3 inch exhaust??

F

fiveo'cobra

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Oct 7, 2004

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Dec 28, 2004

#1

• Dec 28, 2004

• #1

I was just wondering if i would gain less hp by going with a 3 inch exhaust rather than with a 2.5 inch. I have a 94' cobra with all the standard cobra goodies along with some bolt ons. I am planning on spraying it in the near future so a 3 inch exhaust would create less back pressure. But my main question is; is 3 inches TOO big or if i did go with it, will i not gain as much hp or lose some torque, etc??

On the plus side i know a 3 inch exhaust sounds waayy meaner


Thanks in advance.........

 

F

fiveo'cobra

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Dec 29, 2004

#2

• Dec 29, 2004

• #2

c'mon i know there are at least a few of you out there with a 3 inch exhaust??



anyone...........

 

Killercanary

The car that set the bar.

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Nov 29, 1999

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Altoona, PA

Dec 29, 2004

#3

• Dec 29, 2004

• #3

3" what? tail pipes, entire cat back, H/X pipe.... what exactly do you mean. I will say that 3" is too big for your setup except for maybe the tail pipes. Keep everything else 2.5".

 

F

fiveo'cobra

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Dec 29, 2004

#4

• Dec 29, 2004

• #4

yea 1 3/4 inch headers into a 3 inch midpipe, etc. How much of a loss am i looking at here compared to a 2.5 inch?

 

4Jenna

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Sep 12, 2001

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#5

• Dec 29, 2004

• #5

Those headers/exh is overkill for your car by a longshot.

 

iluv95stangs

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Jul 17, 2004

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Walker, La

Dec 29, 2004

#6

• Dec 29, 2004

• #6

I have 1 5/8 shorties with a 3in prochamber and 3in catback and I did not feel any seat of the pants loss. I did notice that the car revs a little easier. I like the way it sounds-different.

 

4Jenna

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Sep 12, 2001

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Dec 29, 2004

#7

• Dec 29, 2004

• #7

i didnt even know u could get shorties with a 3" collector.
Neither of u need that.

 

loud 95

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May 29, 2003

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Milwaukie, OR

Dec 29, 2004

#8

• Dec 29, 2004

• #8

I have been told that you only need 3'' exhaust if you are operating in the 600+ power range. Anything under that and you will lose power. Having said that, you should stay with 2.5 inch unless you are planning much more extensive mods to surpass 600 horses.

 

TheRedBlur

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Jul 7, 2003

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seattle

Dec 30, 2004

#9

• Dec 30, 2004

• #9

the way I always thought of it is that supercharged motors which pump a much higher volume of air will need a bigger exhaust to get all those gasses out without excessive backpressure. naturally aspirated motors depend more on velocity than volume so something smaller will speed up the gasses since there is less exhaust going out the tails.

so supercharged, 3 in.? =
N/A, nitrous, 3 in.? =
*unless HUGE amt's of nitrous.

 

stprorolla49

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Oct 9, 2004

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Fairfield, CT/North Jersey

Dec 30, 2004

#10

• Dec 30, 2004

• #10

you'd need like a 300-400 shot to make a 3" exhaust worth it......

 

TheRedBlur

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Jul 7, 2003

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seattle

Dec 30, 2004

#11

• Dec 30, 2004

• #11

lol word

 

K

KM 94 GT

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Dec 30, 2004

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Dec 30, 2004

#12

• Dec 30, 2004

• #12

A 2.5" off-road midpipe into a 2.5" wideopen (even chambered) would support more then enough flow for you even down the road. Build motor and/or a turbo kit then i'd consider a 3" midpipe back.