S2R front pipes

[Drumnagorrach]

Starting to get a bit of a bee in my bonnet re the Termi front pipes . Not only do they seem to me to have the wrong pipe rotation between bends ,causing the pipes up behind the footrest to stick out ,but the front pipe is a whole lot longer than the rear and the whole lot reduces in dia where the pipes up from the footrests join and then increases to original .
None of which in my humble opinion is right . I spent a few years in my twenties in the R&D of an exhaust manufacturer making and testing prototype exhausts ,mostly for cars,but the principles are the same .
So, do termi pipes really make a difference to power output ?
And ,what is the exhaust cam timing for my S2R , I can work out the exhaust pipe lengths approximately from a formula primary length = 5100x ET over
RPM x 6 . They are just a few constants that seem to work ( not mine ,originally by David Vizard )
The arrow pipes look better ,and their excellent website claims 1 bhp gain ,couldn't find anything on the termi site ,they only seem interested in new Ducati models .

[Funkatronic]

what mid pipe do you have? or do you still have the cat?

[Darren69]

There's a genuine DP de-cat on ebay atm

http://www.ebay.co.uk/itm/Ducati-Monster-S2r-De-cat-Exhaust-1000cc-Genuine-Part/201495822435?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1% 26asc%3D20131017132637%26meid%3D5e7ae494d0c64756be 4db589c9e56755%26pid%3D100033%26rk%3D2%26rkt%3D4%2 6sd%3D401049693791

[Drumnagorrach]

The bike came with the system ,I don't have the original.I i assume that it is a full termi system due to the cans ,but who knows ?

[Albie]

The bike came with the system ,I don't have the original.I i assume that it is a full termi system due to the cans ,but who knows ?

Termi follow their own rules. Some are poorly welded. Some are twisted. Some are perfect. Make good make bad. It's a lottery. Have to say I wasn't going to buy for the Scrambler but I got cheaper from Germany and was a good finish but it seems they designed the brackets wrong at source. Some have had the internals fall off and rattle around inside.

[Mr Gazza]

Please forgive slight hijack Drum', but seeing that you might have some more informed knowledge of exhausts has prompted me to ask a question that I have been wondering how to ask.

I have cored Ducati silencers from a 750 on my 900. They are loudish without being particulaly tuneful. They just have the last chamber opened.

I crave the proper Ducati boom but I'm not that bothered about high volume.
So I'm going for absorbtion type silencers.

The question is about the inner perforated tube diameter....Would it be the case that a larger diameter inner tube would allow the gasses to slow down and emit a deeper (lower) note, and that a smaller diameter would cause a faster gas speed and higher (tinnier) note?

I want to go for a 60mm ID, but I am a little concerned that a big diameter will reduce back pressure, and probably not silence so well as the gas would have an easy path through the silencer without the need to enter the wadding.
I am thinking that, say 50mm would be a bit more resistive and help the gas (or perhaps I should say the shock waves?) into the wadding?

I'm also contemplating a baffle about half way down the tube, in the form of a perforated disc or wedge...Or flattening the tube to a slight oval at about the mid point...What do you think of that?

Out of curiosity what is the length and ID of the Termis? They sound alright don't they..:mand:

[squarehead]

Arrows ooze quality and the noise is good. Very good. Then I opened the airbox, and recently the baffles have come out. Liz. :thumbsup: The 'proper Ducati boom' ensued.

I got lucky and picked up a set here second hand, no complaints about fitting, even I got them on ok.

[Drumnagorrach]

I will e mail an explanation of "sound attenuation " Gazza

[utopia]

I held (well Capo did .. I was on the throttle) two perforated kitchen sink strainers over the ends of my hi-level termi cans (without baffles).
It quietened them by a useful amount but I was surprised how much "tinnier" they made the exhaust note.
My conclusion was that big bore, free flowing cans = more bass boom.

Sorry to continue the hijack.
Actually, I wouldn't mind a dedicated thread on this since I'm about to mod a 2-1 hi-level, big bore Sil system to fit the 750.
Or continue here even, if the semi-hijack is ok .... ?
My new system must be pretty similar to a decat S2 system, I would have thought.

[Drumnagorrach]

You can't go wrong with straight through glass packs , they don't need to be very big bore , just plenty of E glass to absorb the nasty sharpness leaving the lovely deepness . The energy of the higher notes are more readily absorbed by moving the strands of glass wool .
I to am looking to make a 2into 1 ,can't see the point of two silencers up the offside , So very interested in your "hijack " carry on Jeff.

