ESE's works engine tuner

[shnaggs]

Here are the sim inputs for RSA125, about as good as it gets.

Thanks for these Wobbly, but why is your exit roof angle 0.0? Is there a reason for this to be left at 0.0? I have found that changing this value does change the power quit at bit in the sim.

[breezy]

Thanks for all the information on this Aprilia port dimensions.....

[jonny quest]

How much different was the jetting between pipe testing for brst optimization Jan? Are we talking needle tapers.... 1 to 2 mainjet sizes? All of the above plus more?

[TZ350]

Page 1730 links list to go here:-

A-ports timing 130°, roof angle 25°
B-ports timing 132°, roof angle 10°
C-port timing 132°, roof angle 50°

RSW and RSA ducts were the same.
Roof angles did not change since 1995
The RSA cylinder had improved cooling.

Re the RSA, it had the main Ex floor lifted by some 3mm from memory.

Here are the sim inputs for RSA125, about as good as it gets.

You will have to click back to the original post to see the sim data.

Here is the STA result from the late model RSA - and so before you wonder why Jans superb transfers are so far ahead of the Exhaust - ponder this.

The outflow Cd of the Exhaust is hugely influenced by the large radius that was machined onto the timing edge - the strictly theoretical Exhaust timing was around 79* ATDC, but the effective open time of the duct top edge was closer to 82*.

Thus in reality the STA FLOW numbers match perfectly - remember this when dealing with crap transfer ducts, or Exhaust ducts that are WAY too big - ie most of them.

Hi Wobbly,

During 2003 our boss, you know him, designed a new exhaust., no 102. It gave a lot more midrange, but killed revs, the engine stopped at 13000 So the radius of 2,5 was arrived at to recover max. revs.... With this radius also the midrange returned like it was before. And so it stayed....

A couple of years later, after my DERBI interval, he was not there any more. It was decided to compare the latest 6 exhaust pipes. First they were all cleaned on the inside. Which, by the way always cost some power, the power used to come back after a week of testing.

With these cleaned pipes the best carburation was determined for each pipe. There proved to be quite some difference. Then each pipe was tested with its best carburation. The result was: nearly no difference.....

So much about pipe design and development, during some years, it is not easy! Those tests were, of course, made with a radiused exhaust port. Sometimes I still wonder what would have happened if we had insisted with an unradiused port. And the older exhaust pipe!

Refilling the damper and cleaning the pipe on the inside used to cost about 0,5-0,6HP After a week of daily testing the normal HP returned.

At the races all the teams refilled their dampers and cleaned their exhausts before the race.
What do you think of this Wobbly?

Thanks for these Wobbly, but why is your exit roof angle 0.0? Is there a reason for this to be left at 0.0? I have found that changing this value does change the power quit at bit in the sim.

In general repacking the muffler will make a little extra power - but the Aprilia had a very short stinger, so maybe it liked the effective shorter length when the packing wasn’t tight around the perforated tube.

Its easy to understand why a " used " pipe made better power as this coats the inside surface and holds up the internal gas temperature.

Coating the inside with ceramic did the same thing, only way too much as it turned out in testing, as the engine lost all the bottom end power but picked up some top end.

Regarding the down angle of the Exhaust duct in the sim.
As I explained before the timing edge had a big radius on it, and thus the effective Cd was greater than the actual port area would dictate.

Using the down angle reduces the area by the cosine, so to get a better match to real flow conditions using zero gave a more accurate end result.

Here is the inlet input.

Here is the RV inlet inputs.

The Exhaust port itself was already made smaller, as Jan had begun experimenting with lifting the floor, but my comment about size was more directed at the duct exit area.

Simply using EngMod and shooting for a duct exit Mach of 0.8 the result is a huge jump in power when reducing the Aprilia flange area and creating a new transition within the spigot.

The duct length, including the spigot was also increased slightly to 2X bore and the pipe adjusted accordingly.

I remember Frits mentioning it's the best he had used, and also having seen it used here, which is why I'm specifically after Vinamold. There are alternatives however.

Here's a product called Composimold being used by a Thomas H who appears to cruise this forum, if not only the ESE thread. It's far more expensive though at $66NZD + $30 shipping for 20oz of the stuff -_-

http://bucketracing.blogspot.co.nz/2...mposimold.html

OK you blokes chasing Vinamould, here’s the stuff we use. For you kiwi types, it’s “cheap as chups” () around $100 for the 3 kg.

Attachment 330857Attachment 330858Attachment 330859

Looked up your local contact:

Barnes NZ - Henderson, Auckland
B92-94 Railside Ave, Henderson, 0612 Auckland.
T: 09 973 1816
E: glen@barnesnz.co.nz

Google.co.uk came up with:

Vinamold - Best Value - - Direct from the manufacturer‎

Adwww.extruflexonline.co.uk/vinamold‎
Large UK Vinamold Stocks, 24 Hr Delivery

4 hardness types?

I thought Vinamold was american.

[wobbly]

In general repacking the muffler will make a little extra power - but the Aprilia had a very short stinger, so maybe it liked the effective shorter length
when the packing wasnt tight around the perforated tube.
Its easy to understand why a " used " pipe made better power as this coats the inside surface and holds up the internal gas temperature.
Coating the inside with ceramic did the same thing, only way too much as it turned out in testing, as the engine lost all the bottom end power but picked up some top end.

Regarding the down angle of the Exhaust duct in the sim.
As I explained before the timing edge had a big radius on it, and thus the effective Cd was greater than the actual port area would dictate.
Using the down angle reduces the area by the cosine,so to get a better match to real flow conditions using zero gave a more accurate end result.

Here is the inlet input.

