ESE's works engine tuner

[Mollihead]

Cylinder is back. Milled down 0,8mm
So I have the possibility to test different pistons.

[Flettner]

AG100 farm bike cylinder. Not flow restricted at the extremities of the exhaust ports like most bridged ports.

[Mollihead]

I’m not 100% sure what I see.
Does it mean each side has has it's own pipe? Crazy!

[Flettner]

I’m not 100% sure what I see.
Does it mean each side has has it's own pipe? Crazy!

Yes, two pipes.

[Mollihead]

Compared to the same exhaust but single - is it an improvement or was it just for fun to see how it works?

[Flettner]

Compared to the same exhaust but single - is it an improvement or was it just for fun to see how it works?

It was to see if I could cast something with max blowdown, time / area .... flow. Not like a normal a bridged port. And yes also for a bit of fun in the Vinduro farm bike class. It has never seen a dyno so no real idea but to say it goes pretty well.
Problems? Building two identical pipes. Ive ended up building press dies to get them the same. It pulls very well down low (6000 and below) in fact I can almost do a whole event under that figure. Top end (7500 to 11500) it pulls hard.... but the transition it falls flat on its face. This being the none power valve air cooled cylinder.
The new cylinder having a welded on water jacket and twin powervalves Im expecting will sort this flat range.
It still has an unfortunatly rubbish bore and stroke at 48 x 58.
Next series engine will correct this at 54 x 54, AG engine Im using now will not accommodate more that 48 stroke.j
It would be interesting to see this twin port design with a 'proper' twostroke tuner involved, not just my semi educated estimates.
Simply put, for the same cylinder exhaust span as a three port this only has one bridge and minimal flow restrictions at the port extremities.

[Mollihead]

I’m surprised to see an aircooled cylinder with that distance between studs.
Normally there is not enough space for two exhaust ports.
I could imagine that standard exhaust resonance calculations are not 100% valid any more in case two resonant pipes talk with each other if exhaust port is in open position.

[Wos]

Think there is risk of loosing energy / temperature caus of you have much more pipe surface.
According to this loss it is difficult to calculate for two pipes...

And if pipes have minimum diffrences ...they talk 😉 against each other... 😞

Maybe the power flat is caused by that

[Wos]

@flettner

How you did calculation for the two pipes? They look fat at belly!?

Maybe you had calculated each pipe with complet cilinder volume!?

Experts 😉

Isnt it better to take half ccm for calculation for 2 pipes arrangement??

Thanks to help my understandig 😉

Wolfgang

[F5 Dave]

We could argue about this for ages.
Just what the thread needs. Stinger has been covered here but it makes sense to me to have the same combined area as a single pipe (so 1/2 by area) and then experiment.

The belly section should be derived using the same angles but starting with a much smaller header pipe. But my brain is melting here and now I've entered a highly suggestable state so I best go for a walk

Anyway 3 cheers to Neil for not just asking the question but committing it to metal.

[dtenney]

Does anyone have the measurement from the disc to the piston face for the Aprilia RSA?

Thanks

[Flettner]

First off, I make no claims, its an experiment and a bit of fun at that.
Question about the stud pattern, as I make my own stuff I can have whatever I want. Studs go where I decide.
Im sticking to the two pipes for now to see how the powervalve might effect things. If I can't get a resonable result / answer, Im looking at a two into one true volume split header into a single pipe. See what that brings.
With my CNC I should be able to make a press tool to make an accurate volume joiner.
Pipes are loosely based on 2 x KX65.

[Flettner]

We could argue about this for ages.
Just what the thread needs. Stinger has been covered here but it makes sense to me to have the same combined area as a single pipe (so 1/2 by area) and then experiment.

The belly section should be derived using the same angles but starting with a much smaller header pipe. But my brain is melting here and now I've entered a highly suggestable state so I best go for a walk

Anyway 3 cheers to Neil for not just asking the question but committing it to metal.

Think there is risk of loosing energy / temperature caus of you have much more pipe surface.
According to this loss it is difficult to calculate for two pipes...

And if pipes have minimum diffrences ...they talk 😉 against each other... 😞

Maybe the power flat is caused by that

Maybe??
Lets find out.

[Grumph]

Maybe??
Lets find out.

Don't remember what you're using for an ignition - but can you dial in some more advance at that point ?

[F5 Dave]

Gillette principle. Well, we have two pipes.
How about three?