Thank you! I'm afraid that we do not have any more videos from the 9.9 Tohatsu as the owner of it moved on to 18 Tohatsu that has expansion chambers as well. We might be able to have a video or couple about the 18 Tohatsu this summer or in the autumn at the latest :)
@@WalesRR this would be interesting ! I'm used to 2 stroke tuning but in motorbike applications, i can't understand why there are so little informations on outboard tuning
Hi, Thanks for the great video, information on this subject isn't so easy to find. I'm just about to build an exhaust for a Johnson 60hp 2 stroke 2 cylinder, if you look at my channel you will see what I want it for but I was wondering as my application is just a powerhead, is it necessary for me to machine through the exhaust ports or can I leave them coming out the bottom as original? I'm trying to get the engine to produce stock power or a little better and I've gone through the calculations to make a single expansion chamber but I see you have made two which makes more sense. Any advice would be appreciated cheers
Hey, I looked up your project. Very cool project indeed! As for your question, yes I believe that you can leave your exhaust ports and barrels untouched in the powerhead. In your application, I would prefer reliability over the maximum peak power, so the 2-1 (single) exhaust chamber would work just fine as long as the calculations and the fabrication of the expansion chamber are carried out properly. I use MOTA engine simulation and LOTUS Engine Simulation programs to design and verify my builds. The MOTA is easier to use and has a decent manual on how to input the data on the software, but it does cost 195 AUD. Lotus Engine Simulation is now free (Since Jan 2020) but it is way harder to use and to get it to simulate right. If you have no time or/and interest in the simulation softwares, I have found out that the free Pipe Design program from the authors of MOTA (Ian Williams Tuning) is quite ok design tool to start learning and designing the exhaust chambers. One note thought, it does only calculate single exhaust chamber for one cylinder only. But I think that if you don't simulate the whole engine anyway, and the 2 cylinders phases are 180 degrees apart from each others (as they should be) the chamber design could be used for the 2-1 exhaust system as long as you make the collector/divider section properly. Unfortunately I do not have any exact knowledge on the 2-1 expansion chamber exhaust. Hopefully there is something that helps you in this more that complex answer. Feel free to ask about anything if there is something that you would like to know.
WalesRR thank you so much for your reply it's really appreciated! So far I have started making twin exhausts as my thought was that half the sonic waves would be reflecting back into the wrong cylinder but I completely agree with you that it would have been ok to build one expansion chamber in my application, the twin cylinder rotax and Hirth engines only use one. I have used the calculations by the Aumechanic on RUclips there's a great set of videos going through it all and he's provided software to check the figures, the Information he got was from professor Gordon Blair. I used the figures he provided for a broad power rather than peak power I don't know anymore than that on the details, I will check out the software you have suggested (thank you) and see how it compares. The expansion chambers I've started making are aluminium as I wanted them as light as possible, most expansion exhaust are steel so will see if that works, the exhaust gas temperature i believe will be 450deg c so aluminium should be ok temperature wise. Any thoughts on this ? Your exhaust build and engines modifications were really good, very helpful video and the engine sounds superb.
Kun meillä täälä bensan hinta on mitä on niin näistä pienemmistä 2t myllyistä tehojen maksimointi on kyllä houkuttelevaa ja mielenkiintoista puuhaa. On kyllä upea saavutus jos tuosta 2 sylinterisestä padasta on mahdollista loihtia teholukemia jotka ovat jo lähellä V4 koneita. Odotan innolla jos tästä tulisi jatko osaa!! :)
Jatko osaa olen koittanut kovasti saada aikaiseksi, ainakin nyt vähintään pientä 2021 recap videota. Saahan noista vaikka kuinka paljon tehoa irti, mutta jossain vaiheessa tulee vain raja vastaan kestävyyden ja käytettävyyden kanssa. Kulutuskin kasvaa tehojen noustessa melkein samalle tasolle kuin vastaavan tehoisella isommalla koneella, toki moottorin hyötysuhteen kasvaessa pienenee myös suhteellinen kulutus jonkin verran.
Amazing work! Have you ever messed with the old inline 6 Mercury's? Trying to figure out the best way to make a turbo manifold the same way you did the exhaust there.
Hi, I have not unfortunately, but I do recall seeing one without exhaust cover, and the exhaust routing was done on the cover itself, so it would be significantly easier to modify the cover. I think it should be possible to make an turbo manifold for that application without any modifications for the engine block itself, IF its possible to make the manifold to seal properly to the exhaust ports and it needs to withstand the increased heat stress also.
