ESE's works engine tuner

[lodgernz]

What say ye? Snake oil or engineering breakthrough?
I was immediately skeptical when it mentioned the high octane requirement and need for high pressure oil in the transmission but always willing to listen.

https://www.sticsupertorque.com/productinfo.html

Historic discussion starts at post 31977 here: https://www.kiwibiker.co.nz/forums/s...post1131133232

[Vannik]

Since it seems like 1,2,3 and possibly 4 have not been discussed much, or at all, maybe it would be useful to explain 1,2,3 in some detail to ALL. Then from that I can see if your 1,2,3 includes my "4" or not.

Nitro, will do but it will take a few days. I have to put in words what is normally in differential equations in a way that is both still correct and understandable. But it is a good idea to do this.

[Vortex]

Hello folks,
I have been a passive reader here for a long time now and I would like to confess that there is a lot of 2-stroke expertise to be found here, really interesting and great.
I have been working in karting for many years, mainly in the OK engine sector (direct drive). I also own an engine test bench (dynamic, static and dynamic/static combined measurements possible).
We are very limited by the regulations in those classes.
The power density has become extremely tight, many drivers are only separated by 1/10 of a second or less per lap.
I dare to ask a question about the exhaust. The exhaust is homologated for 3 years and is the same for every manufacturer, so the engine or rather the requirements for the engine should be made to match the exhaust as much as possible. So I can only use given tolerances here.
Is there a nice person here who would be willing to maybe make me different simulations by exploiting the given tolerances to then be able to see the different tendencies, it is not enough for me to just drive the whole exhaust long or short, this result is known to me.
The simulations don't have to be for free either.
I bought the EngMod2T software a few years ago, but unfortunately I don't know how to use it.
If there should be this nice person here then please let me know. Of course I would be very happy to provide all the technical details.
Thank you in advance.

[136kg136ps]

Historic discussion starts at post 31977 here: https://www.kiwibiker.co.nz/forums/s...post1131133232

Thanks for that, missed a lot around that time with all the Luc banter.

[wobbly]

Mr Vortex - PM sent re sims in EngMod.

[nitro2tfx]

Nitro , as I am really keen on using any tool I can in the quest for increased speed of analysis in producing new or better designs , can you explain one thing to me
about the way you implement the data analysis of the real time observations.
To me the process is only one step ahead of the old " suck it and see " approach.
As it seems you have to do a test run , analyse the data , then the only way forward is to modify or rebuild the pipe/ports etc , then do another test - still slow and laboreous , but more informed obviously.

Again I come back to the last big project I did for TM.
They wanted more front side power , so it took me about a week of constant small iterations in the sim, and analysis , to discover categorically that the last part of the diffuser , had the biggest effect on this.
I started out with a short , shallow section , just like an Aprillia pipe , and 30 sims later ,ended up with a cone way longer , and steeper , than I could ever have imagined.
Then to supress the tendency to produce more peak ( not wanted , as it creates too much tuning drama trying to supress deto ) this needed a completely differing approach ( from " normal " )
to the header and 1st diffuser % / length.

I built one pipe to dyno prove the diffuser concept , one to prove the header , and one to prove the rear cone matched the sim effects.

Is the real time data analysis able to match or short circuit this process without spending hours rebuilding pipe after pipe iterations - just to see if a theory matched reality.

A long winded question deserves a long winded answer lol.

Basically the short answer is "it depends".

Simulation software and real time pressure measurement are not exactly competing products, they are overlapping/complimentary products. Simulation software does some things quicker and cheaper than real time pressure measurement. Real time pressure measurement does some things better than simulation software.

In the 4 stroke world real time cylinder pressure tuning is king, the intake and exhaust are important but not as much. In the 2 stroke world cylinder pressure tuning generally takes a back seat to porting and exhaust tuning, even though one could modify a 2 stroke combustion chamber any number of ways that could never be done with a 4 stroke. When it comes to cylinder pressure tuning, there is no comparison between simulation software and real time pressure measurement, none, real time pressure measurement is much, much better at it.

When it comes to 4 stroke exhausts, real time pressure measurement is more capable than simulation software.

However, 2 stroke exhausts are a different story, construction is time consuming. What one is trying to do determines which (simulation soft or real time pressure measurement) is more appropriate, though in many cases the appropriate thing to do is use both technologies.

If for example you have something that works pretty well, and your goal is to make it better then carry on with life, perhaps rinse and repeat, then simulation software will be the quickest and cheapest method. Probably no wife approved reason to purchase real time pressure measurement in this case lol.

On the otherhand if you have:

1) something that is fully developed with simulation software and you want to take it further than that or
2) your competition is using the same simulation software as you are i.e. they can duplicate your results or
3) you are trying something radically different with the engine or exhaust system which isn't modeled well or at all in simulation software or
4) you want to verify what the actual pressures are to make sure the simulation software is inline with reality or
5) you are trying to redesign the combustion chamber or evaluate the combustion process in any way (fuels, additives, ignition, chamber shape, chamber material etc.) or
6) you are trying to do something significantly different on the intake side of things or
7) you are testing/tuning/developing an engine that makes a LOT of power or where detonation or pre-ignition is a worrisome issue, real time pressure measurement will keep you from blowing it up during the process

In cases 1 through 7 you would want to use real time pressure measurement, simulation software should be used too for the relevant aspects.

