ESE's works engine tuner

[husaberg]

The Spx is back!

All I did was throw in some random value but humongous jets = 1hp over my best on gasoline. This is looking promising! It's nowhere near tuned at all.

Good to see you back Adegnes
You might find your needle jet is acting as a Mainjet as this will also limit the ammount of fuel that will flow. In this senario no amount of using bigger jets will make any difference at all.

If the needle jet is replaceable try a larger needle jet and Needle combo. Together with a richer cutaway.
If you can't get suitable needles for the carb You can richen the needle easily by simply making it thinner, Or just make you own needles.
I see summer has arrived as well.

[wobbly]

Re the studs for moving ducts to make them bigger.
You dont need to move the thread in the case - if you needed to, the stud could be 13mm say , with a stock 8mm thread into the case,but if the 13 was eccentric
you could bore the cylinder oversize and offset, then locktite the stud correctly aligned into the case.
The TZ shown has 8mm in the case,but 13mm stud diameter, and approx 1/2 this bigger size is ground away when making the inlet wider and adding 3 port Exhaust ducts.

Re the reed block modelling.
This was tested on a fully instrumented dyno with a CR125 for a Uni PhD thesis and checked against the wave action shown in EngMod.
The intake is modeled with 2/3 of its actual length as distance from the carb mouth to the reed block port opening, changes depending upon how much tip lift the petal has.
Fully down it is right to the reed block end, fully up and the tuned length changes to a much shorter effective length.
The 2/3 length is a good working average.

Re the B port hook.This scavenging technique clears away residual combustion gases in a completely dead flow area just in font of the C port.
With no hook, the two B port flows crash into each other, loosing a heap of directional control, and they then effectively block off the C port flow that is trying to attach to the rear wall.
Done right, the C port drags the B port flow into the correct loop direction ( leaning tower ) with it.

[Grumph]

Wob, enlighten me, new nicasil from our mutual friends at NZ Cylinders and I'm told to use castor base as an assembly lube for the bores.
The tip came from you apparently.
I've done it and will wait with interest to see how the bores bed in.
Any comment as to the reasoning behind it ?

[adegnes]

Good to see you back Adegnes
You might find your needle jet is acting as a Mainjet as this will also limit the ammount of fuel that will flow. In this senario no amount of using bigger jets will make any difference at all.

If the needle jet is replaceable try a larger needle jet and Needle combo. Together with a richer cutaway.
If you can't get suitable needles for the carb You can richen the needle easily by simply making it thinner, Or just make you own needles.
I see summer has arrived as well.

Good to be back!
Before this dyno session I had a go with a drilled out needle jet but the same needle(thinking the leakage at closed throttle would just add some to whats supplied by the pilot circuit) Did not work too well. It would start, but die soon after or instantly if I gave it throttle. A larger needle and needle jet sounds like the way to go. Doesn't seem lean up top tho, could be sufficient with just a thinner needle as you say.
I'll look through my collection and see if I've got any, or sand down this one.
I'll also have a closer look at the pilot circuit to see if there's still some restrictions in there.

This could just be the common alcohol problem of liquid fuel just passing through the engine. It is literally pouring out the exhaust.

I'm very happy with the "effortless" 1hp power gain and look forward to seeing what will come out of this!

[SwePatrick]

Good to be back!
Before this dyno session I had a go with a drilled out needle jet but the same needle(thinking the leakage at closed throttle would just add some to whats supplied by the pilot circuit) Did not work too well. It would start, but die soon after or instantly if I gave it throttle. A larger needle and needle jet sounds like the way to go. Doesn't seem lean up top tho, could be sufficient with just a thinner needle as you say.
I'll look through my collection and see if I've got any, or sand down this one.
I'll also have a closer look at the pilot circuit to see if there's still some restrictions in there.

This could just be the common alcohol problem of liquid fuel just passing through the engine. It is literally pouring out the exhaust.

I'm very happy with the "effortless" 1hp power gain and look forward to seeing what will come out of this!

Alex, In my Facebook group the guy named 'hilmersson' have been quite successful with nitro, he might have all your answers you need.
Feel free to ask him public in group.
Would love to see a good discussion on nitro =)

Rgds.

[F5 Dave]

Never tried funny fuel but if can direct you to about page 1 of this epic thread, pull the mainjet out and if it runs but dies when open the needle isn't restricting full open.

[chrisc]

I think I could learn something from hearing about the design intent of this FOS Malossi pipe (quoted post directly below) and/or the matching cylinder.

... Here are some numbers to play around with. Exhaust pipes don't come any simpler than this, but don't let that fool you; this pipe was good for eight championships. ...

I put this pipe into engmod and noted the % almost match the 'FOS exhaust concept' which is unsurprising.

Attachment 301223

I'm unsure why there is no stagger on the transfers, noted on the design as all being 130 degrees. Wouldn't it be better to maximise the exhaust aux port size for more blow down and open the A ports later to prevent the short circuiting? Maybe opening all at once is a compromise but a comment from Wobbly sticks in my head as "enhance midrange power if the A port opens first, or enhances peak and overrev power if the B port opens first." I understand this is due to "the port to open first, flows last" rule due to flow reversal.

The pipe seems to have a long tuned length at 714mm and the ignition was noted at 16 degrees at 13,000rpm. Maybe I'm being presumptuous but the engine seems to be designed to make peak power somewhere around the 13,000rpm mark. Isn't that a bit low for a 50? Maybe there were mechanical limits but engmod reckons this 50 of mine spinning at 14,000 has a mean piston speed of 19m/s. Engmod notes this as being slightly under the 20m/s considered as "performance" and nothing like the 25m/s of "high perf". Am I foolish to be trying to design this 50 to make peak power around 14,000rpm?

