ESE's works engine tuner

[husaberg]

Rods and stuff
http://dl.dropbox.com/u/399336/Pictu...ted/HotRod.pdf
http://www.kingrod.com.tw/products.p...t&pc_parent=22
http://www.crankshaftparts.com/index...7_93&limit=100
http://shop.atlanticmotoplex.ca/prod...catalogId=2016
http://jjmachineryonline.com/snowmob...onnecting-rods
http://www.scooter-center.com/scoweb...y2=CAT&lang=en
http://www.bansheedepot.com/products.asp?cat=17

[Yow Ling]

Rods and stuff
http://dl.dropbox.com/u/399336/Pictu...ted/HotRod.pdf
http://www.kingrod.com.tw/products.p...t&pc_parent=22 Looks like a tkrj rip off?
http://www.crankshaftparts.com/index...7_93&limit=100
http://www.scooter-center.com/scoweb...y2=CAT&lang=en
http://www.bansheedepot.com/products.asp?cat=17

only the last 2 links work

[TZ350]

P 480 Tec interesting posts from last ten pages ... each decade page 440 ... 450 ... 460 ... 470 ... etc has a collection of posts and links from the last ten pages so its easy to skip through the thread and pick up the tec bits.

And I'm pretty sure the length and diameter of that parallel pipe were optimized to the millimeter.
Every duct in an engine plays a gasdynamics role, whether you want it or not, so you better make use of it.

I thinks you should think again, rgvbaz. Pressure differential does not equal flow; it equals acceleration. If there is a lot of inertia in the mass flow (a long gas column and / or a high flow velocity) a negative pressure differential will spend a lot of time slowing that flow down to zero before you will see the first sign of flow reversal.

This is very interesting as you can see the steep drop off in the 31hp graph, and at Taupo after looking at the speed trap times and gearing, the bike was running at 13,000rpm up the back and for a good part of the front straight, well in the exhaust gas down the transfers region.

Attachment 261086

The engine did not seize on full throttle running flat out, but after several down changes, when the throttle had been closed for a bit, maybe the cooling was marginal and when the cooling from the MJ fuel stoped, the engine stoped.

So what to do? an alloy sleeve with large tripple ports, not for power but for better thermal reliability ...

Then don't close the throttle .
The old 100 cc kart engines with direct drive were notorious in that respect. They were air-cooled, iron-sleeved and they revved over 20,000 rpm. When you cut the power at those revs, chances were that the con rod would quit; it needed the help of the compression pressure to stop the piston from going through the roof. So you had to brake first and then cut the power.
Common practice was to put a hand against the carb bellmouth and blip the throttle occasionally during braking to get some fuel through the engine. But more than one rider forgot how close the chain was to the carb, and had to remove his right glove with a finger tip still in it...
My solution was to fit a brake light switch to the brake pedal and connect it to the ignition cut-out wire. Then you could keep both hands at the wheel, saving your fingers, and keep the throttle wide open during braking. I would not advise you to copy this 100%, but think about mounting a kill switch and using it....

And if the triple ports would raise the power by coincidence, you wouldn't object too loudly, would you?
But sleeve and thermal reliability are another set of words I would not use in the same sentence. OK, an alloy sleeve is better than a cast iron one, but there will always be a thermal barrier between sleeve and cylinder body. Even with the best shrink fit, oil will creep between the sleeve and the cylinder; that oil will char, and gone is your heat path.
Believe me, I know; you cannot come up with a single mistake I haven't already made decades ago (there is a fancy word for it: experience).
All in all, I guess the triple ports may outweigh the disadvantages of the sleeve. But couldn't you make the ports without using a sleeve?

Something to think about while the rest of the family occupy themselves with buying, boiling, painting, hiding, searching, finding and eating easter eggs: a couple of recent videos from the Dutch 50 cc scene.
http://www.youtube.com/watch?v=mvV4x...feature=relmfu
http://youtu.be/0odVzSgufjk

It was designed and built by Richard Maas http://www.adriaanmeeuwsen.nl/team-pagina.html. Hopefully we will see it in action next monday.
And if I were you, I would make it go shorter with rpm .