[Drumnagorrach]

There's a genuine DP de-cat on ebay atm

http://www.ebay.co.uk/itm/Ducati-Monster-S2r-De-cat-Exhaust-1000cc-Genuine-Part/201495822435?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1% 26asc%3D20131017132637%26meid%3D5e7ae494d0c64756be 4db589c9e56755%26pid%3D100033%26rk%3D2%26rkt%3D4%2 6sd%3D401049693791

That's exactly the same as mine .

[uncle duke]

Just seen them on fleabay can some one tell me whats that 'extra' pipe coming off the pipe (pic 3 i think) is it a link pipe to the other down pipe so they are joined ??? i see it has a place for the o2 sensor so would it run ok with standard ecu or would a dp one be needed ???
thanks
roger

[Drumnagorrach]

Just seen them on fleabay can some one tell me whats that 'extra' pipe coming off the pipe (pic 3 i think) is it a link pipe to the other down pipe so they are joined ??? i see it has a place for the o2 sensor so would it run ok with standard ecu or would a dp one be needed ???
thanks
roger

Yes that is the link pipe , my bike has the O2 sensor blanked off and I believe the ecu has been re flashed ,because there is no Lambda warning on my clocks but I believe that the bike will run o.k. with the O2 sensor on and the cat off without a reflash .But if it does, it only cost £128 at Avanti racing to get a DP program loaded to your ecu .

[Mr Gazza]

I will e mail an explanation of "sound attenuation " Gazza

Drum'. I just read your email....Thank you, it's fantastic...We should post it up here.

[utopia]

And/or send me a copy too, please ?

I can't see the point of carrying two cans around either.
Though each cylinder exhausts through both cans, so I guess the silencing capacity is reduced with just a single can ... but we don't care much about that, eh ?
So I decided to build a system myself.
I did some rudimentary calcs for length using formulae from a Piper tuning manual that I picked up at the 1974 London bike show.
My conclusion was that the ideal length for max torque was quite a bit longer than could actually be fitted on the bike, so basically the longer the better ... this was the first design criterion, and tied in with my observations of better bottom end response when I fitted the hi-level termis and extension pipes that I'm currently running.
The second design criterion was to equalise the primary lengths (to the first restriction) as they are miles different in the std headers and like Drum, this just seemed quite obviously wrong to me.
I also decided to make the secondary length equal to the primary length, ie from the first restriction (crucifix in the std headers) to the outlet from the can.
And to eliminate the restrictive crucifix, replacing it with a 2-1 collector.

I began by using the longer of two std S4R hi-level link pipes, running from a proprietary Y-piece collector.
I then cut up two std header units to provide the required bends and bits to be able to weld it all back together and end up with equal length primary pipes.
Its now ready for welding.
But then .....

I came across this Sil-moto, big bore system which did a very similar job to my own design.
It wasn't quite so theoretically perfect, but it was a bit better packaged and fitted the bike more neatly, as well as being bigger bore ... though I wasn't sure whether this latter was a good idea or not.
It needed shortening to fit my bike though and I fancy I can blend the std dia headers into the bigger bore of the Sil system as part of that process, ending with effectively slightly tapering primary pipes ... but I'm not sure technically whether this will be beneficial or not.

The Sil system was cheap, cheap, but its been crashed and, while its still straight it does bear some very deep rash on the lower header and some serious dents in the same area.
But I reckon most of this will be cut out when I shorten it and adapt it to my header dia anyway.
Also the carbon can has been chopped (badly) and really only provides the end caps for me to build a new can ... but that's ok as its easy enough to do and I can mess with lengths etc and maybe seriously minimise its weight too.
£65, I paid.
I thought I had a pic but can't find it.
Will post one up when I can get hold of one.

That's where I've got to so far, and now is the time scheduled for finishing it off.
I might even finish my first design one day and compare the two.
But in fact, my gut feeling is that as long as the system design is fairly reasonable from a functional point of view, the neatness of packaging/fitting on the bike becomes perhaps more important than slavishly following best functional design practice to the Nth degree ... and the Sil system scores more highly there than my own design.

And after all that I found that Max (Desmoperformance Parts) sells a nice looking, hi-level, 2-1 system (plug) but I'm committed now.

