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Discussion Starter #1
if im buying cp-e headers with no Y pipe and doing a dual line after. What size the line should be?
and with the Y pipe what size should it be? thx alot for your info!
 

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what kind of m6 do you have, hopefully the 6s right? cause your statement suggest your only talking about 1 header which leads me to believe your talking about the 6i model.
 

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Actually I think the contour guys who were staying NA without excessive mods (like a supercharger) went with dual 2.0 ID. Going dual 2.25 would be more for a supercharger type application. (I think thats what 84ford is doing).

Quick calculation...5 feet of 2 ID dual exhaust displaces about 120 cubic meters of volume.

5 feet of single 2.5 ID (Most common NA recommendation for single pipe in a 3.0 duratec non FI) displaces about 100 cubic meters (I'm rounding off here).

5 feet of 2 ID dual exhaust displaces almost 160 cubic meters...it doesn't take much of an ID change to make a massive difference in the overall volume of the exhaust.

If you aren't pushing FI, you'll lose too much exhaust velocity with too large a diameter pipe. Please search for forums for "exhaust velocity". Here is one thread to start you going.

http://forum.mazda6club.com/index.php?showtopic=41668&hl
 

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Discussion Starter #6
what kind of m6 do you have, hopefully the 6s right? cause your statement suggest your only talking about 1 header which leads me to believe your talking about the 6i model.
[/b]
check my quarter mile time it is with a 6s ;)

Actually I think the contour guys who were staying NA without excessive mods (like a supercharger) went with dual 2.0 ID. Going dual 2.25 would be more for a supercharger type application. (I think thats what 84ford is doing).

Quick calculation...5 feet of 2 ID dual exhaust displaces about 120 cubic meters of volume.

5 feet of single 2.5 ID (Most common NA recommendation for single pipe in a 3.0 duratec non FI) displaces about 100 cubic meters (I'm rounding off here).

5 feet of 2 ID dual exhaust displaces almost 160 cubic meters...it doesn't take much of an ID change to make a massive difference in the overall volume of the exhaust.

If you aren't pushing FI, you'll lose too much exhaust velocity with too large a diameter pipe. Please search for forums for "exhaust velocity". Here is one thread to start you going.

http://forum.mazda6club.com/index.php?showtopic=41668&hl
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thx a lot crossbow.

for now i hesitate going turbo or n/a. if im going turbo its only at low boost 7-9 psi. if im going N/A ill do cpe headers with dual stainless line! with turbo ill keep line stock and later when i have the money ill get another line. if i go turbo will all the car be ok to handle this power ex:tranny,clutch ?
 

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Quick calculation...5 feet of 2 ID dual exhaust displaces about 120 cubic meters of volume.

5 feet of 2 ID dual exhaust displaces almost 160 cubic meters...
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160 or 120? Which is it? Don't you mean Dual 2.5 ID with the 160 cubic meters?

I also find it ironic that you used feet to measure the length of the pipe, but cubic meters to measure the volume.
 

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lethal,

I have an art degree. I suck at math horribly :). Thanks for pointing out my ineptitude!

Please feel free to correct my calculations and repost the comparison!
[/b]

Don't worry. I'm currently attending the Art Institute of Portland. Math was always easy for me, but I was just too damn lazy to apply myself cause I knew I wasn't gonna do shit in math.
 

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LoL damn you! You didn't fix my math! :)

I did pass calc I, after that my left brain died.
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V = pi * r^2 * length

2 ID at 60" long (5ft) = 188 cubic inches
2.5 ID at 60" = 294 cubic inches

I think that's right.

Don't quote me on that. If anyone wants to correct me that gives a shit about math, then go right ahead.
 

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Discussion Starter #13
the thing i would like to know is why going to dual 2.0 id when the headers r 2.25 ? is it for velocity?
 

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It's also much easier to fit dual 2.0's then dual 2.25's. And yes it would be for exhaust velocity. The only person I know of that's going to be running dual 2.25's is 84fordman, and he's supercharging.

If you at any point think you "might" go with a power adder like nitrous, supercharger, or turbo, 2.25 would be a better choice. But dual 2.0 ID or single 2.5 ID for N/A applications is the general recommendation for 3.0 Duratec's.
 
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