I say at 3:05 that the left and right waves are theoretical but that is INCORRECT - they are real but can't be measured. Only the combination of both pressure waves, the superpostion wave can be measured. However, they can be calculated by EngMod2T and seen in WaveViewer2T
Yes, the issue is that it is not possible to differentiate each by simple pressure measurement due to super positioning. Thanks for the shout out too :-)
Nice clear vid, thx! , Now I wonder; since most people cant create a custom pipe, could you reverse engineer it to a bought exhaust pipe and reverse engineer cilinder port timing carbs and jetting? since most of those have many small budged or diy variations and a pipe is in most cases a 1 time high dollar buy, im planning on tunning a 50cc am6 with a LeoVince X-fight and wonder what carb to use, what reeds to use, what should the exaust port timing be to match the exaust best?(if at all possible), any tips or tricks?🤔🤗
Hi Omnificent and thanks. Regarding the exhaust, I had a quick Google of that pipe but I can't see any specs for what timings it's designed for but I guess you could reverse engineer. I used to race an Aprillia RS50 with the AM6 engine. From memory (about 10 years ago) we had a Hebo cylinder (193 ish exhaust 130 ish transfers) running with a KRD exhaust pipe. Carb was a 20mm Dellorto or a OKO 26mm with a sleeve to make it 20mm for the race regs. Ignition was a PVL one. We had about 14 hp at 12500 rpm. Reeds were v force 2 I think but it has been a while. Will your bike be on the road still? Are you planning on tuning the standard barrel?
@@AutoBeta2T thx for the awnser, and sounds like a solid setup indeed, I recently noticed the #Freetech50 races in europe, these guys get 20+hp from the little 50cc, fingers went ichy and wanted to pickup my old hobby from the late 80's (Honda MB8 honed, ported, 8valve reed... scary fast), stock in our country the 50cc2t are restricted to 45km/h, done with rpm limiters and plugs and bushes, so im gonna try undoing that stuff 1st before trying an airsal cilinder with 21mm carb(road use), most pipes dont give specifics though but found one that specifies a 7-11krpm range; SCR Corse Chrome for the 50cc, the fact that most pipes dont specify what they are designed for except maybe the cc's is exactly the problem im trying to overcome.. thx!🤗
@@AutoBeta2T I really wont be able to build my own pipe, but am planning on doing some cillinder and engine case matching/porting with easy to aquire parts (why I chose the am6 Yamaha TZR(basicly same as Aprilia RS50)), thats why I wonderd how to reverse engineer a setup with the bought exhaust pipe as a base.. thx!
Hi Clive, not too bad thanks. Unfortunately I haven't made any progress since before Christmas. I've had a few things to deal with but it's all about done and I hope to get going again in the next few weeks.
My expansion chamber has a 20mm inside diameter pipe for the first 15 inches or 375mm long and then it begins to enter the expansion area. it has a 20mm id stinger as well Is this going to prevent the negetave wave from returning to the cylinder ??? Do I need to taper the header from flange to expansion chamber ??? Should io buy a used 80cc dirt bike pipe and weld it on. to my factory flange ??? On a fixed income / Retired, so budget is pretty well non existant. The engine is a motorized bicycle balanced bottom/ Mineralli top cylinder 47mm piston 40mm stroke =69.4cc. Port timing wheel mounted on the engine, 85+85 = 170-degree exhaust begins to open and closes at, 55+55=110-degree intake transfers begin to open and closes at. 85 - 55 =30 degrees of blowdown, ( the time the exhaust starts to open to the time that the intake transfers begin to open). So 30/110 = .2727 which is 27% blow down. 170ex 110in with 27% Bld. These are the port timings that the Mineralli came with, (I cleaned and de-burred the port openings only)
Hi Dave. Thanks for posting these great videos on the AR. I'm eagerly awaiting the finale of whether you do get a ton out of this thing. I gather the AR playlist is in order and you are still on with the work? Cheers. Barry
Hi Barry - no problems and I'm pleased you are enjoying them 😃 With regards to the play list it should be in order apart from the sim stuff and pipe builds. I do need to review them again. With regards to progress I'm hoping to get in the garage again this week and get the header done 👍
Hi Dave Nice video mate very informative. But in your sim of the TZ you have a major dip in the power curve before peak power. What do you think caused that and how does one find it in the sim data.
Hi Kenny, cheers. I've not really looked at why there is the dip. I did notice it was showing deto in that area so I swapped to a different fuel and it stopped it. Also I think there has been a bit of an update with EngMod2T so possibly that may have caused it?
Cheers Pete, it certainly helps with the visualisation of the waves. I've had to really understand (well... I think I do?) how the waves work in the pipe doing this video. Hopefully I may be able to cut down on waste cones now 😂 Still, I do intend to try plenty of real world pipes too.
