I have invited him to my dyno, only a minor daytrip away.Originally Posted by Sketchy_Racer
Hardcore Biker
I have invited him to my dyno, only a minor daytrip away.
No8 Wire Extraordinaire
Watching your updates with interest. Be freat to see it when it makes it to the track. Ruapuna short track would be fun.
Don't you look at my accountant.
He's the only one I've got.
Forum whore
Here at Team ESE we run a Dynojet.
Richban and Team GPR built their own dyno and wanted to check it against ours by running up Richbans FXR150 on it.
I think Richbans FXR was the first 4 Stroke Bucket to crack 25rwhp and they wanted to verify it on a known Dyno.
There are a number of home made dynos around. The impression I got, was that the people who were clever enough to make their own were also clever enough to calibrate them to display real horse power. Doing anything else made no sense.
A metric horsepower is the power required to lift a mass of 75 kilograms one meter high in one second, which is equivalent to approximately 735.5 watts. This is different from the imperial or mechanical horsepower, which is equivalent to about 746 watts. Metric horsepower is also known as a PS (Pferdestärke), CV (cheval-vapeur), or other variations. That basically read much the same as DIN.
Forum whore
In the pursuit of ever more hp I made a triple exhaust port cylinder. Speedpro helped me with this with some clever milling of the eyebrows.
Initial dyno tests showed a big hole at the rpm where pipe reversion is out of sink. I became suspicious that the cutaways on the side of the Suzuki piston were allowing the pipe to interfere with the crankcase.
So I fitted a Wiseco piston that did not have this problem.
New Wiseco, red line. So, Suzuki piston side cutaways were not the problem?????
Blue line, the old single exhaust port cylinder. Also red and blue lines are offset because runs were inadvertently done in different gears. Blue = 5th, Red = 4th.
Observation, the triple exhaust cylinder ran much better, cleaner at 9,500 rpm than the single. 250cc Kawasaki F81.
Will have more of a look next week. Once I get it sorted, then onto the Nitro injection.
Scooter boy
Talking about dyno figures, I had a huge issue or let's say dilemma this year when I bought new dyno software.
In my country Slovenia with 2M people there is not many dynos and 2t tuning-racing scene is mostly me and my 10 friends / schoolmates and we all know eachother. Me and 2 other tuners, so 3 different home made inertia dynos used dynomec software from Finland (https://www.dynomec.com/). My roller had 300kg and 4,8kgm^2 of inertia, other two had around 3,5. We were using this software (Dynomec WT and is not for sale anymore) for 15 years now and it was very simple and could not be more basic as it is.
In these 15 years we got out rear wheel horsepower figures like:
- Tomos D6 50cc pistonport 14hp @14200rpm
- 50cc freetech 23hp @16500rpm (also raced in Hockenheim)
- Tomos 50cc classic bike with bidalot50 and rotary intake 18hp @14500rpm
- Tomos 90cc aircooled '77 pistonport stock bike 9hp @6000rpm (same as claimed from factory)
- Stock aprilia RS125 24hp, later tuned to 30hp
- Cagiva Mito 125 '93, tuned to 33hp
- Yamaha 125 4t 2006 9hp
- Yamaha YZ125 2015 stock 33hp
- Honda RS125 NX4 2003 40hp (two bikes)
So many bikes were measured. We also tested some on both dynos and measurements were the same or like 0,1-0,3hp difference.
Also one of the bikes Honda 250 4t was measured at Akrapovič facility and one of the dynos was checked with that bike (don't ask me about details how measurements were made)
This year I bought new software from DTec (http://dtec.net.au/) as it is major upgrade as EGT, temperatures, data analysis is much better to do, so many options, and price was good.
So I tested one bike and it was measuring 6hp instead of 9hp. Then tested another 3 known bikes and all measurements were lower for a factor of 1.3. I investigated and my old Dynomec had inside some random factor of 1.3 that I was suspicious of since I bought software in 2010.
So I tried to measure power with weight drop, suspended from 3m of height with rope winded around roller and 8x pulley sistem, but measurements were too slow and friction from the rope was not constant (logically) and did not made any conclusions from that.
I also tested electic bike with in wheel motor with nominal power of 1000W, I measured around 850W with new dyno. EM power could be stated-measured on many ways by factory so I also didn't find any answers.
At the end I adjusted inertia, multiplied it by 1.3 and called it a day. Why? So we can communicate with my friends about power we made and what we figured out. I can compare results with my old dyno and customers have bragging rights with same value if they measure at my place or on other dynos. Life is easier that way.
I know dyno is used for comparing between setups, finding small gains etc and hp number is not so important, but still, as an engineer, it doesn't give me piece of mind. And 30% difference is not small. So are all dynos showing too much, all freetech bikes have 18hp instead of 23hp, but how, 18hp was claimed in 1978 by many 50cc like Kreidlers, Tomos etc. Was it all just propaganda?
Any ideas, so I could sleep better?
Does anyone use some of theese softwares, Dynomec and Dtec and has some experience with similar problems?
Pretengineer
The dyno I built also uses Dtec and I have had exactly the same experience as you in regards to measured power outputs against calculated MOI.
That is what I was referring to earlier that I am almost certain that most dyno softwares are adding some level of "correction" that is not user adjustable.
Where I am, dynojet is the most popular commercial dyno around. There are two local to me that I have had bikes on and the outputs are similar. When I set up our Dtec dyno, the power numbers were very low, so I did the same as you and adjusted the MOI to get them as close as I could to the dynojet figures so that, whilst not perfect, there was some level of comparability.
Forum whore
Yup. My FOS dyno software has a UNIT-option that offers the choice between Horsepower an KiloWatt. It caused one user to call desperately: "My engines suddenly produce a lot less power !" He had not noticed that somebody had changed his Horsepower-setting into a kiloWatt-setting.
No8 Wire Extraordinaire
Talking of Metric, quoting US sources results in spelling mistakes.
A Meter measures something. It is not a unit of length.
'Mericans. Don't use the Metric system, but can't let the opportunity slide to spell things differently to the rest of the world.
Don't you look at my accountant.
He's the only one I've got.
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