ESE's works engine tuner

[wobbly]

The new metering block is really just an expensive way of changing the main air correction system from a primary only
( that is using an extended emulsion tube nozzle ) to also using a normal 4T type with air entering holes along the emulsion tubes
length.
This can have the effect of reducing the atomised fuel droplet size , and thus improving the fuel curve.
Easy to see what its doing due to the big increase in main jet needed.
But I cant help thinking the same effect could be had by a different ratio of nozzle length - shorter = progresively richer , along with
a bigger air corrector ( be it a jet or simply a drilling in the casting ) that by adding more air at larger flow rates offsets the nozzle effect
as well as improving atomisation ( still not as good as the old Lectron ).

[F5 Dave]

Tuned carb looks pretty good.

[TZ350]

The Classical Performance/Development Curve. .



Cheers, Daryl.

Absolutely .....

[shnaggs]

I tried the metering block in a 19 KTM 125. netted about .5hp at peak and overrev. Surely the gains they are claiming can be had when up against stock jets etc. horribly rich from the factory. This is one of my gripes about these types of comparisons, at least jet the bike first for best power and then throw on the metering block...block heads!

[lucf]

Thanks Frits
Just a bit strange, before rebuild, resleeve, etc. we didn`t have the drop and had 151HP on the dyno. Now there is a huge drop and we do 141HP.
We increased ex duration from 200 to 204 and was aiming for more HP at 9500, we had 151 at 8900 rpm.
So with more ex duration I would expect lack at the bottom but perhaps a bit more in the top. Transfer are 130 pipe TL is the same.
EGT in header is 520 C so a bit cold.....
Ignition in the problem area is 30* and doesn`t affect the drop very much....
Attached are dyno of before and after rebuild.

No supprise at all, when you don't calculate.
When knowing the 2t tuning history from the beginning and specially from 1960 to 2007 and than asking yourself "why it took so long, almost 50 years", than you should know what is wrong in your engine.
So calculating with the right data is the only right way to keep a 2 stroke in the right balance at every tuning level.

[shnaggs]

quick question for Wobbly or Frits....or anyone else who knows.

In regards to the exhaust duct outlet ratio of 75% of window area. What if we have a raised port floor? Does the % rule remain the same? If we raise the port floor, than the window area obviously decreases, but should we take that into account when determining the outlet size? Just seems that if we do, than the whole duct area seems rather small, but I guess thats good for velocity.

[rtechracing]

Lucf:
Please explain, I am not sure I understand what you mean?..

[wobbly]

This time Luc you are dead correct , but doing the port time area calculations still has no effect on the scavenging system.
The blowdown and transfer STA could be perfecly matched , but as I said before having an oddball transfer setup with modern axial angles combined
with old fashioned flat opening angles , has no history of development to go by.
Thinking about it further I am tending to believe that the higher Ex timing is the culprit in that it combines two effects that are killing the power
due to overscavenging.
The high timing gives more pressure ratio when the port opens , making the diffuser more efficient , and then it naturally has more time/area
for the diffuser to pull out more mixture around BDC.

[wobbly]

The 75% area guideline was developed on alot of sample engines including several with the port floor raised ( by only 3mm though ).
But the guiding principle was the duct exit velocity approaching 0.8 Mach , above or below this power was generaly less.
Thus the only way to get the exit area on the money is to place the Ex transducer in EngMod at the duct exit length and check the
Mach and the Hp resulting from this

[lucf]

This time Luc you are dead correct , but doing the port time area calculations still has no effect on the scavenging system.
The blowdown and transfer STA could be perfecly matched , but as I said before having an oddball transfer setup with modern axial angles combined
with old fashioned flat opening angles , has no history of development to go by.
Thinking about it further I am tending to believe that the higher Ex timing is the culprit in that it combines two effects that are killing the power
due to overscavenging.
The high timing gives more pressure ratio when the port opens , making the diffuser more efficient , and then it naturally has more time/area
for the diffuser to pull out more mixture around BDC.

Not only this time Wobb, I always tell the truth !!
May be not the full about Ryger, but that story has still not ended, before I can do so.