@@AutoBeta2T Hi Dave. I think you understand how a 2 stroke pipe works as well as anyone else that I've come across on youtube (and a lot better than some people on youtube!). Hopefully you will get the BHP that you are looking for once your new pipe is up and running.
Would be interesting to see the waves in a standard silencer, front pipe, diffuser, belly then a flat plate with a hole to locate the inner end of the baffle
@@AutoBeta2T wish I could send pics, there's a flat circular plate with a central hole the same as the baffle O/D which the inboard end of the baffle sticks thru by a few mm to keep it centralised. After that usually a few more similar plates which the perforated or fluted baffle pass thru to allow the gas to expand in stages thus reducing noise. If you have a worksop manual for the AR there's prolly a cutaway drawing
Come on mate we need more !........... pull a sickie and get a few things done :D Only joking :D great content and I honestly can't wait until its finished ............... If you need a 15 stone test pilot let me know :D
I'm guessing a 2 stroke trials bike essentially acts like the straight pipe in your model. Top end power isn't required and crisp bottom end is far more important so you don't want an expansion chamber complicating your carburetion. Just my thoughts.
Analyser un seul cycle donne un résultat faux. Il faut considérer 7 ou 9 cycles pour voir la superposition de tous les mouvements des ondes dans le résonateur.
Hi, the simulator does at least 15 simulations at each rpm point to allow the calculated dynamics inside the engine settle. This wave would I assume once this has happened. If I watch the pressure wave output as the simulator runs (blue screen) you can see that it take quite a few cycles for the waves to settle and stabilise.
Hi, sorry, I thought I had replied. The sim has to perform a certain amount of cycles at each rpm step, I think from memory it is 15 but you can specify higher. This allows the gas dynamics to settle down and give a consistent result.
I say at 3:05 that the left and right waves are theoretical but that is INCORRECT - they are real but can't be measured. Only the combination of both pressure waves, the superpostion wave can be measured. However, they can be calculated by EngMod2T and seen in WaveViewer2T
Yes, the issue is that it is not possible to differentiate each by simple pressure measurement due to super positioning.
Thanks for the shout out too :-)
@AuMechanic No problems - cheers
Nice clear vid, thx! , Now I wonder; since most people cant create a custom pipe, could you reverse engineer it to a bought exhaust pipe and reverse engineer cilinder port timing carbs and jetting? since most of those have many small budged or diy variations and a pipe is in most cases a 1 time high dollar buy, im planning on tunning a 50cc am6 with a LeoVince X-fight and wonder what carb to use, what reeds to use, what should the exaust port timing be to match the exaust best?(if at all possible), any tips or tricks?🤔🤗
Hi Omnificent and thanks.
Regarding the exhaust, I had a quick Google of that pipe but I can't see any specs for what timings it's designed for but I guess you could reverse engineer.
I used to race an Aprillia RS50 with the AM6 engine. From memory (about 10 years ago) we had a Hebo cylinder (193 ish exhaust 130 ish transfers) running with a KRD exhaust pipe. Carb was a 20mm Dellorto or a OKO 26mm with a sleeve to make it 20mm for the race regs. Ignition was a PVL one.
We had about 14 hp at 12500 rpm. Reeds were v force 2 I think but it has been a while.
Will your bike be on the road still? Are you planning on tuning the standard barrel?
@@AutoBeta2T thx for the awnser, and sounds like a solid setup indeed, I recently noticed the #Freetech50 races in europe, these guys get 20+hp from the little 50cc, fingers went ichy and wanted to pickup my old hobby from the late 80's (Honda MB8 honed, ported, 8valve reed... scary fast), stock in our country the 50cc2t are restricted to 45km/h, done with rpm limiters and plugs and bushes, so im gonna try undoing that stuff 1st before trying an airsal cilinder with 21mm carb(road use), most pipes dont give specifics though but found one that specifies a 7-11krpm range; SCR Corse Chrome for the 50cc, the fact that most pipes dont specify what they are designed for except maybe the cc's is exactly the problem im trying to overcome.. thx!🤗
No problems. I'm not sure if you can get them anymore but I have the dimensions of the KRD pipe somewhere if you want them?
@@AutoBeta2T I really wont be able to build my own pipe, but am planning on doing some cillinder and engine case matching/porting with easy to aquire parts (why I chose the am6 Yamaha TZR(basicly same as Aprilia RS50)), thats why I wonderd how to reverse engineer a setup with the bought exhaust pipe as a base.. thx!
@@omnificent9946 cool... I'm sure the pipe will work okay 👍 Hope the build goes well 😀
Excellent Dave keep up the good work 👍
Thanks Andy - will do :)
Hi Dave,
Hope you are well.
How are you getting on, has the exhaust made any improvements?
Hi Clive, not too bad thanks. Unfortunately I haven't made any progress since before Christmas. I've had a few things to deal with but it's all about done and I hope to get going again in the next few weeks.
