I will give my opinion and it is only an opinion. What you want to control is air speed. You have fast hot moving air and it acts like a vacuum out the exhaust tip. Nature wants to stabilize at 14.7psi. There is a wave pulse in that tube and it is aiming for atmosphere. You mess with restrictions and air-timing, boy, that will basically mess up your tune or say, HP peak/Torque peak moving up or down the pipe range.
A crossover pipe sorta stops air flow. It neutralizes that air speed to slow down not stop, meaning. This is a crossover/torque helper for the bottom and O/L performance. You cannot remove (well, you can technically do anything, but say) the crossover part of the pipe; short of gating the hole with a flap and cable> That is now being used in bike applications, ('08 Honda 1000RR). Bikes being just as high-tech... But getting back to the crossover, this has the effect as a ball chamber. Think > Drill a hole in a beach ball with a pvc pipe attached to one end. You blow air thru the pvc and now it enters the ball. It is going to slow down that air before it continues out the other side through the pvc pipe, (to atmosphere). This ball chamber in a bike's collector section is almost the same 'slow-down chamber' as is the crossover pipe more or less. I keep thinking basic physics to tech my way through a tune or follow the flow of the air speed.
I need a visual to understand the physics, and see if it walks in the absolute. So, between the crossover at the header for it too understands it is a 2 engine 4-cylinder bank working air together. The little ball chamber slows the air so the reversion is somewhat saved. It is way too complex for me, but I sort of understand the basics, I think?
I tried that glass-wrap idea at the header or wrap a cold spot to heat up slow moving air is the idea. The problem with the wrap is the extra speed induced. What the wrap does is keep the heat in so the fast air keeps moving as fast, (or tries with the insulation). I do not suggest you try this little, 'air-cheat.' Headers with wrap, unless you have a dyno and can re-map or re-jet or re-time whatever it takes to cure that phenom>
LAG; you are going to hit the gas pumps a lot sooner if you are not careful with something as simple as pipe wrap!
For example, I played with wrap and I can assist that the hot air will suck the fresh charge out of the chamber if you are not careful. It will sit in a wall of negative or positive is you take the guess watching the vacuum gauge and when you lift or WOT, tell me what pressure you need to follow working with fast air and passing gas, let alone you in front of me with your tuneup.
Here I am in the wrap, and I lift as we are both in a corner heading into the apex. What just happened is that the pressure on lift will clog that fuel chamber to the point you throttle back up; you have a lag before the vacuum finally returns to push the pressure; is now back to the opposite (vacuum at the WOT), where you are firing nothing = The Lag. Ever ear a Mack Truck on the air-brake? Yeah, so you step on the gas and you air brake or air fire is no fire; is to wait for the next cylinder to fire off and ear I am listening to the pit tell me I am a few 10ths off a lap = "WOT DAY Fug A Duck Juice Happened?"
Well eye said data eye did dent tune dat piece of sheet-0-air speed out day chamber wrapped all up nice and pretty.... Lag my corner exit. I do not think someone typing ear is wrapped too tight if you get my drift. I am in the lag behind of air speed was too great a speed. It is not my fault you went and tuned the stock, perfect running engine no matter what foot plant/wrist application.
I cannot drift and lift in the wrapped. It needs tuning and I do not have the $$$ for that study. Days and hours minutes of fun with it thought I can test on my own.
I gas my azz is a wrap wit diss air speed up day tubes. I am writing for one person and one person only = YOU!
It is in my opinion that some sort of air speed in the pipe and what some of it does is what I am now studying. I may have stumbled there in the walk, but I think I am pretty close as to watching hot air moving out of a pipe. Even changing a pipe to one only, no crossover, with crossover, one pipe for each side, equal length with the least amount of curves so the air does not slow down (at the header build), are things to think about changing exhaust systems.
To backup my hot air studies, I try things on a smaller scale. This is a 2008 ZX-14. It is by all the data in, the worlds quickest spinning engine that ramps up faster than the Hayabusa. Both have basically equal torque. If you want to split hairs, then call this bike the fastest production bike in the world, (who spins faster to the same torque = LOL). I like to stay stock and play with the air at both ends. What I know, is what you know about a small part of what all that hot air and pipe changing at the head is all about. Note, that this being an experiment, I have thought of using 4 cylinders as 2 different engines. So my test was to expose the 2 outside pipes a few inches and wrap the opposite inner pipes in the opposite direction as a crossover for both sides of some sort of yin/yang theory. I haven't a clue? But this I do know. You will have an effect and it might lower your mileage just because it is that efficient in the wrap, (taking your fresh spent out day pipes).
http://img110.mytextgraphics.com/photolava/2008/03/09/wrap-49s2hu5p9.jpeg
