Two-stroke performance tuning?

[Skunk]

Bhahahahahhaha!

INTERNET BASED TEXT?????

bwhwhwhahahhahah!

Your complete inability to accept new information is why SOME of you fail to accept that it is possible to make a 125cc air cooled ingine (4 speed) with 30 PS.......

The internet is all I have as YOU haven't given ANY NEW information - just criticized everything anyone posts. Nor have you shown any source of new information. I personally don't see any problem with 30PS 125cc two strokes. I just don't see any INFORMATION on how it can be achieved coming from you.

Oh - I never said 'internet based' either.

[SS90]

The internet is all I have as YOU haven't given ANY NEW information - just criticized everything anyone posts. Nor have you shown any source of new information. I personally don't see any problem with 30PS 125cc two strokes. I just don't see any INFORMATION on how it can be achieved coming from you.

Oh - I never said 'internet based' either.

Perhaps if you contributed in a mature fashion, I would be more forthcoming with information.

Rather than (incorrectly) "knocking" everything I write, some intelligent comments would invoke a more helpful response.

Don't forget Skunk, I feed myself and keep a roof above my head by tuning two stroke engines.... I must know something....

[bucketracer]

Rather than (incorrectly) "knocking" everything I write, some intelligent comments would invoke a more helpful response.

Actually there have been many inteligent comments mostly backed with references from books and the internet.

To advance your opinion you will need to explain it in a way that makes sense.

.

[SS90]

The internet is all I have as YOU haven't given ANY NEW information - just criticized everything anyone posts. Nor have you shown any source of new information. I personally don't see any problem with 30PS 125cc two strokes. I just don't see any INFORMATION on how it can be achieved coming from you.

Oh - I never said 'internet based' either.

Ok Skunk, I have posted this run in the ESE thread, but here is an example of how an expansion chamber DOES NOT "SUPERCHARGE" a cylinder.

The same exhaust,head,primary compression,ignition (and timing) flywheel etc.....

Only the scavenge pattern has been changed (dramatically).........

If a two stroke chamber "supercharged" a cylinder, why would keeping the air/fuel mixture in the cylinder (stopping it heading out the open exhaust port) make such an improvement?

If indeed a two stroke chamber "supercharged" a cylinder, scavenge patterns would be redundant, and we could increase our transfer port area (by simply "squaring" them off on the bore)...... and make power via the "supercharger" exhaust.

This graph shows otherwise.

[SS90]

Actually there have been many inteligent comments mostly backed with references from books and the internet.

To advance your opinion you will need to explain it in a way that makes sense.

.

Ermmm,

So, do you still think this is a correct statement?

Does a scavenge pattern stop the fuel from escaping out the open exhaust port or not?

[Skunk]

Ok Skunk, I have posted this run in the ESE thread, but here is an example of how an expansion chamber DOES NOT "SUPERCHARGE" a cylinder.

The same exhaust,head,primary compression,ignition (and timing) flywheel etc.....

Only the scavenge pattern has been changed (dramatically).........

If a two stroke chamber "supercharged" a cylinder, why would keeping the air/fuel mixture in the cylinder (stopping it heading out the open exhaust port) make such an improvement?

If indeed a two stroke chamber "supercharged" a cylinder, scavenge patterns would be redundant, and we could increase our transfer port area (by simply "squaring" them off on the bore)...... and make power via the "supercharger" exhaust.

This graph shows otherwise.

I'm only knocking your knocking.

Nice chart.
What was the chamber?
Was there a chamber?
What did you do to achieve that scavenge effect?
How does that show the chamber was doing absolutely nothing?

I thought Scavenging and chambers had to work together, along with transfer timings etc. Are you saying the chamber is redundant or doing something other than pushing air/fuel mix back into the cylinder? If the scavenging is perfect what is the chamber pushing back? Is it instead holding the air/fuel mix at the port face while the scvenging does it's job? How do you get that fine balance over such a rev range?

That's it. In the past you have NOT explained these things. That's why you get the response you do.

Here's your chance.

[SS90]

I'm only knocking your knocking.

Nice chart.
What was the chamber?
Was there a chamber?
What did you do to achieve that scavenge effect?
How does that show the chamber was doing absolutely nothing?

That's it. In the past you have NOT explained these things. That's way you get the response you do.

Here's your chance.

What was the chamber? I will sell you one for €500 (incl postage), it will only fit a small frame Vespa (sorry) But it will be hand made in Germany (by a Kiwi)

Was there a chamber? errrr YES.

What did I do to achieve the scavenge effect? Paid attention and accepted advise from people, along with intelligent conversation and constructive critisisim, along with leaning "how and why" other manufacturers did things.

I don't say that the chamber was doing absolutely "nothing", I use this as an example to show that if the chamber was "supercharging" the cylinder, then improvements in the scavenge patterns would have no effect.

[TZ350]

.

Teezeetreefiddy "old boy",

.

