custom exhaust improvement (?)

Hello

I will make later a complete post about the story what I'm doing on my RC but here is a specific topic about the exhaust :

My background is :
- I use mainly the bike on track, but want to keep it almost street legal for potential use on road.
- I HATE the noise of the stock exhaust (2015)
- I like to have the small muffler behind the engine and not a side mounted, for aesthetic reasons, for originality, and because it's less exposed in case of crash (I lay down quite often on track)
- I want better deep noise, but I'm not looking for more decibels
- To get extra horse power would be great, even if this is not the main motivation of change. At least, I don't want to loose anything but kilograms
- I don't want to buy fancy efficient great performance parts, for cost reasons, but also mainly because I have more pleasure to try and build my own thing that making a money transfer to a dealer.
- I love the theoretical approach, calculations, and engineering analyze

So I have in stock an old Termignoni muffler, from Ducati performance application, without catalyst, but with a removal db killer. It has a good shape to be integrated in the bike, with exhaust flow in ground direction.
IMG_20180821_205215.jpg

At your point of view is there any drawback to this mounting? It will probably not be compatible with OEM belly pan, but this is not a killer.

I'm building now the connection to the original header pipe.
IMG_20180821_205202.jpg


Most tricky part will be the bracket... but I will see...
 
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For the moment, I keep the original header and looking at it... it's quite bad.
The junction between cylinder hear and header pipe is dramatically bad :
Header pipe starts with a BIG solder join that reduce diameter by more that 2 mm :
IMG_20180819_191812.jpg


This is easy to solve with a "dremel" :

enhance
 
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The exhaust port is also very restricted :
there is a big gap between the gas flow and the exhaust gasket (in yellow), and the diameter of the cylinder head exhaust port which is much smaller that exhaust pipe diameter.

enhance


This is also easy to solve, at least to correct partially :

enhance



Depending of how the muffler adaption is doing well, I will built my dream long header pipe too.
 
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About the header, my conviction is that the original exhaust line is too short (in case of rear central position for the muffler)
That's why any replacement with the same concept (even very open as Werkes) will not provide the extra power expected, and rear side exhausts are more efficient.
The best design, to my point of view, is not only high flow header, but LONGER header. I would like that, from the cylinder head, it goes first down, then up, then only to the rear.
I would like to add this loop and expect significant gains in power and torque.
1177o80.jpg


But this would be the next step.

I will keep posting info and pics.
(by the way, I'm not confident about the picture I posted. If there is anything not visible on your computer, please tell me in private so I can correct and change of pic hosting)
 
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isaac_

New Member
Hello

I will make later a complete post about the story what I'm doing on my RC but here is a specific topic about the exhaust :

My background is :
- I use mainly the bike on track, but want to keep it almost street legal for potential use on road.
- I HATE the noise of the stock exhaust (2015)
- I like to have the small muffler behind the engine and not a side mounted, for aesthetic reasons, for originality, and because it's less exposed in case of crash (I lay down quite often on track)
- I want better deep noise, but I'm not looking for more decibels
- To get extra horse power would be great, even if this is not the main motivation of change. At least, I don't want to loose anything but kilograms
- I don't want to buy fancy efficient great performance parts, for cost reasons, but also mainly because I have more pleasure to try and build my own thing that making a money transfer to a dealer.
- I love the theoretical approach, calculations, and engineering analyze

So I have in stock an old Termignoni muffler, from Ducati performance application, without catalyst, but with a removal db killer. It has a good shape to be integrated in the bike, with exhaust flow in ground direction.
IMG_20180821_205215.jpg

At your point of view is there any drawback to this mounting? It will probably not be compatible with OEM belly pan, but this is not a killer.

I'm building now the connection to the original header pipe.
IMG_20180821_205202.jpg


Most tricky part will be the bracket... but I will see...

Is this how you are proposing your exhaust look? This can’t be a good idea pointing it down like that. Not so much down but the location.

When you sit on the bike what clearance do you get between the ground and the exhausts? Also... the wheel is right there. And it will throw junk into whatever opening is near it.
 
Is this how you are proposing your exhaust look? This can’t be a good idea pointing it down like that. Not so much down but the location.

When you sit on the bike what clearance do you get between the ground and the exhausts? Also... the wheel is right there. And it will throw junk into whatever opening is near it.