More news from Richard Maas. Did his trombone pipe give the desired results? O yes. At 10,000 rpm it gives 4 HP more than the same engine with a fixed pipe. It runs over 17,000 rpm without the need for a powerjet and with a fixed ignition timing. It is miles better than an engine with an exhaust power valve. And the mapping of pipe length, ignition timing and powerjet pulse width has yet to be carried out. Maybe the powerjet can disappear altogether.
Only problem so far: the piece of pipe that is fixed to the cylinder, is shrouded by the pipe that slides over it, so it gets very hot. Too hot for the Viton O-ring that is taking care of sealing. Any bright ideas, anyone?

WTF ….. The Beast screams around the track on full song for a whole lot of laps then quits when taken out for an easy trot around in the two warm up laps for the next race, what is that all about?????

Attachment 261714

Damage is in the exhaust port area, and thats a steel ring thats cleanly snapped in two.

I will dig out the dyno graph and ignition curve.

The text of an email I received from Neels van Niekerk and posted here with his permission.

Attachment 261733

Hi Robert

I know it has nothing to do with me but if the engine that broke the ring this past weekend was running the attached export it is no wonder. My experiences with these size exports are the following:

1. Never exceed 41mm for your bore ( *** )
2. Use at least 10mm radius for top corners
3. Use 100mm top edge radius
4. use 12mm radius for bottom corners
5. Use 80mm radius for bottom edge

Exceeding these gave more power but lead to the following:
1. Unexplained seizures
2. Broken rings after cooling off at the end of a race - runs fine and wins race, refuses to restart
3. Pinched rings - from severe hammering of piston top edge
4. Broken ring land at export
5. Ring breaks at low speed - not sure why but I think it just have more time to bulge into the export

If the only way to be competitive is to run such a port:
1. Piston and ring life is max 50km
2. Bore must be perfect
3. Very good (rounded) chamfer of top and bottom edge

I really like reading your ESE thread - gives me good feedback about where to improve my software and it is great to see such an enthusiastic bunch.

Regards
Neels

*** 56mm was the bore size enterd into the simulator.

One small point is that in the area off the pipe, I have found that the engine will not make much if any more power, as shown by the dyno load it will pull, but by adding a heap more timing, it will for sure
operate much , much better on part throttle response, on track.
Here is a 125 kart engine curve that made 50RWHp,and won 3 back to back 125 National titles easily.

This thing would deto like mad on part throttle at 6000 if held there, but on track it would pull out of 1st gear hairpins hard enough to spin the tyres on full throttle from the same rpm, then rev out to 14200.

A TPS and a 3D map would achieve a better result, but I didnt have a RS125 Honda carb at the time.

I am wondering if this could be the problem? and I might need to use a TPS and go the 3D map way, or at least switch between 2 maps depending on rpm and throttle position.

The one and only reason you get a destroyed piston like that is DETONATION.

And looking at the Ignition curve you have posted it is immediately obvious why the thing keeps on blowing up.

These issues have nothing to do with an inherent problem with the 2T engine.

Thanks Wob, very informative and encouraging ....

get one of these with the extra wire to ground.
When it sees deto it can ground an Ignitech input and retard the timing automatically.
You get flashing lights and engine protection all in one shot, and cheap as chips - made in Czech so it likes being connected to an Ignitech - same lingo..
Works perfectly - when you get it trimmed correctly it will tell you where to manually pull out timing, then it just operates as a failsafe.

http://www.ebay.com/itm/Knock-gauge-...ht_1582wt_1297

When the ring ends but together, the ring becomes a very efficient oil scraper and you will experience the mother of all seizures.

A 74% port width should not cause any ring problems. If it does, it will be because of radii being too small. With good quality piston rings you can get away with 80% port width. But that will not do your power any good; such a width requires huge port radii that will take away much blowdown area at the top corners of the por tas the picture below shows.
70% width is optimal in this respect. And like Neels says, pay attention to the bottom of the port window. Rings have more time to bulge into the port when the piston is on the way down. And you can apply large bottom radii because that will not take away any blowdown area.

you can improve the power band by closing the disk early at low revs. But then you should also open it earlier because the transfer phase will be finished earlier at those revs and the rising piston will suck charge back from the cylinder to the crankcase if you do not open the disk as soon as crankcase pressure threatens to drop below atmospheric. So the best solution would be to rotate the whole disk.

[TZ350]

Posted because someone asked about them ....

