Engine Capacity

mylexicon · Apr 28, 2012

lil red rocket pilot said:
OMG! You guys screw with my head! I have no idea what your on about or how your getting your readings/outcomes but I find it so interesting reading what your findings are. Even if I don't understand them!

WTF???

It's relatively simple, though it looks complicated. A wave file makes 44,100 samples per second, same as compact disc sampling rates. Using a sound analyzing/editing program, we can see the amplitude waves generated by the engine, and b/c the sampling rate is so high, we can literally zoom in to look at the amplitude waves for the individual combustion strokes. By measuring the number of combustion cycles over a period of time (usually a few tenths of a second), engine rpm can be determined. We are "listening" (visually with the software) for the explosion per minute b/c it is directly related to the crankshaft revolutions per minute.

In this case we are using an analysis function to help us. It displays the amplitude for each frequency, and by examining the frequency rates we believe to be relevant for MotoGP engines (130-150hz for the new engines) we can determine rpm. For example, we select a piece of the engine noise just before the rider shifts. The frequency analyzer creates a file with a bunch of peaks and valleys for each frequency. We look at the 130hz to 150hz area, and if we see a distinct amplitude peak, we can determine the engine's rpm. For an onboard sound recording with no additional audio, the loudest noise in the 130hz to 150hz is going to be engine combustion. Therefore, the amplitude peak represents engine frequency which represents engine rpm. It isn't fool proof, but it works quite well.

Geonerd · Apr 28, 2012

Aprilia Engine Life.

I just realized that WSBK does have an engine life regulation this year. (Right?)

According to http://www.worldsbk.com/images/stories/documents/Superbike Commission, 27 October.pdf

the teams are allowed 8 engines per year. This is actually LESS than the 12 engines allowed in MotoGP.

The 14,8xx readings we saw on RdP's bike are, according to Krop, right in line with the factory Aprilia WSBK rev limit.

Earlier in this thread, we expressed some surprise that the CRT engine was spinning so quickly. I think we had collectively forgotten the WSBK engine limit and assumed the CRT had to be 'something special' to run a greater distance (wrong!) at the same RPM.

mylexicon · Apr 28, 2012

Geonerd said:
Aprilia Engine Life.

I just realized that WSBK does have an engine life regulation this year. (Right?)

According to http://www.worldsbk....7%20October.pdf

the teams are allowed 8 engines per year. This is actually LESS than the 12 engines allowed in MotoGP.

The 14,8xx readings we saw on RdP's bike are, according to Krop, right in line with the factory Aprilia WSBK rev limit.

Earlier in this thread, we expressed some surprise that the CRT engine was spinning so quickly. I think we had collectively forgotten the WSBK engine limit and assumed the CRT had to be 'something special' to run a greater distance (wrong!) at the same RPM.

That release is 8 engines for Supersport. Easy to change engine rules in WSS b/c all engines are 67mm x 42.5mm I-4s. The SBKC proposed engine limits in WSBK, IIRC, but it probably didn't happen b/c it will throw off the competitiveness of the bikes, and the twins cannot last as long as the fours if they extend service intervals.

If engine life rules are adopted, the homologation and tuning procedures will have to be overhauled. New rules next year so maybe it will happen in 2013.

BarryMachine · Apr 28, 2012

lil red rocket pilot said:
OMG! You guys screw with my head! I have no idea what your on about or how your getting your readings/outcomes but I find it so interesting reading what your findings are. Even if I don't understand them!

WTF???

Techo's!

They are like the guy on the right here:

And when the "penny drops" you can hear the gears clink into place and off they go

Geonerd · Apr 28, 2012

mylexicon said:
That release is 8 engines for Supersport. Easy to change engine rules in WSS b/c all engines are 67mm x 42.5mm I-4s. The SBKC proposed engine limits in WSBK, IIRC, but it probably didn't happen b/c it will throw off the competitiveness of the bikes, and the twins cannot last as long as the fours if they extend service intervals.

If engine life rules are adopted, the homologation and tuning procedures will have to be overhauled. New rules next year so maybe it will happen in 2013.

OK, thanks.

