Two to one V11 exhaust?

[GuzziMoto]

 

 

Performance will suffer and noise will be obnoxious OR performance will REALLY suffer and noise will be high.Take your pick.

There's a reason large capacity twins generally have twin mufflers. See if you can guess why.

Ciao

What?

Guzzi sells plenty of big twins with two into one ppipes stock. So do other brands like Aprilia, Suzuki, Honda, Yamaha, etc..

The main reason for two into two exhausts is looks.Being a two into one system does not automatically make it louder than a two into two. It can be louder, but it can be quieter. My Griso with the stock two into two into one pipe is as quiet as the wifes V11 with the stock pipe. My Griso with the two into one aftermarket pipe and the db killer I put in is quieter than either the wifes V11 or my Daytona, both with aftermarket two into two set ups.

You may find that with a large open muffler it is too loud, but you could also restrict that large open baffle with a DB killer if required to quiet it down. It comes down to tastes.

Correct answer.....Unless you want a pig ugly exhaust and muffler system then to get the performance and keep the sound legal you need a 2 into 2.

The Griso is a good example of what I'm talking about,ugly as sin, and although I haven't been inside one its debatable whether its a single muffler or a siamesed unit, what with its twin outlets and all.Wont even bother with the Suzuki twin range and their attractive twin cylinder range muffler....not.

You simply cant keep the noise reasonable and the performance good with a muffler as pictured in the original post.

Ducati tried the single muffler design with their 999 years ago and to get the performance they had to resort to an ugly box.

Do you really think that simply adding a DB killer to your single aftermarket muffler doesn't destroy any perceived performance gains you may or may not have got?

If it was that easy we wouldn't have the giant ugly boxes we all have to put up with stock. 

Ciao 

 

I don't really think my stock Griso muffler was that ugly, but to each their own.

Again, many past and current big twins run a two into one muffler. The wifes Ducati Monster has one, My buddies Aprilia RSV has one, my Griso, the Buell X1 Lightening I used to have, my Honda CTX, the list goes on and on.

 

As to the DB killer in my Griso, it has been dyno'd and runs great. It does make slightly more power without the DB killer, but the difference is tiny. And even WITHOUT the DB killer in place it is only a little louder than the wifes twin muffler V11, in spite of the noticably larger diameter of the baffle tube.

My old Ducati racebikes had two into one systems and just the sound reducing effect of the two into one collector was the only sound reducing we used. And when questioned, we proved via demonstration that the collector reduced the volume of the sound.

[footgoose]

Dr John liked 2-1, at least some of the time.

If they ever photographed the other side of this beauty, I can't find it.... It looks like it terminates under the tranny.

 

 

 

same with this one...

 

 

 

 the MGS-01

 

[toofat2fly]

The 4 HP I'm going to loose or gain is not overly important in my life, more specifically on a 500+ lbs bike.

Just curious if any one of you knew anything about this exhaust, looks like Don G got the raisin pie.

 

I'll slap the silly coffee can on and see what happens. Don't worry, I'll let you guys know if it was a disaster or not.

Anyway...... you'll hear me coming.

[docc]

 

If they ever photographed the other side of this beauty, I can't find it.... It looks like it terminates under the tranny.

 

 

 

 

 

Interesting question . . . I can't find a photo of this Dr. John LeMans from the left side anywhere . . .

[kglm]

bad quality pic ,-from mc magazine page

 

-KG-

[Tom M]

Here's a little video that shows both sides of the Dr John bike.  It sounds great too!

 

https://www.youtube.com/watch?v=tdLHhx7ltP0#t=50.327687

[GuzziMoto]

Every Moto Guzzi racebike I have raced against has had a two into one pipe. I am sure there are people running two into two pipes on their Guzzi racebikes, but the fastest ones I have ran against, like the Raceco Guzzi of Pete Johnson and Manfred Hecht, ran a two into one pipe.

