ESE's works engine tuner

[TZ350]

I get fed up with always that same BS of 'measuring' losses and then adding them, so spoiling a good measurement.

Thanks, I am a bit new to this EngMod2T simulation and dyno lark and have been trying to figure out how to use them both constructivly.

The graphing of a real world measurement with "correction" was to see how my efforts were stacking up against the simulation, not very well as it turned out and I have to look for the reasons.

[TZ350]

Tonights dyno effort ....



OK so now we have joined the 30RWHP Club



Red Line is a 150mj and the Blue Line a 120, everything else was the same. I am not sure what is going on here but it looks like the Blue line is lean in the lower rpm range, maybe need to look into a power jet arrangement.



Blue Line my 30hp compaired to Speedpros Red Line. Mine is short on power spread compaired to Speedpros but if I can get the bottom end back then it should be a fairly good ride.

Power Jet and a bit of a fiddle with the ignition next.

[Yow Ling]

Hi Frits, just for the record could you confirm the intention of the FOS cylinder is for non competition purposes, of course you can change your mind later. It may help clear a path caused by onerous rules in the future sometime

Thanks
yow ling

[Frits Overmars]

... what i think TZ is trying to do is get the sim to match the Dyno. To do that he needs to acturatly establish the crank HP. He want to get it as close as pos.

I can understand that. What I would do: assume a 5 % power loss for every set of gears, for the chain, and for the deformation of the tire on the drum.So what you would measure, is 0.95 (primary drive) * 0.95 (gearbox) * 0.95 (chain) * 0.95 (tire) * crankshaft HP = 0.8145 * crankshaft HP. Or, the other way around: crankshaft HP = drum HP / 0.8145.
Granted, this is not exact, but it's an honest approximation. In any case it is way better than calculating with coast-down losses that you know are not representative of the real losses.
hopefully you noted I spoke of drum HP. That is not the same as rear wheel HP. About 5% of rear wheel HP is lost between tire and drum and what really accelerates the drum, is drum HP. And something which you may not know: Dynojet-readings are already compensated for this loss, and then some. We once did a comparative test at Ten Kate's (umpteen times Supersport world champion, just around the corner from my house). It turned out that the Dynojet is 11% optimistic.

[husaberg]

I can understand that. What I would do: assume a 5 % power loss for every set of gears, for the chain, and for the deformation of the tire on the drum.So what you would measure, is 0.95 (primary drive) * 0.95 (gearbox) * 0.95 (chain) * 0.95 (tire) * crankshaft HP = 0.8145 * crankshaft HP. Or, the other way around: crankshaft HP = drum HP / 0.8145.
Granted, this is not exact, but it's an honest approximation. In any case it is way better than calculating with coast-down losses that you know are not representative of the real losses.
hopefully you noted I spoke of drum HP. That is not the same as rear wheel HP. About 5% of rear wheel HP is lost between tire and drum and what really accelerates the drum, is drum HP. And something which you may not know: Dynojet-readings are already compensated for this loss, and then some. We once did a comparative test at Ten Kate's (umpteen times Supersport world champion, just around the corner from my house). It turned out that the Dynojet is 11% optimistic.

Thanks Frits I had been reading about them the other day on Burgerman he is a bit scathing of them as well.
http://www.dynamometer-info.co.uk/po...ywheel-BHP.htm
Plus another i was on today said just what you said. I note the Bosche Inertia Dynos has two drums and the main drum is twice the weight of the dyno jet.

At the end of the day any time i guess if you estimate one part it could throw out all the accurate work made before hand.

But then again he could always as you say test the hp at the crank and then the output on the Dynojet.

[TZ350]

We once did a comparative test at Ten Kate's (umpteen times Supersport world champion, just around the corner from my house). It turned out that the Dynojet is 11% optimistic.

So, are you saying that I don't need to mark up our DynoJet reading to compare it to the simulation? That could be depressing.

[Frits Overmars]

So, are you saying that I don't need to mark up our DynoJet reading to compare it to the simulation? That could be depressing.

Life's a bitch,TZ. But here is some mathematical Prozac for you: drum HP = Dynojet HP / 1.11 and crankshaft HP = drum HP / 0.8145. So crankshaft HP = 1.106 * Dynojet HP. And don't bother about those decimals; after all it is an approximation. So it would be safe to say that crankshaft HP = 1.1 * Dynojet HP.

[TZ350]

... it is an approximation. So it would be safe to say that crankshaft HP = 1.1 * Dynojet HP.