As we are not friends, to continue to miss use my name and your mock familiarity is childish don't you think?

.

[Skunk]

What was the chamber? I will sell you one for €500 (incl postage), it will only fit a small frame Vespa (sorry) But it will be hand made in Germany (by a Kiwi)

Was there a chamber? errrr YES.

What did I do to achieve the scavenge effect? Paid attention and accepted advise from people, along with intelligent conversation and constructive critisisim, along with leaning "how and why" other manufacturers did things.

I don't say that the chamber was doing absolutely "nothing", I use this as an example to show that if the chamber was "supercharging" the cylinder, then improvements in the scavenge patterns would have no effect.

There you go again! Lots of words and zero usable information. If you want us to listen then you have to be saying something - not a lot of nothing.

Where is the straight out answer to ANY of my questions... oh, right - yes it had a chamber.
As I said - scavenge and chamber MUST work together. Both do a job.

[SS90]

There you go again! Lots of words and zero usable information. If you want us to listen then you have to be saying something - not a lot of nothing.

Where is the straight out answer to ANY of my questions... oh, right - yes it had a chamber.
As I said - scavenge and chamber MUST work together. Both do a job.

Ermmm,

Yes Skunk.

That's what I have been saying, I guess it is a little hard to follow when childish nonsense keeps "popping up"......

However, this particular "series of discussions" is about the (I believe), non exsistant " expansion chamber supercharged" two stroke engine.

No one has convinced me that an expansion chamber "supercharges" a cylinder.

If we all want to improve our knowledge (I do) then we should all look at how things really work.

It's not Magic.

Can you show us anything that an expansion chamber "supercharges" a cylinder (i.e increases the V.E over 100%?)

[SS90]

.



As we are not friends, to continue to miss use my name and your mock familiarity is childish don't you think?

.

We are not friends?

Since when?

[Skunk]

Can you show us anything that an expansion chamber "supercharges" a cylinder (i.e increases the V.E over 100%?)

No. I work in the printing industry. You're the expert. Can you show us it doesn't?

If you can, will you? I'm already guessing I know the answer to that one.

Oh, since when is supercharging defined as over 100% VE? I understood supercharging as increasing normal VE.

[inlinefour]

It would be nice to move this in to the "Mainstream" section of this site, and I hope we can do this shortly, however, "Good things take time", and some co-operation is needed.

Let's all get together and start a "Two stroke tuning" thread that rivals others in the world, as, we are all Kiwi's, and as such have an amazing pedagree (particularly when it comes to high powered racing Two stroke engines (Kim Newcome for example, & the often forgotten B.S.L Team, and it's conceptor, Brian Buckley)...........

Looking at the current NZ bucket racing rules, I see the potential for developing a very special type of engine.

A 125cc, Air cooled Two Stroke, limited only by it's capacity, (and), a 24MM carb............

I am unsure of the rules you can apply when starting a thread, but one I would like to place is that no-one is allowed to

"use words bigger than their I.Q"

What I mean is, lets try to simplify it, so that EVERYONE can contribute

......... many effective solutions have been discovered by in-experienced observers, simply because they applied logic that the rest of us missed , because we where "too involved".........

So.... lets Begin......

Ive not read through this whole thread and I dont intend to, so this is a reply to this quoted post. If there are other bikers etc that shun the 2-stroker in any way, they need a quick lesson in motorcycle history. Almost all high preformance bikes started in one form or another with a 2-stroke engine. I grew up with 2-strokes and had made sure that within my bike collection was several, before the bleeding hearted, possum kissing, tree hugging, politically correct, cry for the environmentilists had them banned in NZ. Which is kind of ironic, because there are plenty of applications where the 2-stroke engine is used/prefferred and Im not talking about bikes. Even one of my RC trucks is powered by a high preformance 2-stroke single that would out drag most bikes, until it hit its top speed. Im not sure about everyone elses experience with tuning high preformance 2-stroke engines, but most of mine didnt need much tuning at all and most issues I ever had was a sign that something had vibrated loose and needed tightening up/resetting again. I say that if 2-strokers are not in the mainstream of this site allready, its probably just a sign of ignorance more than anything else.

[SS90]

No. I work in the printing industry.

The printing industry?

Figures.

I believe I have put a good case forward that an expansion chamber does NOT "supercharge" a cylinder, while at the same time keeping it simple and uncomplicated.

As yet, no one has shown that an expansion chamber "supercharges a cylinder" (Fooman has indicated that there is a " dynamic supercharging effect"

that does not constitute a "supercharged" cylinder.

Fooman seems to have an exceptional grasp of Physics... (Massy it seems) perhaps he can contribute something that disproves my statement.

[SS90]

Oh, since when is supercharging defined as over 100% VE? I understood supercharging as increasing normal VE.

Hmmmmm,

So, back to definitions again.

I would consider that if an engine is "supercharged" it has a VE of over 100%.