ESE's works engine tuner

[wobbly]

One of the first pipes to use the increasing angle idea were early KT100 Yamaha versions that were developed when centrifugal clutches became the rage.
It turned out the best of these used a parabolic shape that was spun on a mandrel.
That TD cone had me fucked for years trying to understand what chemicals were involved in its development.

[husaberg]

Sinply out of curiosity, how does the very early TD pipe with effectively a part - spherical end cone align with this ? Certainly the steepest portion is at the furthest point from the piston, if nothing else.

was that the one that looked like a triumph twin silencer.




This is the ascot version that had the kit pipes


59 Asama racer

the kit yd rr250


Well i never knew this was this set up
Yamaha RA41 around 1961

[Frits Overmars]

Here it is, just in time for the holidays.

https://1drv.ms/u/s!Atyzb5b7jtWNmVcX...5eKjL?e=nxuw41

With this link you can download the most recent versions of

FOS Software

and

FOS Tips & Concepts

I have always written my own software. I wrote these programs in the course of over five decades for my own personal use and I never bothered to make them user-friendly, so you may have to do some experimenting on your own, as I will not have time to answer questions.

The FOS Software runs on operating systems from MS-DOS 6.2 up to Windows 98 (I recommend Win98SE) so either dig up an old computer or use an emulator. On my Win10-laptop I use VMware Player.
I advise against DOSBox 0.74 because that is essentially a stripped-down version of MS-DOS 5; it will run some of the programs, but not all of them.

Everything that I make available here or via open forums such as Pit-Lane and KiwiBiker, may be freely distributed.

Merry Christmas and a Happy New Year !
************************************************

Hier ist es, pünktlich zu den Feiertagen.

https://1drv.ms/u/s!Atyzb5b7jtWNmVcX...5eKjL?e=nxuw41

Mit diesem Link könnt Ihr die neusten Versionen herunterladen von

FOS Software

und

FOS Tipps & Konzepte

Ich habe immer meine eigene Software geschrieben. Ich habe diese Programme im Laufe von über fünf Jahrzehnten für meinen persönlichen Gebrauch geschrieben und mir nie die Mühe gemacht, sie benutzerfreundlich zu gestalten, so dass Ihr möglicherweise selbst etwas experimentieren müsst, da ich keine Zeit haben werde, Fragen zu beantworten.

Die FOS-Software läuft auf Betriebssystemen von MS-DOS 6.2 bis Windows 98 (ich empfehle Win98SE), also entweder einen alten Computer ausgraben oder einen Emulator verwenden. Auf meinem Win10-Laptop verwende ich VMware Player.
Ich rate von DOSBox 0.74 ab, weil das im Wesentlichen eine abgespeckte Version von MS-DOS 5 ist; Es wird einige der Programme ausführen, aber nicht alle.

Alles, was ich hier oder über offene Foren wie Pit-Lane und KiwiBiker zur Verfügung stelle, darf frei verbreitet werden.

Frohe Weihnachten und ein glückliches neues Jahr !
************************************************** ***********

Eccolo, giusto in tempo per le feste.

https://1drv.ms/u/s!Atyzb5b7jtWNmVcX...5eKjL?e=nxuw41

Con questo link è possibile scaricare le versioni più recenti di

FOS Software

e

FOS Suggerimenti & Concetti

Ho sempre scritto il mio software da solo. Ho scritto questi programmi nel corso di oltre cinquant'anni per mio uso personale e non mi sono mai preso la briga di renderli facili da usare, quindi potresti dover fare qualche esperimento da solo, dato che non avrò il tempo di rispondere alle domande.

Il software FOS funziona su i sistemi operativi da MS-DOS 6.2 fino a Windows 98 (consiglio Win98SE) quindi o recupera un vecchio computer o usa un emulatore. Sul mio laptop Win10 utilizzo VMware Player.
Sconsiglio DOSBox 0.74 perché è essenzialmente una versione ridotta di MS-DOS 5; eseguirà alcuni programmi, ma non tutti.

