ESE's works engine tuner

[Flettner]

The uniflow scavenge system neatly accomodates cylinder filling with no fuel over spill, without electronic injection, or patent issues. Has been shown to work.

[wobbly]

Yea Flett, an Iron Horse " works " as well.

[Flettner]

But no where as well as a uniflow scavange engine. Where has there been any real study on the two piston, one cylinder, crank case pumped type engine?
Split singles don't count as they do have efficency issues.

[TZ350]

... Iron Horse ...

Iron Horse ...

[lodgernz]

The wisdom on squish bands, if I understand it correctly from this forum, is that the area thereof should be 50% of the bore area.
My question for Frits or Wobbly, or anyone who knows these things is: Does this apply to small engines? I'm thinking of a 39mm bore 50, where I'm wondering if a 50% squish band might mean having quite a deep combustion space to avoid dangerously high compression ratio.
I'd appreciate any guidance on this.

[speedpro]

To be clear, the 50% figure is area, not diameter. Either way the chamber shape should be the same just scaled up or down depending on the size of the engine.

[Frits Overmars]

the chamber shape should be the same just scaled up or down depending on the size of the engine.

I wanted to approve by just writing '+1' but the forum software reacted with:
"The message you have entered is too short. Please lengthen your message to at least 10 characters."
Well, that has been fixed now.

[lodgernz]

Thank you Speedpro and Frits. Just what I wanted to hear.

[F5 Dave]

Which means it will be quite shallow to get the compression usefully high, which will depend upon which path you choose gas and ignition wise. Welcome to pop over and look at the 50 head- Roger I assume ?

[ken seeber]

Plus 1 for an interesting topic. Questions:

If the 50% rule is the go, then why do KZs come with heads that have squish bands of around 35% the area?

Is there something else going on?

Has anyone tried a 50% squish area in a KZ?

[wobbly]

I detailed everything you need to know about a KZ2 head design back a few pages, experience gained from literally hundreds of dyno runs.
The straight line ignition completely changes EVERYTHING you ever thought was correct in a 2T combustion chamber.
Running 16* at 9000 is 10* not enough, running 16* at 14000 is 10* too much,the chamber needed to deal with the deto caused by this, along with the shit
pump gas we are forced to use, throws all the squish theory out the window..

[lodgernz]

Which means it will be quite shallow to get the compression usefully high, which will depend upon which path you choose gas and ignition wise. Welcome to pop over and look at the 50 head- Roger I assume ?

Yes Dave, you've rumbled me. I'll call you, I have your number.

[TZ350]

If the 50% rule is the go, then why do KZs come with heads that have squish bands of around 35% the area?Is there something else going on? Has anyone tried a 50% squish area in a KZ?

I detailed everything you need to know about a KZ2 head design back a few pages, experience gained from literally hundreds of dyno runs.

It can be hard to find previous stuff so hopefully this link goes back to the start of the KZ2 head posts.

... easy question to answer.....

Follow the link back, others that will be on the following pages.

[SwePatrick]

It is looking like the moral of the story is to keep the transfer port injection time shorter than the real time that the transfer ports are open and at 12.5k that is about 1.5ms.

Transfer port injection has the potential to clean up the 2T's emissions as the first lot of purging air can be sent through with little fuel in it but if I can't get it to work on my bike above 8-9k rpm I will have to go to inlet injection and aim to get a more homogeneous fuel mixture in the crankcase just like a carburetor does.

You got one more problem at hand.
Due to reguested fuel amount you need big injectors, big injectors have longer 'deadtime', the time for opening the injector(time from pulse start, to when the injector acually flows any fuel)
Example, Bosch '465cc' injectors hav about 0.8ms of deadtime, that is about half of the time you got to inject it in.
so with simple calculation,, if you need 465cc, then you have to double the injectorflow or put two as the half actual time to squirt flow is occupied with 'deadtime'.
You can also go with bigger injectors.. but those tend to be more unstable at low openingtimes.
And not to settle with this, the deadtime varies with voltage and fuelpressure,,,,,and bonusproblem!!: backpressure! (crankhouse compression)

[Flettner]

On my Kawasaki I used a "sampler valve", solinoid with the same coil size as the injector that allowed the crank case to only be connected to the computer as the injectors were opperating.

You are talking about adding an extra injector at the inlet for over 8 / 9000 rpm?