ESE's works engine tuner

[wobbly]

Jan , the later Czech visualization machine that Yamaha and Bartol used was CNC controlled and insanely expensive.
It showed the in cylinder flow vectors ( speed and direction ) on a computer screen in varying colors.
Bud Askland the Roberts actual test engineer , was seriously impressed , quite a feat for a guy who absolutely knew everything there was to know ( his words not mine ).

My boss was a NZ multi millionaire , but sadly after all my begging , even he thought the E80,000 was a stretch too far.
This was ( and is ) seriously trick use of digital technology - I can certainly believe that just maybe Harold learned enough to make a better mousetrap , but he was still
constrained by using copied technology he had no understanding of at all.

[husaberg]

multiple people in Italy say that KTM had even more power than an Rsa (56hp) but with less range so they were still slower. If the engine was an Honda copy, how could they match Aprilia's power? wasn't the Honda engine around 50hp?
I'm a little dubious tbh but this is what i've heard...

and another little question, if you can speak publicly about it: when you tried the reduced exit area on Kz engines, how much did you gain? how much was the final port height, something like 28mm? i remember your welded cylinder pics here. the new tm R2 black has the aux ducts "ears" on the exhaust flange but this in fact increases the exit cross section, so i don't know if they're going after your theory

Hi years ago Frits posted the Debri vs Aprilia RSA graph.
pretty sure even with the same cylinder the red valve would cost at least 4-5 hp on a 125 gp bike.
Frits had said Jan had a play after this test and got a few more HP from the copy of the Kit Honda.

I must have a stack of Derbi drawings somewhere back in Holland but don't recall every detail and maybe some mods were never captured; Jan had a knack of modifying and testing first, and having the mods drawn afterwards. But it's safe to assume that Jan tested every mod you can think of, and then some.
Besides, you can ask Jan directly; he is looking in from time to time.

A technical explanation? Nah, too much to do today. But since you were kind enough to post that picture of your sex six sisters, I will show some curves of my own.
When Jan Thiel went to Derbi to design the bike we now know as the Aprilia RSA125, he encountered the 125 cc reed valve Derbi ridden by Lorenzo the previous season. Jan played around with the reed valver as well, because he wanted to find out the differences between reed valve and disk valve power. He managed to extract 2 HP more from the reed valver than anyone else had ever done before (never mind the fairy tales of reed valve 125s producing over 50 HP; those Horses must have been Shetland ponies, probably measured at the piston ring).
My graph shows the power curve for the Aprilia RSA, the Aprilia RSW and that best-ever reed valve Derbi. It's not quite in the same league as the rotaries, hmm?

EDIT: Shame on me; I discovered that I posted a wrong graph (and I do not have the correct one at hand here in Holland). Power curve DERBILOR shows the reed valve Derbi as Lorenzo rode it. After Jan finished playing with it, it had 49 HP. Still, the best-ever disk valver produced 10 % more power than the best-ever reed valver.

https://www.kiwibiker.co.nz/forums/a...2&d=1333621581



click on here to go to graph as the device i am ob will not play ball

Yes, of course it was....

Thanks for your answers Jan, Can you confirm what mods he made to the reed Derbi as frits Alluded to above to boost its HP
or did you just put your own cylinder on it?

[F5 Dave]

So I was idly thinking. We know that Rotax made the road engine and the 256 kart engine. What involvement did they have in the GP years of the 3 classes and when did it diverge?

Was reading a classic race magazine today that stated the RS500 had a RAVE valve which was electronic but a Rotax name I thought.

Same magazine had Holden winning NZ 250 on a 256 in early 80s which is in a mates spare bedroom about 4km from here.

[husaberg]

So I was idly thinking. We know that Rotax made the road engine and the 256 kart engine. What involvement did they have in the GP years of the 3 classes and when did it diverge?

Was reading a classic race magazine today that stated the RS500 had a RAVE valve which was electronic but a Rotax name I thought.

