ESE's works engine tuner

[TZ350]

Thanks for the info on the Data Loggers.

Rob, I thought you have been running that Ex width for a while with no issues ( it was in your original sim file ) - but I have never gone over 72% except in small bore sizes that seem to be able to keep the ring life OK.
Looks like it could now be a combination of too high bmep for the ignition that was OK before, and same with the Ex width, that cant be sustained now its starting to see some serious revs.

Yes, well this cylinder has done hours on the dyno with 200 odd dyno pulls and we have been running wide ports on other 72-75 ish cylinders too but whether this cylinder is exactly 73 or 75% I can't remember. I will have to check, and do you measure it on the inside or outside of the side champher, at this width including the champher probably makes a difference to the mechanical reliability too.

True, this particular cylinder has had little real track time, Te Puke practice & 3 races, Taupo 1 practice session and Kaitoke practice and 1 race.

It seems its on the limit mechanicaly and the ignition phlisophy looks the major culprit, or more likely it has more than one problem.

One thing is for sure though, this is only a small blip on the way to developing a reliable mid 30's hp Bucket

[TZ350]

There has been a lot posted about the piston issue today that makes sense. I will have to work through it bit by bit, I suspect there is more than one problem.

Rob, I thought you have been running that Ex width for a while with no issues ( it was in your original sim file ) - but I have never gone over 72% except in small bore sizes that seem to be able to keep the ring life OK.

I have done a lot of racing miles on this cylinder, The bore is 56.5mm and the exhaust port width is 41.56, so close to 74%. (or 73.55752 for anyone impressed by lots of decimal places).



The cylinder that failed at Kaitoke is also 56.5mm and the exhaust port width is 41.76mm so 74% there too.

It may be the shape and radius of the ports are different enough to be making a real difference.

Wob suggests 72% and Neels 73% so 74% is stepping over the line a bit.

By boring the cylinder to 57.75 I can reduce the ex port to 72% and still be a hair under 130cc.

[rgvbaz]

Frits mentioned a few pages back about insufficient blowdown causing the fresh charge in the transfers getting heated. Maybe this has a part to play also?

Dave

[TZ350]

Frits mentioned a few pages back about insufficient blowdown causing the fresh charge in the transfers getting heated. Maybe this has a part to play also? Dave

Hi Dave, yes, I think there are probably several gremlins with their fingers in this pie and I have to look at everything but suspect the biggest gremlin is the ignition curve I used.

The one front center I think, or was it back right.

[F5 Dave]

. . ., The bore is 56.5mm and the exhaust port width is 41.56, so close to 74%. (or 73.55752 for anyone impressed by lots of decimal places)..

Oohh yes Rob. I'm very impressed by lots of decimal places. . . . Now presumably you measured that size at operating temperature, not machine shop 18deg?

[Bert]

Sort of what I was thinking. Maybe give Andrew a call and see if he can tell you where he got his fancy headphone setup. When I was playing with the igntech on the dyno with FXR it was really easy to hear the detonation with the phones. Might even be easy to make. After playing around at the track trying to jet the FCR I am sold on some actual diagnostics. Was going the wrong way. It wanted leaning not richness. As we are also pushing the limits of an air cooled single I am making a header with a lambda and EGT setup. Blow ups are expensive and really I would rather be racing than swinging a spanner. Maybe marking your throttle with about 10 positions and try loading and listening for det at each poz should give you a good idea of how the carb and ignition are working together. I had a small manifold leak when I was work with the headphones was very obvious something was wrong.

Onwards and upwards mate.

DYI Knock sensor. (I think I've posted this up before; but here we go again as it might interest people).

the start

http://www.clubsub.org.nz/forum/inde...ic=7978.0;wap2

Sensor
http://www.jaycar.co.nz/productView....k&form=KEYWORD

audio amp
http://www.jaycar.co.nz/productView....g&form=KEYWORD

Computer software & electronics info:
http://home.netcom.com/~bsundahl/kno...tm#spectrogram

DYI option
http://www.autospeed.co.nz/cms/A_0353/printArticle.html

interesting calculation for detonation frequency (Khz)
http://www.autospeed.co.nz/cms/article.html?&A=0348
my bike should be around 11.4 kHz...

We use similar technology to record difference size rocks bouncing along river beds (all be it slightly more $$).

Another option is using ones Iphone/other type; and music mixing amp app thingy.
One could plug in a 5volt mic system into the phone rather than a guitar and isolate the key frequencies of det?!?

[TZ350]

Oohh yes Rob. I'm very impressed by lots of decimal places. . . . Now presumably you measured that size at operating temperature, not machine shop 18deg?

Being an industry insider, I will have you know, I casually heated the old calipers up in my hand before miss using them ..... so there.

[TZ350]

Thought I had better check the triple port too. This is also a cylinder I have used a lot, before cutting the extra side ports into it.



Using all the best measuring gear money can buy, I found the bore is 56.5mm and I made the port window 41.13 for 72.79646 or 73% in meaningfull terms and the shape looks OK too.

