ESE's works engine tuner

[F5 Dave]

Taken a while to get my head around the 2 piece pistons.
So what is the weight comparison?
Did you have to experiment with shape of outer piston as no connected boss perhaps just conical which would be easier to machine?
Did you have notable gains from removal of the holes?

Make your own pistons? Are you crazy? It's a brave man to ignore the norms and tread his own path. Outstanding, even if it wasn't a sustainable solution it would still be cool.

Instead of a thread, why not a machined groove and a large wire circlip. Bore would have to be tight for heat transfer.

[speedpro]

Those pistons are clever. Round is OK as the piston without the pin boss will expand a lot more evenly than a regular piston. I would have been real nervous first time out on them.

[RAW]

Hello Frits,
I dug out an old laptop & guess what, it will run your Flywheel Zip file. WooHoooo
Question - Velocity at maximum rpm. Would you explain this please.

[lodgernz]

Instead of a thread, why not a machined groove and a large wire circlip.

Need to prevent rotation of the outer piston, so would have to retain the two-lock-bolt system or something similar.
The thread arrangement probably gives quite good heat conduction from outer to inner, especially at the top.

[Makr]

Are there other events you can participate in before speed week? You would seem to be a very patient man if you had to wait so long between outings.

Used 6061 on our sleeves, having been told they were good with nicosil coatings, the F4 GP will prove or disprove that theory. That 7068 sure does not look like a winner at all...

There is Elmirage dry lake bed in California, and that is maybe the future for me. There are some events run on air strips, but they are about the same time as salt events.

The reason those records on the salt flats are so cherished is you have one tiny window of opportunity and everything has to go perfect. It very rarely does...

Two years ago I used aluminum sleeves that were 6061. They worked fine.

Makr...
Thanks... I often wondered if 2024 might work. Kermit Buller

That seems to be the best commercially available grade. 4032 I can only find in forgings from a piston forging house, and there is a minimum buy in for plain slugs. I think it was $1500 for 20.

Taken a while to get my head around the 2 piece pistons.
So what is the weight comparison?
Did you have to experiment with shape of outer piston as no connected boss perhaps just conical which would be easier to machine?
Did you have notable gains from removal of the holes?

Make your own pistons? Are you crazy? It's a brave man to ignore the norms and tread his own path. Outstanding, even if it wasn't a sustainable solution it would still be cool.

Instead of a thread, why not a machined groove and a large wire circlip. Bore would have to be tight for heat transfer.

I machined them round and used about the same taper as the pistons I have run in the past. It came out about right. I have never done a back to back test between other pistons and these. I will at some point. They are way lighter than any other comparable forged piston. Off the top of my head these were 215 grams and Wossners were 340.

Thanks. I thought about every union possible for about a year. I always came back to a thread. Even at 215 grams the piston is 1400 lbs inertial weight at 11,000 RPM. The threads hold to way over ten thousand pounds and that was when the wrist pin breaks out of the boss it is in. The threads never failed.

Those pistons are clever. Round is OK as the piston without the pin boss will expand a lot more evenly than a regular piston. I would have been real nervous first time out on them.

I was. haha I have run them enough now, I don't think about it any more. Thanks

[Frits Overmars]

Hello Frits, I dug out an old laptop & guess what, it will run your Flywheel Zip file. WooHoooo

Told you so. All programs will run with DOS 6.2 through to Windows 98SE; some will run from DOS 5 through to Windows 10.

FLYWHEEL.EXE will run directly under Windows 7, no emulation required

Question - Velocity at maximum rpm. Would you explain this please.

I tried to make the program self-explanatory:

The program needs to know the total transmission ratio from crankshaft to flywheel, so starting from the maximum crankshaft rpm it can calculate the maximum flywheel rpm. But in case this transmission ratio is unknown to you, the program offers you a second way of answering the question: it asks you to enter the riding velocity at max. crankshaft rpm. The circumferential flywheel velocity will be equal to this riding velocity and as soon as a value for the flywheel diameter is chosen, the program has all the information it needs.

[RAW]

Told you so. All programs will run with DOS 6.2 through to Windows 98SE; some will run from DOS 5 through to Windows 10.I tried to make the program self-explanatory:

The program needs to know the total transmission ratio from crankshaft to flywheel, so starting from the maximum crankshaft rpm it can calculate the maximum flywheel rpm. But in case this transmission ratio is unknown to you, the program offers you a second way of answering the question: it asks you to enter the riding velocity at max. crankshaft rpm. The circumferential flywheel velocity will be equal to this riding velocity and as soon as a value for the flywheel diameter is chosen, the program has all the information it needs.