Nice work mate !
Thank you Trevor ☺️
Loving the knowledge mate 💪🏼
Cheers mate 😊
My expansion chamber has a 20mm inside diameter pipe for the first 15 inches or 375mm long and then it begins to enter the expansion area. it has a 20mm id stinger as well
Is this going to prevent the negetave wave from returning to the cylinder ???
Do I need to taper the header from flange to expansion chamber ???
Should io buy a used 80cc dirt bike pipe and weld it on. to my factory flange ???
On a fixed income / Retired, so budget is pretty well non existant.
The engine is a motorized bicycle balanced bottom/ Mineralli top cylinder 47mm piston 40mm stroke =69.4cc.
Port timing wheel mounted on the engine, 85+85 = 170-degree exhaust begins to open and closes at, 55+55=110-degree intake transfers begin to open and closes at.
85 - 55 =30 degrees of blowdown, ( the time the exhaust starts to open to the time that the intake transfers begin to open).
So 30/110 = .2727 which is 27% blow down.
170ex 110in with 27% Bld.
These are the port timings that the Mineralli came with, (I cleaned and de-burred the port openings only)
Hi Dave. Thanks for posting these great videos on the AR. I'm eagerly awaiting the finale of whether you do get a ton out of this thing. I gather the AR playlist is in order and you are still on with the work? Cheers. Barry
Hi Barry - no problems and I'm pleased you are enjoying them 😃
With regards to the play list it should be in order apart from the sim stuff and pipe builds. I do need to review them again.
With regards to progress I'm hoping to get in the garage again this week and get the header done 👍
Hi Dave Nice video mate very informative. But in your sim of the TZ you have a major dip in the power curve before peak power. What do you think caused that and how does one find it in the sim data.
Hi Kenny, cheers.
I've not really looked at why there is the dip. I did notice it was showing deto in that area so I swapped to a different fuel and it stopped it. Also I think there has been a bit of an update with EngMod2T so possibly that may have caused it?
Enjoy the channel & couldn't resist being sub #1000!
Cheers mate for the thousandth sub 🎊😁🙏
Very good video, that software certainly helps you work out what's going on, in the old days I guess you be up to your neck in discarded cones!
Cheers Pete, it certainly helps with the visualisation of the waves. I've had to really understand (well... I think I do?) how the waves work in the pipe doing this video. Hopefully I may be able to cut down on waste cones now 😂
Still, I do intend to try plenty of real world pipes too.
@@AutoBeta2T Hi Dave. I think you understand how a 2 stroke pipe works as well as anyone else that I've come across on youtube (and a lot better than some people on youtube!). Hopefully you will get the BHP that you are looking for once your new pipe is up and running.
@@sidecarbod1441 cheers Pete
Would be interesting to see the waves in a standard silencer, front pipe, diffuser, belly then a flat plate with a hole to locate the inner end of the baffle
Hi Roy, could you elaborate a bit more in the flat plate with a hole?
@@AutoBeta2T wish I could send pics, there's a flat circular plate with a central hole the same as the baffle O/D which the inboard end of the baffle sticks thru by a few mm to keep it centralised. After that usually a few more similar plates which the perforated or fluted baffle pass thru to allow the gas to expand in stages thus reducing noise. If you have a worksop manual for the AR there's prolly a cutaway drawing
Ah - think I get you. As in the silencer?
Either way, if you have any pics you can email them to: autobeta2t@yahoo.com
Come on mate we need more !........... pull a sickie and get a few things done :D
Only joking :D great content and I honestly can't wait until its finished ............... If you need a 15 stone test pilot let me know :D
Cheers Trevor. I do need to get my finger out! Been a bit slack recently... :)
I'm guessing a 2 stroke trials bike essentially acts like the straight pipe in your model. Top end power isn't required and crisp bottom end is far more important so you don't want an expansion chamber complicating your carburetion. Just my thoughts.
Lewdog, that's how I see it too.
Analyser un seul cycle donne un résultat faux.
Il faut considérer 7 ou 9 cycles pour voir la superposition de tous les mouvements des ondes dans le résonateur.
Hi, the simulator does at least 15 simulations at each rpm point to allow the calculated dynamics inside the engine settle. This wave would I assume once this has happened. If I watch the pressure wave output as the simulator runs (blue screen) you can see that it take quite a few cycles for the waves to settle and stabilise.
Analyzing a single cycle gives a false result.
We must consider 7 or 9 cycles to see the superposition of all the wave movements in the resonator.
Hi, sorry, I thought I had replied.
The sim has to perform a certain amount of cycles at each rpm step, I think from memory it is 15 but you can specify higher. This allows the gas dynamics to settle down and give a consistent result.
Ooh ^^ a man with brain using vannik.
You can debunk all problems with this software.
Wtm, cheers 😊
Yes, Vannik's software is great and always evolving to make it better.