You talk about details, and a good calculation can be made with only the headlines.
All little details of you can be calculated after that.

I don't use and don't need EngMot2t, I use my own, which has been develloped over a periode of about 15 years.
And I do not intend to give my program or details, away after my treatment in the past.
On FB only my friends can read my notes, with much more information.

[rtechracing]

This time Luc you are dead correct , but doing the port time area calculations still has no effect on the scavenging system.
The blowdown and transfer STA could be perfecly matched , but as I said before having an oddball transfer setup with modern axial angles combined
with old fashioned flat opening angles , has no history of development to go by.
Thinking about it further I am tending to believe that the higher Ex timing is the culprit in that it combines two effects that are killing the power
due to overscavenging.
The high timing gives more pressure ratio when the port opens , making the diffuser more efficient , and then it naturally has more time/area
for the diffuser to pull out more mixture around BDC.

Wobbly you are correct, time areas are calculated. The blowdown and transfer STA are matched (Transfer slightly over to sort of compensate for poor design port ducts) I am also aware that it combines old and new way of thinking but my opinion is that if you never try something new you will never achieve anything, only a copy of what everybody else do. Yes, it will give me some good punches in the face but a good way to learn.

I think I will back of 2* degrees on ex duration, stagger transfer opening, try to hook the a-port even more and then back on the dyno.

You think a possible cause is that the axial angles has increased flow quite some and in combination with a more effective diffuser due to higher ex duration is making it overscavenge??

[lucf]

Wobbly you are correct, time areas are calculated. The blowdown and transfer STA are matched (Transfer slightly over to sort of compensate for poor design port ducts) I am also aware that it combines old and new way of thinking but my opinion is that if you never try something new you will never achieve anything, only a copy of what everybody else do. Yes, it will give me some good punches in the face but a good way to learn.

I think I will back of 2* degrees on ex duration, stagger transfer opening, try to hook the a-port even more and then back on the dyno.

You think a possible cause is that the axial angles has increased flow quite some and in combination with a more effective diffuser due to higher ex duration is making it overscavenge??

rtechracing,
with a right calculation, you never get punches in the face.
all knowledge is already in the way of calculating.

[husaberg]

with a right calculation, you never get punches in the face.
all knowledge is already in the way of calculating.

125cc 70HP and 30,000rpm plus 80% less emissions.

Are you suggesting your calculator is better than Mr Thiels Dyno proven results and multiple GP wins and championships.
As i would suggest your own calculator has some history of excreting waste fluids.
Maybe luc you might be better served not to ascribe yourself as being part of the fountain of knowledge, when you have so often and so publicly spouted swamp water.
Or are you going to admit now that the Ryger was foolishly over-hyped to the point of spreading falsehoods by yourself.
its either one of three things Luc. you either lied, or you were wrong, or you both lied about it and was wrong.

[Flettner]

HaHa I wondered how long it would take. 😆😆😆
It's going to take a long time to live that one down.

[peewee]

Wobbly you are correct, time areas are calculated. The blowdown and transfer STA are matched (Transfer slightly over to sort of compensate for poor design port ducts) I am also aware that it combines old and new way of thinking but my opinion is that if you never try something new you will never achieve anything, only a copy of what everybody else do. Yes, it will give me some good punches in the face but a good way to learn.

I think I will back of 2* degrees on ex duration, stagger transfer opening, try to hook the a-port even more and then back on the dyno.

You think a possible cause is that the axial angles has increased flow quite some and in combination with a more effective diffuser due to higher ex duration is making it overscavenge??

i dont know how much time you want to invest in your engine but many things can be changed if you have acess to a welding machine. epoxy is also a valuable tool for making changes, like those flat roofs and radial angles

not to long ago i learned you have to take care with high exp ports, unless you have close ratio 8spd gearbox . ive had better luck with lower-wider ports but my transmission are just three or four useable gears

also about angling the a port more rearward. it may be worth putting a radius wall if you can ,rather than sharp hooks. if you angle it to much rearward it may reduce the flow width however