ESE's works engine tuner

[wobbly]

Jan , thats sad to hear of Rumi - he obviously ripped you off personally.
I always thought his 125 engine design looked really well thought out, with a dead straight inlet above cylinder.
Unlike Vankerveens 45* bent intake on his horribly uncompetitive cylinder down later design.
He probably had no water cooling around the Exhaust Duct as well, as you well know he was adamant that was " better ".

[husaberg]

Jan , thats sad to hear of Rumi - he obviously ripped you off personally.
I always thought his 125 engine design looked really well thought out, with a dead straight inlet above cylinder.
Unlike Vankerveens 45* bent intake on his horribly uncompetitive cylinder down later design.
He probably had no water cooling around the Exhaust Duct as well, as you well know he was adamant that was " better ".

years ago i posted a pic of the jan wittenturd engine.
i cant be assed looking for it but he just got a kart engine and flipped it even the gearbox some plug was left on an upside down position.

[husaberg]

Well i could be assed


TBH i had forgotten about the disc valve rumi


Am i the only one that gets excited about chromate finish on engines?

Yep, here is the Rumi "upside down " reed engine with dead straight inlet ie done right, unlike Mr Ws half arsed attempt.
Then there is the Rumi rear valve - not alot done wrong there, but I dont know the detail.

Who knows the RUMI details ?
Frits your turn

Here is another shot I found on EMOT

This was the engine i was meaning it seems by the simple expedient of turning an existing kart upside down a "new Engine" was thus created.
If you look at the oil Breather/Filler housing and surround on the Kart engine (right pics in compliation), and compare then it to the Maxtra Haojue engine Drain plug, you will see what i mean.

The Rumi engines have there own thread on pitlane.

Here's some more photos of the Rumi GP

http://2stroker.createforumhosting.c...=0&&view=print

Here's a relevant quote too from Jan Thiel: (auto translation from Dutch)

Rumi The engine was not a success but there were still some nice things, and also
some big drawbacks. The gearbox was designed by an artist who also
has signed a number of F1 engines. This tank had no seeger rings and washers and you
could him after removal of the cover without tools apart. There were also 3
different primary ratios, you could cover the primary disassembly without the ignition
rotor disassembly. The crankcase halves and the lids were sealed with O-rings. The engine is the cylinder downwards designed for 2 reasons. Rumi wanted an engine that was different from all others (no good reason) I myself had to Garelli once did a test with a kilo of lead in the tip of the keel of the fairing. Gresini found that the motor thus better sent, so I thought the cylinder down like a good idea. The carburetor was thus rightly at the place where normally the radiator sits. I thought this to fix the radiator in a different place to put behind us, under the tank. Something like the British did. The frame was made ​​by Nico Bakker, with even a monoarm swingarm for more space for the exhaust. The frame is also made ​​but were not collected nor paid. Rumi had a frame in Italy, with the radiator in the traditional place. Thus came the carburetor between 2 radiator little to worry about as a result poor cooling, hot air inlet and no place for a good airbox. Also, it was very difficult to place the outlet to find the thick part came up right where the footrest Sat We solved through a hole in the frame to make the exhaust was then in an s-curve before the rear wheel backwards along with the muffler under the seat. This went well but was very difficult to make. On the test bench to ensure no power cost. There were also problems with the mechanical Niese water pump 3.5 HP cost. A elektriese pump made ​​the ignition after a while too little power and the engine was badly began to walk. Rumi began increasingly to technology to interfere where I think he totally did not know, was also the organization of the team unimaginably bad. then also pay my salary a growing backlog was I decided only to disband, after eighteen months work.

Last but not least, another set of photos through the Rumi pits:
http://www.2t-special.it/forum/viewt...=3333&start=10

Finally, an upside down pavesi :P
http://www.motoripavesi.it/img/motore_moto_6_big.jpg



ps. I have mentioned it before, but it is possible to search any pic through google images. it usually leads to more relevant photos and info.

Sure. Much has already been said in Jan's Google-translated story above. But I'm not sure I would have understood one word of that Googletalk if I hadn't been there myself at the time and could reconstruct ill-translated Dutch words and expressions.
But I've got a problem: I can neither see nor post PNG-pictures on Kiwibiker. I run Windows 7 with Internet Exporer 8. On a friend's computer with Windows 7 and Google Chrome I can at least see the PNGs. Suggestions anyone?

There you go Frits!

http://www.winhelponline.com/article...-Explorer.html

Win Vista > same kernel as Win7, Vista~=7.
Why not also try the IE 9, which is a much better and faster browser than IE8?

Thanks dinamik, but I get this: "Cannot import C:\Users\FOS\Desktop\pngasso_vista.reg: Not all data was successfully written to the registry."
The problem with PNGs refusing to show only occurs when I'm visiting Kiwibiker; all other programs function OK.

Why not IE9? Because Microsoft won't let me install it, saying I should first substitute my beta-version of Windows7 with the final version.
You don't happen to know a way around that, do you?

