I want to know wich one is the best size for the exhaust pipe, 2" or 2.25" I know PseudorealityX says 2" but others say 2.25". What to choose??? this is for a stock SOHC engine.

 

It depends on your use. If all you want to do is drag race, the 2.25" is better. For daily driving, or autocrossing, the extra midrange torque of the 2" is your best bet.

For quietness, I have a 2.25" Walker Turbo muffler. I figure the larger diameter makes up for most of the extra restriction of this muffler compared to a straight through (like a Magnaflow), while still keeping it quiet.

For an explanation of why 2" is better than 2.25", low and mid rpm torque depends on exhaust scavaging, which is where the exhaust pulse from one cylinder creates a vacuum behind it that helps pull the next exhaust pulse along. If the pipe diameter is too large, this exhaust scavenging takes place at less useful rpm (say 5.5k-7k instead of 3k-5k).

Since most people spend more time in the mid-range, it's important to keep the power here. And the intake restrictions at higher rpm make high-rpm exhaust scavenging useless.

No some smart@$$ will no doubt post about how drag racers have no exhaust. But they do tune the length of the pipes to get the maximum efficency out of the pipes. They also have superchargers that push air into the cylinders (rather than using vacuum and other resonance tuning tricks for cylinder filling). Race cars also tune their pipe diameters for maximum area under the torque curve.

 

thanks for the help David

 

I have a 2.25" piping on my 93dx, I use my car for more of the drag racing end of performance. Like Mr Avard said it all dependes on what your intentions are with the car ie drag, autox ect. What i have noticed that when comparing the sound s from a the stock piping to the 2 1/4, the 2 1/4 had a higher pitch sound to it but overall did quiet the sound at lower rpms.

 

its for daily driving but I want power when i need it, 2" seems to be the ideal choice but a lot of people have cat-back exhaust and there probably all 2.25", and they cerainly not all drag racers.

 

We don't have much of a choice if you buy off the shelf...the Pacesetter is your only choice for a cat-back at $150 and it's 2.25", although Mazdaspeed has an SS one for like $650 but i'm not sure of the diameter. Anything else will be custom.

I have the Pacesetter 2.25" piping, wish i had of gone for 2", but will eventually go to 2.5" when the BPT is in.

 

Your cheapest bet is going to a muffler shop and having thr pipe custom bent. For my 2.25 i paid $65

 

But, a muffler shop, non-mandrel bent system probably has enough restrictions in the bends to be pretty close to a mandrel-bent 2" system in terms of flow.

 

Does anyone have sounds clips? I'm looking into exhaust for my car, but I don't want that ricey whine. (sorry if I offend anyone by saying "ricey", I'm used to V8's)

 

http://www.dynomax.com/sounds.stm
check for the civic maybe you will get an idea

 

I have 2.25, on my 2nd gen , no problems there, when you go to the shop they tend to want to use 2.25 anyhow... but if you want to get 2" you can , I figure after all the dang bending that they do , you may be cut down to 2" from a 2.25 any way
Bruce

 

I think u should just buy my exhaust w/ a 2.25 pipe and a banzai muff!!! AND if you give me your stock one (considering it's condition) I'll give u it for pretty cheap

 

hey Elchulo, im just curious, what would you do with a stock exhaust? =D

 

It was really rusted up and it started to crack so I decided it was time to "upgrade" but recently my mom's car died and I want to run more of a stock set up in order for her to use it as transportation during the week.

I'm actually planning on buying an older Mazda B2200 so I can use to go to school. Hopefully I will learn enough about them to be able to trick it out

 

yo, i found a stock muffler on ebay for 24.95

http://cgi.ebay.com/ebaymotors/ws/eB...tem=1838914573