I'm on the lookout for a supplier of titanium, perforated tube for my new can.
I'm told this is a forlorn quest, but if anyone knows different please let me know.
Failing that I might have a go at punching holes in some flat, Ti plate and getting it welded into a tube (....if you're reading this, Oz ;))

Sorry that's very wordy and no pics.
Here's one from the early days, just to brighten up the post ....

http://i1326.photobucket.com/albums/u644/photopia132/GetAttachment13_zps02a7c95b.jpg (http://s1326.photobucket.com/user/photopia132/media/GetAttachment13_zps02a7c95b.jpg.html)

[DrD]

I will not pretend I understand BUT my Aprilia (another big displacement Vtwin) has a Aprilia "racing" Exhaust on it developed for Aprilia SBK (in effecta shotgun exhaust). It has a 2-1-2 exhaust and supposedly improved torque and bhp over an earlier 2-1-1 Racing Exhaust used by Aprilia. With a modified link pipe you really notice the difference in sound and "urge" (this is my seat of the pants smile factor!)

[slob]

...what is the exhaust cam timing for my S2R...

S2r1000 MY06
http://www.thelasturl.net/img/S2R1000_06_Valves.jpg

...I can work out the exhaust pipe lengths approximately from a formula primary length = 5100x ET over RPM x 6...

ET?
how does the formula compensate for pipe diameter?
I've clearly got some reading to do

[Darkness]

I do like the elegance of a well proportioned 2 to 1 pipe that gives sufficient gas flow capacity with minimised weight and clutter, so photo's please.


I'm on the lookout for a supplier of titanium, perforated tube for my new can.
I'm told this is a forlorn quest, but if anyone knows different please let me know.
Failing that I might have a go at punching holes in some flat, Ti plate and getting it welded into a tube.....

I would question the need for TI perforated tube for the silencer core though as the weight saving compared with aluminium would be minimal given the small area needed for a single can, half of which would be "holes" in any case?
If you are relying on an interference fit into the can to stop the core rattling, that would also better suit aluminium.
A downside to aluminium would be corrosion, but it's a lot easier to work, especially during the development/trial phase.
Corrosion wouldn't be too big a problem provided it's cheaply and easily replaceable when you go back in to re-pack the cans.
For weight saving, I would concentrate on the gauge of the headers and link pipes, plus the silencer outer sleeve and fixings as that's where the bulk of the weight will be, and because of that, the greatest potential for weight saving.

To put it simply: half of sod all is a lot less than 5% of a big number.

Please keep posting on the developments as it's an interesting evolution.

[slob]

just use stainless for that bit, as you say it's nearly half air anyway

[utopia]

Yeah, its just that if I'm making the can myself, then that's one area where I have all options open and it seems a shame not to get serious about keeping the weight to a minimum.
The rest of the system is pretty much there already, so pipe gauges are already fixed with no scope for lightening ... which is fine as its pretty light/thin stainless anyway.

Here's an elementary mistake though .... I simply hadn't considered aluminium as an option !
In my mind it was simply stainless or titanium for the inner tube and titanium or carbon for the sleeve.
And every bit of your reasoning, Darkness, makes perfect sense.
Corrosion might not be too much of an issue cos the can sits high and dry, but I would happily consider the core tube to be a consumable item along with the packing, every few years, so corrosion wouldn't matter much anyway.
AND its a tad lighter too, presumably .... well you've got to get it while you can, eh ? (dreadful pun !)
And, by definition, this can's weight sits up high, where its always good to lighten.
Anyone know of a vendor of said holey ally tube ?

Smashing !

[Mr Gazza]

PM me your email Utopia, and I will forward Drum's email.

I ordered my perforated tube yesterday, in 316 Stainless. I'll wiegh it for you when it comes.

Make a very special note of this... http://stores.ebay.co.uk/Every-Exhaust-Part-Limited?_trksid=p2047675.l2563

To find perforated tube, click on tube, then click on your required diameter when the sizes drop down. Then scroll through all the solid tubes to get to the perforated ones.

