3 inch pipework for exhaust

[Caution]

What do u guys think, I have a couple of leak spots in my exhaust, im considering doing a 3" pipework for my exhaust from cat to back! I no ill lose some low end, but ill gain it on top. Also will be slapping on turbo in a few month from now! Think it be a good setup. I have ran only 2 1/2" piping to the end of my shifter on my civic and cut it off there, and it has top end, i like it, but too loud, so i know what it can do!

[NAiL05]

Well if your planning to boost I dont see why not plan ahead a lil so less hassle later on.

[youngJAY]

yeah true...its good to plan further down the road

[sirs1ayer]

if your boosting then yes.
if your not then no.
so yes.

[defjamon22z]

i really dont understand the difference between 2 1/2 pipe and 3" pipe.. i thought bigger is better. to let the air out so it doesnt get clog up in the engine??

[foamypirate]

Too big is a bad thing. Your exhaust needs to have velocity, that is, it needs to be moving fast enough to continue in a straight line. If you have too big of piping, the exhaust stream just gets jumbled all around, which is not good. You need to find a happy medium between the velocity, and less restriction.

[h22sparkle]

i really dont understand the difference between 2 1/2 pipe and 3" pipe.. i thought bigger is better. to let the air out so it doesnt get clog up in the engine??

damn you must be new here bigger is better but for what application n/a or turbo . 3inch or better is good for turbo 2.5 is good also but when your not pushing as much power its good for n/a fully built engines but really not all that great for a stock motor unless its for topend or nitrous. 2.25 is great for stockwise.

[JdmCB721]

2.5 in piping is fine for a turbo setup... u dont need 3. U can use it, but u dont need it. U'll get the same results outta each but do what u want

[h22sparkle]

2.5 in piping is fine for a turbo setup... u dont need 3. U can use it, but u dont need it. U'll get the same results outta each but do what u want

the 3inch setup wont fit as far as the downpipe becuase it wont clear the front crossmember unless you grind it which has come kickback careful with that. Or you can do the other alternative and buy 2.6's traction bar.

[lokuputha]

i really dont understand the difference between 2 1/2 pipe and 3" pipe.. i thought bigger is better. to let the air out so it doesnt get clog up in the engine??

Lets consider the diameters stated as an internal diameter of a pipe.

The cross sectional area between a 2.5in diameter piping and a 3in is 19.63insq and 28.27insq consecutively.

The 3in piping has a cross sectional area 144% larger than the 2.5in.

That means in a 10ft or 120in piece of piping, at any given time, the 3in piping will hold 3392 in^3 while the 2.5in piping will hold 2356in^3; or as above 144% more air.

CONCLUSION...2.5 and 3.0 piping big difference.


Boring math:
__________________________________________________ ____________
Cross Sectional Diameter:
pi x 2.5in^2 = 19.63in^2
pi x 3.0in^2 = 28.27in^2

Volume in 120in/10ft piping:
120in x (pi x 2.5in^2) = 120in x 19.63in^2 = 2356in^3
120in x (pi x 3.0in^2) = 120in x 28.67in^2 = 3392in^3


Percent Difference of Cross Sectional Area & Volume:

[(28.27in^2)/(19.63in^2)] x 100% = 144%
[(3392in^3)/(2356in^3)] x 100% = 144%
Thus, 3.0pipe will hold 144% more air than a 2.5in pipe, which is a lot.

[Hijikata92]

so what would be good on stock??

[defjamon22z]

dont mean to be rude but... lokuputha ... i dont understand what the fuk u just wrote. i'm not a math genius. lol. but okay i see big number and i see a smaller number. i see the difference. thanks. lastnight my homeboy told me i didnt have a 3" . it look huge but they were like 2.5 pipe. as for Hijikata92 i think everybody just answer that.

[Hijikata92]

ok heres a hypethetical (or how ever u spell it) situation im using as SRI which would i go with a 2.5" or a 2.25", both were mentioned for stock engines

[rossisalvage]

Im running a 3 inch cat back on stock engine, it runs great I didn't notice a decrease in torque but it screams on the top end. Its also nice cause I know im gonna turbo it someday.

[lokuputha]

dont mean to be rude but... lokuputha ... i dont understand what the fuk u just wrote. i'm not a math genius. lol. but okay i see big number and i see a smaller number. i see the difference. thanks.

no problem man...just ignore all that bs i wrote. Thats y I highlighted 3 is much bigger than 2.5.

I have a 2.75" internal diameter exhaust system.

Compared to my stock exhaust, according to my butt dyno, the lower end of the rev band ( from idle to 2750rpm) is a little weaker. The midrange (2750rpm to 5000rpm) power has increased greatly, and the higher rpm (5000 to 6100redline) inreased greatly.

Although I think if I put a test pipe and a straight flow muffler instead of my chambered one the higher rmp's would give even more power.