ESE's works engine tuner

[adegnes]

As a big thanks to all in this thread,, i have learned a lot!
Ofcourse i had some knowledge before.
But it has been raised way higher.

Thanks everybody for not keeping things secret. =)

Merry christmas and a happy New year.

From me to all of you:

my little projektengine(beside the big 132cc)

Setup:
Ported Autisa 45.5mm bore, durations: 202/136/138/138
Modified head. 13-1 compression
Top racing crank 41.4mm stroke
std unmodded piston, but just one ring, there are grooves for two, with two rings i don´t see any gains at all, just a lot of wear.
'Derbi style' reed (0.4mm carbon)
Keihin 27mm roundthrottle, from an -83 cr80, totally unmodded. jetted 42/128 and needle in the middle position
CR85 inletrubber
Pvl '458' ignition
6spd gearbox
Cr85 clutch
Morbidelli pipe from the gp twin.

A view down in cylinder at dynosheet(at the sprocket):
Attachment 318090Attachment 318091

Cool, more pics!

Here's an update from Norway:

The Peugeot Spx m50 engine is assembled and ready to be mounted in the frame.



My dyno is up and running. (notice choice of bike)



Made this "arduino shield" to go with it. It has inputs for engine rpm, roller rpm and ambient temp. Next revision will have egt and cht to.



I've experienced problems with noise from the ignition when using the rpm pickup circuit on a breadboard, hopefully thats solved now with this shield incorporating a proper ground plane and more decoupling.

Looking forward to seeing if the 22odd hp engmod is claiming is actually present, though I've probably goofed up something.

Merry Christmas!

[SwePatrick]

I have a lot of noise from ignition too, but i´m running a small easy pull just on a specified rpm.
In that way i can calculate the engine rpm against the dyno rpm.
In Performancetrends dyno setup one can then fill in an gearrate.
Then software knows egnine´s rpm when cancelled that cable.

If nothing is slipping in transmission you get really nice data.

Rgds
Patrick

[wobbly]

SwePat,a free Xmas gift for you, may I suggest you polish that piston in a lathe to a mirror finish.
The dark, crater surface will be absorbing a huge amount of combustion heat ( like having fins all over the surface ) that should be heating the gas
and pushing the piston down - not making it bigger.
This was done at Aprilia, and I have been doing it for years on all race engines.

Re the ignition noise - use a resistor plug and cap, this will remove most of the RF in the ignition lead.

[SwePatrick]

Hi wobbly,,, yes i know about the 'mirror effect', but actually, i can´t see any difference to this surface.
That means i have tested already,(but in an another cylinder).
There are also other theories why i left it as is in this one.
I wanted to let it build carbon.
In Dragracing with foulstrokeengines, turbo or nitrous gas there are gains with carbonbuildup.
As it actually makes a insulatebarrier and is more 'adhesive' for the protective 'surface gas'.
That means you can go harder on the ignition and have some protection.

But still,, i might revert to polished again if i see losses.
Nothing is carved in stone.

And for resistor, yes!
But i have sometimes misfireproblems that nonresistor cable,cap and plug sorts out.

Rgds.

[wobbly]

If the ignition miss fires with resistors then it hasnt sufficient power - drop the spark gap to less than 0.5mm

[TZ350]

My dyno is up and running. (notice choice of bike)

Suzuki GP ......

[TZ350]

Attachment 317983 Attachment 317984
The Dam Question!
Chambers has fitted an exhaust port dam to his RG50 cylinder. It was hand shaped out of alloy and is held in place with a screw and sealed with Balzona epoxy.
The top of the exhaust port is 85% wide and the dam fills the lower part of the original exhaust port and tapers out to the pipe diameter at the end of the exhaust duct.

Attachment 317998

Red line is with the exhaust port dam, no other changes.

Attachment 317999

Blue is where we started at the very beginning and after a lot of hard work and careful step wise development we have worked our way to the Red line. .......

I think there are several interlinked effects of lifting the floor ( and or adding larger bottom corner rads ) to an exhaust port.

First off going all the way up to the transfer height, must be considered an " extreme " case, where any one of the effects that is detrimental to power could easily swamp any smaller effect that would usually be helpful.

