ESE's works engine tuner

[TZ350]

Hmmmm, I didn't know all that goldmine of info I extracted from Frits and Jan had made it into the english speaking world.
Ah well .................................................. ..........

I am glad you got them talking, I recently stuffed up my password or forgotten it and now can't get back on and view the pictures. Anything you wanted to post would be welcome.

[TZ350]

Finaly got the V Tec working..............

closed open

RC Servo, Servo Tester, Signal Reverser and Com/NO/NC relay that the Ignitec can activate.

Video of the V Tec in action http://www.youtube.com/watch?v=FeB9O6rtLXQ

Next step is to fit it to the bike, wire it up so that it opens at 7,000 rpm and see how it all goes on the dyno.

[2T Institute]

I am glad you got them talking, I recently stuffed up my password or forgotten it and now can't get back on and view the pictures. Anything you wanted to post would be welcome.

No need for me to post anything Wobbly's doing a great job already

[Moooools]

Finaly got the V Tec working..............

closed open

RC Servo, Servo Tester, Signal Reverser and Com/NO/NC relay that the Ignitec can activate.

Video of the V Tec in action http://www.youtube.com/watch?v=FeB9O6rtLXQ

Next step is to fit it to the bike, wire it up so that it opens at 7,000 rpm and see how it all goes on the dyno.

Ahhh. The simplicity of two strokes. So few moving parts.

[husaberg]

In a discussion with Thiel he said he tried an RSW with no pipe ( no expansion chamber) it took days to get the ignition curve and the jetting to work at all,cant remember what the power was ( 20% I think).
So you have an engine that makes 12Hp at 8000 rpm and that is supposed to help you ascertain the correct intake length for an engine that makes 55 at 12800 - Puleeeease.

Your post actually got me thinking about something else about pipe acoustics, Something I struggle to get my head around is this.
As I understand the negative wave as well as drawing more fuel air in during the normal indution cycle can also keep a reed valve open to draw in more fuel air mix.
But in a rotary valve engine the inlet is positively closed does this mean a properly designed exhaust would have less effect on a disk valve engine. Or just it will influence over less time with a stronger pulse Are expansion chamber characteristic/perimeters different for Reed vs. Rotary valves?

! million to design the clinders? Sounds like a lot but if you think about it another way its only $333333.33 each

Regarding the breasts cut the breasts off and yes I would still go there, I am a little sadistic though.

I believe one of the other gp racers of the period was even less discerning and had a interesting lady boy encounter which was quite a sore point for a number of years was it lC?

"There are more than one way to skin a cat
Some ways may work better than others,
Some people may think other peoples methods are crap ideas.

But your kidding yourself if you expect the cat to be happy about any of them"

[wobbly]

Well thats one of those old wives tales ( or tuners tale if you like).
The depression created in the case by the diffusers outgoing + wave,sucks like hell on the cylinder, via the Ex duct, around BDC.
That is, if its properly designed for maximum effect at peak torque.
There is simply insufficient time for this effect to suck mixture thru the transfers, empty the case, and then start sucking the reeds open.
It just doesnt happen.Its lies, a myth,not reality at all.
And to make it worse, if the diffuser is designed correctly, when it works best, there is the least time period ie full noise.
In a race engine at peak torque (same as peak power in many cases)the reeds do not start to crack open until the piston is travelling upward and is covering around 1/2 the transfer height.
So in this respect this is about the only similarity a race engine has with your dads old lawnmower,in that the rising piston creates some of the depression needed to initiate intake suction.
As I have posted before,this can be "tuned" in as much as correctly timing the wave return at the reeds as + just as the case starts to go -, you create the max effect possible by using free energy to open the reeds.
Sure, the better the pipe, the sooner the case goes below a zero pressure ratio, and this has only a minor effect on the reed opening point - but there is NO FLOW created by the pipe "sucking" on the reeds, its bullshit.
Rotary valve intake tuning is highly affected by resonance effects due to the very "sharp" open/close scenario,creating high amplitude "shock" and standing waves in the carb - but inherently the pipe is working with the cylinder contents, not the case vol, and thus the design parameters are to all intents identical.


Look again at the F3 engine I am building - the reed tip lift is only just starting to allow real flow, when the transfers are closed.
When in full resonance mode ( in this case its designed to work best in the overev ) the reeds open a little earlyer, and stay open alot longer due to intake "ram" but there is little evidence of pipe effects, even the reed closing side of the trace has nothing to do with "pipe suction"..

[F5 Dave]

. .
There is simply insufficient time for this effect to suck mixture thru the transfers, empty the case, and then start sucking the reeds open.
It just doesnt happen.Its lies, a myth,not reality at all.
. . .

Ooh I love a good sweeping statement. Actually I'd expect this is true, it makes perfect sense.

ok but as a side argument of a slightly different scenario, starting with an old Cameron article he was on about some tests McCulloch or some crowd were doing with high speed cameras & windows in the reed chamber. Their observation was of the intake phase completing & the reeds closing. Later the upper middle finger opened again & fed the boost port. That would tend to indicate;
1. that they weren't working on a chainsaw engine unless it had a 6 petal reedblock fitted to it.
2. the reed was responding to pressure difference in the cylinder.

So the crankcase didn't have to be involved directly. So would you say this reputed direct feed is an exception? Or that it wouldn't happen on a real race engine? Or they didn't interpret it correctly & there was some other reason?