Stock mufflers work primarily by volume, so building a single muffler means it has to be larger than one of the mufflers in a two into two set up. Often it is basically the same size as the two mufflers put together from a two into two set up. Although, sometimes it is not rally much larger. But an aftermarket muffler works differently, and does not really need to be much, if any, larger than one of the two mufflers of a two into two set up to get the same results. One aspect that plays a factor in this is flow. People tend to assume that exhaust gas flow is a steady stream coming out of a motor. But it is clearly not. It is not steady, nor is it always in one direction. Since on a twin like our Guzzi's the two cylinders are never exhausting at the same time you can use that to your advantage when you build a two into one set up. Buell was incredibly good at that, their stock mufflers worked very well.

If you don't like two into one set ups, that is fine. Don't. My wife, as mentioned prefers two into two pipes. But she did not let that stop her from buying a Ducati with a stock two into one pipe. 

 

And Christ, that Guzzi in the video link sounds awesome. Brings back memories....

[Don G]

Bring on that pie! I have one similar on my Cafe Sport, different muffler. I run it with out the DB killer, sounds good, dont know if it affected HP or not, give it a try whats to loose? DonG

[Lucky Phil]

The OP put up a photo of a 2 into 1 exhaust system for his ROAD bike and my comments still stand. You can guarantee 99% that the pictured setup bolted on will have less performance than the stock setup and 100% guarantee it will be obnoxiously loud.

The only solution then in keeping the muffler the same, is that you do some DB killer mod and then you can still guarantee that it will be loud and performance will once again be worse than stock.

The only way to keep a road bike legal/quiet is to have the the muffler volume to attenuate the sound. Different configurations of the same capacity require different muffler solutions in detail.

This thread has now gone down the path of race bikes and their requirements which, although the basics are broadly the same don't have the same considerations with regard to attenuation. IE they can be louder.

So my factory Ducati TT2 from the early 80's had a 2 into 1 reverse cone megaphone without baffles as did the same bike we used at the IOM in 86. There were NO noise restrictions at the time that we had a problem with.

As for the anecdotes about the performance of your bike and how loud it is ...well, we could all go on forever without empirical evidence but the fact remains the OP system shown simply doesn't have the required muffler volume to support a performance increase and a decent/legal level of sound attenuation and any attempt to keep the same appearance and quieten it down will fail on either count and almost certainly both.

As for the advantages of attenuating a twin over any other design of the same capacity, well the advantage you mention is overwhelmed by the fact that for a given capacity the twin creates a gas pulse of twice the volume for the system to deal with and at a lower frequency. The lower frequency is much harder to deal with than what an inline 4 produces and I think its quite well know that a twin for the same capacity is more difficult to attenuate than a 4. Look at the muffler volume required on say a WSB1198 compared to a Honda at the time.The Ducati required much greater muffler volume ( whether it was twin can or the 999 box) to stay within the noise requirements.

My V11 has to date had 5 different muffler configurations and 2 crossover. The only performance difference was with the new crossover which improved the mid range hole. The different mufflers are purely a personal preference but all gave similar levels attenuation but quite different sounds.  

Ciao

           
 

[GuzziMoto]

The OP put up a photo of a 2 into 1 exhaust system for his ROAD bike and my comments still stand. You can guarantee 99% that the pictured setup bolted on will have less performance than the stock setup and 100% guarantee it will be obnoxiously loud.

The only solution then in keeping the muffler the same, is that you do some DB killer mod and then you can still guarantee that it will be loud and performance will once again be worse than stock.

The only way to keep a road bike legal/quiet is to have the the muffler volume to attenuate the sound. Different configurations of the same capacity require different muffler solutions in detail.

This thread has now gone down the path of race bikes and their requirements which, although the basics are broadly the same don't have the same considerations with regard to attenuation. IE they can be louder.

So my factory Ducati TT2 from the early 80's had a 2 into 1 reverse cone megaphone without baffles as did the same bike we used at the IOM in 86. There were NO noise restrictions at the time that we had a problem with.

As for the anecdotes about the performance of your bike and how loud it is ...well, we could all go on forever without empirical evidence but the fact remains the OP system shown simply doesn't have the required muffler volume to support a performance increase and a decent/legal level of sound attenuation and any attempt to keep the same appearance and quieten it down will fail on either count and almost certainly both.

