ESE's works engine tuner

[TZ350]

The Ex Mach thing is easy to understand and use. Once you are into the gas dynamics screen and chose Mach and your project rpm, then the graphical options are

ExPMach - this is the mach number at the port face.

ExMach1 - this is the mach at the sensor position you chose in the Engine screen - in this case we want to look at the Mach usually at the duct exit, where the nozzle area is smallest.

ExMach2 - this is the mach in pipe 2 = the stinger in a normal single cylinder sim setup.

As the piston starts to open the port we have maximum pressure delta and the smallest area, so the initial flow goes sonic in the ExPMach trace.

Then the mach reduces as the area increases and the pressure drops - followed by an increase in flow due to the depression at the port created by the diffuser, this is then followed by the rear cone pressure rise reversing the flow.
At the smallest area of the nozzle ( if one is correctly designed ) the Mach number will approach 0.8. I have found that higher or lower affects the power.

Then we have the flow regime in the stinger, and again the best scenario seems to involve a short period of choked sonic flow, followed by a longer period closer to/below Mach 1.

EngMod2T simulation and engine performance analysis.

Hi Wob, I think I am getting this right, any pointers would be welcome.



Max torque at 12,000 rpm.

ExMach1 - this is the mach at the sensor position you chose in the Engine screen - in this case we want to look at the Mach usually at the duct exit, where the nozzle area is smallest.

Ok this is my Engine screen and Exhaust Port screen with 80% Exhaust port width and 90% equivalent exhaust duct diameter at the flange face. The exhaust duct is 40mm long from port window to flange face.



ExMach1 Not quite 0.8 at max torque.

ExMach1 - At the smallest area of the nozzle ( if one is correctly designed ) the Mach number will approach 0.8. I have found that higher or lower affects the power.

TUBmax (squish band end gas temperature) is highest at 11,000rpm. So there is untapped potential somewhere, I need to find it as TUBmax indicates that it could tolerate being higher at 12,000 plus rpm, but not to sure how to do that.

[F5 Dave]

Rob, the thing is there are fundamental differences between where you are now and where you wish to one day be. Surely you will learn more modelled closer to what you have now and then see the changes. . . . . Says he who has never played with anything more sophisticated than TSR stuff of the 90s. But you have peak power set to 15500. You're around 13 in real life. Also bmep is clearly a lot lower.

What I am impressed with is that the piston hasn't escaped down the duct. Keep that skirt nice and tight to the bore.

[TZ350]

you have peak power set to 15500. You're around 13 in real life

Yes, good spotting, I forgot to set it back to 13. I was playing with it to see what the piston speed would be. At 15,000 rpm it is only just touching the performance range. At 13 it is below industrial, God knows what rpm is required to get an RG50's piston speed into the high performance range 22,000+rpm maybe.



BMEP sets a target for the port STA's so you can compare where your at with where you want to be, funnily enough you can often exceed the required STA on some port and then that is another sort of clue.

What I am impressed with is that the piston hasn't escaped down the duct. Keep that skirt nice and tight to the bore.

Yes it is a bit wild, but now I am trying to bring some science to the party by using EngMod to work out the best exhaust port duct area for an 80% single Exhaust port window. Not finished yet but it looks to be about 22.75mm at the flange face. But what we do know for sure is that the standard RG50 or RMX50 exhaust duct is way to big at 26mm. Who would have thought that.

[F5 Dave]

Thought something else was odd. Stroke std is 37.8 not 37.5. My memory isn't what it used to be but I can still catch the odd (irrelevant) thing.

Perhaps try one of those KTM pistons(never measured one) , the Suzuki ones with the thick rings will be slinging away power as you rev then to heck despite the lower piston speed.

[TZ350]

Stroke std is 37.8 not 37.5.

Thanks for that.

Perhaps try one of those KTM pistons(never measured one) , the Suzuki ones with the thick rings will be slinging away power as you rev then to heck despite the lower piston speed.

I think KTM is to big, may be wrong. I have some 41mm Barrakit pistons with 1mm thick rings. I was truly surprised by how low the piston speed is in a RG50.

[husaberg]

Thanks for that.



I think KTM is to big, may be wrong. I have some 41mm Barrakit pistons with 1mm thick rings. I was truly surprised by how low the piston speed is in a RG50.

39.5mm on the Katie

[TZ350]

39.5mm on the Katie

Ok to small, a lot of 50 pistons are. I must have been thinking of the KTM65 maybe.

[husaberg]

Ok to small, a lot of 50 pistons are. I must have been thinking of the KTM65 maybe.

The stoke is pretty much the same. I are meaning the KTM50's and 60'S within a smige.. the KTM 60 cylinder fits on the KTM50 on the Beta engines (up to 1998) not sure if the later 50-65 works or not but judging by the cylinder (the 50 looks like it was designed as a 65)
There is a KTM60cc (up to about 1998) version as well plus an overbore 50/60 that likely uses the KTM60 piston the there is an over bore for the 60-85cc kit plus the factory 85-105cc which is a 52mm piston with a 14mm pin.
plus there is other earlier versions and other 50CC MX engines

[teriks]

In the Help file I was able to drill down through the index but was unable to open the related help document. As I have not needed the Help file for a while I am not sure when it stopped working properly for me. I probably inadvertently killed it when I was doing a re organization of the files.

I don't think you did anything wrong with the file shuffling, it's a single file, so if you can open the help at all, the topics should be there.

I did run into a similar issue though when reading the updated Dat2T help file.
The "+" on each topic disappeared making it impossible to expand the sections, that is until I found the scroll bar at the bottom of the navigation pane.

Just move that thing marked yellow around and I bet you'll find your topics again.

Many thanks to Neels who goes to a lot of trouble supporting the EngMod2T program.

Agreed!

[AndreasL]

Maybe obvious to all others, but you did your measures at max torque TZ.

I have just played around a small bit with the mach numbers...at peek power...

I guess both can be interesting to analyze, but is one "more right" then the other?

Great summary of this feature and big thanks to Neels as well!

[Lef16]

Hey guys,
any news on ryger engine?
Cheers

[Martin1981]

Hey guys,
any news on ryger engine?
Cheers

No. If there were any News they would have been posted already. Without anybody asking for it. Happy New Year!

[peewee]

hey wob I see a lot of rods have the rib in the center from the manufacture process. do you bother polishing it down ? so far ive never had a failure and never polished them down but none of my engine have extreme power. if they were polished wouldn't that remove any shotpeening from the surface ? whats the inside scoop on this

[TZ350]

Maybe obvious to all others, but you did your measures at max torque TZ.I have just played around a small bit with the mach numbers...at peak power...

I guess both can be interesting to analyze, but is one "more right" than the other?

Peak Torque or Peak Power, I chose peak torque because that is where everything is working at its best and I wanted to keep it simple by displaying only one trace.

But in fact the Wave and Mach action can be investigated at any rpm point in the search for improvements.



Here is a trace overlay of Mach numbers for 10-11-12-13K rpm taken at the flange face 40mm down the exhaust duct. It is interesting to compare them to the torque curve.

[TZ350]

Just move that thing marked yellow around and I bet you'll find your topics again.

Thanks, I will try that.

...... nope, that did not work for me.