1 vs 2 muffler exhaust design

JeepGuy

Maybe a stupid question, but it seems to me that the most efficient design would be the one with the least restrictions, turns, etc and get the exhaust out as quickly as possible (without having no back pressure at all of course).

So why is it that we're seeing so many styles that seem to have a single shared muffler for the two pipes (eg Nismo and HKS) versus 2 individual mufflers a la Mine's and EXAS Evo.

Single Muffler


Two Mufflers


I'm sure eventually dyno's will tell the tale of what works best, I'm just wondering why we would have the different takes on this, or if one method would be clearly superior.

Also, why no options like this yet

Nismo 370z

The main difference would be the sound. But i assume that a true dual with straight through mufflers would yeild more power. Correct me if im wrong.

JoeyD

I thought you would only want 0 back pressure on a turbo application. Right? Isn't back pressure related to torque? I am also fairly certain that you should have some type of cross-over (x-pipe or h-pipe) in order to balance the two banks of the engine.

Jon@Altered

I recognize that photo; I shot it! Actually, our 3 inch True Dual Exhaust is designed specifically for the twin turbo charged VQ35/37 engine to achieve the greatest exhaust velocity for better mid-range boost response and high-RPM power. With turbo cars, the straightest exhaust path is the best way to allow the turbos to run at their maximum efficiency, which over course, helps the car produce more peak power. For N/A applications, the 3 inch turbo exhaust works well with supporting modifications(i.e. High Flow Cats/Test Pipes, ECU Flash/Tuning), however it does tend to shift the powerband to higher RPMs. We are in the process of developing a 2.5 inch true dual exhaust for the 370Z, and it will be very similar to our current 350Z 2.5 inch exhaust, shown here:




And hey OP, there is no such thing a stupid question! Ask away!

-Jon

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Endgame

That dual 350Z exhaust is sweet....

Nikon FM

However, the real proof of the system will be the dyno numbers.............can't wait to see them.

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Crash

Right. I wouldn't want LESS back pressure until I got my turbos installed. The last thing this car needs is to LOSE torque!

I'll be leaving the stock exhaust on until I get my turbos.

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TerribleONE

exhausts WILL gain HP and TQ on a NA set up...

JoeyD

That is COMPLETELY dependent on the exhaust system. It is much easier to lose HP and Torque than it is to gain it. That was a fairly assanign comment actually. Too little back pressure and you WILL lose torque.

370ZDreamer

Great looking exhaust, I have a question though. I come from a muscle car background, particularly Mustangs and the difference between having a dual exhaust with a crossover vs without one is significant. You even find differences between different types of crossovers.

It doesnt look like you have a crossover in your system. Any particular reason why? Does this V6 engine family not react the same as a V8 engine with their exhaust pulses?

370ZDreamer

Absolutely 100% correct, this happens on Mustangs too when you go with off-road exhaust. Good peak power in a narrow band up top but no balls down low.

JoeyD

I think he mentioned this earlier but. The system in the pic is designed for a turbo application. V6 should still have some type of X-over in both NA and supercharged apps. In a turbo app. 0 back pressure is the goal thusly no x-over is really necessary.

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370ZDreamer

Must have missed it. Thanks for the info!