As a rule of thumb simulation software is the quickest way to get from A to B. Real time pressure measurement is the best way to get from B to C and often the only way to know C even exists. No matter what you build, how you build it and whether you pegged the imagination/ingenuity meter doing it, real time pressure measurement will handle it. The 2 technologies are overlapping and complimentary.

The next time I post I will post a screenshot of the pressure waves from a unique pipe we have used on 4 strokes. Yes I know nobody wants to hear about 4 strokes lol, but 2 stroke//4 stroke is not the point, the point of showing it is to show that a 2 stroke like exhaust pressure trace can be generated without using a 2 stroke type exhaust pipe and it can even be generated on a 4 stroke engine.

[TZ350]

The next time I post I will post a screenshot of the pressure waves from a unique pipe we have used on 4 strokes.

I am always interested in real time/world measurement. Please give us more info on the hardware used.

[Vannik]

Nice discussion Wobbly and Nitro!

As promised, a first attempt at explaining some gasdynamic reflections without using differential equations. Please comment, ask questions etc so I can improve it.

[Condyn]

Excellent info Neels. Thank you. I hope I am not jumping the gun on commenting because there is a lot to take in with that. I would like to know what effect, if any, intersecting waves have on one another. If a closed pipe baffle wave has a slightly reduced amplitude, how is it strong enough to push the spilled, untrapped, cold slug back into the cylinder? I know you have provided some pipe development examples with your software, I am interested in more info like that if you or anyone else reading this would be interested in sharing that kind of thing. Cause and effect of what to change and why while developing a pipe. The paper you just released certainly helps paint a picture for us of what is going on. ( Also slight typo on Number 2 I believe ) Thank you again.

[Frits Overmars]

Nice discussion Wobbly and Nitro! As promised, a first attempt at explaining some gasdynamic reflections without using differential equations. Please comment, ask questions etc so I can improve it.

I love it Neels! It also makes me feel young again; it takes me back 44 years, to 1977, when I made an attempt to do what you are doing right now: to put in words what is normally in differential equations in a way that is both still correct and understandable.
At the time I was technical editor of the motorcycle magazine Moto 73 and I wanted to do something a bit more satisfying than just explaining combustion engine basics for the umpteenth time. The chief editor warned me that most readers would not appreciate an in-dept treatise in a popular magazine but I was as stubborn then as I am now, so I carried on. Over the years that treatise became the most-sought-after story ever from Moto 73.
Below is a picture from it, trying to explain how a diffuser functions, and a PDF containing the complete story. It was written in Dutch (although I keep adding that all drawings are in English) but I know you won't have any difficulty reading it.

[teriks]

As promised, a first attempt at explaining some gasdynamic reflections without using differential equations. Please comment, ask questions etc so I can improve it.

Great write up, impressive to condense all that into just a couple of pages.

[Vannik]

Condyn,

Thanks for spotting that, I will fix it in issue 2

The more difficult part to explain is that there is both energy and inertia involved and sometimes amplitude is converted into inertia and sometimes the other way. The differential equations are: 1. conservation of mass, 2. conservation of energy and 3. conservation of momentum. All three must be satisfied at all times. So sometimes you can fool yourself if you just look at pressure amplitude as it is not the full picture. I do not know how to elegantly explain that.

Frits,

I can read that just fine thank you. Seems I follow you by about ten years, in the early 80's I was technical editor for a local magazine, Bike & Track and tried to do similar. I still have a handwritten copy of an article I wrote on blowdown specific time area!

Anyway, let us see what Nitro comments.

[wobbly]

Condyn - Neels has given you a clue to the answer about how the overscavenged gas slug sitting in the duct is reversed back into the port by a returning reflected wave of lower amplitude,
arriving from the closed end rear cone.
The clue is " contact discontinuity ". Thus the cold gas slug is much more able to be influenced by the hot return wave due to a large difference in all of the variables - pressure , density , temp and inertia.
Seeing that in print further reinforces the test I did to prove Jan correct and "the great leader " more of a tosser than we already thought.
The colder the duct surface surrounding the excess charge is , the bigger the " discontinuity value " and thus the stronger the push is to return the slug from whence it came.

[Vannik]

One of the things I am not sure about, but suspect about contact discontinuities is that is the difference between a header where the first part is straight compared to one that starts curving immediately from the cylinder interface. It should be obvious that as the gas travels down the pipe the cold and hot gas will mix more and more as it travels down the pipe. A curved pipe where the length the gas has to travel along the inside of the curve is much shorter compared to how far it has to travel along the outside of the curve. This creates a smearing or mixing of the contact discontinuity and lowers its effect.

A strong well defined contact discontinuity formed close to or inside the exhaust port passage seems to be a major advantage. This might be one of the reasons for the Wobbly Exhaust Port. If an engine is not developed for it, it will cause detonation if it is applied to the engine. I think the purpose of Yamaha's "detto button" in their straight pipes on the 500cc GP bike was to smear the contact discontinuity.

[jonny quest]

Vannik, you're starting to hit on why some engines don't care if it has a straight pipe attached to it, or one with many curves. Some engines lose power with a twisty pipe, others don't.

I'll add my thoughts to this after I figure out how to put my thoughts into words