[aljaxon]

hi everyone, ive been awol for a long time. good..... i hear some of you saying.

for years i was of the understanding that it was the crankcase and crankcase compression that delivered fuel up through the transfers into the cylinder.
then a couple of years ago i read on here or on pit lane biz that on modern designs the crankcase was only of use for starting the motor and once running it was down to the exhaust pipe to draw fresh charge up.

i just searched on google to find this and cant see it anywhere. is this belief still so? has it been shot down? or did i imagine reading this? old age and memory etc
cheers

[wobbly]

Crankcase compression is only a direct factor for transfer charging flow in a lawnmower.
In modern engines with a " proper " expansion chamber it is the diffuser that creates a depression around BDC that pulls mixture from the case, thru the transfer ducts
and into the cylinder. If the axial and radial angles of the transfers are correct, this negative pressure ratio at the port creates a coherent intake charge column that is angled back toward the rear wall,
and this then loops across the cylinder head and down toward the Exhaust port.
The larger the depression, and the better the transfer design, the higher the Scavenging and Charging Efficiency within the cylinder.

[aljaxon]

Crankcase compression is only a direct factor for transfer charging flow in a lawnmower.
In modern engines with a " proper " expansion chamber it is the diffuser that creates a depression around BDC that pulls mixture from the case, thru the transfer ducts
and into the cylinder. If the axial and radial angles of the transfers are correct, this negative pressure ratio at the port creates a coherent intake charge column that is angled back toward the rear wall,
and this then loops across the cylinder head and down toward the Exhaust port.
The larger the depression, and the better the transfer design, the higher the Scavenging and Charging Efficiency within the cylinder.

excrellent thanks wobbly. glad i'm not losing my marbles after all.

[ApolloMotoMoto]

As usual, I'm seeking advice.
My water-cooled Honda 50, with a 26mm carb, has EO 192, the ex port extended to twice the bore and water-cooled, with the Wobbly reduction to 90% at the flange. The CR is 14.0:1, running on 98 pump fuel with Motul 800 at 30:1.

I designed and built a pipe using a planned peak power RPM of 13000, using guessed EGT of 470�C. This gave SoS of 546m/s, and Lt = 672mm.

After much racing with this pipe, a dyno session showed the peak power RPM to be at 11800.
Of course, with a single ex port, blowdown is compromised, but there is reasonable over-rev (see graph), so I don't think the low RPM is due to that.

Calculating back, with known Lt and peak Power RPM, the actual average SoS is only 496m/s, suggesting an average EGT of only 340�C.

If I now make a new pipe, using this EGT and SoS, and still aiming for 13000RPM peak, Lt will be 610mm.

But maybe the higher peak power RPM would produce a higher EGT, so the pipe would then be too short.

So should I compromise somewhere between the two values of Lt for the new pipe?

Attachment 357691

If I were to channel my inner "wobbly" and attempt to throw down a hand at 'long distance troubleshooting roullette'


My first question is, why so cold, Batman?

Targetting 470c with the pipe design???

That should be ~600c if you want to make real power.

Only achieving a derived (not directly measured with high speed EGT probe....) 340c?

Re-running the pipe design for 340c would NOT be my first advice.

I would first wonder why your pipe is so cold to begin with, assuming it truly is.

The most likely culprit from a general theory perspective would be the tailpipt outlet diameter. Often termed "D_restrictor" in some pipe formulas....

If you have the exact diameter in your pipe on the bike from the formula you used, and you are that far under the formulas target EGT, I would have questions about the engine actually meeting the input parameters that went into the pipe calculator, or the pipe calculator itself, is it the FOS formula?

You should be closer to 600c EGT for an incredibly general ideal.

Being cold either means you are not delivering the heat energy that the calculator assumes you would have been delivering to the pipe or the tailpipe diameter on your actual pipe is larger than the calculator actually spit out.

Making the tailpipe restrictor diameter smaller WILL increase the pipes EGT, and if you are currently "too large", making it smaller WILL bring with it an increase in power up until the point where you go "too small" and you burn holes in your piston, so there is a balance point to be found, and the pipe formula wont give you the EXACT perfect number for your engine. It SHOULD give you a generally safe place to START, and you tune it from there.

Generally speaking shrinking the tailpipe diameter is going to increase the EGT.

Inreasing the EGT will increase the net temperature of the pipe.

Increasing the temperature of the pipe will make the speed of sound within it FASTER.

Faster speed of sound = faster wave travel.

Faster wave travel = pipes natural "resonant frequency" goes up.

Well look at that:


1. You pipe is too cold (not metting the formula number).

2. Your pipe is peaking at too low an RPM (resoanant frequency LOWER than formula number).

So, logic says:

Make the pipe hotter (decrease tailpipe restrictor diameter) and you will see an attendent increase in pipe resonant frequency, maybe even landing exactly where the formula said you would be once you actually achieve the 470c EGT you entered into the formula.