You're right it is a risk. On the picture, it is not the final height. I try to make the connection with the header as short as possible in order to have the muffler as high as possible.
I still do not know what will the the final height. I expect to finish this tomorrow. In any case, for track I do not see this as an issue, even for strong compression.
For street, it could be an issue while mounting to a pedestrian street. I have to take care.
Thank you for your warning and your sharp eye
 
Not to mention having a muffler exit there will get many components too hot and will melt your belly pan, which as you know is a huge issue for the track and cannot be overstated.

Other things that might get too hot to function properly:
Shock (which has oil in it)
swingarm bearing
Rubber seals around airbox?
Rear tire rubber.

Man this is just an all around bad idea. Also if you "lay down quite often" on the track you need to re-evaluate your approach. How you ride, how hard you push and even if your bike is completely straight and functions properly. I had one year where I crashed very frequently and had to fix myself to stop.
 

mattv

Member
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This is batshit crazy and I love it. Maybe consider shortening the muffler a few inches.

Trailerboy531 makes good points. Though, I'm not sure heat would be much of an issue for the airbox and shock. It looks far enough away to me. My yoshi race pipe is closer to the shock, I think. I haven't tracked my bike yet, though, so it doesn't get ridden as hard.

It does initially look like a bad idea, but button it up and try it out little by little in a parking lot or something [FONT=&amp]¯\_(ツ)_/¯[/FONT]
 
Thank you trailerboy531. Your comment is tough but valuable.

About belly pan, I see no issue to make shorter, like KTM performance or Tyga. So I see no issue on this point.

About heat, this is indeed a serious issue.
I'm still far from the swingarm axle, and finally not in the middle of the tire but on the side.
Main risk is for R6 shock absorber, and also maybe the throttle body, because I need to finally build a header higher than the original one.
I consider thermal protection will be mandatory to be safe.
About airbox : no risk at all as I plan to design my own airbox system, in a very different way than the original.

About thermal management, I'm very surprise to see the header going so close to rubber cooling system pipes. I expect my setup to not be worse.
We will see...

So finally, because of ground clearance, I have to build my custom header in order to have the muffler higher. At the end I expect to have it about 1cm below the belly pan. Work in progress...
IMG_20180825_114504.jpg
 

Formula390

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Uhm, KTM Performance pipe and Tyga pipe are both longer than your system length here. Too short a system length is going to cost you power. Period. I don't want to rehash the testing I've done here (there's a thread on that) but really, the only way to get this right is to get your exhaust length right. The Tyga system manages this via the dual exit. Otherwise, it would have to be stuck out the side of the bike like on the Akra pipe. If you are too short, about the BEST you can hope for is -3 HP. MINUS THREE. On a bike that makes ~40. That's not only going to be noticable, it's going to be a loud fat turd too. The exhuast can is also MUCH hotter than the exhaust pipe, because it's catching the exhaust to muffle it. That concentrates the heat. You are going to cook your shock if you keep your exhaust can there. it's going to get hotter than a catalytic converter on the outside of the pipe, and that's GOING to radiate heat into your shock. I like the idea of development. Innovation is wonderful. Adding some system length to the front is an idea a few have played with to try and get the extra system length that's needed. None of it ever was very successful however. You may want to seriously pay attention to the prior work that has gone on here tho. Retention of the location you have now is bound to cause you a lot of problems. Consider that feedback for what you may. I wish you success, but honestly, I've already got a pretty solid idea of exactly what you are going to see both on the dyno and what it's going to do to your suspension.
 
Thank you for your sharing and warning.

About power, I do not expect to have more power than akra side exhaust. I just want to not loose HP respect to the stock ugly KTM muffler (that also has short pipe).
I fully agree that increasing the total length would be a must to gain power, that's why I add a "loop" with the header in front of the engine.

About heating the shock, I try to manage to be as far as possible and rely on heat screen that will be mandatory.
I understand you think it will not be sufficient. I hope it is. In any case I will try and tell you.
If it not successful, I will not say "nobody told me"!

By the way if anyone has advise about thermal insulation, I'm interested!
 
I had to put back the stock horrible muffler for a track day, as my custom exhaust is not finish.
Then I check the clearance between R6 chock and the KTM exhaust : is very close!
IMG_20180901_210128.jpg
My custom exhaust will be not as close as the OEM... Then I start to be more confident...
 