@WalesRR hey man, thanks for the reply. Since then, I've come to the conclusion that it would be easier to modify the exhaust tuner in the mid and the mid itself to get exhaust feed. Maybe losing some efficiency but the motor itself stays factory like. Haven't started on anything yet, still trying to map everything out and another project has taken priority rn lol. I will get this done one day tho.
@@thelikebutton4405 Sounds like a good plan, but remember to watch out for the water surface level when taking the turbo manifold out from the mid section of the outboard engine. The turbo itself could easily end up being submerged at some point depending on the application.
@WalesRR it'll be mounted high on the powerhead, only thing coming from the mid is exhaust plumbing. Gonna 2" 1/4" wall stainless and plug the bottom of the tuner with plate welded on. It'll still be partially water cooled that way.
I have a 1985 brown band 90hp six thats stickered up like a 1968 1250bp with 25hp stickers on the lower cover, Haha. I would love to see a boosted tower of power!!!
The mufflers are coming, they have carbon fiber casing and are packed with glass wool. Also there is about 350 mm long tail pipes, but they are installed inside the expansion chambers to make the overall length of the pipe shorter.
I can't see why not if you make the modifications for the exhaust to exit on the side of the engine. Although if the expansion chamber is not designed for that specific engine, you more than probably lose a lot of the engines potential and the power change compared to the stock engine could be even on the minus side.
Sen takiahan perämoottoriin on kuutiota pitänyt saada jolla saadaan tehoa. 2tahti tarvitsee luonnollisesti pakopainetta sopivasti. Perus 2t virittämistä. Kelkoissa esim sama teho mutta puolet vähemmän kuutioita.
Kuutio eron suurin syy kelkan ja perämoottorin välillä on voimansiirto tapa. Kelkoissa variaattori antaa anteeksi paljon alaväännölle, joten voidaan käyttää pienempiä ja ylävireisimpiä koneita. Perämottorissa taasen välityssuhde pysyy kokoajan samana, jolloin alavääntöä on löydyttävä riittävästi jotta vene saadaan liikkeelle ja täten moottorille optimaalisemmalle tehoalueelle. Tilannetta voi miettiä myös sillä tavalla, että autoissakin olisi vain esim. 5 vaihde ja pakki. Tällöin liikkeellelähtö olisi hyvin hankalaa jopa kytkimen luistattamisella, jota ei sitäkään löydy perämoottoreista.
Sen tarkemmin tuntematta tapausta tai kyseessä olevaa. moottoria, vaikea äkkiseltään sanoa. Kuten aina virittämisessä, varsinkin noin pienen moottorin ollessa kyseessä voi helposti käydä niin että virityksen haitat menevät mahdollisten hyötyjen edelle. Toki mikäli virittämisen tarkoituksena on pääasiassa oppiminen ja/tai kokemuksen kartuttaminen, 2t perämoottorin virittäminen onnistuu aivan samoin kuin muidenkin 2-tahti moottoreiden, kuten mopot, krossipyörät, moottorikelkat, yms... Virittämiseen liittyvää asiaa löytyy netistä runsaastikin mikäli kiinnostusta löytyy.
@@mercuryforlife969 He did not remember the exact data file which he used for the pipe and also he thought it wouldn't help much either to send the pipe dimensions alone if the other modifications are not done also
At 10:44, I said that the Yamaha is 600cc, 85 mm piston. The true size for the piston is 75 mm.
The video the world didn't know they needed
can you show more info about how you make the exhaust? both exhaust tube and how to make the exhaust not go in the water?
I will try to make a new video about showing the process in detail after I have finished building my new garage.
