OK, the Buell thread

[Guest captain nemo]

Oh, David - I wanted to also ask if this muffler got in the way of the gearbox drain bolt. It sits right over my crossover, but I'm able to get to it. I was wondering about the Furia deal. Also, (and this is a very silly question) in what way is this muffler different from a crossover? Is a crossover simply an expansion chamber? What is its purpose? And why do performance crossovers look like pipes with no expansion? I don't understand the purpose of them. Is the Furia muffler just an empty box that provides the exhaust with some back pressure?

[al_roethlisberger]

That's correct, even with the stock dual-can configuration, each muffler is not exclusive to each cylinder as the cross-over connects both sides of the exhaust system. So whether is a single or dual outlet, that consideration isn't terribly relevant.

 

This is why when tuning the bike, the tuner's gas analyzer probe only needs to be, and often is, inserted and left in one side.

 

Here is your answer to the "hows" and "whys" of exhaust tuning and scavenging:

 

Forum Crossover Thread

 

al

[zebulon]

Hey Zeb - is that you with your bike?  Damn, that Guzzi is perfect!  I'd love to hear it and take it for a spin.  Wow.

 

Yes this is my bike, like Paul, a 2 year project.

Our 2 bikes are unique prototypes.

 

To see and hear Static Video (11.2 Mo)

The exhaust is about to be modify for a 2 in 2 instead of 2 in 1

 

The website : http://supertwin.org/

[dlaing]

The muffler does not really get in the way, but it makes the tranny oil change a little messy you just let it drip over the muffler. No big deal and plenty of wrench access.

 

I am not an expert but here are some attempts to answer(ie. I could be full of Sh^t)

" I was wondering about the Furia deal. "

The Furia muffler will not fit....hearsay.

 

"Also, (and this is a very silly question) in what way is this muffler different from a crossover?"

This muffles the sound more and turns two intakes into one out take.

A crossover brings the Left and Right air flows partially together to more efficiently share the two mufflers.

 

"Is a crossover simply an expansion chamber?"

No, but your mind is. The stock crossover allows for some expansion and also muffles the sound a little. The Stucchi and FBF crossovers do neither and work better.

 

"What is its purpose?"

Increase power and possible weaken power around 4000rpms to piss us off.

 

"And why do performance crossovers look like pipes with no expansion? I don't understand the purpose of them."

I don't understand the purpose of expansion before the end of the tunnel.

I imagine it to be like two lanes of traffic merging out into six lanes for 1/4 mile and then merging back to two lanes....the traffic is not going to flow any faster.

The Stucchi crossover merges 2 two lanes into a four lane and back into two 2 lanes so that when the traffic is more busy on one freeway it can flow to the other.

The Stock crossover merges 2 two lanes into a six lanes (ie expansion) and back into two 2 lanes so that when the traffic is more busy on one freeway it can flow to the other, but the six lanes may produce more chaos than control.

The FBF crossover probably relies more on mutual air pressure assistance rather than direct flow share, if you know what I mean? In any case the FBF does not follow the traffic analogy as well as the Stucchi.

 

" Is the Furia muffler just an empty box that provides the exhaust with some back pressure?"

It is not empty, but presumably a tuned labyrinth, possibly with sound damping material such as stainless steel wool embedded in perforated walls.

 

Oh, my last complaint about the Quat-D muffler is that I think I lost about one or two mpg.

[dlaing]

The exhaust is about to be modify for a 2 in 2 instead of 2 in 1

Zeb, how are you going to do that?

I suspect your bike is going to be even more powerful with the mod!

[zebulon]

Actualy working on the subject

 

In fact my exhaust is actually an empty box with only one way out, really bad for gaz flow, so i m about to modify the inside of the exhaust.

 

It ll be an inisde like Paul 's one or Dynotec Guzzila one.

[Paul Minnaert]

Mine was custom made, in a shop in the netherlands, www.startwin.com

It's now to the polisher, should shine before christmas:-)

[Guest captain nemo]

Ok, to continue my 'out of the box thinking' to our exhaust box here.......let me ask this:

 

Aside from decibels, what would be bad with simply taking off the mufflers and keeping the crossover with its short little exit pipes? I mean, we've all seen (and heard) all the Harley guys running their straight pipes. I had straight pipes on a Honda 90 when I was a kid. It was my 'mud bike' but it ran fine.

 

Theoretically, if I had a map made for crossover WITH NO CANS, I suspect that it would run fine, but very loudly. As far as I can see here, the Furia box is just a bigger box with maybe some tunneling for tuning the rpm response and maybe some sound damping. I suspect I could put some sort of 'glass pack' on the ends of my crossover. Maybe I could even find those old Supertrap mods to put on them so that I could play with and adjust the output. Like Jeb says, he is running an empty box. See????

 

I sure like the idea of dropping 30 lbs for the cans; and I like the clean look of NO CANS. Can anyone supply me with good reasons why my idea couldn't fly? I don't want to spend a thousand bucks on a can when I can fool around with what I have for free (maybe add Supertraps).

[Admin Jaap]

Can anyone supply me with good reasons why my idea couldn't fly?

