ESE's works engine tuner

[Buckets4Me]

cool whats this C.V.F you speek about

28 hp sounds scary

pitty you when't up this way show us all how it's all done

[Yow Ling]

Honestly SS90 you look like you could contribute some interesting/usefull info that we would all like to read and benifit from but your attitude is getting in the way. Lose the imature "Need to be Right" chip on your shoulder and then we can be friends otherwise bugger off and be an "EXPERT" (as you define it) some where else.

So whats it to be

.

Dont be so harsh on him, read this thread and understand something about Germany http://www.kiwibiker.co.nz/forums/sh...t=german+jokes

[TZ350]

CVF

Screen Scrape:-

Malossi 166cc Kit for P125X-PX150-Stella
Part Number: M314093
Price: $346.00
On Sale: $269.00

Malossi 61mm, 166cc kit, fits Sprint, Super, GTR 125, TS 125, P125E, PX125E, P150X, PX150E, Stella and COSA 125 (can also be modified to fit on some old 125 and 150's). Extra 2 stroke power, larger transfer ports, and a larger exhaust port. Includes BIG bore cylinder, high compression head, CVF flow piston, rings, wrist pin, pin clips, gasket set, carb jets, Malossi stickers, and instructions. This will bump up your old Vespa in horsepower, and with a pipe and carb you can increase it much more. (This kit needs the ports chamfered. We can do this for you)

Related Items:
Ports Chamfered

I had not thought of looking at Scooters for tuning ideas before.

SS90 I don't understand how this works, can you explain it to me??

[Yow Ling]

http://cgi.ebay.com.my/ws/eBayISAPI....2BSI%26otn%3D4
http://galerie.competition50cc.info/...lbum=16&page=1

Ive been looking at this too, looks like the transfers are duplicated below the rings when the piston is at bdc as well as your normal transfer flow up the transfer poert the lower "duplicate transfers" are opened up to the inside of the piston crown which shortcut to the main transfer channels, I guess this provides better piston cooling and a less torturous path for the last of the crankcase contents . pretty clever really. have a look at the piston in the ebay link

[TZ350]

Some more Scotter stuff here

http://images.google.co.nz/imgres?im...%3D60%26um%3D1

Looks pretty trick.

[Buckets4Me]

http://galerie.competition50cc.info/...lbum=16&page=1

[TZ350]

The rear port on this cylinder looks like a gully port just like the GP125 has, flanked by ordinary transfer ports.

The main side transfer ports have extra mixture entry windows. I would not have thought the short transfer ducts would produce enough inertia in the transfer streams to work well.

Looking at the piston I can see how the mixture traped under the piston crown is suposed to be ejected into the main transfers through the extra side ports.

All very interesting stuff. Does it work? Could it be adapted to the GP125???

IF SS90 wants to put some ideas and sketches on paper I would be happy to see if they can be implimented on the GP125.

[TZ350]

A MALLOSSI Kit:-

The data:
Compression: 14,8:1
Max power: 31,15 CV @ 8250
Max torque: 2,4 kgm @ 7250

Besides mounting the new Cylinder you have to work on the APTS Power Valve wich is to be made a bit bigger, change 2 clutch springs with the enforced ones in the kit and adjust the Power Valve, your Carburetor set-up and timing.

[koba]

Max power: 31,15 CV @ 8250
Max torque: 2,4 kgm @ 7250

CV?
kgm?

crazy euro speak...?

[SS90]

Honestly SS90 you look like you could contribute some interesting/usefull info that we would all like to read and benifit from but your attitude is getting in the way. Lose the imature "Need to be Right" chip on your shoulder and then we can be friends otherwise bugger off and be an "EXPERT" (as you define it) some where else.

So whats it to be

.

For the record, I NEVER referred to myself as an expert, and never will, I said

"If you consider yourself an expert, and you don't know what C.V.F is....."

I'm sorry if I am coming of condesending, it's not intentional!

[SS90]

The rear port on this cylinder looks like a gully port just like the GP125 has, flanked by ordinary transfer ports.

The main side transfer ports have extra mixture entry windows. I would not have thought the short transfer ducts would produce enough inertia in the transfer streams to work well.

Looking at the piston I can see how the mixture traped under the piston crown is suposed to be ejected into the main transfers through the extra side ports.

All very interesting stuff. Does it work? Could it be adapted to the GP125???

IF SS90 wants to put some ideas and sketches on paper I would be happy to see if they can be implimented on the GP125.

O.K, I will try to answer everything in one post...to make it easier to read.

First..... before I explain C.V.F, a little information on "CYLINDER SCAVENGING", because this is what it is about

ONE (there are quite a few) of the problems with a two stroke engine is that they are VERY inefficient in achieving "a pure charge" when it comes to the power/exhaust stroke.

(some of you MAY know this, but I suspect that you havn't fully explored it to the fullest extent....as if you did, you would have some more powerfull engines)

Again, please don't think I am being a "know all", I'm just stating the facts as I see them, and trying to help.