Job (slowly) on going...
ZopfBi1s9NbMDliQDcL7Mzwho-TQz-RMEtsgs0_xNsEQPfzX6XdYMffpUItuTHW8lhYW26-mq-i_ejCKZ9UsPMQVX0GcsYocPL9Ptn_-5bxx8BVU4sL0qYPCfRtiOrBzYm7h41KSsnbZmf8fgZtK_8wnFjXe_uKkyr6MUNOuQX6eT7F6Gl5OMh1xFQ-TEtg-ygzLzXuEY2sU9Dz0F9CnUsjWtPb1g6nJdq7os9oDRYd4Idby-Ypzs4ESbyJDTJe5PMaFGrhVp2wwDk-M_L5qq19evRqoh7Gzy6_LGfi6Ev6BCPfjLBW52ZmygOAukVAi82ZOwhCBpgpqMIMYi_-tw3w5Rdj3jOK80rN0t_8p6yidDmle7WpVXrH9CJbdB6eiMUUuvt-zA2PimkxM-fsevL2fApIsScYl5tgRhUwRL2IrV5TXnu_xd3dnxH5K3d6VvQ35EIHGy97OZHsZL4t4jUiOmuuHmUb-YjOZPNThORzdio1jx4LU_QKwatd5DC81ZTGJ5kkmL-VAwfYPE5V1G2DpZBHXVKw9JiqprCcZKgkoP-g83JQmEdGKupgbLRz1fUHh8rY9EGTjKfmBtCLi1AMA9sxHtrkvKD1xuM5G5oMKE1u3B98wrpy6ZSgJDJgsZdvjJtsrrqcUNFn03VuOSBFO=w901-h920-no


on the right the OEM exhaust.
On the left the custom made, with
- higher internal diameter,
- beter connection to the cylinder head,
- bigger length in order to have the advantage of side exhaust while keeping the central exhaust.
 
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Done!

Here are the header (I let you recognize the old and the new one)
IMG_20190317_163009.jpg
So I did it longer in order to compensate the position of silencer (I want to keep it behind the engine and not on the side or below the seat)
We saw with Werkes that even with no restriction, the original is too short to get extra HP.
Having a long exhaust line is also the solution used for example by Suzuki on DR-Z 400, otherwise the line is too short to get HP.

Main risk for me is about thermal compatibility.
So I finally used professional thermal insulation from plumber warehouse (it resist to very high temperature, but maybe not enough time. I do not know)
It is easy to cut
IMG_20190317_155824.jpg

I put some of this material in critical location...
IMG_20190317_155935.jpg
Then use a fashion horrible thermal insulation around to maintain in place and save some additional °C (even °F)
IMG_20190317_161705.jpg

Here we are!
IMG_20190323_145243.jpg

About distance between exhaust and R6 Schock :
- It's not worse that original exhaust line
- I have the thermal protection added.
So I'm confident.
 
I had my first ride (after 9 month in the garage) with the bike modified, and ... It works!

My intivation was about the noise. I'm fully satisfied : the bike makes noise or real men's bike. kind of 450 WRF noise. Not too loud, but deep. Thrill is back!
My gear was about thermal behavior, but i'm able to put my fingers where the protection is without being burnt. So this is fully satisfying.
About performance itself, I did not push to full load until now, as the calibration is not started. An in any case I expect a dramatic calibration change needed because of the custom intake, so it will be hard to find what's come from the exhaust or from the intake.

The second lambda sensor plug is OK too, as I have now the system O2 sensor connected to the ECU via "O2 optimizer" (I'm thinking to remove it), and a wide band O2 sensor for AFR display at dashboard.
I will use this display for initial rough calibration.
 

ReidMcT

Active Member
Premium Member
Elite Member
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Whether or not it works, I really, really like reading and looking at your work, chevaliernoir! Bravo!
 

John390

New Member
so, you inspired me to pull my header off.

I did it today. not too tricky to do but a bit of a pain in the butt.

My cylinder head was not anywhere near as bad as yours. In fact I didn't touch it at all. It was smooth,and the transitions were nice.

I did take some time inside the header at the cylinder head end.

Some welds, some less than optimal manufacturing etc.

I have decent die grinders and bits, so it went quickly.

Happy with how it came out.

Pretty sure its not going to make any more power in reality, but I now know its not as bad as it was.
 
so, you inspired me to pull my header off.

I did it today. not too tricky to do but a bit of a pain in the butt.

My cylinder head was not anywhere near as bad as yours. In fact I didn't touch it at all. It was smooth,and the transitions were nice.

I did take some time inside the header at the cylinder head end.

