So, i had cut tip that came with the car cut off preparing for a dual exhaust setup in the future. then i had to drive it to school, (automotive program) to get a free brake job from a classmate. went to local mechanic (same guy who cut the tip off for me), he welded on a new stock muffler for me, but we started talking ideas about a dual exhaust set up. He said too me to get a true dual exhaust setup and performance benefits from it, i need a new header, (current header 4-1), so he can run two separate exhaust pipes.

Im still relatively new to being car guy let alone hondas specifically. so down to my question do they make just a 4-2 exhaust header for b series hondas or how do you think i should run this new exhaust setup. he also mentioned running two separate turbos so i would have minimal lag.

thanks.

 

I encourage you to search out reputable sources for information on basic automotive technology including performance improvements and their respective applications.

in general, 4-1 will favor high-rpm torque at the expense of mid-range torque. not ideal for a daily driver or primarily street-driven car.

4-2-1 tends to offer more mid-range, less high rpm torque. great for street driven cars. many Hondas (4cyl) come from the factory with this design.

dual exhaust pipes are used in cases where a single pipe that can handle the required flow rate would cause a clearance issue. your civic will fit a 3" pipe without issue. this is too big for a stock or even mildly upgraded b-series. smaller dual-pipe exhaust sized to not loose power would only add weight in this case

 

The general consensus was that the b16 had zero torque so you want to have the free flow of a 4-1 header to move the curve higher in the rpm range

A b18 typically has better mid range torque and you want the 4-2-1 for better mid range torque to balance the high rpm horsepower, otherwise the power was not efficient for daily driving

So what does that mean

A 4-1 has better horsepower where as the 4-2-1 has better mid range torque.

Your small displacement motor really won't have noticeable gains. If you really want to get into specific science exhaust velocity plays a more critical role and you would notice more benefit in heat wrapping your current header than swapping out for a different style

 

You guys are missing his question.

he wants to do a 2-1 dual exhaust.2 cylinders on each exhaust pipe.

While it might be possible, I don’t see any benefit to it.

the idea of 2 small turbines on 2 cylinders may work, but I don’t see it being advantageous.

@TheShodan , any input?