[41juergen]

In general repacking the muffler will make a little extra power - but the Aprilia had a very short stinger, so maybe it liked the effective shorter length
when the packing wasnt tight around the perforated tube.
Its easy to understand why a " used " pipe made better power as this coats the inside surface and holds up the internal gas temperature.
Coating the inside with ceramic did the same thing, only way too much as it turned out in testing, as the engine lost all the bottom end power but picked up some top end.

Regarding the down angle of the Exhaust duct in the sim.
As I explained before the timing edge had a big radius on it, and thus the effective Cd was greater than the actual port area would dictate.
Using the down angle reduces the area by the cosine,so to get a better match to real flow conditions using zero gave a more accurate end result.

Here is the inlet input.

Thank's a lot Wob, I was more referring to the inlet port with the RV (as I have absolute no experience with RV engines... )

[41juergen]

Hi Wobbly,

During 2003 our boss, you know him, designed a new exhaust., no 102.
It gave a lot more midrange, but killed revs, the engine stopped at 13000
So the radius of 2,5 was arrived at to recover max. revs....
With this radius also the midrange returned like it was before.
And so it stayed....

A couple of years later, after my DERBI interval, he was not there any more.
It was decided to compare the latest 6 exhaust pipes.
First they were all cleaned on the inside.
Which, by the way always cost some power, the power used to come back after a week of testing.
With these cleaned pipes the best carburation was determined for each pipe.
There proved to be quite some difference.
Then each pipe was tested with its best carburation.
The result was: nearly no difference.....
So much about pipe design and development, during some years, it is not easy!
Those tests were, of course, made with a radiused exhaust port.
Sometimes I still wonder what would have happened if we had insisted with an unradiused port.
And the older exhaust pipe!

Thank's a lot for all the insight Jan! In the drawing no rear cone nozzle / venturi is shown. Wasn't that in the design in that years or only not shown in the drawing?
cheers
Juergen

[husaberg]

Anyone know how these turned out?

EMOT Racing 6 April 2016
AND THE OTHER SIDE HAS A CLOSED PINHOLE TOO..!!
How we did that will not be released yet.
For now we are looking for a few brave guys to test it.
We designed Kreidler and Ktm 50 pistons with the system.

[Norman]

Hi Wobbly,

During 2003 our boss, you know him, designed a new exhaust., no 102.
It gave a lot more midrange, but killed revs, the engine stopped at 13000
So the radius of 2,5 was arrived at to recover max. revs....
With this radius also the midrange returned like it was before.
And so it stayed....

A couple of years later, after my DERBI interval, he was not there any more.
It was decided to compare the latest 6 exhaust pipes.
First they were all cleaned on the inside.
Which, by the way always cost some power, the power used to come back after a week of testing.
With these cleaned pipes the best carburation was determined for each pipe.
There proved to be quite some difference.
Then each pipe was tested with its best carburation.
The result was: nearly no difference.....
So much about pipe design and development, during some years, it is not easy!
Those tests were, of course, made with a radiused exhaust port.
Sometimes I still wonder what would have happened if we had insisted with an unradiused port.
And the older exhaust pipe!

Jan, Wobbly, can I ask, should not the exhaust valve (which should be lowered?) eliminate/decrease the exhaust radius effect on the midrange? Thank you.

[husaberg]

We never made port maps, sorry...
Only the distance from the top was measured.
And the chordal width, which is what really counts.
Using the circular 'feelers' shown in the picture.
They are attached to a piece of welding rod so you can bend them any way you want.
Very useful for measuring ducts and ports!

Jan whats the paper stuffed in the cylinders for?
i noticed its also in the pic with the cylinder comparsions that (i think Riley Will) posted once.

Edit It might have been Frits i can't recall.

[Frits Overmars]

Jan whats the paper stuffed in the cylinders for?

That will be the chief mechanics' wish lists, accompanied by photographs of their daughters.

[husaberg]

That will be the chief mechanics' wish lists, accompanied by photographs of their daughters.

The wish list is always more power with less maintence.

[TZ350]

Ken Seebers sliding cylinder engine...........

SLIDER UPDATE.


Finally got the thing running on the dyno frame. No load being applied by dyno, still got some software and hardware issues to be resolved. Main purpose was to see what falls off and even if it still works.


Not too much to say other than it makes some noise (apparently it could be heard over in kiwiland !!). Seems to zing with a bit of throttle, but then so does any 2 stroke really. Felt like 71 hp though.


Obviously the next thing is getting the dyno sussed.

[breezy]

We never made port maps, sorry...
Only the distance from the top was measured.
And the chordal width, which is what really counts.
Using the circular 'feelers' shown in the picture.
They are attached to a piece of welding rod so you can bend them any way you want.
Very useful for measuring ducts and ports!

Jan , with the auxilary exhaust ports being directly above the transfer ports did you think before arranging this set up that it would be power sapping with short cicuiting? also with the auxilary exhaust ports closing before the main exhaust port that fuel pulled into them would not be fully pushed back into the cylinder by the returning exhaust pulse again reducing power? Wobbly also mentioned that most exhaust ports are too large anyway , other than raising the exhaust port floor is there anything that you would have done to chase more power from that cylinder?

[wobbly]

Here is the RV inlet inputs.
The Exhaust port itself was already made smaller, as Jan had begun experementing with lifting the floor, but my comment about size was more directed at the duct exit area.
Simply using EngMod and shooting for a duct exit Mach of 0.8 the result is a huge jump in power when reducing the Aprilia flange area and creating a new transition within the spigot.
The duct length, including the spigot was also increased slightly to 2X bore and the pipe adjusted accordingly.