Some welds, some less than optimal manufacturing etc.

I have decent die grinders and bits, so it went quickly.

Happy with how it came out.

Pretty sure its not going to make any more power in reality, but I now know its not as bad as it was.
That's good, but I'm surprised, to be honest.


Here look at my exhaust line :

e_PBOQMWFvsSNkATNN9KiUOIfDzjmTGbDeChFYE3O_EfX3_qQisjP_SWnhYRdwhFCfQRZ0hXmNGJSJT6ykR8NhuLfI2ncd1cNlVbYMbuH1ydLvb_K_jfiqHpgKWMF8PD5QENysUshmPkG0QRzoS3OrisfWZ5YLEXYI2JUglgSQPdFUHqWS-uXBWGCmEAd45PgbfMqhF4j6d5dgYERnifsn-MVdGpW8OeoME9cJswzySu9wtd68MmH6-dsRqf2h2-XFp6K38CyS94m2Z5gcVNbcKvHmNH9ZIGJdz7IDia6wfI_-EMTyTScAjJWX3YJQfyVOcfmz7cMCS5uRXcnXfbr-fmJ3VEWayrTHGDw2z2qaUnKRCprqAi3lmDf04izvD9ruuG2DqKYyYb4QtawTGl_dobF_RGW64_9ffjRv7GtATC0l-t-XzudW4dZsIcK4y4r5qonh4eD5T1v-XfHvnIIN1CCkeHXnwKV_VIkqhS8kHsGRJGoJc0Dg_AgAem55RUZ8St-tP5d3l9sxB1X0EEzk4dq3J79fU1oEVK2f020CDSTtyCKlPi0JF2S9aJ15sWLpawuAJBOXgWOwA1OvIw5-qh7Kv558FrmRjDAHZV6JZRDpYdEGJnzChImE9iWjWdI0Py9pVtmJiasHvVQk2Qb57p3vbl8yw=w1012-h772-no


I understand you also had to grind a little to have something nicer (I reached this :)

K6dzHxrD5zGJOIJKWrhkjVlwf6__JgNAGzRhr0vVeEKSHBBybdbsrV1vnXm3qdhnaQp2TQbLDmZkBg_1nFmvQosv07BkxDvz_dfcnYZCIyDREe2Klb6S55MezzTumBnsqFXyyt3d16KZAJtQoVxdB_Opog0K3BcXsmCkPZjtAem1Eqw0SZINX_ZEJCGe-e-ex6P-G88dPbsB1j8dTLf1k1eFw6qpN5k2PrSqreRK-03NgfXxAyComggDF38eglHg9F-zRDBkh-evoyBEcedcgydJCGp8cF6NhIP44jlV7gNvsZZw2bsVoP7QBaMs4tpZBt-i3hn-0H7RWGNXNhrZOjCGl9vpYVe_hNmXZqMkbktrtDIM6w9oD-9wUL_NFmuBlx3ZVVi7_Gqr5LG3Vy3MmkusRfe4aOjfK_zh34TxPwPo5vy7FlCT0O5ELtQvfDfWdDTmzthFxSfTCPyNsGSh6f_nIfmoHvJbuqAD3a9LLyyGwmwNAZ6I8zsH6UnKpJC70Diz7ZaV7YvNp6unsl17T8J_AY7NXd86elpN6J3QsGk7KttsNXQv89LM_LCKaPVWy5DUfDQeOtF3LmzpCnMsYsUhzkW4HBwVHf_kw388TA1K_L2S0snC7aji3gNVemhw1opbj8SLQFywO626SHOFCvzD5unnzIY=w773-h772-no


But if you look carefully, I think the exhaust gaz should have the complete surface inside the gasket to flow, in order to use full capacity of the header.
But when you (at least I) look at the exhaust port, the diameter for the gaz is much lower than the inner diameter of the gasket.

