"Engine's peak volumetric efficiency?" What's that - peak torque or HP? Around 5200 RPM? OK - SLP Loudmouth mufflers...............let's see - how much different will it sound than say a Dynomax Bullet, or a Flowmaster single chamber? You are trying to re-invent the wheel here - there have been SO many different variations guys have tried on these trucks, & still no "silver bullet" as it were. Also - X-pipes vs. H-pipes - which makes more power? Well, while I was with Tenneco (Dynomax/Walker) I was working with a couple guys from Ford that spent a year wringing-out the H-pipe vs. X-pipe dilemma. They finally concluded the following: gains in HP anywhere from ZERO to maybe 5 HP - both ways. Sometimes a run yielded a favor to the X, sometimes the H had an advantage. In conclusion, use which sounds better to you. Yes an advantage in going with a crossover on a dual exhaust setup to help equalize pressures between both banks, so on dual exhaust systems, I like to use an H. That being said, I have heard some clips of Tundras with X's & I like the way they sound.I've track tested a 5.7L with an X and an H, there was absolutely no difference in times. This was tested on a Naturally Aspirated 5.7L that ran slicks and very consistent 9.2 sec. 1/8 mile we have no 1/4 mile in SoCal.
It was 9.2 sec. either way and that was his brick wall, so he installed a turbo. :lol5:
but in the mean time, I can say that running true duals on a stock manifold, stock catted truck will lose a lot of low end torque.
The pic above with the AeroTurbine exhaust looks great!! That works real well on a stock manifold truck.
Here's how I set em up with a muffler that releases it's backpressure right at your engines peak volumetric efficiency:
Untitled by bamufflers, on Flickr
I will say this, if you want a unique tone to your Tundras, use mufflers that "tune" the sound, not just make it louder. SLP Loudmouths, Dynomax Bullets & Ultra Flows, & Magnaflows do NOT do sound tuning. Look at the internals & the way the muffler is designed to move the soundwaves around.