Great Thanks,

Dynojet HP = 30

1.1 * 30 = 33

33 crankshaft HP (approximatly)

Ohhh well, its not quite the 36+ of the simulation with the RS pipe but there are a few more things to try yet....

[Frits Overmars]

Were other carbs tried or were the Dellottos better suited to the Disk valve engine or were there other considerations. Such as their Italianess or sponsorship (I see there is a sponsor sticker on the fairing) or just as case of sticking with what the team was familiar with.
One last thing was that you mentioned in the pit lane thread about the electric power-jet when did Aprilia implement this?. You also mentioned about a car solenoid or stepper motor. A Fiat Uno one why did you go to a Keihin part.

When Jan Thiel was developing the Derbi DRVE (now known as the Aprilia RSA125) it turned out that with the engine in the frame the carb was tilted too far forward.
Jan then tried a Keihin that could cope better with the tilt-angle. But there was a contract with Dellorto...
I do not recall the exact date that the electronic power jet was first used. Must have been after Witteveen left the building at the end of 2004 (when he realised that he would be losing Jan Thiel to then-rival Derbi) because Witteveen was always opposed to the powerjet even though Jan Thiel had been asking for it for ages.
The first powerjet version had a stepper motor borrowed from a Fiat Uno where it used to govern idle rpm. In the Dellorto it operated a needle valve.
It was later superseded by a Keihin solenoid valve. Keihin just used it as an open/close valve but with some electronics of their own Aprilia turned it into a pulsating valve (13 Hz). The picture shows those Keihin valves on Simoncelli's Gilera RSA250.

[Yow Ling]

So how much mass do we need in a drum for an inertial dyno for up to say 40hp engines?
would a couple of Petter diesel flywheels do the job ?

[wobbly]

You have to be careful when using the sim as a predictor of actual power.
You see even using the scavenging model of a RS125 isnt strictly accurate, as the GP has a huge A port and small B,C.
The axial up angles may be the same but I doubt the scavenging and or trapping efficiency are equal.
If you reduce the combustion efficiency a few % then you will get alot closer to reality.

The other issue is that to do what you are trying to do properly, you seriously need to plot egt against rpm on the dyno..
If you get such a huge difference in power by changing the main, then it was well wrong in the first place.
And yes, an electronic powerjet will add at leat 800 rpm of free power to that graph, if switched correctly with the right jet ratios - blowing Speedpro of the planet, unless of course he does what I told him.

[Frits Overmars]

when are the FOS cylinders going to be available in a 50mm bore?

That may be quite a while. But the idea is so simple; build one yourself. In fact that would be much easier than building a conventional cylinder. In a conventional jug you need five differently-shaped transfer ducts; in my system you need only one shape, six times. And you need one bridged exhaust duct, twice. Don't you love symmetry?

Yes i do love the idea so logical and elegant in afterthought for me, Genius in forethought for you. But I don't believe NZ has a foundry capable to doing that now, or that would be willing to do it as a one off.

What is wrong with a hand job? Several of my acquaintances are carving such a cylinder out of a lump of aluminium. If they can do it, so can you.

[Kickaha]

.But
I don't believe NZ has a foundry capable to doing that now, or that would be willing to do it as a one off.
.

A friend of mine made a pair of cylinders to take a TZ250 V twin out to 350 I have seen the cylinders but can't remember how they made them, I will find out

[Grumph]

A friend of mine made a pair of cylinders to take a TZ250 V twin out to 350 I have seen the cylinders but can't remember how they made them, I will find out

If it's the one i know about, the barrels were bored and linered. these days you'd bore them and re nicasil them. I built the pipes for that one.

There used to be a few foundries here of high enough quality. Not many remain. Talking to Mo Haley today the subject of foundries came up and he recommends the guy in Nelson who does TT Industries gearbox shells. Best work he's seen in NZ.

[husaberg]

What is wrong with a hand job? Several of my acquaintances are carving such a cylinder out of a lump of aluminium. If they can do it, so can you.

WOW

A little bit flasher than i imagined love the curves.
refresh my memory what the estimated output was per liter and rev range.

Although i think your aquantances are a little more skilled than i am.

Remember i am the guy who put a dellorto slide in backwards on a mineralli once.
I am still messing around with cardboard a protractor vernier a paper cup a piece of pvc and a bit of clay for the offset question you made me try and solve myself.
Getting some er...interesting results. Bloody geometry who would of thought it could be useful in real life.