ESE's works engine tuner

[F5 Dave]

I was using the same dynojet for maybe 25 years but running it myself for 10-15, heck time flies. Mostly it was arrive after dinner, roller door up, dirty big fan on, rug up of it was cold.
Turn off any correction. What you did that night was measured in apples so improvement (or usually deprovements) could be measured. Previous runs were taken with grain of salt.

For a short while Chris built a room in room with extraction and inlet. Didn't know we were born.

[Frits Overmars]

Sorry Frits, the search function makes me nuts, can you share that again, I would try to see if DynoJet would also implement that in their software.. Edit: done, got that already from Neels... thank's a lot!

Thanks Neels.
You can find the 'FOS two-stroke air density correction factor.PDF' in 'FOS tips & concepts':
https://onedrive.live.com/?authkey=%...D58EFB966FB3DC

Thankfully most dyno rooms are shielded from the weather so the air temperature and pressure in a good dyno room can adjusted independent from the weather.

Me thinks you are spoiled rotten by the SOTA apparatus at Aprilia Frits. The only " shield " most dyno rooms have from the ambient weather is the workshop front door.

You should have seen my dyno room in 1978: an inertia flywheel built out of two tractor flywheels welded back to back, plus a Heenan & Froude water brake, salvaged from a technical university that was going to throw it away after 20 years of service, coupled to a central heating radiator with long hoses, so I could put the radiator outside the dyno room in summer and inside in winter.
There was a blower for engine cooling that accidentally cooled the exhaust pipe more than the engine radiator, which taught me not to cool the pipe too much, and a fumes extractor, sucking the exhaust gases through a giant bong that caught most of the smoke and smell in order to keep the neighbours at peace. Finetuning of cabin temperature and pressure was done by opening the door more or less, provided there was no one else in the building trying to make a phone call.

The Aprilia dyno department was a somewhat different kettle of fish. Controlling the air humidity was taken care of by an air conditioner that cooled all incoming air, condensing the water vapor, and then heating that air up again to the required temperature. That airco consumed about as much electricity as Aprilia's home town Noale.

[Frank S.]

... just to make you guys a little jealous, that's where I work

[ApolloMotoMoto]

I have sent 2 screen shots with differing weather to Rein, showing the FOS corrections to send to Performance Trends so they can confirm the code changes needed are correct.

(...)

For those people who have not actually seen the FOS code in action , here is a shot of the real time screen on my dyno.
The SportDyno digital weather station is calibrated to the local airport, about 5Km away.

Heya Wayne, I just got an email from PerformanceTrends this moring saying they had not received these two screenshots from the SportsDevices software so they can confirm the code is working properly;


Can you post that other screenshot here?

***EDIT***

-JUST NOW received another email from PerformanceTrends, they just got the email with the SportsDevices screenshots (both of them)

Thanks again!

[ApolloMotoMoto]

Looks like PerformanceTrends received everything they needed to confirm the code was working as intended;

PerformanceTrends Dyno DataMite Version 4.2 B.045 was just released today.

Changelog Entry:

----- Jan 14, 2025 Version 4.2 B.045 -----------------------------
Added 2 stroke FSO correction factor, Pro or Enterprise Dyno versions
only.



...lol at the typo in the changelog, should be FOS, not FSO...

[wobbly]

HaHa - Frits's Sublime Offerings - FSO, I think we should keep it.

I assume that whole facility at Aprilia is still in operation Frits ?

[41juergen]

... just to make you guys a little jealous, that's where I work

Ok, only Horiba setup, one can do better.. (just a joke, looks very nice!)

[Frits Overmars]

HaHa - Frits's Sublime Offerings - FSO, I think we should keep it.

I finally thought I had a chance to become world famous and then all the credits go to a Polish Car Manufacturer

[Frits Overmars]

... just to make you guys a little jealous, that's where I work

Allrad-Prüfstand, auch nicht schlecht. Now we just have to wait for the first 4-wheel drive motorcycle at KiwiBiker . Neil Hintz, are you there?