Now, I believe I have clearly explained the BASICS of how fuel gets from the crankcase to the cylinder, (and as such, the importance of carful attention to primary compression, and it's ratio)

Mistakingly, it was said (not by me, by another poster)

"that the only reason the fuel gets into the combustion chamber is that it is sucked into the cylinder when the transfers are opened"

I believe I have broken that myth (a very common one it seems)

What is important to note though, is, (along with a correctly designed expansion chamber), the transfers, if they are designed well (here in lies some clues of where the REAL power is......) actually "extract" more fuel from the Crankcase than the primary compression differential (the difference between the crankcase pressure and the cylinder pressure), which on it's own, makes the engine function, but VERY inefficiently, much like a 1923 Villiers, or an old two stroke lawn mower.

At this point, I am saying that the transfers are vital in regards to "SCAVENGING" the crankcases, and achieving a "more complete" evacuation of the crankcases.

The method used in pretty much every two stroke you will see in your life is called "Schneurle Loop", (ironically, a German.....), which is sometimes called "Loop scavenge"

This system was patented by Dr Schnurle in 1925, which meant, for quite some time Germany was at the front of Two stroke development, because, with the patent, no-one could use the system.

Then, when the patents ran out (end of 2nd War I am guessing), anyone could use it, and, it rapidly was used by every manufacturer.

Now, of course, the original "Loop Scavenge" system was quite basic, and it wasn't long before it was improved (but, it is, pretty much the same as it was, just with some clever development as time progressed)

All the engines you guys are running are "loop scavenge"

ONE of the main focuses today for modern two stroke engine tuners is this this area, and improving aspects of it........

I'm not going to give all my secrets away...what I will say, what is done here, is considered to be your "signature" when it comes to porting work and design.......

Now, C.V.F

Which is copyrighted by Mallossi.

Sorry, no cylinders sitting at home just now to take photo's, but I'll see what I can find if enough people don't understand what I am saying.

When the piston is at the bottom of it's stroke (basically, with out using too much "tech words") this is the time that a two stroke has to empty the burned gasses, and fill it with fresh charge (from the crankcases), and, as we know, while an expansion chamber has the effect of "pulling back" some of the good charge that consequently goes out the open exhaust (unevoidable), still, alot just goes to waste.

Now, there is still some "good" air/fuel trapped under the piston (on every stroke), that normally, (with a basic set up), never gets put to good use, and is as such "wasted"

What C.V.F does is, when the piston is at B.D.C, holes in the piston (above the gudgeon pin) see pic, align with corresponding holes in the cylinder, so, that this "good fuel" get used by going up the transfers

What I learned (not discovered), high tech Japanese two stroke teams found this out years ago, but only now people are starting to pay attention....... There is a way of designing the transfers that will effectively "scavenge" the crankcase as much (I believe possibly more...that's up for debate)

I'm not going to hand feed you on that one tho.....

At this point I am going to dissapoint evey one, and not show detailed pictures of my cylinders.......

If I did, it would just give away this information (possibly, maybe you would still miss it), and where is the fun in that

Also, TeeZeeeTreeFidddy asked for some pics of me "at work" (I have heaps...but at this stage I would prefer to remain anonymous (just for the fun of it all), but all in good time......

But, a few answers to his questions
By the way, they are good ones!

The pics I showed are indeed 2 years old, and that particular cylinder (used in the pics) is still in use (modified in port height, width etc), and has (I think the best spread of power of any engine I have made (altho not the most peak)

TeeZeee....... You are right about the bridge (with a port that small, the bridge was not needed), but as you know, if you have a bridge (and you are developing an engine) you can go REALLY wide.

Basically, the prototype was designed as a "base" and I was able to see results from incremental widening of the port (to eventually exceed 70%, and I am only limited by the studs in the latest incarnation)

Also, "For the same port area", "an unbridged port will only flow 4% more than a bridged one"

I believe that

"4% more exhaust flow can be offset by advantages of having an exhaust port area wider than 70%, (up to as much as your piston (or in this case, workable area) will allow"))
This has been verified by some clever people (in Austria), who have the gear to do such testing....

Also, in regards to the boost port system I have, there is HUGE power gains there as well (The gully thing you refer to TeeZee, was actually designed by Kääden (the man himself,granfather of two stroke tech) as a way too cool the underside of the piston, but, after testing, it had an unexpected power gain........ when it has relivence, we can develop that idea too!!


I am not trying to highjack this thread either, just trying to help.

Let's not forget, that this post is about TeeZeeTreeFiddy and his GP125 Bucket..... That runs too hot.....and loses power.ö

On a personal note.....

No will not start my own thread, (or Blog), while I respect that many people would have a real intertest in this "Kiwi guy in Germany" at this stage I am not willing to do that.

Maybe some stage in the future.

However, I will "help the boys back home"

I appreciate your respecting this.

I have some good working pics too, but, I want to stay "annon." (for now)

Thanks

[SS90]

As a little extra, here is an excerpt from a very clever guy (one of the best), in regards to C.V.F..... (translated from German)

I am only posting this as a way of "stirring up debate", and hopefully encourage everyone to find "the better alternate" to C.V.F......Which incidently, does actually work, but only if the cylinder has an excessively long spiggot (therfore obscuring better evacuation of the crankcase....)



