ESE's works engine tuner

[jonny quest]

TZ, regarding your center section bleed. I found similar results on a test pipe.

I always wanted to build a one way reed valve. The performance gain could possibly be outside air cooling down pipe gasses.

[wobbly]

The bottom line is that a pipe bleed will always make much more bottom end and less top.
This is one reason why Jetski's make so much bottom end power,using a big stinger, thus reducing the pipes effectiveness by dropping the low rpm retained
back pressure, as this effect cranks up the bottom end.
Then as the engine comes onto the pipe, they squirt water into the stinger, effectively reducing the exit discharge coefficient and pumping up the top end power.
A variable exit stinger Cd will be a great way to optimize power , no matter how its done.
But sadly it has no effect on the injection issue TZ is struggling with - I wish I could help , but no free lunch yet - sorry.

[husaberg]

TZ, regarding your center section bleed. I found similar results on a test pipe.

I always wanted to build a one way reed valve. The performance gain could possibly be outside air cooling down pipe gasses.

[Ocean1]

Bruce's youchoob stuff

Probably safe, as long as it don't have wings...

https://en.wikipedia.org/wiki/Bruce_Simpson_(blogger)

[husaberg]

Probably safe, as long as it don't have wings...

https://en.wikipedia.org/wiki/Bruce_Simpson_(blogger)

I heard the cruise missile is tucked away somewhere near Ahaura

[Flettner]

[QUOTE=husaberg;1130978502][video=youtube;hQTPNdOuzwE]https://www.youtube.com/watch?v=hQTPNdOuzwE[/video/QUOTE]

Is that not the Ryger, just add a piston and cylinder in there and you have it!

[jamathi]

Yes, the idea is to make the piston skirt 'water ski' over the oil film instead of scraping the oil off. You don't really need a radius there, a 5° chamfer will do fine.

Corrected that for you Wob.

The main problem with Derbi and Aprilia RSA steering was the fairing.
It was made by Porsche.
At high speeds there was too much directional stability due to the fairing.
It was difficult to incline into a fast corner.
Fitting an Aprilia RSW fairing resolved this problem.

[husaberg]

The main problem with Derbi and Aprilia RSA steering was the fairing.
It was made by Porsche.
At high speeds there was too much directional stability due to the fairing.
It was difficult to incline into a fast corner.
Fitting an Aprilia RSW fairing resolved this problem.

Welcome Jan we all hope to hear plenty more from you.

[jamathi]

That is great news Wob . You'll be just 1400 km away then instead of 19000 km. Hope to meet you there.

So my friend Franco listened to me, I am happy to hear that!
I told him that in my opinion you are the best tuner in the world.
Pesaro is a very nice place to be, I worked there for 1 year.
Hope you'll enjoy it!!
And you will love the food.

[jamathi]

Congrats Wob! Maybe after the Work at TM is done you could help the Ryger Guys with their next Homologation Design.

The Ryger guys certainly need some help.
Their engine doesn't last for more than half an hour.
And there also seems to be not much power....

[jamathi]

The belly diameter as far as I can see has no relationship to the engine displacement.
Its all down to effective energy recovery within the pipe,and as the energy is finite you can decide where that energy is used.
As Frits says, the latest really fast 125 engines are a bit over 130mm, and use steep tapers to extract the maximum ( optimum ) depression
and reflection pressure ratios at the Ex port.
The bmep sets the available energy, and as you go up in displacement it becomes harder and harder to get anything like the bmep numbers of the square 125.
If you tune a MX250 to the highest possible level for road racing, then the long stroke limits what can be achieved and I found that when going thru the exercise
of developing a pipe for this class that a belly over around 140 ( with steeper angles ) makes no more power.
The square bore/stroke Gas Gas for example can go a somewhat harder, but it then topped out at about 145mm.

Re the Jante CNC driven scavenging vector visualizing machines.
These use a small tube with several pitot sensors linked to a computer that shows the velocity and the direction of transfer flow.
They take a huge amount of time and experiment to determine what the effect of these vectors have on scavenging.
But when finally understood, the Yamaha chief engineer that developed the cylinders for the 500GP machines that went on in 2000 to win the 250GP class, said to me it took him 3 years but he was now
able to predict the power curve with his Jante,without needing to use the dyno for confirmation.
Bartol had one for years but I dont think he ever really got a handle on what he was seeing on the screen, as most of his later work I have seen was basically a copy of Honda technology.
But the Roberts guys had one at Bud Asklands workshop, and he really knew what needed changing,and this helped Rainey and Yamaha immensely when Kenny was allowed to overule
the factory engineers with his own work.

As far as I know Yamaha just copied the Honda cylinders to win the 2000 250 championship
Later they even produced an SAE paper about this....
Fitting a Honda cylinder on a Yamaha engine was first done by my old friend Cees van Dongen
On his son's 125 Yamaha.
Later he sold the casting models to Bartol, who then became a Yamaha consultant....

We had such a Jaros machine at Aprilia, it proved to be useless.
Above all the results were not repeatable.
DEA engineering made a far better version of it himself.
I don't know anything about it's results.

[Flettner]

The Ryger guys certainly need some help.
Their engine doesn't last for more than half an hour.
And there also seems to be not much power....

So where did their claim of 70HP come from? And the 30,000 RPM, that had us guessing for a long time. Perhaps someone in the team opened their mouth too early? Disappointing to see it all come to nothing in the end, never the less it was a good guessing game

[jamathi]

So where did their claim of 70HP come from? And the 30,000 RPM, that had us guessing for a long time. Perhaps someone in the team opened their mouth too early? Disappointing to see it all come to nothing in the end, never the less it was a good guessing game

Just bluffing.
70 HP was never measured on a dyno.
I still wonder how many people could believe this, without seeing a power curve
Probably it was calculated, using Mota.
And of course talking about 30.000 revs has always been ridiculous...
The main problem seems to come from the nikasil plated piston.
The far too short connecting rod surely will not help.
Just imagine the friction between the small diameter part (46MM) of the piston an the separator plate with such
a very much inclined connecting rod at maximum piston speed....
Impossible!

[husaberg]

Here is the cylinder I have sitting on NSR20 MC21 cases.
The reverse stagger is obvious, I will check what casting this came from.

Wob I found this
You had a bit to do with some of his stuff earlier on.

http://nsr250.freeforums.org/tuckerb...s-t414-20.html

have definitely made an error with the different height of the A port in relation to the B and C ports.
In reality they seem to be identical, height-wise. This throws doubt on the whole picture.
I need to do a total re-measure. Well spotted and thanks for pointing it out.

I do NOT know what I was thinking to get it so wrong. D'oh!
Maybe I just had the Aprilia "reverse stagger" on my mind, and added in a bit of wishful thinking??
In reality I probably just mis-read 42.1 as 43.1 or something completely stupid like that.

Hopefully I can re-measure this weekend and get a corrected port map put up.

[tjbw]

Welcome Jan we all hope to hear plenty more from you.

Seconded!

Welcome Jan.

I was just thinking the other day, about the remarkable quality of information shared here on KB, by wobbly, Frits, flettner, Ken, husa and many others. Now Jan is contributing too, that's the best news.