Thank you Frits
The value velocity, what is this in, feet per second as an example.
Actually all the values are in what format, HP, is etc
Run time, seconds as such, I've just guessed to explore.
Thanks in advance

[Frits Overmars]

The value velocity, what is this in, feet per second as an example. Actually all the values are in what format, HP, is etc Run time, seconds as such, I've just guessed to explore.

I must admit that your question is somewhat justified. You may have guessed that I will not lower myself to using the furlong-fortnight-hundredweight system (which some people keep calling imperial, even though Great Britain and the USA have committed themselves to the worldwide meter-kilogram-second standard).
So to be consequent the program should expect a velocity input in meters per second. But that is still one step too far for most people, so the program assumes kilometers per hour.
By the way, if you press the Repeat key in the program and then re-answer the transmission ratio question by entering a zero, you will get a survey of all the units used.


Now for the power. Most people are still hooked on horsepower even though we should all be using kiloWatts by now, so the program assumes HP.
But there are other options that you can control by the way you call the program.

FLYWHEEL.EXE assumes horsePower

FLYWHEEL.EXE P : ditto

FLYWHEEL.EXE K assumes kiloWatts

FLYWHEEL.EXE W assumes Watts (in case you are working with really small engines or if you are a really bad tuner).

[SwePatrick]

Is there any guys with experience in tillotsontuning in here?

I have reached 27.14hp with my keihin 27mm roundthrottle.
And I´m curious if this PCR slide carb will take me further:



But as it is 29mm big it seems to lose either pumpsignal or loss of airspeed.
Can´t get it to run on full throttle if I tune the idle perfect in AFR
There a HUGE gap, can´t give it full throttle until AFTER 10000rpm.
Then it screams
If I´m turning out the highspeed nozzle to get it to answer earlier it runs rich as a pig at 12000rpm and upwards.
If i´m turning out the lowspeed nozzle it idles really really rough and I need to raise idle to about 6000rpm to get it to run at all.
But then it answers, taking full throttle all the way to 14000rpm.
Engine is 68cc big

Would a powerjet fix this?
Problem I would say is to much flow in carb, so it stalls.

[jfn2]

A few years ago I talked to Brian Callahan when he was building a dyno for testing small motors and he sent me a excel spreadsheet that worked really well in figuring out ineria weights for different materials. If you got a hold of him he might send you acopy if he still has it. In fact I need another copy myself, if your out there Brian.

[SwePatrick]

Jfn2, try this site:

http://www.dtec.net.au/Downloads.htm

[bjorn.clauw.1]

Told you so. All programs will run with DOS 6.2 through to Windows 98SE; some will run from DOS 5 through to Windows 10.

I just run it on my smartphone


Frits, is there a place/site where we can find your programs in one location?


Makr, thanks for sharing all this information! Did you try 2618 for the outer shell of the piston? The design is really sound and well thought off. Do you think opening the dome of the outer shell and letting the inner part fill this hole could help the loosening? (Will post a drawing in a minute). So the inner part also heats up directly from combustion gasses so both threaded parts heat up at the same ratio. Maybe also thread at (A).
Do you happen to have a pic from the inside of the inner piece?

[wobbly]

Pumper carbs are alot more complex than you would think.
The 3 main tuning variables are pop off pressure, diaphragm lever height, and needle positions.
What are these variables at the moment - if you dont know, and or cant change all these,then you cant tune one.
If you can tune the top end OK with the H needle, but need the L out too far to get response off idle then you need to drop
the pop off a couple of psi.
This will then allow much less L needle but still be rich enough to accelerate off idle.
But then the H needle will need to go in some to lean off the top end.

The other issue I can see is PVL.
What is the stator coil resistance - as most of these ignitions are useless on a racing 2T as they have almost no retard at all.
If its 50 ohms you have a straight line ignition off a KZ2, useless - if its 200 ohms then you have around 7* retard, still useless.

[Frits Overmars]

I just run it on my smartphone

Great! Can you tell us how you di dit?

Frits, is there a place/site where we can find your programs in one location?

I just tried to upload the lot in a zip-file but probably it was too big (3,5 MB).

[bjorn.clauw.1]

Great! Can you tell us how you di dit?
I just tried to upload the lot in a zip-file but probably it was too big (3,5 MB).

Hello Frits, just look for 'aFreebox' in the android playstore. Is a port of latest dosbox.
Should be working with your graphic functions also. If you need more info just let me know.
If you like I can host your files on my server.