Liked and subscribed ! Can you please make another video of the 9.9 tohatsu ? Looks really cool
Thank you! I'm afraid that we do not have any more videos from the 9.9 Tohatsu as the owner of it moved on to 18 Tohatsu that has expansion chambers as well. We might be able to have a video or couple about the 18 Tohatsu this summer or in the autumn at the latest :)
@@WalesRR this would be interesting ! I'm used to 2 stroke tuning but in motorbike applications, i can't understand why there are so little informations on outboard tuning
Hi, Thanks for the great video, information on this subject isn't so easy to find. I'm just about to build an exhaust for a Johnson 60hp 2 stroke 2 cylinder, if you look at my channel you will see what I want it for but I was wondering as my application is just a powerhead, is it necessary for me to machine through the exhaust ports or can I leave them coming out the bottom as original? I'm trying to get the engine to produce stock power or a little better and I've gone through the calculations to make a single expansion chamber but I see you have made two which makes more sense. Any advice would be appreciated cheers
Hey, I looked up your project. Very cool project indeed! As for your question, yes I believe that you can leave your exhaust ports and barrels untouched in the powerhead. In your application, I would prefer reliability over the maximum peak power, so the 2-1 (single) exhaust chamber would work just fine as long as the calculations and the fabrication of the expansion chamber are carried out properly. I use MOTA engine simulation and LOTUS Engine Simulation programs to design and verify my builds. The MOTA is easier to use and has a decent manual on how to input the data on the software, but it does cost 195 AUD. Lotus Engine Simulation is now free (Since Jan 2020) but it is way harder to use and to get it to simulate right.
If you have no time or/and interest in the simulation softwares, I have found out that the free Pipe Design program from the authors of MOTA (Ian Williams Tuning) is quite ok design tool to start learning and designing the exhaust chambers. One note thought, it does only calculate single exhaust chamber for one cylinder only. But I think that if you don't simulate the whole engine anyway, and the 2 cylinders phases are 180 degrees apart from each others (as they should be) the chamber design could be used for the 2-1 exhaust system as long as you make the collector/divider section properly. Unfortunately I do not have any exact knowledge on the 2-1 expansion chamber exhaust.
Hopefully there is something that helps you in this more that complex answer. Feel free to ask about anything if there is something that you would like to know.
WalesRR thank you so much for your reply it's really appreciated! So far I have started making twin exhausts as my thought was that half the sonic waves would be reflecting back into the wrong cylinder but I completely agree with you that it would have been ok to build one expansion chamber in my application, the twin cylinder rotax and Hirth engines only use one. I have used the calculations by the Aumechanic on RUclips there's a great set of videos going through it all and he's provided software to check the figures, the Information he got was from professor Gordon Blair. I used the figures he provided for a broad power rather than peak power I don't know anymore than that on the details, I will check out the software you have suggested (thank you) and see how it compares. The expansion chambers I've started making are aluminium as I wanted them as light as possible, most expansion exhaust are steel so will see if that works, the exhaust gas temperature i believe will be 450deg c so aluminium should be ok temperature wise. Any thoughts on this ? Your exhaust build and engines modifications were really good, very helpful video and the engine sounds superb.
@@Ben-Dixey hello , any work on online 4 strokes
Kun meillä täälä bensan hinta on mitä on niin näistä pienemmistä 2t myllyistä tehojen maksimointi on kyllä houkuttelevaa ja mielenkiintoista puuhaa. On kyllä upea saavutus jos tuosta 2 sylinterisestä padasta on mahdollista loihtia teholukemia jotka ovat jo lähellä V4 koneita. Odotan innolla jos tästä tulisi jatko osaa!! :)
Jatko osaa olen koittanut kovasti saada aikaiseksi, ainakin nyt vähintään pientä 2021 recap videota. Saahan noista vaikka kuinka paljon tehoa irti, mutta jossain vaiheessa tulee vain raja vastaan kestävyyden ja käytettävyyden kanssa. Kulutuskin kasvaa tehojen noustessa melkein samalle tasolle kuin vastaavan tehoisella isommalla koneella, toki moottorin hyötysuhteen kasvaessa pienenee myös suhteellinen kulutus jonkin verran.
Hienoa osaamista! More videos like this please! 👌
ps. Damn that 2-stroke engine sounded good with those better exhaust pipes.
Kanava tilattu!
Amazing work!
Have you ever messed with the old inline 6 Mercury's? Trying to figure out the best way to make a turbo manifold the same way you did the exhaust there.
Hi, I have not unfortunately, but I do recall seeing one without exhaust cover, and the exhaust routing was done on the cover itself, so it would be significantly easier to modify the cover. I think it should be possible to make an turbo manifold for that application without any modifications for the engine block itself, IF its possible to make the manifold to seal properly to the exhaust ports and it needs to withstand the increased heat stress also.
