ESE's works engine tuner

[mr bucketracer]

Start another thread on hydroforming. It's been talked about on this one a bit but it's specialised enough - and enough are interested - to warrant it's own thread. And it gets your post count up as well....
Nice to see what you've done. Good work. Those long winters in Finland are obviously productive....

dont mention the war

[WilDun]

dont mention the war

No doubt, you mean the war between four strokes, two strokes and the inefficient use of fuel - (I hope!).

Thread on hydroforming sounds like a good idea - or on making and desigining pipes in general perhaps? especially as this Ryger thing will most probably change things considerably.

Just random thinking (out loud)

[adegnes]

What are the dimensions of your dyno roller TZ? Asking for a friend.

Ok, there's no friend. I'm in the planning stage of a dynobuild.
How does your dyno cope with more/less powerfull bikes? I was hoping to be able to run bucketish stuff, but also old 90hp+ force fed fire breathing dirt trackers - might be a bit much to ask for...

[JanBros]

We´ve been building mopeds and two stroke parts with very small budgets in our garage.
Sorry if too many pictures!

great pictures

went through all of them on your site. one question : what is it with that MIG welding torch sticking inside the boxes ?

[Frits Overmars]

What are the dimensions of your dyno roller TZ? Asking for a friend. Ok, there's no friend. I'm in the planning stage of a dynobuild.

Try this:FLYWHEEL.zip

[Tunisti]

Thanks guys!

I´ll make the exhaust pipe thread, when I have time to do it. It´s actually quite usual in Finland, that boys even under the age of 16 hydroform exhaust pipes to their mopeds... I think I was something like 14 years old, when me and my friend made the first exhaust pipe, it was ugly as hell and made of cones.

Adegnes: I was not asked, but our DIY dyno has inertia of 5kgm^2 and roller circumference of 1280mm. Rotating mass is about 170kg (including lake-ship´s flywheel and tracror compressor´s belt wheel). Even though, I´d say that even rather small inertia values can be enough (say 2-3kgm^2 in your case?) when the roller can tolerate high speed pulls and the data logging is accurate enough. Ofcourse there is also that variable, how fast your bike´s rear wheel tends to spin on top gear pull, say 140kph top speed (with 50rwhp and 5kgm^2 inertia) could easily lead in to too short pull, distorting the natural thermal etc. loads compared to driving situation.

JanBros: Do you mean these pictures?


That´s the poor man´s sodium silicate hardener! I use CO2 as MAG welder´s shielding gas, so it´s a good way to "gas" those sodium silicate bindered silica sand cores into solid form. I´ve calculated the right gasing times for different amounts of core material, so no extra gas is accidently added in to the boxes. I can publish those calculations later, in the raport.

War.. If you mean the Soviet thing, that´s not what Finns are nervous about now. Middle east refugee invasion is happening right now, thank´s to EU...

[adegnes]

Try this:FLYWHEEL.zip

Thanks Frits, I'll check it out in the morning.

Adegnes: I was not asked, but our DIY dyno has inertia of 5kgm^2 and roller circumference of 1280mm. Rotating mass is about 170kg (including lake-ship´s flywheel and tracror compressor´s belt wheel). Even though, I´d say that even rather small inertia values can be enough (say 2-3kgm^2 in your case?) when the roller can tolerate high speed pulls and the data logging is accurate enough. Ofcourse there is also that variable, how fast your bike´s rear wheel tends to spin on top gear pull, say 140kph top speed (with 50rwhp and 5kgm^2 inertia) could easily lead in to too short pull, distorting the natural thermal etc. loads compared to driving situation.

Thanks for the info, you are of course welcome to answer!

[2005bully]

Tunisti.... Looking forward to hearing a lot more about the projects you have been working on.

[peewee]

Hmm.. I think that there must be somewhat dirty mixture inside the barrel, when all ports have closed. At least if the combustion is somehow sorted as knocking. Haven´t really figured out, but I have a theory that mixture involving exhaust gases tends to have lower peak temperatures and the "flame" speed of "knocking" is reduced to moderate rate via the impurities bethween ignitable "packages". This would not only lower the NOx emissions, but also allow leaner mixtures to be used -> reduced HC emission.