[Frank S.]

Allrad-Prüfstand

We also have a few engine test benches, but unfortunately not a single 2-stroke engine in the entire company
I had to take an official picture because posting my own photos would be quite bad for my career

[_____]

The Aprilia dyno department was a somewhat different kettle of fish. Controlling the air humidity was taken care of by an air conditioner that cooled all incoming air, condensing the water vapor, and then heating that air up again to the required temperature. That airco consumed about as much electricity as Aprilia's home town Noale.

Hi Frits,

If I recall an older comment of yours correctly, the tests were performed at 25°C.
Did you add water after removing all of it? Or did you operate the engines as 0% relative density?
Because humidity has a big influence on knocking!

I am asking, since modern car engines have a map sensor that is measuring not only temperature and pressure, but also humidity.

BR
Chris

[Frits Overmars]

Hi Frits, If I recall an older comment of yours correctly, the tests were performed at 25°C.
Did you add water after removing all of it? Or did you operate the engines as 0% relative density? Because humidity has a big influence on knocking!
I am asking, since modern car engines have a map sensor that is measuring not only temperature and pressure, but also humidity.
BR Chris

In practice, you don't always need to remove all the water but only bring the relative humidity to the desired value. Sometimes you have to remove water to do that, sometimes you even have to add it.

I didn't know about a MAP sensor that measures temp, pressure and humidity. Do you have any further information on that?

[ApolloMotoMoto]

So, the team is pretty close to running the first validation pulls on our brand new inertia dyno, and I have a question for those with knowledge and experience using a simple inertia dyno (with fixed flywheel mass and no braking) to develop 2 stroke engines...

PerformanceTrends says in their documentation that the flywheels inertia should be "sized" such that the "acceleration time" of a "full pull" to maximum RPM should take between 5 to 10 seconds in order to get "good accuracy".

Quote:

"You need an acceleration time of 5 to 10 seconds for good accuracy."

They ALSO SAY:

"Use moderate acceleration rates, like 300-500 engine RPM per second. Very quick acceleration rates, like 1000 RPM per second are less accurate."

I am assuming a pull of less than 5 seconds is not going to suffieciently load the engine to accurately measure the total torque capacity?
-What insight can those with actual experience provide for this "bottom threshold" for the time, in seconds, of a pull on an inertia dyno.

Next up, what about the 10 seconds on the top side of their range?
-Why would pull times exceeding 10 seconds detrimentally effect accuracy?
-I have seen recommendations for longer pulls on 2 stroke engines to allow the pipe to sufficient heat through the pull, but I dont recall what the time in seconds was recommended to be...?
-again, any insight can be provided on this "top threshhold" for acceleration time?

If I use the "moderate acceleration rate" recommendation, for the pulls I want to do, we are talking pulls from 4k - 16k RPM; thats a sweep of 12,000 RPM's...

12,000 / 300 RPM per second = 40 seconds

12,000 / 500 RPM per second = 24 seconds

12,000 / 1000 RPM per second = 12 second (already longer than 10....)

[Haufen]

So, the team is pretty close to running the first validation pulls on our brand new inertia dyno, and I have a question for those with knowledge and experience using a simple inertia dyno (with fixed flywheel mass and no braking) to develop 2 stroke engines...

Use an acceleration time that is equivalent to what you are going to have when you ride it. Ideal case: the acceleration time in each gear is the same on the dyno and on the road. For that to be the case the roller has do be twice the weight of the bike including rider.

As long as you are unsure about jetting and ignition timing, fuel supply etc, use a shorter acceleration time as it is less likely to destroy an engine with lighter load. Once you are more comfortable with the setting you can switch to longer pulls, using a higher gear. Extra long / longer acceleration times would be the equivalent to driving uphill and vice versa.

[husaberg]

Just seen this

Garelli