Bored at work and was just thinking about how sweet quad tips looks, meanwhile contemplating fabbing some straight pipes once I'm done with my 6sp swap. So everyone knows that like all things involving gases or flow, there's that compromise between resistance and velocity. That compromises also ties in to where you want it in the RPM range. On the 1uz it's been agreed upon dual 2.5-2.75" is that sweet spot for the best overall performance.

So my idea was to run a system similar to what the c6 vettes have , right after each header have a Y-pipe with one side blocked with an electronic solenoid. Then run both with say 1.75-2" pipes leading to quad tips. Then you can wire up the solenoid to open up at say 3.5-4k RPMs. That in theory would give a much flatter torque curve, plus a nice purr when cruising and a gnarly growl when you let her loose.

Given this wouldn't really apply to those rocking the turbo lifestyle, but for those wanting the most N/A power it might be worth trying. What do you guys think?

 

You mean you want to run a vacuum controlled cutout? Or a secondary exhaust? Cause when speaking about the C6 Vette, I have never seen one with a factory y-pipe, only the "bimode" muffler, which is vac controlled to simulate a straight pipe and bypass the factory internal muffler baffles. This paired with the 1.75" exhaust pipe actually hurt the C6's performance greatly. Yes low end torque was maintained, but at higher RPM levels even with the bimode muffler, the car suffered when compared to a C6 with a full 3" dual exhaust and an x-pipe in place of the factory h-pipe.

Also keep in mind your comparing a 4.0l 8 cyl to a 6.0 (base) 8 cyl. When discussing flow and velocity, the displacement does have a factor.

I would say a simple 2.25" exhaust (2.5" with cats) and an x-pipe would compliment the 1UZ by increasing dynamic flow, and balancing velocity between banks with the inclusion of the x-pipe, all while not "over-sizing" the ID and allowing pressures to remain in a nominal range.

However, exhaust threads like this can be beaten with a dead horse millions of times, and with no solid resolve. There are too many other factors from altitude, temperature, other modifications, length of the exhaust, and the choice of pipe material used and considering expansion rates at running temperature. Only way to determine whats "best" or most beneficial is to do several different setups and do several baseline dyno pulls to watch increase or decrease.