If the A port has already a large wall or septum dividing it off from the main port - then I can see that any advantage from the lifted floor via a reduction in short circuiting would be minimal.

Creating a high dam at the port, by inference then means we get back to having a very tapered "diffuser" like duct, with a much bigger exit area than that at the entry point. And as is well documented, the exact reverse makes better power.

In this case the sim is not very helpful in determining what is optimum, as it takes no account of the change in short circuiting efficiency, only the flow effects on the Mach numbers of the area changes.

Then lastly we have the thermal issue of the insert overheating, due to lack of an efficient heat path to the cooler water or finned cylinder.

Very much a can of worms, not easy to sort the positive effects and be able to identify any general pointers to guide other tuners.

Hey TeeZee, as a favour can you try a radius on the leading edge of floor dam, before you do anything else.

Be interesting to see if that helps the outflow Cd sufficiently to increase power, and wont affect the A port short circuiting efficiency at all.

Radius edge on the exhaust port dam



Red = radius on the leading edge of the exhaust port dam, Blue = sharp edge.

Radius is better.



Red = radius edged dam, Blue = No Dam.

Making progress, so what is the next step, suggestions welcome.

[seattle smitty]

Funny thing, that mirror-polishing piston crowns, one of the oldest tricks in the racing engine-builder's bag, dating from the Thirties and possibly earlier, a technique that COSTS NOTHING (compare with ceramic coatings!) but a little time, is done by very few. Every engine I've built in the last forty five years, from lawn mowers and chainsaws, to Onan twins for welder/generators, to family cars and trucks, ALL of them get polished pistons . . .

. . . AND of course, port clean-up always, even the lawn mowers!!

Once a 2-stroker, always a 2-stroker; a friend still is telling a story on me of coming into my shop where I was "porting" (removing sharp internal edges) a brand new shop vacuum for a little better suction . . . or just because the urge to grind overcame me, LOL. Well, I might save time in other areas (no television). I hope you'll tell me I'm not the only one with this compulsion.


At risk of momentarily creating a silly distraction in TeeZee's thread, shouldn't there be a coat-of-arms for 2-strokers; what elements should we include? One guy suggested our universal symbol should be a piston with a big ugly skid-mark down the side. I would add crossed flex-shaft Foredom right-angle grinding handpieces. Ideas??

Anyway, wishing y'all a good holiday.

[SwePatrick]

If the ignition miss fires with resistors then it hasnt sufficient power - drop the spark gap to less than 0.5mm

Tried that already. =(

[speedpro]

When people say the resistor cap or wires causes a misfire there is a serious problem. Lets say the resistance is 5K. The current may be 20-50mA, I don't really know. Ohms law says E=IR so E=.02X5000=100v or E=.05X5000=250v. Subtracting 100v or 250v from the 20,000v thrown at the spark gap is .5-1.25% less voltage. Yes I realize there is a bit more to it but in all reality it should make next to no difference.

[SwePatrick]

Yes!
Somehow it made the difference for me.
But i´ll measure things up, i just swapped to the std cable,cap that came with PVL when i bought it.
And at the same as i wanted to test non resistor system, i swapped the plug to an oldschool b9hs plug

I still had it working earlier with resistorsystem, something has fouled for me.
I´m at this point in the middle of sorting this out.

Ignitionpower is measured in Joule?

[Frits Overmars]

a friend still is telling a story on me of coming into my shop where I was "porting" (removing sharp internal edges) a brand new shop vacuum for a little better suction ...
I hope you'll tell me I'm not the only one with this compulsion.

You're not.
Merry Christmas to all .

[teriks]

Making progress, so what is the next step, suggestions welcome.

Well, the original plan of lowering it a bit at the time makes sense.
Personally Id go a slightly different direction, if I had the time and resources that is.
-My next step would be a varying radius on the dam, making a full round at the center of the port and leaving the ends as is.
Something like this:

After that, back to your original plan.

[peewee]

Teriks with the center rounded and sides left as is up high you must meen like the latest generation KTM 250. I'm sure there's a port map of it around here

[teriks]

Teriks with the center rounded and sides left as is up high you must meen like the latest generation KTM 250. I'm sure there's a port map of it around here

I don't know, haven't seen the latest KTM250 cylinder.