"i personally believe the cvf thing was more of a marketing measure than a true performance must. i can't remember seing a single other two-stroke piston which has it, and unless i'm mistaken, even malossi has dumped it on anything but their oldest designs, that's their vespa stuff. no idea why one would want to spend time and effort on that. as far as i remember it has been proven that a polini is good for 24 brake or so (at comparatively low rpm), which, in my book, equals a pretty high bmep, hence i guess that even more power would be possible at slightly higher rpm "

Like I say, it does work, but only has a big effect on cylinders with long spiggots.......

There is a better way............. And it's not as hard as you might think...........

Note it's mentioned that a "Polini is good for 24 brake or so......."

Now, that's really "worked", but it is a cast iron Cylinder, with 130cc's.........

GULP!



If did it all over, knowing what I know now..... I would look at HONDA engines (racing ones that is)......

there is a good clue in that.

Some people in Europe have 30 P.S...........

But they use a Nickasil cylinder......

Which is very special.

[SS90]

Found this on wikipedia for all you guys interested.....

READ IT CAREFULLY, THE ANSWER IS HERE, YOU JUST HAVE TO LOOK FOR IT!


Loop-scavenged
Main article: Schneurle porting
This method of scavenging uses carefully shaped and positioned transfer ports to direct the flow of fresh mixture toward the combustion chamber as it enters the cylinder. The fuel air mixture strikes the cylinder head then follows the curvature of the combustion chamber then is deflected downward. This not only prevents the fuel/air mixture travelling directly out the exhaust port but creates a swirling turbulence which improves combustion efficiency, power and economy. Usually a piston deflector is not required, so this approach has a distinct advantage over the cross flow scheme (above). Often referred to as "Schnuerle" (or "Schnürl") loop scavenging after the German inventor of an early form in the mid 1920s, it became widely adopted in that country during the 1930s and spread further afield after World War II. Loop scavenging is the most common type of fuel/air mixture transfer used on modern two stroke engines. Suzuki was one of the first manufacturers outside of Europe to adopt loop scavenged two stroke engines. This operational feature was used in conjunction with the expansion chamber exhaust developed by German motorcycle manufacturer, MZ and Walter Kaaden. Loop scavenging, disc valves and expansion chambers worked in a highly coordinated way that saw a significant increase in the power output of two-stroke engines, particularly from the Japanese manufacturers Suzuki, Yamaha and Kawasaki. Suzuki and Yamaha enjoyed success in grand Prix motorcycle racing in the 1960's due in no small way to the increased power afforded by loop scavenging. An additional benefit of loop scavenging was that the piston could be made nearly flat or slightly dome shaped. This enabled the piston to be appreciably lighter and stronger and consequently tolerated higher engine speeds. The "flat top" piston also has better thermal properties and is less prone to uneven heating, expansion, piston seizures, dimensional changes and compression losses.

No, this is not where I got my information, I read the book

"THE TWO STROKE TUNERS HANDBOOK", By Gordon Jennings (among others)

It's all in there..... (well it's old, but the physics of it all is the same)

[Yow Ling]

OK, ss90 reading your posts , I get the Idea that you think that nobody in NZ has made a 2 stroke capable of much more than powering a lawnmower. 20hp from a 100cc engine seems common 23hp less common but still done.
Your style of "I know it but arent going to tell you" isnt going to win you any admirers.
If CVF is the answer , what was the question? Overheating? If cvf was the true path to power GP teams would use it, and motocross would have adopted it. It seems like a solution looking for a problem, mask the transfer tunnels so the cvf will work, getting tha last bit of good mix from under the piston at the expense of the good mix in the bottom of the crankcase.

My understanding of "scavenging" seems to differ from yours, scavenging is the process of sweeping the exhaust gasses from the cylinder after combustion, the better the scavenging the less the fresh charge is diluted/polluted by the spent gasses. The crankcase is not scavenged just pumped out or emptied into the cylinder , the depression caused by the pipe assists in this.

High crankcase compression and skinny pipes results in peaky engines , low crankcase compression and fat pipes wider power.

bucket racing isnt just about flash motors, you actually need to be able to ride to win, a 28ps motor isnt a ticket to win, plenty of guys kick my arse on bikes making less powerthan mine because they know the real secret, but I cant tell you what is is because that wouldnt be any fun

[saxet]

Well I've been reading this thread as it progresses and it's gettin more and more interesting. I think SS90 may have surprised us all ( well me at least, but I'm no expert at all). It can be hard to accept someones claims when we can't see the evidence ourselves, that does'nt mean they're not true. Most of us are limited by time, money and access to resources( info and equipment).Also by not knowing where to look. Thanks for your tips SS90, I do understand you don't want to give away all your info but any more hints would be cool as I'm nowhere at the level of TZ350, F5 Dave and all the others who have commented.
Awesome thread and keep up the dialogue and , in particular the good work and hard effort by TZ350.

Looks like I should read Gordon Jennings book a few more times. I think I may have some clues as to what SS90 is on about but don't want to comment yet as I need to do some reading before I spout forth and look like a drip.