will flow best in a design that has minimal bends and is a shorter distance from the start of the pipe to the end. Make sure you have a resignator (performance one) so that the exhaust gas can resignate properly.
This should be in the Other Cars forum.
Nov 18, 2004, 10:00 AM
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wait..... a 2000 civic si should have 160hp. 140whp sounds about right if the exhaust is being restricted. thats honestly no that bad considering the exhaust problem as danno stated. my buddy has a 2000 honda prelude sh with an intake, header, and catback exhaust. he only dynoed at 160whp. man was he pissed. you have to take everything into consideration though.