Same magazine had Holden winning NZ 250 on a 256 in early 80s which is in a mates spare bedroom about 4km from here.

here is the early Aprilia story.
and next post
https://www.kiwibiker.co.nz/forums/s...post1130170725

https://www.kiwibiker.co.nz/forums/s...post1130170848

i also posted about the other chassis makers that used Rotax engines and there relationship with them here.
https://www.kiwibiker.co.nz/forums/s...post1130222016

But it would be great to hear from Jan and Frits....

[aljaxon]

Al , I sent a DM so you can pay for lunch , just for starters you have a THREE cone header and why do you want a diffuser after the rear cone - absolutely wrong.

the first part of the header ive drawn is the wobbly duct from piston to end of duct. 2 x bore with 1.5 x converging and 0.5 x bore diverging.

the last diffuser after rear cone is a restrictor i saw on here. with a 10 degree cone after it.


i had previously been inserting the stinger inside the pipe as far as the belly but can imagine a strange object inside the cone could hinder the waves somehow.
saw that thought id try it. is it a bad idea?
just tried sending you a dm but the dm factory at my end is broken. it wont allow me to type anything. i havent got engmod or indeed any software.

WARNING - to anyone like me who trawled though this thread stealing pipe designs these next designs are not very good.
ive made these different end sections to try just to see what they do and if they behave as they should.


no need to go into depth on my query, im guessing you havent enough time for your own projects never mind for the likes of me asking questions from all directions. any info or judgement you care to pass on would be much appreciated. i should be doing other stuff myself but there is something about making a pipe as if you are bringing something to life. but like anything im guessing the novelty will soon wear off.

[Wos]

@12palof

Your cr 500 ...what is your purpose you are aiming for?

A 500 cc will never reve easily high... especially if you have less blowdown as needed


21 degree on the bottom rpm is possible as you increased the msv of quish

You set ignition to 15 degree at 8000 ...realy?
Cant beliefe 8000 is peak power at old reed 500cc engine

My guess would be peak much under 8000...

To much advance after max power / running out of breath surly kills every free reving..

One way for first shot to set timing at peak power is to look where is peak in datasheet from original bike...

Your exhaust duct / flange...are there steps inside to the header ?


Edit...please google for "cr500 vhm dyno tests"

Peak of cr500 is about 5500... and "on pipe" is lower than 4000...

Have made a quick and dirty ignition curve that should fit to cr500 ...only for a first shot and maybe your next dyno run..i bet fits better...please let me know

If you need the tunebox file...let me know too

Grüße Wolfgang

[Gradella23]

Al , I sent a DM so you can pay for lunch , just for starters you have a THREE cone header and why do you want a diffuser after the rear cone - absolutely wrong.

Gradella , there is alot I cannot say about the R2 on here , but alot of work inside the duct was tested at the factory that I did not do.
Yes , the duct exit area is a bit too big , and the ears transition in the spigot is not elegant CNC programming at all - it could be done way better.
Here is my hand prototype.

And regarding Mr Bartol - yes he did copy and take credit for others work , but he also had access to a Czech flow analyzer that as I said other top class tuners regarded
as a seriously good tool.
Jan didnt like it , others did , so maybe Harold understood enough from its results to achieve serious power.
But then again , he simply copied an A Kit Honda exhaust , and even Witteveens attempt that Jan was forced to engineer around , was a far better pipe.

thanks wob. Is this pic the welded one with reduced cross section or just a standard one with ears added?
where should we draw the line in terms of cross section% at the cylinder exit with a Kz like long duct (around 60mm)? From your tests, is it still worth to go 75% even with a lot less lenght?

