ESE's works engine tuner

[husaberg]

The roof axial angle should be about 20° down; the floor could use a bit more downward angle, but that would land you in the A-transfers, so you'll have to becareful there.
The radial position angle of the RSA's aux. exhaust ducts is quite radical; past mid-cylinder. But the radial direction angle is less severe.
The drawing below shows that the flanks of the aux ducts start with 20° less than the radial position angle, irrespective of the radial position angle that you may choose. And don't overdo it or you might get massive short-circuiting from the A-ports to the exhausts, even when using RSA-type closed-end piston pins.

Frits this is the bit I was meaning, just at the start of the Aux port, the pics don't clearly show it (the flat roofed area)so well, hence the kids felt used to highlight it. (Right side second Pic)
Is this an error of interpretation in the DEA version I have?

[peewee]

The roof axial angle should be about 20° down; the floor could use a bit more downward angle, but that would land you in the A-transfers, so you'll have to becareful there.
The radial position angle of the RSA's aux. exhaust ducts is quite radical; past mid-cylinder. But the radial direction angle is less severe.
The drawing below shows that the flanks of the aux ducts start with 20° less than the radial position angle, irrespective of the radial position angle that you may choose. And don't overdo it or you might get massive short-circuiting from the A-ports to the exhausts, even when using RSA-type closed-end piston pins.

cant see the pic for some reason. maybe its just my computer. ill try my phone and see if i can see it

anyways the cylinder i been working on is a cheapie i picked up from ebay for $50 to practice on. seeing how thick material is in certain areas. where i have to weld. how big i can make the boyesens. how bad the transfer tunells are etc etc. so when i port my good cylinders ill know what to expect and maybe make less mistakes

if the aux is tear drop shape and protrude slightly into the wristpin path dont you think the benefit of a wider exh area outweighs the drawback of possible linking bewteen the exh and A transfer ? it doesnt seem like the linking would be that harmful if the aux upper/outer corner is only hanging into the wristpin by 1 or 2mm but maybe im wrong.

[TZ350]

Making progress, touching 12,000 rpm and nearly 25hp 3 to go.



At 12,000 rpm the transfer is open for 1.8ms and looking at the Ecotrons run data the injectors at 12,000 rpm are open for 1.9ms so we are pretty stuffed for much more progress.

Maybe I think its time to change tack and start thinking about Injection into the inlet.

Transfer injection on an engine that revs to 8-9k would work very well (Flettner has done it on a big Kawasaki single) and with careful timing you could get some fuel efficiency's but the much reduced time available at 12k rpm to get things done. Lack of time makes it hard to do on my little 125.

[SwePatrick]

With a set amount of energy it must take a little to suck and drag along that extra weight of fuel from a traditional carb, so the gain in inertia has to be paid for. But an interesting idea and a bit off normal thought process.

But maybe gains are a bit higher, therefor more gain of power at high rpm´s.
Next, when comparing to fourstroke engines, highrevving models of those do have the injector way back in the inletrunner, sometimes actually above the velocitystack.

This to gain 'time' for atomizing the fuel before entering the cylinder.
AND,, what i mentioned earlier higher inertia of gasflow.

A little clip to visualize a bit:
https://www.youtube.com/watch?v=y2iBbwocYZw

Rgds

[wobbly]

If the main Ex is at 72% and 200* then you have no choice but to add Blowdown STA by widening the top of the Aux.
In this case the positive Blowdown power tradeoff is a desireable one against a small amount of port linking power loss.

[speedpro]

A little clip to visualize a bit:
https://www.youtube.com/watch?v=y2iBbwocYZw

Rgds

The thing I am interested in with this video is that you can see fuel running down the surface of the intake. The Ecotrons system actually has a value you can change that allows for the fuel dropping out of suspension and also the reverse depending on whether the throttle is being opened or closed. Obviously if fuel drops out the mixture will be lean for the duration of the event, and vice versa. By allowing for it the fuelling can be made more precise as throttle position changes. Sort of like an accelerator pump.

I feel for Rob with the lack of time for the injection to happen. Even on my 4T the injectors are getting close to 100% duty cycle, and I have 720degrees of crank rotation. I've actually installed bigger injectors because of it and I think it still leans out right at the top, 16,000rpm. I've had the engine over 18K so have unused rpm available. However the motors originally made max power at somewhat lower rpm so I'm not stressing.