So 14,8xx from a CRT engine that needs to last ~1.5 race weekends IS, perhaps, indicative of 'special sauce.'

lil red rocket pilot · Apr 29, 2012

mylexicon said:
It's relatively simple, though it looks complicated. A wave file makes 44,100 samples per second, same as compact disc sampling rates. Using a sound analyzing/editing program, we can see the amplitude waves generated by the engine, and b/c the sampling rate is so high, we can literally zoom in to look at the amplitude waves for the individual combustion strokes. By measuring the number of combustion cycles over a period of time (usually a few tenths of a second), engine rpm can be determined. We are "listening" (visually with the software) for the explosion per minute b/c it is directly related to the crankshaft revolutions per minute.

In this case we are using an analysis function to help us. It displays the amplitude for each frequency, and by examining the frequency rates we believe to be relevant for MotoGP engines (130-150hz for the new engines) we can determine rpm. For example, we select a piece of the engine noise just before the rider shifts. The frequency analyzer creates a file with a bunch of peaks and valleys for each frequency. We look at the 130hz to 150hz area, and if we see a distinct amplitude peak, we can determine the engine's rpm. For an onboard sound recording with no additional audio, the loudest noise in the 130hz to 150hz is going to be engine combustion. Therefore, the amplitude peak represents engine frequency which represents engine rpm. It isn't fool proof, but it works quite well.

Cheers Lex,

I can sort of get my head round it now

Mental Anarchist · Apr 29, 2012

Watching the race, when ever they cut to onboard I was thinking, "wish the bloody commentators would shut up so the guys can get a clean piece of sound for their analysis!"

Jumkie · Apr 29, 2012

Mental Anarchist said:
Watching the race, when ever they cut to onboard I was thinking, "wish the bloody commentators would shut up so the guys can get a clean piece of sound for their analysis!"

had same thought. How sick are we?

JohnnyKnockdown · Apr 29, 2012

Mental Anarchist said:
Watching the race, when ever they cut to onboard I was thinking, "wish the bloody commentators would shut up so the guys can get a clean piece of sound for their analysis!"

Was thinking......keep talking so we can put a fork in that ....... idiotic dorkfest thread.

mylexicon · Apr 29, 2012

Mental Anarchist said:
Watching the race, when ever they cut to onboard I was thinking, "wish the bloody commentators would shut up so the guys can get a clean piece of sound for their analysis!"

It would be nice to have rev numbers for a different round, but Geo's work is probably enough to make a conclusion about the capacity of the bikes.

I wish we could replicate Dorna's data for the Ducati, but we don't have an archive with all of the 2011 footage nor do we have the time to go in search of clean onbaord footage. I think we have gathered as much info as we are going to get.

I would like to retract my 916cc theory. Not that it isn't possible, but Honda and Yamaha appear to be achieving 26.4m/s mean piston velocity. I think those values are believable b/c MotoGP is fuel limited so the engine departments have been friction plating everything and redesigning engine bearings and the rest. If Ducati can make 26.4m/s, they can reach 17,500rpm with a 930cc (45mm stroke) engine.

Geonerd · Apr 29, 2012

Mental Anarchist said:
Watching the race, when ever they cut to onboard I was thinking, "wish the bloody commentators would shut up so the guys can get a clean piece of sound for their analysis!"

Thanks for the thought!

No kidding! All during the race I was alternating between cursing the "F-ing ..... director" and the "babbling morons" for, respectively, either cutting away from an onboard before the rider reached a good zing, or drowning out the rare engine sample with their drivel.

I'm REALLY hoping Dorna continue this year's 'habit' of releasing an onboard version of the race, as they did for Qatar. While that video didn't have much Ducati footage, there was enough to broadly support the working 'Duc=~930cc' theory.

I want to offer a public "HURRAH!"

to Mr. Tequila for offering to share his MotoGP site password so that I may search for more onboard vids.

Keshav · Apr 29, 2012

Geonerd said:
Thanks for the thought!

No kidding! All during the race I was alternating between cursing the "F-ing ..... director" and the "babbling morons" for, respectively, either cutting away from an onboard before the rider reached a good zing, or drowning out the rare engine sample with their drivel.