Tutto ciò che rendo disponibile qui o tramite forum aperti come Pit-Lane e KiwiBiker, può essere distribuito liberamente.

Buon Natale e un Felice Anno Nuovo !
********************************************

Hier is het dan, net op tijd voor de feestdagen.

https://1drv.ms/u/s!Atyzb5b7jtWNmVcX...5eKjL?e=nxuw41

Via deze link kunt u de meest recente versies downloaden van

FOS Software

en

FOS Tips & Concepten

Ik heb altijd mijn eigen software geschreven. Ik heb deze programma's in de loop van meer dan vijf decennia voor eigen persoonlijk gebruik geschreven en ik heb nooit de moeite genomen om ze gebruiksvriendelijk te maken, dus misschien moet je zelf wat experimenteren, aangezien ik geen tijd heb om vragen te beantwoorden.

De FOS Software draait op besturingssystemen van MS-DOS 6.2 tot Windows 98 (ik raad Win98SE aan), dus graaf een oude computer op of gebruik een emulator. Op mijn Win10-laptop gebruik ik VMware Player.
Ik raad DOSBox 0.74 af, omdat dat in wezen een uitgeklede versie is van MS-DOS 5; het zal enkele programma's uitvoeren, maar niet allemaal.

Alles wat ik hier of via open forums zoals Pit-Lane en KiwiBiker beschikbaar stel, mag vrij worden verspreid.

Vrolijk Kerstfeest en een gelukkig Nieuw Jaar !
************************************************** ****

[andreas]

Frits,
do you know which specific wrong turn I made?
Used VMware workstation 17.

[p12palof]

Thank you very much Frits, for sharing your knowledge

[SwePatrick]

I played around in the programs and found that the app for calculating combustionchambers are really good.
But for exhaust, it misses the desired tuned rpm with almost 2000rpm in my case, i wanted 12500rpm as peak, i got 14300rpm.

I discussed this a bit on facebook in my group(Swedish speaking group, 'Advanced twostroke technology') and there was more guys that has experianced the same problem.

Rgds

[Frits Overmars]

I played around in the programs and found that the app for calculating combustionchambers are really good.
But for exhaust, it misses the desired tuned rpm with almost 2000rpm in my case, i wanted 12500rpm as peak, i got 14300rpm.
I discussed this a bit on facebook in my group(Swedish speaking group, 'Advanced twostroke technology') and there was more guys that has experianced the same problem.

I wonder what you mean by 'peak rpm' Patrick. Is it rpm of maximum power, as required by the FOS exhaust concept, or is it maximum rpm?
Anyway, the concept mentions: "Starting with a speed of sound value of 550 meter per second will get you in the right ballpark, after which you can vary this value according to your own findings".
So apparently you have a higher speed of sound in your exhaust system, either thanks to an above-average cylinder filling, a low compression ratio, a late ignition timing, a lean mixture or a non-standard fuel.
I seem to remember you mentioning methanol or nitromethane...

And remember the first line of the concept?
"This exhaust concept intends to help beginning tuners on their way". From what you have shown us here in the past I don't think you qualify as a 'beginning tuner'

[Condyn]

The long ( over 32% ) header length scenario with its reduced overev is easily seen and understood when looking at the depression values around BDC .
As the rpm rises the max depression point moves to the right , leading eventually to virtually nil depression before BDC. A short header starts the depression earlier in the cycle , thus keeps the leftward biased wave shape for longer.

In a CVT especially my opinion would be you don't want a long ( 68%) diffuser either , as this will naturally dictate shallower angles than is possible with a short ( 64% ) length - as always , tempered by the law of
diminishing returns.
In this case where you are never low in the power band , I would be looking at 29/30% - 64/65%.
Having a short header with a long diffuser makes the angle issue even more evident - thus is a classic mismatch for the end use.

Yes , a sharp power drop after peak may be affected by heat - too much com or to much advance ( high MSV, same effect ) due to more heat being transferred into the piston/water , than is dumped into the pipe at EPO.
An overly steep rear cone will have the same effect after peak as well - but a 3 angle setup makes it a lot easier to fine tune the peak vs overev dichotomy.