Darcy Pipe specs:- http://homepage.mac.com/rg500delta/d...cyPipeSpec.txt

[Yow Ling]

Would be good if we could dream up a way to use these old RZ 250 barrels in buckets 54x54 pv watercooled , reed valve, one of them has a factory boysen port

[husaberg]

Would be good if we could dream up a way to use these old RZ 250 barrels in buckets 54x54 pv watercooled , reed valve, one of them has a factory boysen port

Strap 4 or better still 5 of them together and make a sidecar engine.
As far as i know there is no rules discriminating against home build 2 strokes in the sidecars.


Sorry I can't find a picture of the Bill and Bob speedway one.

[Kickaha]

Strap 4 or better still 5 of them together and make a sidecar engine.

We could use 10 of them, we're allowed 1300cc two strokes in sidecars, fuck knows where all the exhausts would go though

[husaberg]

We could use 10 of them, we're allowed 1300cc two strokes in sidecars, fuck knows where all the exhausts would go though

I was meaning the engines but a quick add up reveals he has enough cylinders so he could build 2 of them.TEN cylinder engines.
F the pipes routing problems think of the noise.
They built that v4 Cr500 in CHCH didn't they. So a V10 should be a doddle

[F5 Dave]

Rob, with the RG50 what you've done with the cage is much like an RM or RG250 tending to flat (mine may be slightly flatter) & I filled in the area between the back of the barrel & block with Devcon. I don't think the flow to the rear transfers will achieve much.

[TZ350]

I don't think the flow to the rear transfers will achieve much.

Yes, not to sure about them myself, I intended modifying the cases to match, sort of a Boyson port thing.

[dmcca]

Im getting an error message in Engmod2T that i havent seen before... SINGULARITY - INFLOW SUBSONIC

Any ides what it means? It reoccurred at every rpm point throuhgout the sim. Ive emailed Neels but thought id post up here also just to keep the engmod info flowing

[husaberg]

I came upon this today.

Slippy exhaust pipes
Why they're so difficult to pull, and how to fix it...
There has recently been a thread on the Mailing List in regards to the amount of effort required to "pull" the typical slippy (adjustable) exhaust pipe that is common in many road racing classes.
Well... A bit over 20 years ago, I had the same frustration, and I'll explain what I found, and how I solved the problem.
The image below show's an approximation of a "typical" slippy exhaust pipe. I have not shown the outlet hole in the "can"... (and a number of other things are missing as well), but this will serve the purpose for now. The moveable rear (convergent) cone is shown in its "out" position by the blue lines... and in it's fully "in" position by the green lines. The thick magenta line is a rough representation of the cable which pulls the rear cone/stinger assembly.

OK... here's the problem in a nutshell: The amount of effort required to "pull" the rear cone is directly proportional to the difference in pressure between the front and back sides of the moveable cone. (There's some other minor things like friction, but they're insignificant compared to the pressure differential).
Since the the rear cone (at its big end) does not fit the large center section perfectly, some "pressure" leaks by the outside of the cone into the area behind the cone. If the outer rear cone (the one that supports the stinger) has too much clearance on the stinger (where I wrote "Here's the problem"), then the pressure behind the rear cone can "bleed" into the can (which has lower pressure than the inside of the exhaust pipe). This results in a pressure differential between the front (engine) side of the rear cone, and the back side.
THAT is what you are pulling "against" when you try to pull in your slippy pipe.

Now here's how I fixed the problem...
Years ago, Hartman Engineering made some very nice spun "outer" rear cones especially for slippy pipes. I started with one of those. They were made with a very large hole on the small end. (Oh... the other thing that was really nice about those Hartman cones is that they were very short. This allowed you to get the weld to the center section a long ways away from where the adjustable cone would be sliding.... which made it easier to keep the center section nice and round).
I made an insert for the small end of this cone (shown in red in the drawing below). This "insert" had a bit of a "bell-mouthed" shape to the inside diameter. I did this so that I could run a very tight fit to the stinger, without the stinger "binding" due to any misalignment that might exist. I also took the stinger material (before welding it to the cone) and had it hard-chromed, and then ground the outside diameter. This made it perfectly straight and round, as well as giving me a super fine finish that would resist any sort of galling or seizing. I gave the insert about .005 clearance on the stinger (as I recall).
How did it work?
Too well. At the time I was running Open class. Due to the power, Open engines were notorious for being almost impossible to pull the exhaust pipe for the full race (an hour long at the time). My first time on the track with this pipe was a complete surprise. The very first left-hand sweeper I went through, the rear cone went all the way in by itself, just from cornering force! The pipe was actually far too easy to pull. My solution was to experiment with "vent" holes into the can. With the clearance that I had given the stinger in my "support sleeve"... as well as the fit of the large end of the cone in the center section of the pipe... I ended up running a 3/16" diameter "bleed hole" from the outer rear cone (the short steep one in the drawing below) into the can. This gave just about the perfect "feel" in my case. I could operate the pipe handle with one finger... yet there was enough pressure on the cone to move it back out fairly quickly when I let go of the handle.

