if i run a 3.25 in pipe from my headers to my muffler, replacing the small thin, stock sized piping there now, will i notice a way differnt sound? deeper?

 

and i forgot now to add, now i have a bad metallic sound coming out and im thinking its the cheap stock piping all worn out. I have the Monza muffler, thanks!

 

It will slow your car down, and be wayyy to freaking loud.

On an N/A application you really don't want to run any pipes larger than 2.25 inches.

 

how many inches is the stock pipe?

 

How does a larger pipe slow you down?

 

you lose the affects of scavanging by reducing the velocity.


if you've every siphoned gas before, it's the same principal. which is easier to syphon the gas through.. a narrow tube or a large one.

you generally want to find a middle ground where back pressure is minimal but velocity is optimal.

 

so what do you guys recommend? the stock connecting pipe to the cats from muffler they gave me is VERY thin and feels so cheap? what size is the stock? is i dont have cats its connected to the rb headers, will i get a less metal sound if i use the right pipe? and what size? i want it loud, not so damn metallic sounding though.. is there another type of muffler thats very deep? Please help and i apprecaite it!

 

answered already.

 

Also, with a slower velocity, the exhaust gasses have more time to cool off (not to mention a larger surface area of exhaust pipe for heat transfer). Cool gasses are denser than hot gasses so there is more mass to push through the exhaust.

 

Monza is crap IMO, thats likely the reason it sounds all metallic. Everyone hear swears by RB powerpulse, but I'm sure there are other decent mufflers to use.

 

I'd have to see dyno proof directly comparing on the same car, 2 different pipe sizes. I just don't see how the exhaust has an active role in the power the engine produces.

 

it makes sense if you think about it... there would have to be an optimal exhuast pipe size..

example: sipping from 2 different size straws..

sipping from a small straw: you get your drink in your mouth pretty quickly, but you don't get a lot of drink..

sipping from a big straw: it takes a little longer getting the drink, but you get a lot of drink..

so you'd want to have a straw size in between so that you get the drink fast and a good amount of it too...

So, seeing how exhaust would need some pressure to keep it flowing out the back, having too big a pipe would cause power loss, whereas having too small a pipe would have too much pressure...

 

I just don't see it that way.

Sipping a straw is not like pushing exhaust out a pipe.

You have 1 fixed size to deal with- the port size. I would think an exhaust pipe with the total cross-section area of the total number of ports would be the largest pipe needed. Any larger would be a waste, and any smaller would be a restriction.

Put the fluid in your mouth, and try pushing it out a straw. There's no benefit from "scavenging" is there?

The exhaust "stroke" doesn't make power. Any effort used to push the exhaust out, is wasting energy and creating heat. The less energy used, the better. Which is why I say, the larger the pipe, the better.

 

Believe me when I say that I used to think the same thing. Another thing to look at is this: when the pipe gets too big it actually INCREASES backpressure. Between exhaust strokes air will suck back into the pipe, with a smaller pipe it takes longer for the gasses to come out so this effect is minimalized. However, with a large pipe most of the gas is evacuated at once, leaving a vacuum to be filled with outside air. The air rushes into the pipe, making more work for the engine to push the exhaust out. Because of this, as well as the other reasons mentioned, at a certain point, a larger exhaust pipe will begin to lose power for the engine. What is needed is a balance of volume & velocity.

 

you're forgetting that exhaust gasses that aren't scavenged dilute the incoming air/fuel charge therefore giving you a smaller bang next time around. It's not all about energy used to push the gas out but why the gas needs to be out in the first place.

 

http://www.yawpower.com/techindx.html

You should read through the exhaust articles. I think the one concept that you're missing is port scavenging. You're only thinking about one exhaust pulse or that the pressure is constant and in the same direction.

 

I see. I'm not breaking the cycle down small enough. I was looking at the net effect of getting the exhaust out- not the micro steps involved.

So an overly large, or nonexistent tubing would be perfect for dissipating the exhaust, but not for pulling it out of the chamber, which would just get spun back into the intake cycle.