long pipes

[thegoochking]

Does anyone make pipes for the 3rd gen magnas that are longer than the stock? like the ones that extend as far as the end of the fender? Seems like all the after market pipes sound different but non of them look different besides being thinner the whole way instead of getting fat toward the ends

[Greg Cothern]

I've never seen pipes as you describe for a Magna.  Grab a welder......   

[lragan]

And find a good chrome shop!

[thegoochking]

So with someone that has welding skills which i have a friend that does welding and powder coating and such for a living, would it be possible to fabricate straight pipes to get rid of the upward slope to give it that sleek look and more clearence for bags?

[Magniac]

Back in the day, I was involved in tuning exhausts for racing. Drastically over-simplified, long pipes like you describe are generally not advised for high-rpm engines. The pulses travel down the pipe to the end as positive pressure waves (with negative pressure areas between), and then reflect back up toward the exhaust valve as negative pressure waves (with positive pressure areas between). Ideally, the negative wave should reach the valve just before it closes, helping to scavenge the combustion chamber, allowing a full intake charge to enter. If the positive pressure area arrives at the valve at this time instead, it can cause the combustion chamber to partially refill itself with exhaust gas, preventing a full charge of intake, at a cost of power output. Knowing that these waves travel at ~ the speed of sound, it is possible to tune the pipe length to use the waves beneficially. In general, the higher the rpm, the shorter the pipe needs to be.
Disclaimer:  This is not intended as a 100% accurate representation, but rather a generalized sketch of the theory.

[lragan]

Very well explained.  I think I understand this.  Similar to radio transmission lines in concept.

One of the benefits of the slash cut is that it softens the reflection a bit by spreading it over a longer distance. 

In theory, one can tune the exhaust correctly at only one rpm setting, given a perfect pipe, etc.

I would  have to go through the math, but it doesn't seem to me that a few inches onto the several feet that already exist on my header/exhaust combo would change the resonance all that much...

[thegoochking]

that would explain the short pipes on the magna chopper mod i posted in another thread.

[Magniac]

Yes, the slash cut helps a little, reverse-cone megaphones even more, and it's amazing just how much difference a few inches can make. (Ask your gf, lol.) And it's true that power output is optimized at one specific rpm, but done properly, it can be spread so as to be beneficial over as much as 20 to 25% of the rpm range of an engine with a 5,000-6,000 rpm redline. In the case of a 10,000 rpm engine such as the Magna, however, it would take considerable massaging to gain over a range of more than 10-15% (at the expense of losses everywhere else). Bottom line: if it were mine, I'd leave it alone. YMMV   

[L J VFR]

So... Does this mean that the factory exhaust has been tuned to give the maximum horsepower, torque, etc..?  If this is the case, taking out baffles, cutting exhaust, could be bad..Correct??   I am also amazed that companies like vance and hines, jardine, cobra etc... can build a better exhaust than the factory.. Is this the case??  I read on this site somewhere were someone had mentioned that honda pretty much is squeezing the most out the magna engine with the stock exhaust..      I understand that aftermarket exhaust means better flow, more horsepower, sound better, etc. etc. But, how much more.. If we talking about 10-15 horsepower differences I could understand paying $300-600 for exhaust, but to gain 5 horsepower??  Hmm...  Lance     

[dgc67]

A gain of 5 hp in an engine making under 100 hp is actually a decent gain and will be felt by "seat of the pants" testing.  It all goes to percentages.  While 5 hp is nothing in a 350 hp engine, you will smile when gaining it on a 100 hp engine.

[Magniac]

Aftermarket exhaust makers ADVERTISE better flow, more power, etc., but in actuality, it's all about the sound. Most times they can cost you power, unless you make other mods at the same time, regarding air-fuel ratio, cam profile or timing, or a myriad of other things.

The factory exhaust is not optimum for any specific rpm, but has been tuned to give the best compromise over the broadest rpm range. If you want to change the sound, by all means you can modify or replace the stock setup, just don't expect any huge gains. Do a dragstrip run with stock exhaust, then do the same run under the same conditions on the same bike with a modified or aftermarket exhaust, and no other changes. You'll be surprised.

That being said, I have drilled end plates on my stock exhaust, but it wasn't for performance. I just wanted to be able to hear the exhaust over the wind noise at road speeds, to assure myself that the name on the side of the tank isn't "Singer".  lol

[L J VFR]

I once owned a 96 chevrolet pickup with factory exhaust. After I went to the exhaust shop I choose to put a flowmaster exhaust on and cut off the exhaust after the new muffler. When i left the muffler shop, it sounded awesome.. however, I could tell immediately  that i had lost some bottom end torque... But it sounded good...    Lance

[L J VFR]

I have drilled end plates on my stock  exhaust                                                                                                                                                                                                                                                                                                  Hey magniac... Could you explain this procedure a little more.. Did you like the sound after you did this mod?? Did you just drill the rivets out or did you drill extra holes?? Thanks   Lance

[Magniac]

I drilled 6 extra holes, evenly spaced between the rivets. Drilled 'em right on the bike. I suggest if you do this, start with smaller holes, maybe 5/16", then you can enlarge them if you want more sound. Mine are 1/4".

[Greg Cothern]

I once owned a 96 chevrolet pickup with factory exhaust. After I went to the exhaust shop I choose to put a flowmaster exhaust on and cut off the exhaust after the new muffler. When i left the muffler shop, it sounded awesome.. however, I could tell immediately  that i had lost some bottom end torque... But it sounded good...    Lance

Back pressure is the name of the game, included in this is the pressure pulse's as mentioned.  Basically we have to setup for how we plan to use the bike and tweak the setup/adjustments to fit that scenario.  If ya want more sound then get the sound you want and then chase the carb settings to work with that flow/pressure.  ETC.