Complex subject a good exhaust
Northern Rider said:
Mmmm, nummy, Zilla.
Are you running the FM's now? The install appears to have no crossover - did you use one? what does the system sound like?
System is not mine, mine’s still stock. Yes I too noticed apparent lack of X-over; that’s why I showed the x-over pics. It may be a slit cut in each pipe and the pipes welded where they "kiss". I believe retaining the X-over is essential.
I hope you don’t mind if I include a bit of background about X-overs and why they work; It’s stuff you’re aware of, however some reading this may find it informative, for those that glaze over reading tech stuff see the last paragraph:
X-overs: All the vehicles I have owned, that I could put a balance or X-pipe on, have responded by giving a big fat torque boost at low RPM. This started with a simple “balance pipe” on 1960 twin cylinder Triumph Bonneville motorcycle; changed from stock separate pipes. The last one was a V-12 Jaguar, every single one showed improvement.
A bit of background: an exhaust gas travels as “slugs” of gas down the ex. pipe. This happens at a very quick pace; at 3000rpm, it occurs at 25 times a second. (One exhaust/scavenge event per cylinder per two crankshaft revolutions). A V8 has 200 gas shots a second. When the exhaust valve closes, the slug briefly slows and partly reverts backwards along the exhaust pipe. Then along comes the next slug of gas after it, pushing along the pipe. A slowed visual would show a series of machine gun-like staccato bursts, finally combining to a smoother but pulsed flow out of the tailpipe.
With an x-over both exhaust pipe runs and mufflers past the x-over are shared. Part of each exhaust pulse goes down the other pipe creating an extra vacuum behind it sucking along the pipe, or “scavenging” the next alternate pulse. It is this scavenging effect adding efficiency that really noticeably boosts the torque.
The effect on system noise is: without a muffler change, the vehicle becomes quieter, probably because with X-over each pipe is then served by 2 mufflers, and also the added “smoothing effect”on the exhaust pulses.
My personal experience using an X-over with after-cat performance-type mufflers and resonators: the sound has been most pleasing, though with V8s the X-over did eliminate some of the aggressive V8 “exhaust lope” at idle.
Of course with the 300c MDS joins the mix and exhaust drone must be taken into account, when enough aftermarket systems are installed a poll would be in order: noticeable power increase, sound at idle, lack of drone, overall positive or negative, etc. If you design your own you may be redesigning MDS drone into the exhaust, as shown by an excerpt from a Magnum Hemi forum thread "The Magnaflow setup I made with just two mufflers in the center, and tips in rear was way too loud on the highway. You can hear the exhaust, and it sounds kinda strange when it kicks into 4 cylinder."
While we are on the subject I notice that the Magnaflow factory system contains a resonator that they say contains a “TruX crossover pipe” I would love to see the insides. Note the Magnaflw tips are right on the mufflers so you will see the mufflers from the rear. Yes NR
pictures of a stock 2006 exhaust system to compare would be interesting too.
So retain an x-over (more torque) - Something to think about.
More pics: some more x-over pipes - and Magnaflow with Tru-x resonator