OK, I know theres some fabricators on this forum... have at it
Ive been thinking of getting a Muzzy Pro pipe for my 1287 to help it flow the nitrous, but Im not convinced that the 4-1 option is the best design seeing the shift to 4-2-1 sidewinders, especially if i want to retain some street ability. Karl (entropy) got me some measurements from his Pro pipe and BDE SW
muzzy ti propipe
OD's: header: 1.60" taper to 1.75", length=4.5"
header: 1.75", length = 13.5"
header: total length = 18"
4:1 collector: length = 5"
mid pipe: 2.25", length = 25"
can: 5" X 4" oval, length = 18.5"
outlet: 2.25"

BDE SW
header OD's: 1.5"mm tapering up to 1.7"mm,
2 section = 2.0", at meg inlet = 2.3"
4 -2 - 1

my bike currently has a regular Muzzy 4-2-1 street system, and dads has a Muzzy SW
Muzzy 4-2-1:
OD's: header: 1.50" about 4.5 in long then 1.60" (no tapered section, just a small pipe welded to a larger one. the taper may only be a chamfer on the inside of the pipes?)
(forgot to get 2 section, but not really needed for what im interested in)
mid pipe: 2.25"
outlet: 2.25"

Muzzy SW:
OD's: header: 1.60" till 4-1 collector (not sure why no size change?)
at meg inlet = 2.25"


My understanding is that the main "problem" with the pro pipe was that it was designed to move so much exhaust flow that a stock motor couldnt put out enough volume to keep a good velocity going out the end which hurts performance(they stated 1270cc min/high rpm) . the other thing is that its a 4-1 which doesnt seem to have the best street manners. the smaller SW doesnt work well down low either. it seems to me that the 4-2-1 is the best type.

so, my idea
use the best "parts" from each pipe and make a custom header. I believe my 1287 is moving a fair bit more air than a stock motor, and when its being force fed nitrous, it could definately use a larger exhaust. i would basically use the pattern of my 4-2-1 but use a mix of Pro pipe and BDE SW pipe sizes.
start with the Pro pipe sizes of 1.6 to 1.75 and have the 2 section in the same location of the regular 4-2-1. use the BDE SW 2 section size of 2.0 and make it the same length as the 2 section of the regular 4-2-1. end with the same size mid pipe as is shared by the regular 4-2-1 and the Pro pipe.

Using U bends and collectors the correct size, Im confident i can cut and fit the tubing correctly, spot weld most of it with a mig, and have a muffler shop tig it up. I had originally thought that 304 ss tubing would be the best option, but then remembered that my uncles drag vette (548ci V8 900hp NA with 300hp shot of nitrous) uses mild steel exh tubing and it holds up just fine. which is good considering its half the price of ss and is much more my price range. spray it with high temp black paint when finished to combat rust. I dont think the gains would be very high NA, but im convinced it would help running a 100+ shot of the giggle juice

your opinions?

Sounds involved. Can you get your hands on each exhaust unmodified and see how your bike responds to each exhaust first?

decided to go with a Hindle step tube. the BDE SW was based on it and they share the same tube ODs. Karl has dyno runs showing very minimal hp diff readings between the pipes he has. a buddy of mine in ontario told me his buddy has a hindle he isnt using (switched to a ti arata) so im getting that... i think. havent sealed the deal yet. hopefully tomorrow i will... :fingerscrossed