You may not care to build your own slippy pipe... and we're seeing less and less classes where slippys are allowed... but hopefully this might help some of you that still run them.
Just remember: the effort required to pull the rear cone is directly related to the pressure differential on the front and back sides of the moveable cone. Anything you can do to prevent leakage around the stinger and into the can will make the pipe easier to operate... up to the point (I discovered) where it's too easy.

[TZ350]

Thats interesting. After looking at the trombone pipe I was wondering how the very long variable header fitted in with the requirements of keeping the header and diffuser within certain % limits of the pipes tuned length but combined with the slippery it might be possible.

[Frits Overmars]

There are several options in lengthening a pipe. You can move the end cone, like on the above drawing, or you can lengthen the header, like on the trombone pipe.
The gas pressure generates a force that is proportional to the cross section area of the moving part and proportional to the pressure difference at either side of that area. For a moving end cone this force can be up to 4 times larger than for a sliding header. That is one reason to go for the trombone system rather than the moving cone system.

The second reason: say you wish to lengthen the total length of the pipe by 10 %. If you do it by moving the end cone, you will also enlarge the pipe volume by a little over 10 %.
But in a good pipe configuration the header length is about 1/3 of total pipe length, so in the trombone system, lengthening the pipe by 10 % will result in lengthening the header by about 30 %. That gives a far greater variation in the pipe's Helmholtz frequency than a 10 % volume change.

It is true that the length percentages of all pipe components should be in a rather fixed relation to each other. Varying the lengths of all components by the same percentage would be the theoretical optimum, but that is not feasible.
Lengthening the belly will disturb the optimum relations, as will lengthening the header. So the pipe in its lengthened version will not be the optimum for the low resonance rpm dictated by the length. But it will be a hell of a lot better than using an exhaust power valve that spoils the 180° effective exhaust timing, necessary for true resonance.
And a pipe shortened beyond its optimum may not show the optimum length relations between its components either, but it will be a lot more effective in overrev than artificially raising the exhaust gas temperature by retarding the ignition, or by weakening the mixture strenght through closing a power jet, which has the disadvantage that not all inhaled air is used for combustion.

[TZ350]

... weakening the mixture strength through closing a power jet, has the disadvantage that not all inhaled air is used for combustion.

I thought that closing the power jet after peak power only restored the proper air fuel ratio? And the over rev was extended because the exhaust gas was not being cooled by an over rich mixture.

... It is true that the length percentages of all pipe components should be in a rather fixed relation to each other. Varying the lengths of all components by the same percentage would be the theoretical optimum ...

I guess that's what happens when water injection changes the temperature of the exhaust gas, water injection looks like it would be a good idea if it was practical and didnt have any down sides.

... say you wish to lengthen the total length of the pipe by 10 %. If you do it by moving the end cone, you will also enlarge the pipe volume by a little over 10 %.

But in a good pipe configuration the header length is about 1/3 of total pipe length, so in the trombone system, lengthening the pipe by 10 % will result in lengthening the header by about 30 %. That gives a far greater variation in the pipe's Helmholtz frequency than a 10 % volume change.

I have simulated the Slippery pipe in EngMod2T before and was not that encouraged by the results but your explanation of the Trombone looks interesting and I will try that in EngMod now.

Lengthening the belly will disturb the optimum relations, as will lengthening the header. So the pipe in its lengthened version will not be the optimum for the low resonance rpm dictated by the length.
... And a pipe shortened beyond its optimum may not show the optimum length relations between its components either, but it will be a lot more effective in overrev than artificially raising the exhaust gas temperature by retarding the ignition, or by weakening the mixture strength through closing a power jet, which has the disadvantage that not all inhaled air is used for combustion.

More good old engineering and design compromises to play with.

But it will be a hell of a lot better than using an exhaust power valve that spoils the 180° effective exhaust timing, necessary for true resonance.

Do I understand this correctly, given sufficient blow down and exhaust STA an exhaust duration of 180 deg would be the optimum at any rpm?

Thanks Frits ..... gives me a bit more to think about.