ESE's works engine tuner

[F5 Dave]

Pressure will be equal inside the cylinder, and high pressure at that. It can only squeeze out one port.

Geez, that didn't make much sense at the end. Dont post after 9pm on a weekend.

[wobbly]

Jhonn , the KTM engines have some well designed features , but several years ago i was offerred free engines and parts from the importer to use in our 125 National karting class.
This was due to my TM ( MX ) engines winning everything.
Being given new stuff seemed like a great idea , untill I discovered that a huge amount od work was needed on the transfer radial angles , no so bad , but what killed the whole thing was the
extremely wierd PV setup.
The main blade operates as normal , lifting with rpm , and was easy to repower with a servo electronic drive.
But the Aux ports operate back to front , that is as the main blade is lifting , the Aux drum type PVs open from the top downward.
This is about as idiotic a system as could possibly be imagined , and made PV tuning all but impossible to get working efficiently , as all the initial blowdown pressure is dropped thru the top opening " slit " at
some stupid high timing number - but the main port is still all but closed off.
I thought the cylinder had been assembled wrong at the factory - but no.
So i gave all the engines and parts back - not sure if they still do this dumb setup , if they do they should be shot for being lazy or maybe just being ignorant.
Im not even sure if Engmod can model this correctly , dont want to know really as I would not even try to tune one.

[jfn2]

Wobbly:
Thanks alot for the T-port info. I know you informed us a while back about trying to reach .8 mach with the T-port but couldn't find it. Thanks to all. Jeff

[wobbly]

When doing the Mach in the Ex duct you set the Ex sensor position to the length of the duct, then do a sim run.
Then do another sim run with the sensor set to the length from the end of the rear cone to middle of the stinger nozzle ( say 10mm ).
Then you can look at both the Mach levels at the duct mozzle point and the stinger nozzle by selecting each Mach reading from the two sims.
When close to being optimum , both will approach 0.8 Mach.
ExMach 1 is the duct end and ExMach 2 is the stinger nozzle.

Jhonn - post the pack file here , or send me a PM for my email address.

[Jhonn]

Jhonn , the KTM engines have some well designed features , but several years ago i was offerred free engines and parts from the importer to use in our 125 National karting class.
This was due to my TM ( MX ) engines winning everything.
Being given new stuff seemed like a great idea , untill I discovered that a huge amount od work was needed on the transfer radial angles , no so bad , but what killed the whole thing was the
extremely wierd PV setup.
The main blade operates as normal , lifting with rpm , and was easy to repower with a servo electronic drive.
But the Aux ports operate back to front , that is as the main blade is lifting , the Aux drum type PVs open from the top downward.
This is about as idiotic a system as could possibly be imagined , and made PV tuning all but impossible to get working efficiently , as all the initial blowdown pressure is dropped thru the top opening " slit " at
some stupid high timing number - but the main port is still all but closed off.
I thought the cylinder had been assembled wrong at the factory - but no.
So i gave all the engines and parts back - not sure if they still do this dumb setup , if they do they should be shot for being lazy or maybe just being ignorant.
Im not even sure if Engmod can model this correctly , dont want to know really as I would not even try to tune one.

Thanks Wobbly,
DM is sended to you.

[Condyn]

I believe I understand the principles behind a proper exhaust duct. I am looking for an acceptable method to add a stuffer to the floor of mine. I should add that I am armed with only an oxygen acetylene rig for welding. It works excellent for welding filthy cast aluminum, however I struggle with anything as thick as an exhaust duct. Anyway, I have previously read about somebody attaching a stuffer with screws through the bottom of the duct. One concern I have is an exhaust leak under the stuffer. Curious as to if anyone has a fool proof plan for such a contraption. Much thanks.

[andreas]

I imagine there will be a problem with heat accumulation in the stuffer. But maybe there is a solution to that.

[wobbly]

Adding a stuffer is not a good idea , as it will over heat no matter how its done.
A simple way to do this is to use aluminium stick welding repair rods.
The small diameter rod makes it easy to get into the duct and add material.
The trick is to angle the cylinder downward so that the molten flux runs down over the weld pool.
If you practice you can achieve a pretty good build up without too many porous holes , but even these can be "spot welded " to fill them after basic grinding of the shape.

[Condyn]

Such a brilliant method that I overlooked. Thank you Wobbly.

[TZ350]

[SwePatrick]

Just a warmup to see if everythings ready for dynosession upcoming weekend.

I have dynoed 70.1hp to the wheel so far.
Made some updates since then as:
Heat isolated pipes
V-force 4 reeds from banshee
Made sure the throttles opened the throat fully.
New clutch, carbon fiber lined discs from yz250f
E85 fuel with 10% methanol.

[Niels Abildgaard]

I have dynoed 70.1hp to the wheel so far.

The last Aprilia125 powerlimit was 52 horsepower (from memory) and had cost phantasillions to attain.
Let us enlarge all dimensions from that cylinder with cuberoot of two (= 1,26) and make a 250.
In that cylinder blowdown area will be these 1,26 squared (= 1.59) time so big and powerlimit for same state of art will therefore also be 52 times 1.59 horsepower equal to 83 horsepower.
70.1 hp in rural Sweden whith no official support is impressive.
Hold i gang.

[SwePatrick]

The last Aprilia125 powerlimit was 52 horsepower (from memory) and had cost phantasillions to attain.
Let us enlarge all dimensions from that cylinder with cuberoot of two (= 1,26) and make a 250.
In that cylinder blowdown area will be these 1,26 squared (= 1.59) time so big and powerlimit for same state of art will therefore also be 52 times 1.59 horsepower equal to 83 horsepower.
70.1 hp in rural Sweden whith no official support is impressive.
Hold i gang.

When i dynoed 70.1 i used e85 fuel, it can in perfect tune give about 6-7% more power then petrol.
And i aim for about ~80 to the wheel, so if it all goes as planned i´ll be in the nieghbourhood of 83hp on the sprocket as they measured.

I have used a lot of tech from aprilia when i ported the cylinders actually.
So all their money they spent is still making it self worth something, as all we amateurs can copy a lot of Jan Theil´s(and others like Overmars) work and thinking, and actually get a better understanding how things should be, huge props to those guys!

And thanks for the nice words

[JanBros]

The last Aprilia125 powerlimit was 52 horsepower (from memory) and had cost phantasillions to attain.
Let us enlarge all dimensions from that cylinder with cuberoot of two (= 1,26) and make a 250.
In that cylinder blowdown area will be these 1,26 squared (= 1.59) time so big and powerlimit for same state of art will therefore also be 52 times 1.59 horsepower equal to 83 horsepower.

only IF you can rev the 250 as high as the 125

[F5 Dave]

Don't you just hold the throttle open longer?

Or change down to 3rd from high speed. That'll do it.