b4JP8QgLSH4ppttkpZy9hoJMlwU3cjXotNvrV6KGQpKNzg4XGVL7DmPRmuO67CiJ-KQAq40ibWdEtx-Ghl-_xEN0Cgpc6HbV6ePBDvaiR338PBB5kRP2VZC_cbQNmyOPjjnZBnk063urIVhscTV-OpgJPqPmD0fQFcWuX5ou64NYxi54hD0kzOWvfjt49rg8GJDQJx5GC64lHJqvJr6WJRnHdEo5vxY2Qcd2JBKFgx_qQpcgDEznK38sSZAhE7N7WHtklmOJKghWMa_6DfIU4YJssG8TQSDBDqbG1JHmcikJ9tdtb3XKxxyI6NAVeWhcqJCB6yXLKiSMfuq-LpUxk2lh83FkdwtK1zICIo_t2i6V4hVxXxnD2WS8KyWmxA2PWVwrV4dVfpgeOVIWMHD8Bc3nm_MOVJFLlc6FFE7_GwO9t6ijPxR1OhdWZUKd22LdfsbrdDwHJUgDOBXGDUUV9OIfr_CU1g2of-nJ1h-iFAft_Sy7-tX_klN-sfnjIWB1ewLOxqNuEm0VK0Jt7R0NJnyfehIA66AhDlInm964UP3WtaNjjo7P9RSg-TSGeFO2WKuexWdlh4PIY5gDtR59Slgjb8Mfi68gVjUdRSzPYT2kbalToYaaldcD09AI3Dsu_JpgbsuM6HlHdj9i3Wy8RcdYkEQmB7s=w1030-h772-no


I think it would have sense to remove this part : (mainly with high flow header)
BD4s8zXEkomu-IoonVr5ttUq6fi8P9o79Y4n9Np3CkhOuox3aL36Ag-euu8HUj2Mv321iMZvvrOCSogPNuz9N2QHGuE7TSe5hc2T5-qEjqLTLdN30x6lV9r_t8mD_btINRgqUs_Jn9CRn2bVj93tqPu0nnG0lqPOobzf0nSVsp9aYjZ0z9z1AtQ6fMhvkX2B0tzqxSNcRks1JQkbWuTT2PthZk9KZtYGLv--c2_fC-UvHZrjOk-3Q7igUuoPjxF0hvDhvMDwKAqWYZORHGVOU1etIC2uD3R0S9RLuWgM3ukQG434IwZSks0pTkplVc_oPvsPxJ7hE2TjhlwpQR5_QZuTpGr3bfMnKD3_MDjoj-iHvzlj5UaX7VOXiAbXscxwtAJw-0-giX0oLn1ToTSlxJEEWx-g57kIlKPcaW44njz1a63N-GtXylkNnD5Qn6RrjOFOYGgEnzIe5hzo-rm5QGoqVAXZ8HO6CT75LaOrvmXBeLiu_7-wBKhYTB4OhAsySpufr-w-CZf8N2gh5g8MPkLO7Ml28obCdkI3QBGfNR2n9iTJ8uhGkgifal5siL6g5cliAPLuv5GZlBy8zStsiaLzBea0CwH3_0R8mHbkPiInOIdJk5FQq-HiVfjZEQiQhp-z5PCFDmYApSnUr5ghdZdLlOZUTSA=w1030-h772-no


I did it only very partially (and it's uggly)
6f3XbeeiRV5n2zViY856SGsWKfkLG1d1wGE_eeKtbepHtCNjAMXl5Mut1uZII99YBvsLfKOqioo1RWqWtN-Kct5nzFckOt4F_kF_k1biZ4ESBmHnLh3GI_mxepSfYy98y_NcK9CMd1VZDV6vuydRt-FD6NKFvTE6l-LWWY9zjXfWiNdfRTUIT6LTkUDW86nNdKqQjCqGeP3ZiLFLxQSLGukwofpe7u4kmuS5OdNUZpQk3oGt56ls1RdnPMgLNRiveMMA3l_NKinntsxYueHUOfAat5Wj9ozB_JB-bAZO35Rg1Woyok5vQfT0Vwzv-YX2dBcns9vaExcT_rbFz1y4P_W9AJ4rr-FvGIefmSH-gCWh_uufERpFrfQkpLPZNRwVyieAXWy2T02P3Rq2bCYTAqmi3dn-_j5AcQcl4FyW2iKmRm6UdSCJxnEpXWkncj30SXLqFHBou316mq0Qxc-sC_jYaXn5--y5PtLvjOen2ZPEZUaZVijZqxuWI8W6JGlHmNUNLhI3bSfQzazRIjoKJ9-Uag2BDc2zCwjn3oluL5ttfcj7IB2zqIzcT3gF37IOmRP5G_Xz1iwhO9SYdZaHMptzklM3L6eTuJcWHHt8GpUxPnEOguXQHJGeQE5GOKmcV_nLFNusgmliLq6ZrXwFPvb6mR0y38Q=w1030-h772-no
 
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