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Unpacking the cans... don't bother-

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snip... the end of the perforated pipe is neither open nor perf'd.; it's a blank end! Ergo outflow thru this pipe is reduced to perhaps 1/2 of its "normal" flow capacity...

 

42722[/snapback]

Thanks Skeeve! AWESOME post!

Do you think just cutting off the perforated pipe in the first chamber would reduce back pressure? If what you said above is true, that is the biggest bottleneck.

Or just cutting out the final exhaust pipe in the third chamber would allow for a shorter, less restrictive path.

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Or how about this, assuming you have not cut open the muffler yet, you could take a half inch drill(neon laser drill not yet available to the public) and drill through like so, and then you could just seal your holes with muffler tape slide the cover back on and 100 HP awaits!lafranconi3rddrill.jpg

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Or how about this, assuming you have not cut open the muffler yet, you could take a half inch drill(neon laser drill not yet available to the public) and drill through like so, and then you could just seal your holes with muffler tape slide the cover back on  and 100 HP awaits!lafranconi3rddrill.jpg

42737[/snapback]

 

:bbblll:

If you're going to that extent to make noise, it's much easier & efficient to just pull off the beauty cover endcap, use a holesaw on the interior endcap and pull out all the stuffing. About the same effect, 100+ dB :vomit: with much less restriction...

 

Sorry if I misconstrue your post as sarcasm: I tried to propose some changes that would be liveable while providing increased performance. Since the internal structure is now available for anyone to view, any V11 owner can use the info to examine their options & make their own decisions. My decision goes something along these lines: since I don't ride my Bike exclusively on a track or other private property/roads, and I do value my own hearing, the tranquility of my neighbors & fellow roadgoers, and try to keep money in my own pocket by not incurring the wrath of the rolling tax collectors [aka "police"], I'll forego making my pipes unnecessarily noisy, [Elvis] thankyewverramuuuuchmamabaybuh! [/Elvis]

 

OTOH, by targeting the neon laser drill method you suggest on chamber 2, it might prove liveable. Hard to say: ya pays yer money & ya takes yer chances!

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Thanks Skeeve! AWESOME post!

Do you think just cutting off the perforated pipe in the first chamber would reduce back pressure? If what you said above is true, that is the biggest bottleneck.

Or just cutting out the final exhaust pipe in the third chamber would allow for a shorter, less restrictive path.

42732[/snapback]

 

Yes, I do think cutting off the perf'd. section would provide a substantial increase in flow (& hence, reduced backpressure.) It also would have virtually no impact on noise signature. :) This coupled with judicious drilling into the internal endcap so as to maximize functionality of the steel wool in chamber 4 is what I intend to do when I "zip up" the pipes I sectioned for these photos.

 

As for cutting out a section of the exhaust pipe in chamber 3, see my previous response to your second post on that topic with the pictures...

 

[ :doh: Don't you hate it when you reply to a later post first? Oy! :o]

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Skeeve,

a truly excellent and informative presentation. From myself and i'm sure many other members, many thanks for your time, effort and information.

 

Auldy

 

:bier:

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:bbblll:

Sorry if I misconstrue your post as sarcasm:

42784[/snapback]

No sarcasm intended. The only attempt at humor was aimed at the result of my photoshop interpretation of drill bits. I truly appreciate a good hack job!

And your documentation was excellent.

Other great muffler hack jobs were done by Frank, and Enzo, and I forget his name, begins with S? who shortened his stock muffler.

I too, am after increased flow without excessive noise. So, drilling or otherwise opening up the exit pipe sounds like a good way to get just a little more flow without a great increase in noise.

I want to keep the packing in as it seems to be killing the most decibels while not greatly reducing flow.

I also want to fit the mufflers under the gearbox and that poses a greater challenge.

I like your idea to copy the design with wider diameter piping.

I wish I had welding skills.

The other alternative of replaing the core with a steel wool and glass packed core might be fairly simple and could be done with rivets and wire.

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...[snip]

I also want to fit the mufflers under the gearbox and that poses a greater challenge.

I like your idea to copy the design with wider diameter piping.

I wish I had welding skills.

The other alternative of replaing the core with a steel wool and glass packed core might be fairly simple and could be done with rivets and wire.

42875[/snapback]

 

For fitting the muffs under the tranny: better to find a glasspak car muffler that can be modified. Same thing goes for the core of the stockers, if there's anything out there that has a 2" inlet & appropriately sized oval body. Cherry Bombs [glasspaks] have been around since the 60s & probably have something that would fit one of these applications... :whistle:

 

I wish I had the time to have the welding skilz that I might if I only spent more time welding... ;)

 

WRT replacing the core w/ steel wool & 'glas via rivets & wire: Hmmm. I'm thinking at this rate that it'd be quicker just to fab something from scratch (that would fit into the stock envelope) out of mild steel and paint the heck out of the thing w/ BBQ paint before buttoning it up. Yes, it would rust out in 6 years or so. So what? You'll have the stock core to put back in while you fab up another, or you'll have had the time to save up for a "proper" hi-perf can! :thumbsup:

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Something like this, but shorter, and packable.

Dynomax from summitracing.com

wlk-17231.jpg

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Something like this, but shorter, and packable.

Dynomax from summitracing.com

wlk-17231.jpg

42922[/snapback]

 

Hard to get an idea of the scale, but I suppose if those fittings are 3" car size, it would be a bit big for tucking under the tranny cross-ways... But yes, something along those lines would be what I had in mind.