Also check out the mandrel bends...and any other stuff you need to make exhaust systems....Good shop..:thumbsup:

[Drumnagorrach]

S2r1000 MY06
http://www.thelasturl.net/img/S2R1000_06_Valves.jpg



ET?
how does the formula compensate for pipe diameter?
I've clearly got some reading to do

Thats great thanks . pipe dia is worked out from volume, primary pipe should contain twice the swept volume . So 500cc per cylinder x2 = 1000 cc .divide by 16.4 to bring it to cubic inches - divide by calculated length ( in inches ) . divide by 3.142- find square root -multiply by 2 thats the i/d . If it's very contorted give it 10% extra . All this is theory ,but you will be surprised by how small the pipe dia is. when Triumph was developing their 500 cc twin to beat Harley at Daytona , they gained a lot of power by using smaller dia down pipes than the early pre unit motors , just have a look at the tiny down pipes on a 1970's Daytona. Works out at 704 mm long x 43 mm i/d roughly

Squarehead . Could you measure the pipes on your Arrow system ? I'll bet they aren't far off ,
Oh B.T.W. primary length is from the valve ,so knock off the length of the exhaust port .

[Drumnagorrach]

PM me your email Utopia, and I will forward Drum's email.

I ordered my perforated tube yesterday, in 316 Stainless. I'll wiegh it for you when it comes.

Make a very special note of this... http://stores.ebay.co.uk/Every-Exhaust-Part-Limited?_trksid=p2047675.l2563

To find perforated tube, click on tube, then click on your required diameter when the sizes drop down. Then scroll through all the solid tubes to get to the perforated ones.

Also check out the mandrel bends...and any other stuff you need to make exhaust systems....Good shop..:thumbsup:

Had a look at the Bends Gazza , they look like the bends we use at work for the distillery pipes , only down side is the 2mm wall thickness ,makes em a bit heavy , but nice and easy to weld .

[Drumnagorrach]

Yeah, its just that if I'm making the can myself, then that's one area where I have all options open and it seems a shame not to get serious about keeping the weight to a minimum.
The rest of the system is pretty much there already, so pipe gauges are already fixed with no scope for lightening ... which is fine as its pretty light/thin stainless anyway.

Here's an elementary mistake though .... I simply hadn't considered aluminium as an option !
In my mind it was simply stainless or titanium for the inner tube and titanium or carbon for the sleeve.
And every bit of your reasoning, Darkness, makes perfect sense.
Corrosion might not be too much of an issue cos the can sits high and dry, but I would happily consider the core tube to be a consumable item along with the packing, every few years, so corrosion wouldn't matter much anyway.
AND its a tad lighter too, presumably .... well you've got to get it while you can, eh ? (dreadful pun !)
And, by definition, this can's weight sits up high, where its always good to lighten.
Anyone know of a vendor of said holey ally tube ?

Smashing !

Interested to see if the shock waves work harden the alloy . It's all suck it and see , you would be surprised at the attitude I saw back in the seventies by development engineers at both ford and lotus re design faults that clearly weren't right but were going into production anyway because the time allocated to get it right had been used up. You don't have that time constraint .

[Mr Gazza]

The Every Exhaust Part mandrel bends seem to typically be 1.5mm thick for the diameters that we would be interested in.

I have looked for perforated alloy tube. This seems to be made, but not in UK. I can't find anywhere that will sell the odd meter...They all seem to want to sell several hundred meters at a time.

Perforated ally sheet seems to be readily available...Why not make your own tube?

My first attempt at a home made straight through silencer was nearly forty years ago. My Dad and I found some perforated zinc sheet (for meat safes, I imagine).
We managed to roll it round a broom handle or something, then pop riveted the join.

It lasted all the time I had my Honda 175, inside reverse cone megas. The fiber glass building insulation that we packed it with, used to get full of the semi-burnt oil that got past the rings.
Every now and then it would catch fire and send huge showers of sparks and smoke out...:chuckle:

[Darkness]

My first attempt at a home made straight through silencer was nearly forty years ago. My Dad and I found some perforated zinc sheet (for meat safes, I imagine).
We managed to roll it round a broom handle or something, then pop riveted the join.

It lasted all the time I had my Honda 175, inside reverse cone megas. The fiber glass building insulation that we packed it with, used to get full of the semi-burnt oil that got past the rings.
Every now and then it would catch fire and send huge showers of sparks and smoke out...:chuckle:

Reminds me of an S+S pipe I fitted to a Honda: to get it through the MOT I would stuff the mega with wire wool to quieten it. Afterwards, the engine would bog down when a plug of wire wool blocked the hole at the end of the mega, but a quick blip of the throttle would fire a wad of burning wire wool out of the end.

