ESE's works engine tuner

[SwePatrick]

patrick i put more than 11 liters nitro in the ktm this past summer and the nicasil (millenium) and devcon putty is doing fine. flush it with petrol at days end and youll be fine

Yes, i know, but that´s not the issue.
I´m making insurance if having a seize
It isn´t funny to send the barrel for re-plating every once in a while, way to expensive

[wobbly]

The 6 port TZ350G cylinder had the A front radial increased slightly and the axials that were stock all the same were given stagger to increase the bandwidth that is limited by
the very high Ex timing and no PV ( 115 116 116.5 117 } This increased the A port upward angle the most - with 8 transfers there was no issue getting enough STA.

I have never looked at the effect of squish on the combustion data - just simply always entered the historical min height and adjusted the width to get around 38M/s.
So as an exercise I ran the RZ400 engine in Turbulent with 2mm squish = 15M/sec against the as built sim with 0.9mm = 38M/s.
All of the combustion numbers are completely different in this case ? but I havnt looked at the effect of this on power etc yet.
Though from previous experience the combustion parameters have a huge effect on the powerband shape and output.

[jbiplane]

Russian guy emigrated to USA made this amazing toy

Simple idea - may be usefull for local comunity

[TZ350]

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That 3D printer is just amazing....... ... I would love one.

[TZ350]

Had an interesting project on the dyno today, Speedpro's CVT scooter.

We have had CVT engines lying around the workshop before and Cully has even made a Bucket sidecar with one. But this is the first CVT machine I have had a close look at on the dyno.



It was a whole new learning curve for Speedpro and myself. We had no idea if the dyno graph is normally so erratic on a CVT, maybe its the belt flapping about. And the results of normal tuning things like changing the main jet and ignition were not very obvious. We figured we need to lock the primary pulley in some way.

If 20 hp is enough power to push the scooter through the air at 170 kmh then the speed range of 40 to 170 kmh is pretty impressive. I think I could get to like CVT's.

[Frits Overmars]

We had no idea if the dyno graph is normally so erratic on a CVT, maybe its the belt flapping about.... We figured we need to lock the primary pulley in some way.

Better get rid of the V-belt altogether. You can sets of toothed belts and pulleys with the correct centre distance for most scooters at info@hvg-engineering.com

If 20 hp is enough power to push the scooter through the air at 170 kmh then the speed range of 40 to 170 kmh is pretty impressive. I think I could get to like CVT's.

20 rear wheel-HP may just be enough for 170 kmh on a scooter if you have a very small rider and a straightaway over 1 km long. But I like CVTs anyway.
This is why: https://www.youtube.com/watch?v=EFjakgypqSs

[flyincat]

Wobbly - I went back and took another look in EngMod with a little more controlled experiment. It looks like I was kind of right and kind of wrong in my initial speculation. Moving the squish from high to low does have a significant affect on the TUbMax and MaxDeg, similar to the moves in compression or timing. However, the HP curve shows relatively little change from a big squish setup change (39m/s --> 15m/s). I think the most important observation of all this is the spacing of the curves on the different plots. If you consider the TUbMax penalty of adding 1pt CR vs 2* timing, the CR change seems a much better option. It appears the squish would have the least HP benefit per TUbMax penalty. In hindsight, I probably should have started MSV around 25 m/s so I could go up and down like the other variables to give a more clear picture. But, that's for another day.

Baseline - 14:1CR, MSV 39m/s, ~12* timing

[peewee]

Yes, i know, but that´s not the issue.
I´m making insurance if having a seize
It isn´t funny to send the barrel for re-plating every once in a while, way to expensive

that makes sense but i think you will see its not easy to seize. at close throttle the nitro makes a noise thats easy to hear its lean. lectron needles work good because you can measure the width with calipers and grind off small increments as needed. for full throttle just add some extra powerjets so you have plenty of adjustment for a wide range of conditions

[TZ350]

20 rear wheel-HP may just be enough for 170 kmh on a scooter if you have a very small rider and a straightaway over 1 km long. But I like CVTs anyway. This is why: https://www.youtube.com/watch?v=EFjakgypqSs

Interesting that 20 rwhp may be just enough. I did not wan't to fall into the trap that just because it was 170kmh on the dyno that it could achieve that on the road. I have often looked at CVT as an interesting prospect for racing. Cully has built a CVT sidecar but we have not had it on the dyno yet to try setting it up properly, so a bit to learn there yet. A CVT engine/drive in a bike is an exciting possibility if we can find a way to package it.

[husaberg]

. A CVT engine/drive in a bike is an exciting possibility if we can find a way to package it.

Yamaha Y cat

Yamaha Lexam

[Muhr]

or like the 50cc freetech guys

[wobbly]

Its interesting to see the use of EngMod in a different way to how I have developed the strategies to extract best power from a project.
In reality I would never even think of actually building any engine with an MSV down at less than mid 30M/s as hundreds of dyno runs have proven that the strategy of optimizing
this variable by first using the minimum allowable mechanical depth ( just short of piston clipping ) and then varying the width ( usually around 50% ) to achieve a theoretical 38M/s always works best.
This statement assumes that an ignition system is being used that is capable of tailoring the advance to achieve the powerband shape needed for the application.

One very obvious exception would be KZ2 where only a fixed flat line " curve " is allowed , and this mandates a very low MSV to prevent the squish induced flame front turbulence from killing the much needed overev power.

But I have found that in every other case where you can tune the ignition setup , that 38M/s is always real close to optimum , be it an MX , GP or LSR type race engine.
Of course the reality is that all this is highly theoretical , as if you are actually running as close as is physically possible, then at peak rpm the squish velocity will be hugely higher ( zero gap ) , and the trapped end gases will be at a minimum volume .

In my world of supplying detailed sim information to a paying customer , I simply dont have the luxury ( read time ) to be messing about with , for example , small changes to squish velocity or duct exit Mach numbers.
I start by using what I know the dyno says will work , every time , as a baseline - and only if forced into some weird tuning corner , do i need to resort to serious " fiddling ".

[TZ350]

TZ350 Were in the garage yesterday and sanded on a PV similar to the one you have, then come and think of that you discussed it a while ago. The one I did was also cast, we preheated them to about 300 ° C and then TIG welded with 316. Also had a 3d model on nsr j20 do not know how similar it is but. Probably you've already solved it.

Thanks for the info and pictures. The later NSR blades seem to fit better so I have not tried to build a set up yet.

Oh, thats damn clever! What is the original inner and outer diameter of the SR50 Flywheel? Regards Tim

The inner diameter measured inside the magnets looks to be 85.5mm and the inner diameter of the steel shell maybe about 97mm.

[katinas]

In reality I would never even think of actually building any engine with an MSV down at less than mid 30M/s as hundreds of dyno runs have proven that the strategy of optimizing
this variable by first using the minimum allowable mechanical depth ( just short of piston clipping ) and then varying the width ( usually around 50% ) to achieve a theoretical 38M/s always works best.
.

Wobb, maybe, for best performance is some ratio between squash width and crank/flywheel inertia, conrod length.
With very light crank and ign. rotor, my engine always down on power at higher revs with 50% in comparison with 20-30%. Now I am testing with additional mass (maybe too heavy) on rotor and 50% squash, engine power at hi rpm feels better but lost too much in 8000-11000 rpm zone.
Still in tests so I am not sure.

[wax]

Damn this engine mod I cant get past the exhaust pipe error
" There is a section with a zero length that has to be fixed"
I start a new exhaust and straight away i get this. Before I throw this thing out the window does anyone have a help please