3in Pipe on H23A VTEC All Motor Build

[lucky#sleven]

Right now I have the motor with full MSD ignition with stock headers n stock piping and a street tune. I already have a skunk2 intake manni and headers to put on there and I was gonna add 3in piping to the mix and get it retuned. Bigger injectors and a head build for nitrous in the winter. But yeah right now, like within the next week or so, 3in pipe with the other bolt ons. Yes or no. Keep in mind I'm working with 2.25in right now O_o

Any suggestions, opinions, or facts are welcome.

Thanks!!

[Jarrett]

What stock piping do you have that's 2.25"? Honestly, I'd say that 2.5" is where you'd want to be for primary street driving. The H23A VTEC is meant to make power a little lower than the H22A and by putting huge piping on it you'll be hurting it. Until you are winding it up very regularly or running some form forced induction then I don't think there's a reason to have 3" exhaust on a 4-cylinder street car.

[lucky#sleven]

Cool. Thanks for the insight man. Really appreciate it.

[uglygc2]

a 3" exhaust (from the header back) will reduce your torque output but give you good power in the higher rpm's. i had a full 3" exhaust on my itr swapped db8, youre 4-5 tenths of a liter higher in displacement and my torque levels felt great in the integra. i say if you arent concerned about noise a full 3" would be a good power adder after tuning with the right intake, spark and fuel upgrades. if i can run 11.8 in a sedan, so can you ^_^ (that e.t. was with a cluthmasters stage 3 unsprung clutch, not a very good mod on a street car..)

[Mt.HOODrat]

kinda off topic, but i always wonder why guys go full MSD ignition on bolt on street cars with B series or H series. I always thought the stock Honda ignitions are more than sufficient for bolt on cars. there are guys around here running over 300 whp on stock ignitions and doing so just fine. just wondering, because i always thought the money would be better used elsewhere.

[dockinrez]

kinda off topic, but i always wonder why guys go full MSD ignition on bolt on street cars with B series or H series. I always thought the stock Honda ignitions are more than sufficient for bolt on cars. there are guys around here running over 300 whp on stock ignitions and doing so just fine. just wondering, because i always thought the money would be better used elsewhere.

I've been told stock ignition is good for 400+ but it won't satisfy a 9k rpm rev

[Jarrett]

The same reason people buy anything that's marketed to them.

[deevergote]

Yeah, the stock ignition system is just fine. The only real reason to get an MSD setup is if you want to use their "2 step", which is a programmable ignition cutoff. It's a bit safer than an ECU-programmable fuel cut, which is what many people use for launch control.

As for the piping diameter, 2.5" will work just fine for most things, though that nitrous build will benefit from 3".
Too large of an exhaust pipe diameter can cause turbulence, which becomes a restriction itself... so essentially, a system that is too large for the engine's output can end up being MORE restrictive than a narrower pipe that allows for optimal flow velocity. 3" should be workable on that H23A, though.