Happy days.......

[Dave G]

.....work for the distillery



....suddenly pays attention to this thread.:mand:

[BigOz]

Utopia

Several places will supply perforated titanium tubes including:

http://www.jpc-ltd.co.uk/products.aspx

http://www.paulgooderham.co.uk/exhaust-cans Uses it to so might be a good contact.

If you end up with some rolled sheet and need it welded let me know.

Andy

[utopia]

Andy ...

Once again your information is top notch.
You have even offered an alternative between, on the one hand, a one-man show which will produce almost anything as a one-off, and on the other, a more corporate option who will not only supply perforated titanium tube but can do so in a wide range of sizes and even offer options on hole size, shape and density for the perforations.
Bulls-eye mate ... all three darts.
And I reckon it must be my round.

Righto then, its gonna be a superlight can.

While I'm asking, I'll be needing an oval sleeve and I reckon that titanium will suit my bike better than carbon.
I think my oval section (from the Sil end caps) is about 120mm x 90mm.
Any suggestions for a supplier of that ?

[Nottsbiker]

Very interesting as I too need to source some perforated tube for my silencers (lol) ready for when I get round to building them. Just have to figure out what diameter will fit and work best in cored stock cans.

[BigOz]

Something like:
http://www.ebay.co.uk/itm/Micron-Exhaust-Small-Oval-Titanium-Replacement-Sleeve-ONLY-/161661816077

Or give someone like Quill exhausts or SP engineering a call in see if they will sell you just a sleeve.

[Mr Gazza]

My Stainless inner tube came today.
I went for 63.5mm OD, as this will match the outlet size of the standard cans. The ID is 60mm.

It looks intimidatingly large, but then I guess the outlet of the standard can was never intended to be the physical outlet size, but more of a styling thing to make it look more in keeping with a "Big bike".....I just can't see it ending up very quiet..!!

The whole thing wieghs 1.756kg At 1250 length. I think I will be using about 500mm per silencer, so I am expecting about 700g of tube per side.... You should be able to beat that in Titanium Utopia? But I am happy that mine will still be a good bit lighter than standard.

[BigOz]

As a comparison, just what I have to hand and not perforated:

500 mm of 45mm x 1mm wall Ti tube weighs 317g
250mm of 45mm x 0.5mm wall Inconel 625 tube weighs 120g

[Gino]

If it's any help, on my 600ss I completely cored the silencer.

It was fairly difficult to dismantle the original silencer without causing external damage, once in bits I had to do a small amount of fabrication to make the thing work. The aluminium sleeve became the outer surface of the silencer & I chose the perforated tube size to slip over the pipe coming into the silencer (from memory I think it was 32mm)
The wadding was the stuff you buy cut in a roll (a bit like heavy cotton wool).
Having read a few articles on home modification of cans, quite a few of the builders recommended wrapping steel or stainless steel wool around the perforated pipe in order to stop the padding being degraded. I bought a couple of those stainless steel scrubbing pads from Asda (they come in a ball) using gloves stretched them out into long pieces then wrapped it & held it on the tube with stainless locking wire. It was probably about 1/8" thick by the time I finished.

The result was bloody awesome! Not too loud but deeeeeep!

In order to use the standard mounting points I made a st.st plate with a couple of st.st bolts stuck through (I think they are M8??), tacked the heads in place & dressed them, then inserted them through the aluminium tube from the inside.
A couple of thinned out nuts can be used to hold the plate in position on the outside then the exhaust can still be mounted as original - with a bit of jiggling.
The result is instead of having a couple of captive nuts in the silencer you have a couple of studs sticking out which I thought was more manageable & not prone to seizing.

More luck than judgement - did a couple of plug chops and the colour was spot on - with standard jetting / air box & no flat spots. It looks completely standard from the outside, apart from the big hole in the end.

My regret is that I didn't take any photos.

Hope it might help in some way.
G

[utopia]

On a similar tack, I have recently heard of a packing kit which contained a piece of ultra-fine stainless mesh/gauze to wrap around the holey tube to keep the hot gases out of the wadding.
It also contained a thin, insulating cloth to wrap around the outside of the wadding, to keep the can sleeve cool.
Both sound like a good idea ... if not essential ?