Maybe the law suits from your neighbours?

[Paul Minnaert]

Why don't you try?

[dlaing]

You know it might just work. Just add a restrictor about the size of the stock mufflers out let, dyno-tune, and you may be good to go.

The stock crossover weighs a lot lesss than the Quat-D.

I have run my engine with just the crossover, and it sounds AWESOME except for the popping when you let off the throttle.

You might want to have the restrictor aim the air flow away from your legs.

I am liking this idea!

[dlaing]

As an experiment, buy a six pack of beer in cans.

You drink one and let Motomonster drink one.

Cut off the bottom of cans.

Drink more beer.

Clamp the beer cans to the ends of the crossover.

Fire up the engine.

Drink more beer.

Does it still sound good?

If yes, your problem is solved, just spray paint the beer cans, dynotune the bike, and you will be all set.

If no, try drinking Redbull, the stuff that gives you wings.

It is probably a better size, and it is safer to ride after a redbull than after a beer.

If the aesthetics bug you, atleast you know how big to make the restrictor opening.

I think anything bigger than an inch is gonna be too loud.

 

If you wanna go the glass pack route.

Take some aluminum perforated sheet metal available at the mega hardware store or the Home Heating and Air Conditioning Store,

bend it around the crossover end pipes and clamp it down so it forms a pipe, wrap it with fiberglass wool, and then get creative about how you wrap the wool.

You could use sheet metal or muffler tape, or just wire and aluminum foil and then carbon fiber with fiberglass resin.

But I still think you need a restrictor to give you some back pressure.

[Guest captain nemo]

David, Motomonster will not thank you for giving me more funny ideas. And especially combining the whole project with beer.

 

I have in fact decided to do it myself. And, I am already done. Yes, stay tuned for some new pics tomorrow of the 'Enter the Dragon Guzzi' with 'Bow Wow racing system.' Yep, I went back over to my favorite mod store - the VW Bow-Wow supply store and looked around for a solution to my problem. I FOUND IT!!

 

This involves two 6 inch chrome mini mufflers for dune buggies. With a little J & B 'welding' cement, they go right on my crossover and stick up like drag pipes, but shorter. Believe it or not, they exactly match the V engine configuration - thus "repeating a beautiful theme." It actually looks pretty good and really cleans up the tired looking back end. More sporty.

 

BEST OF ALL IS THE MOST KICK-ASS SOUND I'VE EVER HEARD ON A BIKE!! Yes, my friends let me explain it. It is NOT a straight pipe sound. These little pods are stuffed with baffles so they cut off that harsh 'call the police' NOISE. NO. It idles at a respectable volume. And, I found, it even cruises at a respectable volume. BUT, when you want to IMPRESS - such as engine braking or a hard throttle - IT IS FRICKING AWESOME! The overall tone at all times is even deeper if that is possible. It has a real authority to it, whereas before it was simply superior.

 

I only ran one pod and one regular Minstral when I went out for an experimental voyage, but I can clearly see and hear the difference. I wanted to see if it would run ok. More about this tomorrow when they are both on. For now all I can say is that it did not pop or backfire and seemed to run fine. I'm happy - and I saved $970 dollars. (pods were 30)

 

Oh - Zeb, I loved your movie. Too bad you can't really hear sound on the internet. Still, you are providing me with lots of inspiration.

[dlaing]

This time we want dyno results!!!

Careful though. If the bike runs too lean, you could burn valves.

[Guest captain nemo]

Mod update:

 

Last night I cemented the new 'bow-wow' pods directly onto my crossover. Today I painted one pipe and its pod WHITE. (I've always wanted white pipes for some reason, and now with this mod, it seems to work). THEN I WENT FOR A RIDE. - with both pods on now.

 

First, here are three pics of the job (seat is removed because it is under the Christmas tree - all done in leather with red stitch - haven't seen it yet):

 

pipe1

pipe2

pipe3

 

And now......the sound and ride report. My first impression on fire up was that it is not that loud at all - not much louder than stock. Good. In gear and on the gas it is a little meaner, but not annoying sounding. I noticed right off that it seems 'looser'. That is, the engine braking is not as 'tight' or quick. It seems to glide down now instead of jerk almost. It is also smoother all over the place - again, not so tight on the throttle response. I don't know if this is a good thing or not, but it smoothes out the ride. (Any comments on what you think is happening here?) The power seems about the same - perhaps it is not in as big a rush to rev, but it continues to make power all the way up - more linear. If it is making any more power it would be at the very top end. It did not pop or backfire and it idled normally when warm. It is odd to me that no matter what I do to this Guzz it keeps running fine.....

 

I'll have a look at my plugs after some more outings, and, I'll go back to Moto for a new tune and see what that does. The white paint is good for 1200 degrees, but I noticed it wants to start turning brown on me. I either need more coats of paint, a different brand, or to keep a can handy for touch up. Does anyone know about this? Can you keep pipes white?

 

Anyway, I'm happy with the results. I think it looks a bit 'trickier.' And it sure sounds better. My 15-year-old son thinks the white side is better than the other side. That's always good to hear what he thinks.

 

Don't worry, be happy.