trojan

hi i did a swap to B18c. what do you suggest me to make the diameter of the piping of the exhaust system from the header to the back muffler pls to get some gain?

thanks

Libertariat

3" is superior on all engines.

The backpressure theory is/was a myth.

You're going to be paying for it in decibels though. You'll gain power all across the band if you're upgrading from a 2.5" -> a 3.0" for example, but it will be a lot louder for a ~5-10hp gain on a pretty modified engine.

trojan

so if i make it 2.5" will be enough? though if i make it 3" i think it will be too loud..

thanks

Wrona

my friend has 3 inch piping on a WS2 its not that loud but its louder than a reg ws2

flmzero13

3'inch function>form

jollygr33n

What are the plans for the car? If you'll be going turbo eventually then go with 3" and re-install your cat to keep the noise down. If no turbo is in the future, the gains from a 3 over a 2.5 or 2.25 are not worth the noise IMO.

Libertariat

2.5" at a minimum. I was just stating a point-of-fact that 3" is more power across the entire power band on every application.

NotAJDMFanBoy

3" is not necessary on an NA b18c unless you're heavily modified. You'd gain top end, but lose bottom end. You need to maintain exhaust velocity or you don't get the scavenging effect and the system becomes a hindrance.

2.5" is good. Yonaka makes a knockoff of the 2.5" WS2 system and it has a straight through muffler yet is fairly quiet, at least with a turbo. I'm considering selling mine to go 3" here probably in the spring.

CdLem1

^ i agree...what are your plans? if turbo..go with 3'' and if N/A go with the 2.5"...or if your not concerned with the noise level just get a 3"

trojan

thanks for the info guys...no dont think i will make a turbo in the future...at least for now for sure..or i will make it half way then...2.75"..what do u think?

motegicivic

I do not think 2.75 is really a standard size, I am sure it is out there.

Do not go 3" even 2.5 is plenty, I would sick with a 2.25".

Do have an aftermarket header?

motegicivic

I am pretty sure the Yonaka inner diameter is 2.25"

JTTeG_X

2.5" is ideal if your car will be driven on the street and occasional track/strip. I could see 3" being necessary if you were going for a full build and/or turbo. 2.75" would more than likely have to be custom piped. I'd consider 2.5"

speedjunkie_g35

3"= a pissed off bumble bee sound
I went with the yonaka ws2 with 60mm piping for my GSR swap. I am pleased for what I paid

otvcoupe

I got a swap on my 00,civic si, b18c1 boosted bigass turbo, I put on 3" piping but I'm working on the exaush part I want a sound just like a subaru , I want something different than usual Hondas. I been searching YouTube on hondas with subaru exaush but they don't tell much... What do you guys sugest?

Hidenplanvew

buy a subi... I have one for sale.. 04 wrx...

Subis sound the way they do because of unequal headers... You can make subis sound normal with equal length headers

otvcoupe

Lol its possible to get a.really close sound to a Subaru, any other suggestions besides buying a subi lol...

speedjunkie_g35

A scooby is going to be my next car project after I build a bigger garage. Wife hates me having so many cars

otvcoupe

Any suggestions? What should I use? Should I just snap a sti muffler?

speedjunkie_g35

The only way your going to get the same sound as a subi is pulling a spark plug wire of and run on 3 cylinders or as mentioned un equal sized header tubes. muffler won't help you. If you really want a subi sound you will have to do a subi motor swap or this

https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/project-first-world-civic-powered-subaru-2763036/

It is in the engineering of the motor and its components as a whole that make a subi sound like a subi!!!

otvcoupe

Wow!!! my respects... Any muffler suggestions I should use to get a different sound. I don't like my car to sound like a bee... Something stronger deeper sound?

comarv

keept it at a 3 inch diameter

colorfulej1

Im trying to make same decision

otvcoupe

I'll keep 3" but what muffler should I use?

jbpnoman

Whatever muffler you like the sound of.