[husaberg]

Thought I had better check the triple port too. This is also a cylinder I have used a lot, before cutting the extra side ports into it.



Using all the best measuring gear money can buy, I found the bore is 56.5mm and I made the port window 41.13 for 72.79646 or 73% in real terms and the shape looks OK too.

Found this Rob

Yes ... I found much the same, the triple port was not much better than the single when they both had to suck through a 24mm carb but when a biger carb was simulated the tripple produced more power up top and significantly more drive down low.

If they are both limited to a 24mm carb and similar power curves, then a good reason for making a tripple port cylinder would be for mechanical reliability with the triples main ex port width at 62% of bore diameter instead of the singles 75%.

[TZ350]

Yes, well every one knows that blowdown is everything and more is better. So I had adapted an old cylinder I had already ported before to a triple port before I had the EngMod2T software and could see what was likely to happen.

The future could be another triple port cylinder with the std GP exhaust port width or a purpose made sleeve or better yet, cylinder.

In the end, because of the 24mm carb I may not get much more power but I can see that reliability could be greatly improved with a triple port setup. Including the hot exhaust gas down the transfers gremlin.

[wobbly]

Forget the homemade bullshit, get one of these with the extra wire to ground.
When it sees deto it can ground an Ignitech input and retard the timing automatically.
You get flashing lights and engine protection all in one shot, and cheap as chips - made in Czech so it likes being connected to an Ignitech - same lingo..
Works perfectly - when you get it trimmed correctly it will tell you where to manually pull out timing, then it just operates as a failsafe.

http://www.ebay.com/itm/Knock-gauge-...ht_1582wt_1297

[TZ350]

Just brought one now. thanks.

[Frits Overmars]

....when the ring ends but together the ring would bulge out into the ex port.

When the ring ends but together, the ring becomes a very efficient oil scraper and you will experience the mother of all seizures.

The cylinder that failed at Kaitoke is also 56.5mm and the exhaust port width is 41.76mm so 74% there too.
It may be the shape and radius of the ports are different enough to be making a real difference.Wob suggests 72% and Neels 73% so 74% is stepping over the line a bit.

A 74% port width should not cause any ring problems. If it does, it will be because of radii being too small. With good quality piston rings you can get away with 80% port width. But that will not do your power any good; such a width requires huge port radii that will take away much blowdown area at the top corners of the por tas the picture below shows.
70% width is optimal in this respect. And like Neels says, pay attention to the bottom of the port window. Rings have more time to bulge into the port when the piston is on the way down. And you can apply large bottom radii because that will not take away any blowdown area.

[bucketracer]

A 74% port width should not cause any ring problems. If it does, it will be because of radii being too small.

That cylinder of TeeZee's was one recovered from a previous bad experience when a ring turned and got caught in the ex port. TeeZee is not one to waste anything. It was recovered by razing and enlarging the port to clean up the damage but it looks like that left the top and bottom edges a bit square.

As a prof of concept exercise I guess it has proved its point, low 30's hp Buckets are possible.

Just have to do it again with a better cylinder and ignition curve.

[husaberg]

When the ring ends but together, the ring becomes a very efficient oil scraper and you will experience the mother of all seizures.
A 74% port width should not cause any ring problems. If it does, it will be because of radii being too small. With good quality piston rings you can get away with 80% port width. But that will not do your power any good; such a width requires huge port radii that will take away much blowdown area at the top corners of the port.
70% width is optimal in this respect. And like Neels says, pay attention to the bottom of the port window. Rings have more time to bulge into the port when the piston is on the way down. And you can apply large bottom radii because that will not take away any blowdown area.

Hello Frits i may have got this a bit confused. With all this talk of exhaust ports i had a bit of a troll around while i was looking into aux exhaust ports and was looking at Kawasaki kips system (i had never actually noticed the aux port were in this system higher than the main port.)Having a aha moment i looked at your down loads of the Aprilia stuff to see the Aprilia system and i noticed this.
The Aprilia aux ports seem to be the same height (or possibly a little lower)as the top of the main port but the power valve seems to only control the height of the main port or does the edges of the blade in fact also control the aux ports entry to the main port. Is that how it works?
I also noticed the cylinder head on one of the 250 twins seem to have what i assume is the water exit at the bottom of the head pointing down.The 125 pics also seem to have the what i assume is the exit on the lower part of the head.(I are assuming of coarse the water flows to the crankcase the cylinder then on to the head. Is that not correct?)

Also did you miss the question a couple of pages back regarding the retarding of the disk valves or was it a silly question?

With the RSA being gear driven disk was there ever any consideration given to reversing the rotation to allow for a rudimentary retard function along the lines of a centrifugal advance ignition.
I ask because Bell quotes significant high rev gains from a mildly retarded opening and closing and visa versa (He even showed curves). So it would seem (if bell is right) the timings could be varied it could to allow for a broader output if timed for normal peak at full retard. Just a thought possibly retarded.

Oh with the pipe sealing if dykes rings were to be used inverted and back to front they would possibly take up little space and should also seal.