ESE's works engine tuner

[Frits Overmars]

On the off chance that somebody here is interested in motorcycle racing:
live-stream of the Italian Grand Prix at Mugello
http://live.drakulawidget.com/stream...g-4669250.html

EDIT: here's another link in case the first link stopped working, as it did on me:
http://www.fixalen.tv/20180601/vv-19....87771154.html

[Muhr]

Yes constant radius is good as air takes it 'shape' and you don´t 'alter it'.
But what i find might cause a problem is that the runner is tapered to hard.

And to use in calculations, the highest crankpressure is just before you open the transfers.
Some sort of a small blowdown(blow in?) period so to speak.
Thereby you would have the highest airspeed some degrees before btdc.

I have done many different simulations with many different speeds and designs, even blow back.
below might explain why this was done.

[teriks]

Happy birthday Jan and many thanks for your contributions to this thread.

Happy birthday, and.. what TZ said. Cant come up with anything better to say..

[katinas]

Happy Birthday Jan, best wishes and thanks.

https://www.youtube.com/watch?v=UQD3LJhwDt0

[Muhr]

I have not met or talked to you but I have spent many hours trying to understand and learn from the imprint you put in 2-stroke development. Thanks and happy birthday

[TZ350]

.
Ok, another little step along the way.



Gave the Arduino concept a try out today.

The EFI CPU was still running on only the Alpha-N map so I expected it to run fairly badly (to rich) but only really wanted to see what the crankcase pressure readings looked like and whether it looked like it might be useful for seeing changes in air flow at low throttle settings.

Fired the Beast up and gave it a few blips.



Map sensor = Green line, TPS = Blue and RPM = Brown.

The MAP sure looks responsive enough and the numbers make sense.

It looks like we can now see real time changes in air flow at throttle settings below 25%.

The next move is to re do the mapping to include a VE table (may take a week) and see what the drivability looks like.

I am starting to feel hopeful that we are on the right path now.

[peewee]

happy birthday jan. thanx for all the great work you did over the years. it has helped me a lot, as I was able to apply it to my own engines . thnx

wob you might be interested to know the bored out 3.5 float valve is working great on a running engine. worked good on all bench tests but I wasn't sure if the engine vibration or head pressure from the tank could cause a unforseen problem but it did fine. spent atleast 5hrs today tuning and Its running real well, maybe the best its ever ran. lowering the com ratio from 16 to 12.5 seems to really help it rev more easy. im not sure how much the new exh spigot reducer is helping but I don't think its hurting. for the first time ever, i was able to use 20% volume nitro with no run away at close throttle , I think partly because the fuel mix was 26.5c. unfortunately the needle was richened far as it can go, so i have to make it richer somehow if i want to go above 20% or if the fuel density goes higher. i thought of grinding a small groove in the top portion of the needle to supply more fuel at close throttle but a guy told me i could get 400grit sand paper and sand the top portion. you ever tried the sand paper trick ? seems like it wouldn't be difficult to sand off .25mm at a time and try it. video camera died but i have still photo from my secret testing facility

[TZ350]

.
That sir is a real Beast, very impressed, good work .....

[wobbly]

You can easily tune a Methanol motor by " sanding " a needle in the correct position where you want to adjust the mixture.
We used to do this all the time with the needle in a battery drill and 300 wrapped around a 6mm axle key.
But just remember that Keihin who only change needle diameter, and Dellorto say that change the tube diameter ( needles as well ) only go in 0.01mm increments.
I know that for example changing from a 2.64 tube that runs perfectly, to a 2.66 tube makes a 125 a blubbering mess on petrol.
Same with a needle that runs perfectly at 2.5mm dia, then go to a 2.48mm parallel section and its rich as a dog fart.
Changing from a 3.15 tube that is a little rich on Methanol, to a 3.2 tube, makes that a blubbering mess.

[Martin1981]

Wobbly,

could you please tell me what limits the Banshee/RD350 engines Power and maximum rpm?

it has a 54mm stroke so one could think it should or could make peak power at 13000 and rev on to 14500 like your kz engines. but it doesn`t. even tuned engines with cpi cylinders seem not like to rev much more than 10000rpm.

i think one of the reasons are the oversquare layout and the narrow cylinders (piston center to center distance)


what was the most powerfull rd350 engine you ever built (350ccm) and what was it`s max rpm?

Thanks!

as usual i appreciate answers of other members (Frits for example) as well of course!


Jan, belated best Birthday wishes!

[shnaggs]

Sorry fellas, I had to scrap my PC and got a newer one, and I do not have any of the links saved. How are you guys doing advanced searches for this forum again??? I know its been posted multiple times, and of coarse I cant find it


Also Frits, not long ago you were talking about piston pin location of the 2 stroke in relation to the foul stroke. I am trying to remember why it is that the piston pin is so low on the 2 stroke? Why can we not move it up closer to the rings, and reduce some of the piston rock?

[DoldGuy]

"" exhaust duct site:https://www.kiwibiker.co.nz/ "".... sure makes finding stuff on the ESE thread a breeze.

Works well for me....

[DoldGuy]

Leverage is not my main concern and neither is dwell time at TDC/BDC; the variation would be minuscule.
Reduction in con rod angle and a corresponding reduction in friction is one good reason. Crankcase volume is another one. But my main reason is piston mass.
The bulk of a piston's mass is concentrated between its crown and the gudgeon pin holes. Raise the pin and you'll lighten the piston, simple as that.
This does not even depend on con rod length. It's true that I prefer a long con rod, but I would prefer a high piston pin in combination with any rod length.
And don't worry about the piston tipping over. Just look below at the piston hight, or rather lack of it, that four-strokes get away with. And two-stroke piston skirts are invariably longer than their four-stroke counterparts because when in TDC, they must keep the exhaust port closed.
Attachment 333883 Attachment 333884 Attachment 333885

And Frits reply to the Pin Height...

[peewee]

i once seen a diagram of heat distribution in a piston. seems most of the heat is at the crown and gets lower down the skirt. wouldnt this be a good reason to have the pin lower ? (less heat transfered to the small rod end and bearing). just thinking

[TZ350]

Sorry fellas. How are you guys doing advanced searches for this forum again??? I know its been posted multiple times, and of coarse I cant find it

"" exhaust duct site:https://www.kiwibiker.co.nz/ "".... sure makes finding stuff on the ESE thread a breeze.

Works well for me....

Another search method is to flick through the 12,000+ pictures on this thread.



"Thread Tools" then "View Thread Images"




Use the sort function to get 70 to a page.



Click on the blue "N/A" to go to the associated post.