As for the advantages of attenuating a twin over any other design of the same capacity, well the advantage you mention is overwhelmed by the fact that for a given capacity the twin creates a gas pulse of twice the volume for the system to deal with and at a lower frequency. The lower frequency is much harder to deal with than what an inline 4 produces and I think its quite well know that a twin for the same capacity is more difficult to attenuate than a 4. Look at the muffler volume required on say a WSB1198 compared to a Honda at the time.The Ducati required much greater muffler volume ( whether it was twin can or the 999 box) to stay within the noise requirements.

My V11 has to date had 5 different muffler configurations and 2 crossover. The only performance difference was with the new crossover which improved the mid range hole. The different mufflers are purely a personal preference but all gave similar levels attenuation but quite different sounds.  

Ciao

           

 

Well, I can respect your conviction in what you believe, but I have to disagree with your opinion.

I am sorry that bringing up racebikes and their exhaust systems has confused you or made you feel this was off topic. In the end, comparing a two into one and a two into two racebike is about the same as comparing a two into one and a two into two street bike. But if you feel that is not relevant, we can stick to street bikes. I have already listed a direct comparison between two Moto Guzzi of the same displacement. This is not opinion, this is two 1100cc Moto Guzzi's. One has a two into two system using aftermarket Mistral mufflers, the other has an aftermarket two into one set up. They are both of comparable loudness, and power is within a couple hp between them, as tested on a dyno. The two into one pipe does have a considerably larger baffle tube, and if you looked at it you would think it would be substantially louder than the other system. But, likely due to the sound reducing properties of the collector, it is not much louder at all. And with a honey-comb type db killer it is actually quieter with no real loss of power. In fact, the two into one system makes more mid-range than the two into two system.

Again, if two into one systems are so bad on big twins, why are so many manufacturers switching to them?

I am curious to see how the system works out for the OP. I doubt it will be a reduction in power from the stock system, but it is possible that it may need some fueling tweaking to get it right. It may be too loud for his tastes, noise levels are a matter of personal taste. But the notion that the exhaust in question doesn't work and can't be made to work is laughable. 

[Scud]

Too bad Australia and South Baltimore are so far apart... or we all get together for an exhaust-swap. sound meter, and dyno-run party.

 

I saw what appeared to be the same exhaust on a 2000 V11 Sport for sale on Craigslist recently - so the OP is not alone in running this system. When I first saw it, I assumed it was a custom job, but seeing this thread, I realize it must have been commercially available.

 

TooFat - will you be ending the suspense this weekend for us? As for data - how about the number of car alarms that go off in a crowded parking lot or structure?  My Scura with stock exhaust sets off zero. My LeMans with sawed-off Titanium cans sets of several.

[GuzziMoto]

None of mine set off any car alarms. I like louder than stock, but not so loud I annoy people. I hate the stupid "loud pipes save lives" bullshit.

[toofat2fly]

I will be taking the mistrals and exhaust off this weekend, dissolving the butt ugly chickenpox paint from the motor block and reprinting it with Harley engine paint. If it dries fast enough, I'll put the shiny coffee can on. I wish there was a dyno closeby, so I could do before and after charts.

Bike gas been tuned at Fast by Ferracci and it runs really strong. Dyno would be nice to solve the discussion about loss of power or not. I'll let you guys know...

[Scud]

None of mine set off any car alarms. I like louder than stock, but not so loud I annoy people. I hate the stupid "loud pipes save lives" bullshit.

 

I hate that too. And I was surprised when my LeMans set off the alarms (FYI, it was when riding very close to some parked cars). They're not obnoxiously loud, but they do have a palpable pulse - I can feel it when I start it up in the garage. 

[sp838]

That is indeed a GPR. I have one, it is very loud w/o the baffle. Performance will suffer with the baffle. It will improve without it. I had mine tuned on a dyno by a very reputable racebike builder. Net gain was about 3 HP, and the system is pounds lighter than stock, and looks way better. A definite win if you don't care about the noise. And Lucky Phil is a troll who shouldn't be fed.