As per usually Wobbly sniffed that one out before I even tested it.

I learned the hard way at the dyno over the weekend. Going backwards for the first time with close to 100 hours of work invested in pipe and cylinder labor. 2% down on power!!

I tested a variety of pipe designs this time, different header and diffuser percentages with the best being 30/69. The plus side is the front side is finally smooth with the shortest head pipe I have tried so far.

At the end of the day the same idea of steepening up the diffuser with a longer dwell section was proposed to me by the well accomplished dyno operator/engine builder. Time to sit down with the sim and try to make sense of things.

[wobbly]

Just as a guide the header length , and the first diffuser cone angle sets the shape of the overev potential.
The length and the steeper the final diffuser angle , this determines the upper front side power.

[SwePatrick]

I wonder what you mean by 'peak rpm' Patrick. Is it rpm of maximum power, as required by the FOS exhaust concept, or is it maximum rpm?
Anyway, the concept mentions: "Starting with a speed of sound value of 550 meter per second will get you in the right ballpark, after which you can vary this value according to your own findings".
So apparently you have a higher speed of sound in your exhaust system, either thanks to an above-average cylinder filling, a low compression ratio, a late ignition timing, a lean mixture or a non-standard fuel.
I seem to remember you mentioning methanol or nitromethane...

And remember the first line of the concept?
"This exhaust concept intends to help beginning tuners on their way". From what you have shown us here in the past I don't think you qualify as a 'beginning tuner'

Sorry for bad explanation, i meant at where peak power occurs.
I used 550ms as the same reason you mention.
And my comparison is 'my engine'(same hardware config with both pipes) with my pipe and a fos pipe(your program) using MotaX.
So no real world dyno runs, just what the software´s are telling me.

No data about fuel, just 550ms.

Rgds

[JanBros]

does the length of your calculated FOS pipe corresponds with the pipes you are using now ?

if not, keep changing the speed of sound until both pipes (yours and calculated) are the same length and that speed of sound will be a better match for you than the 550. than peak rpm shouls also match.

[Frits Overmars]

my comparison is 'my engine'(same hardware config with both pipes) with my pipe and a fos pipe(your program) using MotaX. So no real world dyno runs, just what the software´s are telling me.

I would be interested to see what the dyno is going to say. Could you keep us informed Patrick? Thanks.

[Condyn]

The first big fat FOS pipes I made (not for my beloved air cooled) using 550 m/s were within 1% HP peak of a well developed tried and trued pipe. They were just a smidgen too short. Unfortunately never got around to building any more of them yet.

[andreas]

Teezee, I'm reading in the 400's pages, when the gp 125 was still a single ex-port waiting for the Wobbly-Piranha. I had a similar tune a long time ago: 198 ex-dur and 130 tr-, RD 125 lc, so obviously not RV, but YZ125 reeds and carb 34mm, Out of curiosity: Do you know how fast it was top speed? Mine was up from 125km/h to 162 km/h (speedo). One (of many) limiting factors, I now belive was my determination to use G. Blairs Pipe design. I know how to extract power increase from higher speed, but it would be interesting to see how it compared to your 31hp GP.

[SwePatrick]

I would be interested to see what the dyno is going to say. Could you keep us informed Patrick? Thanks.

My pipes designed in MOTA as for now just misses the peakpower rpm by 200rpm´s in dyno, therefor i state that the motasimulation shows close to real data, coming to tuned rpm.
My pipes is tuned for about ~85rwhp at 12500rpm in Mota, and so far has given me 87rwhp at 12280rpm in my dyno, and taking the 'FOS pipes' tuned to 12500rpm into Mota the peak power rpm shoots up above 14000rpm.

A friend of mine who is a good mathmatic has seen the same problem, and used into your variables some Blair math, using excel file he created(based on FOS concept but with Blair math) corrects the pipelength and gives me the correct tuned rpm in Mota.

Rgds.