ESE's works engine tuner

[Yow Ling]

Attachment 262562

A reed valve cylinder on a rotary valve bottom end. Could the cylinder be turned so you could more easily fit a Trombone pipe and the reed valve cavity used for a variable crankcase volume or better yet fit an exciter to it that sends the case volume into resonance. 12,000rpm is only 200Hz, there must be all sorts of audio drivers that could be used.

Cylinder can be turned around, exhaust points downwards so would need to remove the old gp air hole. I was going to make a stuffer to fill the old inlet and use the boysen port to feed the boost post that way the sleeve can cover the old inlet ports. Exciter ? we dont need any of your fancy talk round here yet, havnt done any of the tricky stuff yet. Was struggling to hold it in the mill, rigid enough to bore the spigot, had a small emergency and thought the cases were going to be smashed , like what happens to so many fxrs without my machining help

[TZ350]

Nice!
In the tripple ex setup, perhaps you should rise the TFRs a little more.
And on a side note: in the sim, I always see a drop in power when Aux. Exs are at the same opening height as the main. I believe it's best to 'retard' them about 3-5 degrees.

I am a bit stuck with the timings as I cut the secondry exhaust ports a bit big. It was my first effort and more about seeing if it could actually be done.

At 116 the front transfers come very close to the underside of the side exhaust ports so I cant move any more there and the rear transfers need to open a little later than the fronts, so its all a bit compromised really.

I originaly wanted to make a broad spread of power but have allowed myself to get distracted by the side show of building a racing Bucket engine that reliably makes over 30hp and my tripple port is aimed at that.



50hp 125 Aprilia racing engine.

Side Ex boost ports are the way to go to get the blow down STA needed to make real power and to allow a smaller width main exhaust port for piston/ring reliability.

I have had some concepts about auxillery exhaust ports explained to me, and the crux of it was that not all calculated auxillery exhaust port time area is applicible, and the main advantage is not time area as such, but rather improvement of scavenging of the exhaust port when the piston is halted at BDC... better for touring engines than racing engines.

In all fairness, there are other people in the Tuning Industry that have their own ideas about the worth of Ex boost ports for racing .....



I think they are the Bizz but don't like wasting good cylinders on experiments, so I used an old damaged cylinder to see if it was actually possible to cut these side ports, turned out OK but not to sure about racing reliability. Although the main exhaust port is not as big as the 31hp cylinder that failed at Kaitoke so that must help.

Should be interesting on the dyno ....... and if its any good then we will see if it holds together on the track.

[dinamik2t]

Yes, unfortunately it seems there's no room for more duration. Perhaps you could try the Aprilia pattern, with the B tfr higher than the front one.
And your vertical deviders are quite wide, if you need more TFR t-a!
Have you tested the new piranha pipe yet?

[TZ350]

Have you tested the new piranha pipe yet?

The 31hp single Ex port cylinder was not supposed to destroy itself at Kaitoke as the Piranha pipe was designed for it and was scheduled to be tested after that meeting. I have had to make a new head and copper cooling fin arrangement and re-jiged the tripple port to better suit the Piranha. I hope to get the engine all back together for testing in the next few days, fingers crossed.

[dinamik2t]

fingers crossed.

I can spare 2/20 of mine also for a few days.
I would love to see a video from a dyno session, if you have the equipment!

[TZ350]

I would love to see a video from a dyno session, if you have the equipment!

Will see what can be done, if there is a spare pair of hands at the time its easy enough to make video clips for youtube with my camera.

The plan is to try the Pirana pipe and setup a safe ignition curve for it.

Then compair a 30mm OKO carb to the 24 OKO taper bored setup.

And if there is a real difference between them, try the Plenum again to see if it can overcome the restriction imposed by the 24mm carb.

Previously the plenum worked in so much as, it was able to be ridden around but at the time the restriction on power turned out to not be the 24mm carb but the lack of real blowdown STA so the plenum did not show any significant gains and there were some practical difficulties with lubrication.

Anyway if the 24mm carb looks like it has now become a real restriction then we will try the plenum idea again.

[wobbly]

Rob you could look at lifting the B,C transfers like Aprilia, and move the front of the Ex Boosts forward to gain more blowdown to suit, as the bridges
on each side of the Ex are wide - will heat up alot and expand out toward the piston - eek.

[dinamik2t]

Regarding a proper timing curve, you could find the max torque rpm from EngMod and -as Wob pointed in the past- set 28* at the mid RPM, when pipe effect starts, then 13-14* at max torque RPM and caclulate the in-between from those two.

Wob, do you think that the purity traces from Post2T can be used as an accurate tuning indicator?
I have been testing an Aprilia-like pattern, with 116-115-115 TFRs and the C-port had very low purity -unless I decreased it's timing a couple of degrees. It didn't have an impact on power, but then again scavenging was RS125-type.
Is this indicative of what happens or it's best not to rely on that parameter, since the sim already uses a fixed scavenging pattern?

[TZ350]

Rob you could look at lifting the B,C transfers like Aprilia ....

Does someone have the numbers for the Aprilia handy?

move the front of the Ex Boosts forward to gain more blowdown to suit, as the bridges on each side of the Ex are wide

Do you mean narrowing down the area between the Ex boost port and main Ex port?

.... as the bridges on each side of the Ex are wide - will heat up alot and expand out toward the piston - eek.

Yes eek is right, I am not to sure about this bit myself and had thought about releving them a bit.

[dinamik2t]

Here's the EngMod equivalent of Aprilia Tfrs. It a mix of RSA/RSW cylinder derived from Frits' info on durations and data from the whiteprints from his files. But don't take the radial angles to be 100% correct.



As for the bridge between main & auxiliery exhaust. A couple of lubrication holes on the piston or a vertical lubrication band, like the aprilia piston below, would mess with the transfers??

[TZ350]

Thanks for that .....

[husaberg]

Here's the EngMod equivalent of Aprilia Tfrs. It a mix of RSA/RSW cylinder derived from Frits' info on durations and data from the whiteprints from his files. But don't take the radial angles to be 100% correct.



As for the bridge between main & auxiliery exhaust. A couple of lubrication holes on the piston or a vertical lubrication band, like the aprilia piston below, would mess with the transfers??

[wobbly]

The Aprilia has the B,C ports opening 1* before the A port.
So you could leave the A port at 116 and open the rest at 115.
This will of course drop the Bl STA, so to get it back you may as well reduce the bridge width to gain some area.
Reducing the area reduces the heat soak into the bridge,thus reducing the expansion.
But it also reduces the support area for the ring and piston.
You choose the compromise.
Having all 3 ports open together will lower the midrange power, so you could also lift the main port a little to get some stagger as well as widen the top of the Aux.

The purity in the ducts is a function of the fact that the port (s) that open first, flow last due to reverse flow of the blowdown pressure into those ducts.
Thus they will have more impurity than those that open later.
You cant change the fact that the excess blowdown has to go somewhere, you choose the scavenging pattern to get the STAs needed, and you live with the result.

[SwePatrick]

TZ350..

I have ported my Kawasaki cylinder like this:


Hard to see, but the A transfers are a couple of degrees higher at the rear end.
And then the B,C ports are all equal as rear of A port.

Mine are open in 138Degree duration and the front of A transfers are open 136.
Exhaust is 198degree´s

[dinamik2t]

Woah, 111/112 degrees! Isn't that a lot? I think you would lose a lot of power with those timings! And there seems to be quite a lot of area to be gained from the dividers.