If the knocking-like combustion would occur in pure charge, there would be large broblems with heat and shock-type stresses to mechanical parts. I remember Frits or Jan talking about the knockings effects on macroscopic levels: The shock waves tend to "blow off" a thin layer of insulating gas from the metal surfaces (ie. piston), introducing the surfaces into situation where the heat conductivity increases significantly. I wonder whether the Ryger concept has some kind of trick to keep the insulating layer of gas on the surfaces, despite the exposure to shock waves.

And then there´s the theory, that spark plug would give many sparks or one "conitnuous" spark, meanwhile there would be huge squish velocities forcing the charge right into the spark gap. Meaning that the flame speed would be artificial or the charge would be ignited in several points (spark plug stays in place, mixture to be ignited moves due to the shape of cylinder head). At least, the melting of the electrode would be an issue to be considered, when knocking-like combustion would occur with fresh mixture... Continuous or multiple sparks could also build up excessive heat to the electrode, I guess...?

Btw. I´m about to order some 20kg of Vinamold. I was wondering whether to buy only red, yellor or half and half both of them. I would need to take some castings from exhaust- and transfer ducts, but I don´t have a clue how well the yellow one wants to settle in the duct and how hard it is to get out of there. On the other hand, I don´t know how floppy stuff the red one is, since it`d be bad thing if the castings would bend under their own weights. My plan would be to copy the Vinamold pieces into plaster of paris, so it is important that the pieces would bend as little as possible. Any tips what to do?

Thanks for the comments! I´m going to post some DIY casting reports to Bucket Foundry topic, after I´ve translated them. Where should I post step by step instructions/reports about manufacturing of hydroformed exhaust pipes?

Btw. How much do I have to spam, before I can send private messages?

red vinamold works well but ive never tried to make a plaster mold over the top of it. i dont see why it wouldnt do fine however. one thing that i found is to put a small amount of 2t oil on your finger and grease the duct walls. this will make removal very easy. have a look at the pdf files i posted if you havent already

one question about hydroformed pipes. are they easier to make and require less tools than coned pipes ? what about if the pipe needed to have several turns ? i would like to try and make a pipe but i dont have anything to cut or roll the cones

[mr bucketracer]

No doubt, you mean the war between four strokes, two strokes and the inefficient use of fuel - (I hope!).

Thread on hydroforming sounds like a good idea - or on making and desigining pipes in general perhaps? especially as this Ryger thing will most probably change things considerably.

Just random thinking (out loud)

last time I bought up hydroforming I got my head riped of

[husaberg]

last time I bought up hydroforming I got my head riped of

There is a real good video on it on pitlane I think. That ended in an argument as well.
I will see if I can find it. I can't it not the one in the thread
this is the thread anyway Howard Gifford is bloody good at it.

https://fbcdn-sphotos-g-a.akamaihd.n...8b1e7698dd8b81
http://www.pit-lane.biz/t3107-gp-125...s-welded-cones
Here is some pipes he did

[seymour14]

last time I bought up hydroforming I got my head riped of

That's because you are one of the few people who can successfully do it.

Otherwise it's those godawful cones...

[Grumph]

last time I bought up hydroforming I got my head riped of

yeah, well, according to wob the dyno doesn't lie. From my point of view, there are people who want to try doing it this way and some guidance from those who have done it successfully wouldn't go amiss.
Remember too the pipes made don't just have to be for 2 strokes...which is why a separate thread makes sense.

Personally, i've just done a set of four curved megaphone exhausts for a big CB350/4 - and now know just enough to be dangerous.

[WilDun]

last time I bought up hydroforming I got my head riped of

Persistence is the answer,
No doubt you had plenty of that when trying to master the art!
Don't allow anyone give you negative criticism if they haven't produced something acceptable themselves or at least made a good effort (with evidence)! - if they have done well, then listen.

[Lightbulb]

When making pipes for the N40 6.5cc engine, the pipes with the sharp edges, ie cones , did not perform as well as the CNC from barstock can parts brazed together. There was numerous challenges to make the sections in 1 operation, instead of making the inner shape and transferring to a mandrel for the outer. I even made some steel pipes to see the differences in performance. All the CNC section pipes out performed the cone pipes for our engine at the time. I have not done more pipes for a while as the one we have is still doing everything we need from it.
Neil