[Frits Overmars]

Frits this is the bit I was meaning, just at the start of the Aux port, the pics don't clearly show it (the flat roofed area)so well, hence the kids felt used to highlight it. (Right side second Pic). Is this an error of interpretation in the DEA version I have?

I can't see any contradiction between my description and your pictures, husa.

[husaberg]

I can't see any contradiction between my description and your pictures, husa.

the pics don't likely don't show it to clearly? I will post one with it marked better.
The original question was.

it appears the floors angle down immediatly from the bore edge. the roof however looks to be flat for a few mm into the duct and then angle downward. ?

[Frits Overmars]

At 12,000 rpm the transfer is open for 1.8ms and looking at the Ecotrons run data the injectors at 12,000 rpm are open for 1.9ms.

'Open' does not cover it in your case, TeeZee. You'll need to match the mass flow, which is zero and slowly rising in the case of the opening transfers, versus zero and much quicker rising in the case of the injectors. And I'm afraid you can't do much about either of those.

Maybe I think its time to change tack and start thinking about Injection into the inlet.

With the experience you must have gathered by now it will be a piece of cake to get indirect injection working. But the real job is not to find the power you got with a carburettor; the real job is making that power controllable. What you really want is a linear relationship between throttle position and rear wheel torque. And yes, that means looking at the transmission too. That is why Honda is using a 'torqductor' between the secundary gear shaft and the pinion on their MotoGP works bikes (the client bikes don't have them).

[Frits Overmars]

the pics don't show it to clearly? I will post one with it marked better. The original question was: "it appears the floors angle down immediatly from the bore edge. the roof however looks to be flat for a few mm into the duct and then angle downward."

Yes, now I see what you mean. The flow can't turn at a sharp 90° angle there, so there will be turbulence at the port roof.

[husaberg]

Yes, now I see what you mean. The flow can't turn at a sharp 90° angle there, so there will be turbulence at the port roof.

I have suspicions we are talking two different subjects.
So I will try to explain better.

What I am suggesting is, the cylinder I have here, has a flat top roof (ie that is approx. 90 degree angle to the cylinder walls for a few mm of its length) then follows the same approx. 30 degree angle of the main ex port.
The floor of the aux ports however appears to follow the same angle downwards as the main ex post for its entire length.

At 12,000 rpm the transfer is open for 1.8ms and looking at the Ecotrons run data the injectors at 12,000 rpm are open for 1.9ms so we are pretty stuffed for much more progress.

Maybe I think its time to change tack and start thinking about Injection into the inlet.

Transfer injection on an engine that revs to 8-9k would work very well (Flettner has done it) and with careful timing you could get some fuel efficiency's but the much reduced time available at 12k rpm to get thing done just makes it to just to hard on my little 125.

Rob You don't have additional time for injection to meet the demands at high revs, but you do still have the option to apply MORE PRESSURE.
It would be a shame to give up on it now to go to Throttle body injection.

[teriks]

husaberg, that looks like something Id be tempted to do on a production cylinder.
-Should see much less variation in height of the timing edge after machining than if the cast port had an angled roof.
Ah well, only speculation...

EDIT: Fixed speling... doh..

[TZ350]

Hi, A little question, Have you considered loss of 'inertia' in the fresh mixture entering crankcase as a factor of loss of power? Now with 'dry' flow your inertia is way lower and doesn´t fill the crankcase as a carburated engine does. Rgds

Good idea and I thought about it for a while but in this case I am pretty sure the missing 1000 rpm is due to time considerations, there is just not enough time for the injector to do its business. There are still one or two small tricks left. Might try them tonight but its getting pretty desperate.

I have increased the injection pressure from 3bar to 4.5. I will also look at endpoint timing carefully and change the injector minimum off time for the No2 injectors so that the No1 injector will have to start working again earlier at higher rpm. The way the injectors work is :- No1 then N02 then No2 + No1 to make up any shortfall in time ava to No2 at higher rpm.

[F5 Dave]

So hybrid system with an added inlet injector for high rpm? The Willis cocktail?

[FastFred]

The Willis cocktail?

TeeZee has not started talking about fuel yet, but a little bird has told me, that now fuel additives aren't banned anymore he is looking at adding a little water to 91 oct for combustion control and detonation suppression.

Water in Petrol everyone knows water and petrol don't mix .... ..... or do they ....