;)

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Hard to get an idea of the scale, but I suppose if those fittings are 3" car size, it would be a bit big for tucking under the tranny cross-ways... But yes, something along those lines would be what I had in mind.

;)

42976[/snapback]

They would be a VERY tight fit.

If anyone finds something like this, but a little smaller, let us know!

Ideally something allowing more ground clearance and a couple inches shorter in case length.

Here are the specs:

Price $90 (a little cheaper than a QuatD, but maybe not after the labor...)

Muffler, Ultra Flo Welded, Dual 2 1/2 in. Inlet/Dual 2 1/2 in. Outlet, Aluminized Steel, Each

Product Line Dynomax Ultra Flo Mufflers

Universal Yes

Case Shape Oval

Inlet Diameter (in) 2.500

Inlet Quantity Dual

Inlet Location Center

Outlet Diameter (in) 2.500

Outlet Quantity Dual

Outlet Location Center

Internal Construction Glass-wrap perforated tube

Muffler Material Steel

Muffler Finish Aluminized

Case Length (in) 14.000

Overall Length (in) 19.000

Thickness (in) 4.500

Width (in) 9.750

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Guest clymehighercolorado

Did you ever get a response back on this? I would like to do this to my V11 Sport too, but I don't have the money to do a new power commander, air intake, etc.

 

Please let me know what you found out.

 

Thank you,

 

Gerritt@gerrittkaufman.com

 

Hey, nice work.

I am interested, do you hawe to make adjustmens on the fuel intake, the electric system, or do you just drive along.

I am going to strip the ROSSO MANDELLO one of these days

regards :mg:

27350[/snapback]

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I feel that the stock ones sound the best

64099[/snapback]

 

The stock ones are pretty darn quiet, which I don't mind, but their BIG drawback is they strangle the motor w/ too much backpressure at high rpm. [Guzzi high rpm, not J-brand high! ;) ]

 

The car aftermarket scene has gone to very efficient hi-flow mufflers that if one could be found that fit inside the stock beauty covers, would be a great alternative to the stock cans. Plan B would be to go for a box muffler like the DynoMax illustrated above to replace the Guzzi factory "premuffler" collector box & cans, a la' the Quat D.

 

Plan B has the nice advantage of the whole mass centralization thing, along with eliminating the need for passengers to sit w/ their knees up under their chin due to high footpegs brought on by the desire for adequate ground clearance, so let's move it into Plan A's slot & vice versa. I'm more interested in going with the replacement cores inside the stock beauty covers, simply because I dislike the looks of the colostomy bag muffler tucked up under the bike, but that's a personal choice issue.

 

None of that is as pertinent as the simple pursuit of a cost-effective muffler that balances the desire for less backpressure with reasonable noise control, & oh yes, lighter than the stock cans would be a nice bonus! :grin:

 

Unfortunately, the MG Ti exhaust system is outrageously expensive, as are pretty much all of the aftermarket options due to the low production volume of Moto Guzzis.

 

Que sera sera!

:mg:

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Hello you all :luigi:

 

A short introduction of myself:

I am a 47 years old guzzist from Austria and I own 3 Guzzis: A V7Sport 73, LM2 80 and a 2000 V11 which I bought new 3 years ago.

 

I am happy to discover this thread on a subject in that I investigated.

I want to describe my modifications on the original exhaust cans of my V11. The result of my modifications was 3 HP more on the dyno in the higher rpms with an exhaust note almost stock.

My mods: The idea was to let the gassses pass the muffler without changing the direction. Originally, the gas enters through to to chamber 3, turns back to 2, 1 and back out via the very long end tube.

In the first chamber I cut' out 50 mm from the tube which enters from the collector. (On the mufflers I modified, there was the catalytic converter in that place).

The 2nd chamber remained untouched.

In the 3rd chamber I cut' out 50 mm from the upper tube which goes out.

The 4th chamber with the steel wool remained untouched too.

So the exhaust gas flow finds an open end in chamber 1, passes to chamber 2, 3 and can leave from there via the much shorter end tube. No change in direction.

Additionnally I fitted the mufflers tighter to the bike and twisted them slightly upwards on the front end to increase the cornering clearace.

I performed these mods during last winter. It was a very sweaty job, but I think the results are worth the effort. Unfortunately I have no pictures about this.

 

My next step would be to eliminate the wall between 1st and 2nd chamber (drilling out the welding spots). The wall between chamber 2 and 3 has no spot welding. I leave approx. 50 mm of the tubes on both sides of that chamber wall. This will be welded into the can to divide the volume in now only two chambers of similar volumes. Chamber 4 remains untouched again.

So the gasses enter chamber 1, pass via 4 tubes into chamber 2 and leave from there through the end tube. The gas flow passes now 2 chambers of a bigger volume and have more room to move. The backpressure will further decrease, the power will (hopefully) make another step upwards and the noise level will slightly increase. I intend to perform this during this winter.

I hope my descriptions are clear, the pictures on the previous posts should help that.

Attached is the power graph: completely stock, slight modifications on engine with CR +0,5, like above with my modified mufflers.

 

All these modifications leave the mufflers completely stock from outside with all the informations the police likes to read on a muffler. Also the noise does not get too loud. And I like quiet mufflers. If you perform a long ride on the bike, you enjoy that smooth sound at the end of the day.

 

Have a good day

Ernst

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Excellent!

I was hoping somebody would be able to get power improvements with a modest sound gain.

I wish you had taken pictures, but the dyno graph looks excellent! :bier:

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