@WalesRR hey man, thanks for the reply. Since then, I've come to the conclusion that it would be easier to modify the exhaust tuner in the mid and the mid itself to get exhaust feed. Maybe losing some efficiency but the motor itself stays factory like. Haven't started on anything yet, still trying to map everything out and another project has taken priority rn lol. I will get this done one day tho.
@@thelikebutton4405 Sounds like a good plan, but remember to watch out for the water surface level when taking the turbo manifold out from the mid section of the outboard engine. The turbo itself could easily end up being submerged at some point depending on the application.
@WalesRR it'll be mounted high on the powerhead, only thing coming from the mid is exhaust plumbing. Gonna 2" 1/4" wall stainless and plug the bottom of the tuner with plate welded on. It'll still be partially water cooled that way.
I have a 1985 brown band 90hp six thats stickered up like a 1968 1250bp with 25hp stickers on the lower cover, Haha. I would love to see a boosted tower of power!!!
this is good shit
Nice video and amazing work.
I see on your RUclips page , some title in French .
You speak French ? I have more questions for you 😅
I really like your video, two-stroke outboard Engine. How do I contact you
mielenkiintoista , kanavan laitoin tilaukseen
Kiitos! Koitetaan pitää myöskin tulevat videot mielenkiintoisena.
Kul. Väntar på en fortsättning!!!!
Nice video! Well made expansion chamber
Thank you!
why no glass packed muffler - tail pipes. 2 Stokes like 700-1200mm long tail pipes. also and I think you said it - but your gearing was rubbish
The mufflers are coming, they have carbon fiber casing and are packed with glass wool. Also there is about 350 mm long tail pipes, but they are installed inside the expansion chambers to make the overall length of the pipe shorter.
Thanks for the sound
more pitch on the prop :)
Could i use a mc expansion chamber and fit it on an outboard?
I can't see why not if you make the modifications for the exhaust to exit on the side of the engine. Although if the expansion chamber is not designed for that specific engine, you more than probably lose a lot of the engines potential and the power change compared to the stock engine could be even on the minus side.
Hello have you tried with inline 4 strokes
100hp
Hi, sorry, I have not. 4-strokes are more complex and weight too much for my application.
@@WalesRR Expansion chambers do not work on 4 strokes.
Sen takiahan perämoottoriin on kuutiota pitänyt saada jolla saadaan tehoa. 2tahti tarvitsee luonnollisesti pakopainetta sopivasti. Perus 2t virittämistä. Kelkoissa esim sama teho mutta puolet vähemmän kuutioita.
Kuutio eron suurin syy kelkan ja perämoottorin välillä on voimansiirto tapa. Kelkoissa variaattori antaa anteeksi paljon alaväännölle, joten voidaan käyttää pienempiä ja ylävireisimpiä koneita. Perämottorissa taasen välityssuhde pysyy kokoajan samana, jolloin alavääntöä on löydyttävä riittävästi jotta vene saadaan liikkeelle ja täten moottorille optimaalisemmalle tehoalueelle. Tilannetta voi miettiä myös sillä tavalla, että autoissakin olisi vain esim. 5 vaihde ja pakki. Tällöin liikkeellelähtö olisi hyvin hankalaa jopa kytkimen luistattamisella, jota ei sitäkään löydy perämoottoreista.
Oisko sulla tietoa miten voisin virittää 4hp 2t yamahan perämoottoria
Sen tarkemmin tuntematta tapausta tai kyseessä olevaa. moottoria, vaikea äkkiseltään sanoa. Kuten aina virittämisessä, varsinkin noin pienen moottorin ollessa kyseessä voi helposti käydä niin että virityksen haitat menevät mahdollisten hyötyjen edelle. Toki mikäli virittämisen tarkoituksena on pääasiassa oppiminen ja/tai kokemuksen kartuttaminen, 2t perämoottorin virittäminen onnistuu aivan samoin kuin muidenkin 2-tahti moottoreiden, kuten mopot, krossipyörät, moottorikelkat, yms... Virittämiseen liittyvää asiaa löytyy netistä runsaastikin mikäli kiinnostusta löytyy.
Hello! i got myself a hand on one of these 9.9 tohatsus would it be possible for u/ ur friend to send a file of the sheet of the exhaust pipe?
I will ask tomorrow if he is willing to share it :)
@@WalesRR so it was a no?
@@mercuryforlife969 He did not remember the exact data file which he used for the pipe and also he thought it wouldn't help much either to send the pipe dimensions alone if the other modifications are not done also