I'm REALLY hoping Dorna continue this year's 'habit' of releasing an onboard version of the race, as they did for Qatar. While that video didn't have much Ducati footage, there was enough to broadly support the working 'Duc=~930cc' theory.

I want to offer a public "HURRAH!"

to Jumkie for offering to share his MotoGP site password so that I may search for more onboard vids.

You might not want to broadcast that here as it is clear that Dorna does monitor this site. Really. Tho I doubt he uses his nickname on his account.

Geonerd · Apr 29, 2012

Keshav said:
You might not want to broadcast that here as it is clear that Dorna does monitor this site. Really. Tho I doubt he uses his nickname on his account.

Prolly right - better go back and edit your own post!

JohnnyKnockdown · Apr 29, 2012

Geonerd said:
Thanks for the thought!

No kidding! All during the race I was alternating between cursing the "F-ing ..... director" and the "babbling morons" for, respectively, either cutting away from an onboard before the rider reached a good zing, or drowning out the rare engine sample with their

Your the ....... moron

Those babbling idiots happen to be the best in the business and are actually doing their job which is to commentate.

That director just showed us the longest onboard shot in GP history, something that everyone watching wants more of and he's a ....... ..... because you couldnt collect your pointless junk science data.

Mick D · Apr 29, 2012

JohnnyKnockdown said:
Those babbling idiots happen to be the best in the business...

What feed are you getting? I often turn the babbling idiots off and watch the feed without sound 'cause their inane ramblings annoy me so!

Geonerd · Apr 29, 2012

JK, I don't mind the Eurosport or BBC commentary, but have never liked it when they talk over the onboard engine sounds. When I'm trying to record a peak rpm sound, they become an outright irritant. Is that such a difficult concept?

Kropotkin · Apr 30, 2012

Geonerd said:
.

JEREZ

Youtube MotoGP just posted 3 new onboard vids from Jerez.

It looks like one of the practice sessions, with a rather damp track.

Audio level is low, and some of the samples are a big dodgy. The Duc is actually the easiest to hand analyze; it has a nice, easy to spot, repeating pattern. The other two are more chaotic and I occasionally found myself leaning on the spectrum sniffer to determine likely wave pattern periods. Once identified, these weaker patterns are, IMO, good enough to verify the spectrum values. Still, there is a bit of circular logic at work with the Yam and Honda numbers.

Duc RPM: 16,680 16,560 16,540 16,800

Yam RPM: 13,800 14,100 14,600 15,500 14,200 15,600

Honda RPM: 16,300 15,700 15,900 16,100

A word of warning from Ramon Forcada: They use funny gearing at Jerez because it is rather tight. So you rarely rev out completely. Hector Barbera apparently told one of the journos that he saw "about 17,000" on the rev counter.

Geonerd · Apr 30, 2012

Kropotkin said:
A word of warning from Ramon Forcada: They use funny gearing at Jerez because it is rather tight. So you rarely rev out completely. Hector Barbera apparently told one of the journos that he saw "about 17,000" on the rev counter.

Yea. Jerez - particularly in the wet - is hardly an ideal dyno-track.

What does the rumo(u)r mill say about the engine in Barbera's Ducati? Do the satellite bikes get a different, presumably 1000cc engine?

Geonerd · Apr 30, 2012

I think I've found a way to bypass the babbling fools.

With the right tweaks, the spectrogram view can show the characteristic engine signal even when the commentary is underway. When zoomed in along the frequency axis it shows a narrow line, only ~2hz wide, that should be able to accurately indicate RPM, even in the midst of assorted noise.

More later....

mylexicon · Apr 30, 2012

Geonerd said:
I think I've found a way to bypass the babbling fools.

With the right tweaks, the spectrogram view can show the characteristic engine signal even when the commentary is underway. When zoomed in along the frequency axis it shows a narrow line, only ~2hz wide, that should be able to accurately indicate RPM, even in the midst of assorted noise.

More later....

If you've figured out how to do it consistently, let me know. I played around with the 2011 Brno clip for about an hour before it began yielding relevant information. I couldn't figure out how to get rid of the noise consistently.

Engine Capacity

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