I'm presuming the info to create these sims must come from observation of engines & localised pressure measurement & high speed video. Having trawled through some of the SAE & Belfast stuff I suspect getting those numbers is 9/10 extremely boring with the tid bit of hey this is really good.

[wobbly]

Only the middle reed opened - wow, a real odd artifact you would never expect,but that sort of shit happens all the time.
I would get a migraine trying to fathom that one.

One other point to mention here, one I have posted before somewhere.
If you look at the delivery ratio of a race engine, then calculate how much actual mixture is transmitted thru the transfers into the cylinder - compare that to the swept vol of the transfers, you realize that in most engines,what is sitting in the ducts is more than the vol going to the cylinder.
So where is all this so called case flow that supposedly opens the reeds, it aint there at all.
This is why new technology has the transfer ducts getting smaller and smaller,the stored volume has less inertia and gets into the cylinder quicker with the same pressure ratio across the ports.

[F5 Dave]

Oh boy & on a friday afternoon you have me having to think?

Wouldn't the boost port act like a vacuum cleaner pipe aimed at a stack of leaves? A localised suction of the closest leaves, meannig the middle upper finger reed would be affected by the boostport. Perhaps. Hey just shooting the breeze.

. . .
If you look at the delivery ratio of a race engine, then calculate how much actual mixture is transmitted thru the transfers into the cylinder - compare that to the swept vol of the transfers, you realize that in most engines,what is sitting in the ducts is more than the vol going to the cylinder.
. . ..

erm, presumably pressurised in the ducts flowing into a what becomes a vacuum & hopefully still flowing as pressure rises with inertia. Is the volume comparable?

Don' you want the inertia to continue filling?. On the other hand if you have mega flow area then the transfers close before they used to have to.

[husaberg]

This is why new technology has the transfer ducts getting smaller and smaller,the stored volume has less inertia and gets into the cylinder quicker with the same pressure ratio across the ports.

Wouldn't the increase in velocity balance the decrease in volume (mass) so the inertia be the same.
What basic bit am I missing.

ps what did you think of the alpha conrod any merit for a reed engine?
never seeen a yzr rod but i guess they pretty much looked pretty much like any other.

Also did any other Gp teams use slave engines like buds old test mules?

I have a good job.
I pay my taxes.
Part of my taxes goes to support the unemployed.
I am ok with that it kind of makes me feel good about the world and all.
As part of my job I have to submit to random drug testing
I am ok with that too because life’s depend on me doing my job well.
But why is it the recipients of my tax money don't have to do a drug test before they get my tax money.

[Henk]

I'm guessing that the decrease in volume does lead to a decrease in mass and therefore inertia leading to an increase in acceleration of the charge.
The lost volume if I'm reading this thread right is gas that can't be accomodated in the cylinder anyway so you aren't trying to moving gas that that can't be used in any case.

[husaberg]

I'm guessing that the decrease in volume does lead to a decrease in mass and therefore inertia leading to an increase in acceleration of the charge.
The lost volume if I'm reading this thread right is gas that can't be accomodated in the cylinder anyway so you aren't trying to moving gas that that can't be used in any case.

Sorry Henk.
I am still not quite getting it

Surely these left over gases lurking arround in the transfers contribute to the first part of the charge for the next revolution or are we trying to minimise this because it has a some kind of stalling effect because the charge has to be accelerated again?Or is this charge lost in the pipe and not rammed back because its to early.Wobbly should be able to correct my faulty underdstanding of this I hope.

i understand the f=ma stuff but wobbly didn't quite say this i think. but I will re read his post - beer fog input

Just re read - fog and I think he is say newer versions have smaller transfers so they have to use less force to acelerate the charge and there for will maintain a higher velocity?

I'm guessing that the decrease in volume leads to a decrease in mass giving an increase in acceleration of the charge.

So early development of the 2 stroke was about pressure ratio to give good cylider filling?

Later it was tried to get a good (volume) mass of mixture to flow .but it lead to, too much pumping losses?

And now its all about a fast velocity of fuel air charge and at the same time to lowering pumping losses by running a low presure ratio.being more effiecient.

[Yow Ling]

Seeing as this is the thread for engine development stuff, I thought I would add a bit more about my Moto4 Engine

I had to cut the kickstarting stuff off the back of the engine so it would fit in the RS125 frame, I took it to the leading bucket welding tech in Christchurch, Darryl Cotton at Advanced Autohomes to have the gash patched up. Ready the next day. Cost $42 cheaper than getting tyres changed at Haldanes.

Just needed to tidy up the mating surfaces, after a bit of head scratching I came up wuth a setup that would work. Cases tidied up ready for the stuffing everything back in stage, which is tricky because its over a year since I unstuffed it.

Heres a few pics of the machining work, not sure about the order

[TZ350]

I had to cut the kickstarting stuff off the back of the engine so it would fit in the RS125 frame.........

Interesting to see the progress, and whats needed to get the RG100 into the RS frame .........

[Yow Ling]

Oh yea , ordered a piston the other day from Strike in perth, somebody posted a link on this thread . They make a range of pistons for yamaha Kart engines. Normally KT100 pistons start at around 52mm but they make pistons starting at 50.00mm for the junior classes, I ordered a 50.6mm so will end up at 101.75cc, oversizes are tiny so you only need to hone to the next size. About NZ$100 for a piston. Built a crank a couple of weeks ago, motivation is high , very cold in shed tonight !