ESE's works engine tuner

[F5 Dave]

But the BMEP of a gaser isn't particularly high, or the revs for that matter.

Actually on old gas (quite common on a lesser used dirtbike) I do get a few knocks up steep hills.

300 is an awesome engine for intended purpose.

[Frank S.]

Its very easy to have the inner surface of just the bowl ceramic coated to reflect combustion heat back into the gas and not wasted by disappearing into the water system.

Hi Wobbly,
I have some questions about the ceramic coating.
What kind of coating works here? Can I just anodise the aluminium to get an AL²O³ coat? This could be done by DIY.
Or do we have to apply extra ceramic material?

Greetings from Germany

[teriks]

Hi Wobbly,
Can I just anodise the aluminium to get an AL²O³ coat? This could be done by DIY.
Greetings from Germany

That would actully increase the heat transfer, at least for thin layers where insulating properties are of less importance.
-The emissivity of anodized al is ~0.8, while a polished al surface is only ~0.04! In terms of radiation, a clean polished surface is the clear winner.

[Frank S.]

I agree about radiation.
So the coating needs a certain thickness for insulating. And the best would be a polished coating.

[Flettner]

I agree about radiation.
So the coating needs a certain thickness for insulating. And the best would be a polished coating.

Too thick and the surface itself gets hot and becomes an ignition source. I tried a ceramic coat years ago to pistons, just created detonation. Surface was approx 0.5mm thick.

[Larry Wiechman]

I really like that design. How does the coolant exit spigot attach/seal?

https://www.kiwibiker.co.nz/forums/a...4&d=1643275156

[Frits Overmars]

Too thick and the surface itself gets hot and becomes an ignition source. I tried a ceramic coat years ago to pistons, just created detonation. Surface was approx 0.5mm thick.

Same here.

[wobbly]

I use a company called HPC , they have a Thermal Barrier coating specifically designed to prevent heat going thru to the substrate material. Its used on 4T pistons and valve faces and is very thin.
If you coat the chamber inner only , NOT the squishband , this reflects heat back into the combustion gas , rather than the water ,and doesnt cause deto.
I use Mothers Mag Wheel alloy polish on the piston surface.

[flyonly]

If I wanted to run an O2 sensor in my expansion chamber. Where should it be located?


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[husaberg]

If I wanted to run an O2 sensor in my expansion chamber. Where should it be located?


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on exhaust pipe of the car you use to tow the bike to the races...

Okay here is Wobs posts

Hi David, yes I got the PM with your home address, but not an email.

The Lambda I use is from Innovate Motorsports with a Bosch heated wideband, and it can read out in various formats.
It will convert directly to A/F ratio, Lambda Number, or 0-5V, I use the A/F ratio as an input direct to the dyno datalogger so as to see
the power overlayed with A/F as well as deto etc.
The probe is in the front of the muffler,with a threaded insert that sits right on top of the perf tube.
It has a gauge reading out A/F, but you for sure havnt time to watch that when doing a dyno run.

One take on the dam idea affecting the top end so much, is that is exactly the effect you see by putting a 75% nozzle in the duct exit when running a sim.
This is why I thought the next step should be to extend the floor right out the flange face.
Gaining all that top end means you have an option to redesign the pipe for better mid, or use the overev capability and use the pipe to make even more power up top.

The Ryger homologation is due to be published publicly by the CIK on the 1st Jan.
I will be onto the site all day looking for the info we all are screaming for.

Re Vegas - here is some cut and paste from a report on the result I did.


We were top 3 fastest thru all the sessions, but the engine guy for the team we race for didnt tighten the new sparkplug prior to qualifying.
Of course it wound almost all the way out and our pace dropped by 3/10s, enough only for 6th.
In the first heat we were up to 4th pulling in the top 3 easily within 2 laps when the 3rd place missed a gear mid bend under big pressure and spun
right in our karts path - DNF.
Means we went into the final from 12 on the grid, got to 5th place and ran out of time - track position is everything when only a few 1/10ths cover the top 5 pace.

I took the deto gauge off the dyno and ran the 0-5V output into the Pi datalogger, and was very surprised to find that after leaning down enough to get hits, that the only place
it deto'ed was the acceleration phase after 2nd, 3rd, 4th gearchanges, when dropping back to near peak power after overeving to 12200.
The 5th to 6th change stayed above peak power and didnt deto at all down into the shute.
So I fitted the new header with the deto button installed and the gearchange deto dissapeared completely.
That allowed another 3 jets leaner before it started again.

Get this - the egt at that level was 1390* F with no sign of deto or piston heat stress.
This is due to the fuel octane being too high for the com, and the fact that the SKUSA advance restrictor plate doesnt allow us to add enough static timing to create more power - only pipe heat.

I think I have worked the logic of the deto button - it creates turbulence in the top 1/2 of the duct, allowing the smooth flow along the floor to return easily up the duct and be aimed upward off
the ski jump at the closing Ex port.
This came from finding that having the floor of the oval/round transition spigot co linear with the duct floor, and all of the transition angle in the roof made best power.

So here is the jetting chart prior to adding the new header, based on safe deto level, not egt as I would usually use.
The Lambda ( in the muffler ) showed the kart was fastest at 13.8 :1 ( and it hardly varied anywhere within the usable power band ), going leaner or richer was slower on track.
We tested both VP C12 ( 108 octane ) and VP98, the 98 being both faster and easier to tune to the edge.

[koenich]

I agree about radiation.
So the coating needs a certain thickness for insulating. And the best would be a polished coating.

So you want to again win Liedolsheim with knowledge from here? :-P

Reg coating - total heat transfer at combustion temps is partially depending on thermal radiation. If you can stop that quite a bit is already maintained in the bowl.

[Frank S.]

So you want to again win Liedolsheim with knowledge from here? :-P
.

Yes, the 3rd win would be nice😎
Let's hope it will take place this year.

[lohring]

We ran a stinger lambda sensor. This was for test purposes only.

Lohring Miller

[wobbly]

In the front of the muffler has proven to be the best spot for Lambda imho - the need for Lambda is another story.

[Javier Ruda]

In the Rotax 122, I did some modification for making shorter and easier the flow from reed case to crankcase. Not sure if it helps or not because I cannot measure the effect accurately.

Does it make sense to copy that cut to the bottom of the piston skirt, and matching the cut edges at BDC?

I read from wobbly that the reeds open at some point between BDC and TPC because of the crankcase pressure becoming lower than intake pressure, but I cannot imagine if the piston cut would help on that process, or the collateral effect on the cylinder intake hole.