Hey !

Can somebody tell me the sound-difference between 2.5" and 3" piping ?

I want to buy the Top Speed Pro1.

No turbo etc.

 

2.5 inch pipes sound like vaaaarooooommmgggerrrryenyenyenzzzoooommm
3.0 inch pipes adds a little more yenyenyenvaaaroooom but they don't have as much zzzzzoooom.

 

ahahaha great discription but i think he was asking in terms of performance. Still funny though

 

The 3" will definately have a better sound to it and most likely better performance because of the less restriction.

 

on NA? i'd say 3inch isn't the best thing to do, too much back pressure a big loss in low end.

 

3" being too much backpressure? and he was also speaking about a FI system!

 

for FI then yes 3" all the way hell 3.5" test pipes too ;p

 

just because having 2 2.5" piping has larger cross sectional area than 3" doesn't mean that you would be moving more volume. fluid velocity is largely based on the diameter. fluid will have maxium velocity at the center of the pipe, and having a larger radius will promote a faster maxium fluid velocity. also, with having more circumferance it will cause larger drag on the fluid. i have 3" piping, and i love the sound.

 

op specifically asked for the "sound" difference and listed "no turbo".

 

 

@ the people with 3" piping

does anybody feel a difference between the power ? more, less ?

I have NO TURBO, just STOCK !

now, im thinking about the backpressure. the stock-engine needs the backpressure, right ?
is threre still enough backpressure with the 3" piping ?

 

I have 2.5 dualed from the cats back custome setup, I am N/A. You will lose low TQ but you can make it up with other mods...with me running 2 2.5inch pipes big loss of TQ down low but my pulley got some of that back. I am happy with my setup.It is loud as heck just wait till I put HF cats on then I will lose more lower T/Q , I might take theem off if I do...I like low end TQ ,it is important on the street.

 

So... basically you are saying a single 3" exhaust should move more air than a true dual 2.5" exhaust from the same motor?

Not saying you're wrong, just trying to clarify a bit.

 

Im not saying 3" is better than dual or will it necessarily have more airflow. Im saying it has more to do than just cross sectional area. Fluid velocity (air is a fluid) has tons of factors, like temperature, friction, viscosity, .....etc, so it is just annoying when people automatically bigger is better. Fluid that is further away from the piping wall will have a more maxium velocity than a smaller piping. Yes, maybe having 2 smaller ones may be better, but that isn't aways the truth. The velocity profile of a fluid in a pipe looks like a parabola ) with the fastest part in the center. So if ure 3" pipe has a bigger parabola than the two smaller parabola made by theduals,then ure going to have a better flow. But like I said, it depends on tons of more factors than just area. Think about it like this. Try sucking water out of a cup with 100 coffee straws. Then with one tapiocia express straw. the 100 coffee straws probably have more cross sectional area, but i bet u can suck a lot more water easier with that one single straw......why?

 

I have the 3" Pro-1 and I did have a noticable loss of low torque from 1k to 3k rpm. I can't say I noticed any horsepower gains but that's probably because everytime I hear the car with the exhaust in the upper rpm's, I am too busy listening to the amazing sound. Here's a video of mine. The only mods I have are JWT Intake, Pro1 exhaust, and OBX ypipe.

http://videos.streetfire.net/player....E-71CDC9C697CB

 

how much horsepower can an exhaust yield? like 10hp? thats a small percentage ....and if u can tell sweet.

 

If it is NA, I would keep stock exhaust unless you are just looking for sound. The net power gains might not be worth the $ spent IMO.

Warmly,

Michael
VRT

www.ViolentRacing.com

 

So are you saying we should get ure turbo kits? =)

 

you dont need a 3.0 inch exhaust unless your pushing over 450 horsepower, 2.5 is fine....don't waste your money...there will be no performance difference

 

You dont need it but if you get it you will have more flow for the turbo's meaning more power. Only do this on FI