[gamma500]

Kevin Cameron article about 2t scavenging and the Jante flow machine:

https://www.cycleworld.com/searching...nging-schemes/

Edit: another one

https://www.cycleworld.com/colliding...flow-symmetry/

[wobbly]

Al , I still dont get it - the diameters are 25/30/36.3/41.2 , where is the converging duct , and where is the short divergent transition section before the header?
And the nozzle with diverging cone at the stinger entry has been superseded by a short section with a step - more power.
The stinger up inside has no real effect on power - just makes it alot quieter.
To even begin a new design we need the area and timing of the port , the duct length and desired peak power rpm.

GRAD - the pic shows my welded and CNC cut duct with 75% at the cylinder face.
If you measure an R2 Black you will find the smallest duct height is about 2/3 of its length from the port, but I didnt tell you that.

[Haufen]

I think there may be a bug in the attachment, wob


Did I see something that is not there in reality on the KTM head, or is it just that nobody has an idea about the strange shape of the squish?

[aljaxon]

apologies, my error in not putting dims on the first bit of the header which is part of the cylinder duct that ive altered to follow the 75% duct convergence then back to 100%.



47mm bore so that first bit without a measure bit was my duct 94mm long. amended in the pic above

port area is 491mmsq which is 25mm diameter equivalent. so 75% or 491 is 441.8 which gives diameter of 23.8. (narrowest bit of wobbly duct. then short length of 23.5mm back to the 25mm. which is where the header proper starts even though ive used the initial 94mm as part of the header length.

and ive just blown my head off thinking that hand drawn sketch was for me and the stepped stinger and trying to fathom it out lol.

been a long day for me trying to understand the instructions on one of those chinese diesel heaters.

[aljaxon]

ive got 180 degrees ex duration, i wanted peak at 8800 and i worked that out to be 916mm long. im used to working with small aircooled motors and 1mm mild steel and find i usually get the tuned length not far off if i use 509 as my speed of sound. (working backwards from a dyno read out.)

i tried 0.8mm mild steel this time and i dont know if its thrown things because my motor just wont rev past 8500.
with another pipe it revs to 10krpm and that one also has the cooling vanes on the first converging part of the duct.

it could be the long belly?

just for kicks i did a comparison speedo video. almost better than a dyno. i tried to change gear at the same revs each video but the tacho is a bit wayward.
ive been done in my van by dash cam twice in the last 2 years. dunno if that is a thing in nz? my footage even got shown on a local tv's program about crap driving.

so thats why i blanked it out because there was some highly iregular traffic negotiation on show.

for anyone whos bothered heres the video
for anyone whos botheredheres the video

the latest pipe is on the left and you can see the massive improvement in accel in the rev range i wanted.
ive since geared it up to gain 5 more mph and its still faster accel. so its not all bad news.

[husaberg]

Did I see something that is not there in reality on the KTM head, or is it just that nobody has an idea about the strange shape of the squish?

Oddly the for me pic you posted didnt seem to come from the pic i posted?
oh, it was out of the album.
on the colours and areas of your pic i thought it was a insert of two different alloys?
but that last one looks odd?

[Haufen]

but that last one looks odd?

Yes, I am wondering only about the last one. The others seem fine / normal to me.

On the strange head, there seems to have been detonation on the second / middle (yellow) part of the squish. Or maybe there was contact contact after the engine had sucked some sand / dirt / broken off pieces etc.

[husaberg]

Yes, I am wondering only about the last one. The others seem fine / normal to me.

On the strange head, there seems to have been detonation on the second / middle (yellow) part of the squish. Or maybe there was contact contact after the engine had sucked some sand / dirt / broken off pieces etc.

that last outer bit seems to be about the same width as the radiused edge of the flat top.



Oddly the skirt profile appears to be very different from the sculptured skirt of the NSR500 and 250's

nsr500


Bartol KTM


oh i see why

KTM


NSR500




RS125 second on left looks sandcast?
or vapour blasted?

this one has a PV but i guess could be 250



This one below was in my album not sure what RS125 they are nx4 i think according to the name....
one looks like it has been dingle berried .the other au natural



What was this pipe Frits?