ESE's works engine tuner

[F5 Dave]

I bought a small electric weed eater for the wife. Only works on small stuff.

The Grass cutterer guy has progressed to doing our lawn with a weed eater as he's transferring from heavy lawn mowers as he's well past 80. He'll probably stop all together soon. Can't rely on the in-laws forever.

So where can I get a tuned weed eater? Sounds like it could make the mundane fun.
As long as it siezes occasionally and throws me to the turf. Roughly.

[Jan Van Hamme]

Also, if you are absolutely insistent on accelerated engine wear, and loosing Hp, carry on using Motul 800 @ 30:1, I wouldn't use that cats pee if it was free even @ 20:1 where you should be.

Yes, damn it, I've made the “right” choice again.
A few years ago, I bought a pack of 12 x 1 litre cans of Motul 800 road race oil because I thought it was very good oil.
It is unopened and waiting to be used when my motorbike is assembled.
Now, after reading that message, I won't be able to get rid of that “cat's piss” anymore. Does it really cause so much wear and tear that I'd better not use it?


Translated with DeepL.com (free version)

[F5 Dave]

Works great in my trials bike.

[Jan Van Hamme]

In case you wish to compare it to the original text and at the same time brush up your German a bit:

Hi Frits,
I had already saved and printed your text on ignition curves for later use.
Now, in order to find and compile an optimal ignition curve, with your text in mind, I ran a simulation (in turbulent mode) in Engmod2T for every half degree of advanced ignition across the entire rev range.
So 8° fully from 3000 rpm to 9700 rpm.
8.5° fully from 3000 rpm to 9700 rpm....
up to and including 28° fully from 3000 rpm to 9700 rpm.

When I combine all the highest horsepower values per half degree in a curve, I get a strange ignition curve.
Namely, a flat curve of 15.5° over a large part of the rev range.
Could that be useful in practice?

Regards,
Jan

[Wos]

LODGER - I see a few things that have set you off on a dead end tangent.
You say you used an EGT of 470* - this is completely erroneous.
Any engine with that number in the header is about as well tuned as a weed eater.

All of the pipe compute programs are using the BULK AVERAGE PIPE TEMP, including the cooler duct, and this is in the range of 550* to around 625* dependent upon the fuel quality.
This gives an average speed of sound of 560 to 610m/s, thus a pipe average wall temp of around 425*C to 450*C at peak, and the EGT as measured in the header well into the 600*'s.
Quit working in the dark, even after a ton of carrots, IMHO it is absolutely impossible to do any meaningful engine design work, let alone accurate track/dyno tuning without using a data logged or at the very least a max recall EGT gauge.

Also, if you are absolutely insistent on accelerated engine wear, and loosing Hp, carry on using Motul 800 @ 30:1, I wouldn't use that cats pee if it was free even @ 20:1 where you should be.

The Wobbly Duct info sheet also states a recommended cooled duct length @ 1.5 bore for a square engine, with the header entry @ 2X bore - you stated a cooled duct out to 2X bore, this is NFG
as the A/F out at 2X bore is never going to make it back into the cylinder due to the return wave, as the port is closing.

EDIT - again, taking a suggestion the 192* " is a bit conservative ". What the hell does that mean, what is the actual Blowdown STA, and what are the transfers doing. JanBros has a free , really good port calculator.
Quit working in the dark - free technology is at your fingertips.

Dear Wobb,

For sure i am not experienced in diffrent 2 T Oils like you.
We run motul 800 in 8 h race liedolsheim where the best 50cc bikes have about 20 hp13000 and reving over 15000. Mix is 1:25

Which negative experience do you have with the french cats pee

Which oil would you adive for pump gas 98 mixture ?


Thanks a lot

every little step forward is a part of the puzzle ��

Grüße! Wolfgang

[Frits Overmars]

I ran a simulation (in turbulent mode) in Engmod2T for every half degree of advanced ignition across the entire rev range. So 8° fully from 3000 rpm to 9700 rpm. 8.5° fully from 3000 rpm to 9700 rpm.... up to and including 28° fully from 3000 rpm to 9700 rpm.
When I combine all the highest horsepower values per half degree in a curve, I get a strange ignition curve. Namely, a flat curve of 15.5° over a large part of the rev range.
Could that be useful in practice?

Jan, I dropped my crystal ball, so I don't know anything about your engine. I assume it's a two-stroke, but I'm not even sure about that. That's not much to base an opinion on...

[Jan Van Hamme]

Jan, I dropped my crystal ball, so I don't know anything about your engine. I assume it's a two-stroke, but I'm not even sure about that. That's not much to base an opinion on...

Sorry Frits,
I didn't phrase my question clearly enough.
The ignition curves for 2-stroke engines that I see here and there always start low in degrees, then rise steeply to +/-30 degrees and then drop back down at the start of the power band. Around max hp and rpm to 15° and from there further down.

What I mean is, an almost flat curve of 15.5° is very different from the usual curve shape I describe above. Would that still be useful in practice?
My engine... See attached screenshots.