Was this Malossi engine runing on unleaded fuel?

[adegnes]

Alex, In my Facebook group the guy named 'hilmersson' have been quite successful with nitro, he might have all your answers you need.
Feel free to ask him public in group.
Would love to see a good discussion on nitro =)

Rgds.

Thanks, I'll do that!

Never tried funny fuel but if can direct you to about page 1 of this epic thread, pull the mainjet out and if it runs but dies when open the needle isn't restricting full open.

Thanks. Probably a wise move to avoid ending up with melted parts again, tho it seems to be well rich on full throttle.

I'm not sure if the 1/8 throttle bog is lean, could be "drowning".
I'll lift the needle in the next session to see if it gets better/worse. It seems to happen at the point were the needle's straight upper section is going into the first taper and is beginning to let fuel through.

Another note, it is acting alot like before I found out the powerspark was more retarded than it should be when running gasoline - going flat at higher revs. I'll start adding in advance when I've got the carb sorted.

[shnaggs]

Jan is correct, I did a simulation of what I think a Ryger engine looks like. In the simulation I assumed good scavenging and good normal combustion. The layout is a stepped piston with the step smaller than the main piston, unlike the traditional stepped pistons where it is bigger than the main piston. The rest is just gas-dynamics and plenums. If this is close to the Ryger in its current format I do not know.

Attachment 331683

Vannik, How could you simulate this when the sim wont allow you to get the CCR into the Ryger realm? Or am I missing something?

[Vannik]

Vannik, How could you simulate this when the sim wont allow you to get the CCR into the Ryger realm? Or am I missing something?

How high is high? There is quite a large chamber at the bottom of the cylinder, almost all the way around that is part of the bottom compression chamber. At least that is how it looks in the homoligation papers and in the patent papers.

[TZ350]

I am not sure why the pictures appear upside down. Maybe because its a 4T, ......



For something different we spent an evening finding the sweet spot for a 4T's exhaust length.



Started with an overly long pipe and cut it back in short sections, 50mm then 25mm at a time.

After that we worked on the inlet but in only 10mm then 5mm steps.

[adegnes]

I am not sure why the pictures appear upside down.



For something different we spent an evening finding the sweet spot length for a 4T's exhaust.



Started with an overly long pipe and cut it back in short sections, 50mm then 25mm at a time.

After that we worked on the inlet but in only 10mm then 5mm steps.

Always fun to mix it up a bit!

[Jannem]

Attachment 274209

And why is there a shadow (clean area) on the piston next to cylinder wall area between the ports? I would have expected the area in front of the transfer ports to be washed clean from the fresh mixture, not between the ports.

Maybe, even probably. But not certainly. Clear patches on pistons can also be an indication of hot spots. Yeah, those simple two-strokes.....

Old post, but seems worth commenting.

I'd say because fuel wash at the piston top in the combustion temperatures cannot be viewed the same as washing parts. Clean areas are the ones that are not fuel washed and vice versa.

Take a polished piston and put a single drop of fuel in the center of it. Then burn it with a torch. Repeat as many times as it takes to get patterns in live engine. Will take forever, but eventually you will find accumulation of carbon (fuel is hydrocarbon) where you repeatedly put that drop. the rest will be clean.

Saw this doing wet flow tests of 4-stroke chamber. The black areas are the ones where fuel "washes".

I know many experts disagree, but that's my .02.

[wobbly]

Re the running in of a newly Nicasil cylinder.
The best way is to use a HEAP of castor based oil plastered all over the piston and bore, and when first started only slowly idle the thing for 5 mins with NO throttle.
The castor has a very smooth wear characteristic on parts that should match closely ( bore wall,rod bore etc ) and at idle with no throttle
there is very low combustion pressure that doesnt push the ring out hard onto the bore.
This prevents the micro scratches that run up the bore randomly from seemingly perfectly smoothed port edges, due to the ring pressure.
The idea has proven itself on dozens of new bores, with the vertical scratches ( that soon disappear as the bore surface is rubbed away by the ring ) being non existent in new cylinder builds.

And regarding piston darkening - you can substitute " cooler area " with "fuel washed " as the combustion process only burns on a black surface on the piston where it gets hot
enough to do so.
If your squish is working correctly, there will be no black marks in that area as it will be cooled by the boundary layer at TDC.
I have seen countless engines where the piston is clean alloy directly in line with a port divider - ie no cooling flow to prevent oil deposits burning on a coating.

[Lightbulb]

Thanks for this explanation. So do you think this is a direct result of the fuel not being atomised enough by the time it has gone through the transfer ports? If there was more turbulence, or more happening to smash up the air fuel mix, do you think this will still be happening?
Thanks again,
Neil

Old post, but seems worth commenting.

I'd say because fuel wash at the piston top in the combustion temperatures cannot be viewed the same as washing parts. Clean areas are the ones that are not fuel washed and vice versa.

Take a polished piston and put a single drop of fuel in the center of it. Then burn it with a torch. Repeat as many times as it takes to get patterns in live engine. Will take forever, but eventually you will find accumulation of carbon (fuel is hydrocarbon) where you repeatedly put that drop. the rest will be clean.

Saw this doing wet flow tests of 4-stroke chamber. The black areas are the ones where fuel "washes".

I know many experts disagree, but that's my .02.