Engine Capacity

BarryMachine · Apr 25, 2012

Bunyip said:
You,re a funny fellow. When things go over my head, I keep quiet and hope nobody notices.

You, you want to advertise the fact, and then , just when some have forgotten, you need to emphasise it again.

Humour is a valuable contribution to any endeavour ...... well apart from still births .... Johnny should get credit for the humour! God knows Valentino has stopped being the clown, so we need someone!

Got any humour involving eggs and chickens Johhny ?

mylexicon · Apr 25, 2012

BarryMachine said:
Just out of interest, what version of Audacity are you guys using?

I have stuck too a version 1.3 Beta cos everything I got after that had a limit of about 1 minute for any processing of the waveforms. Not that this task needs 1 minute, I guess. But in the past I went ahead and processed a bucketload of stuff then burned all the waveforms to what I thought was going to be a usual full cd, instead I got a CD full of 1 minute cuts

That was when they went 1.4 so as I said I have stuck with 1.3 ( before they got all bigheaded and uppity and were happy to freely spread their good work around

v1.3.14

povol · Apr 25, 2012

Barry, Geo, Lex, impressive stuff, but now Lex. what do you think is the secret rev limit for WSBK

gui22a · Apr 25, 2012

Geonerd said:
Low-mid 16s are the most I've seen from the 1000cc Honda.

The few brief clips I found from the race might suggest that Rossi's Duc was dialed back somewhat. At the time when the samples were taken, he was all alone on the track with little hope of improving. He may well have decided to drop the thing into put-put mode.

It's a bit odd because these engines usually rev significantly higher. I think mylexicon measurements are a bit more accurate, but maybe I'm missing something.

povol · Apr 25, 2012

OK you big brained fuckers, If Ducati chose to go with 916-930, was it because it was easier and cheaper, or did they do it because they didnt think they could make it work with 1000cc's and fuel. If its a fuel consideration, will they be facing a different set of problems if they come with a new larger capacity engine.

gui22a · Apr 25, 2012

povol said:
OK you big brained fuckers, If Ducati chose to go with 916-930, was it because it was easier and cheaper, or did they do it because they didnt think they could make it work with 1000cc's and fuel. If its a fuel consideration, will they be facing a different set of problems if they come with a new larger capacity engine.

I think their true 1000cc engine is in development stage and the current one is just a stopgap. Maybe it was safer to go for a 930cc until the true 1000cc is ready. There are rumors about a lighter, tighter V new motor coming after Estoril.

mylexicon · Apr 25, 2012

gui22a said:
It's a bit odd because these engines usually rev significantly higher. I think mylexicon measurements are a bit more accurate, but maybe I'm missing something.

I tested a clip of the 800s to see how accurate Geonerd's method was compared to official onscreen data. Youtube says the footage was 2011, but the onscreen graphics are the 2010-spec, I believe.

The observed 16,XXX rev ceilings are consistent with an 81 x 48.5mm engine. Ducati revs higher b/c it has less stroke, but peak hp is the same.

povol · Apr 25, 2012

mylexicon said:
I tested a clip of the 800s to see how accurate Geonerd's method was compared to official onscreen data. Youtube says the footage was 2011, but the onscreen graphics are the 2010-spec, I believe.

The observed 16,XXX rev ceilings are consistent with an 81 x 48.5mm engine. Ducati revs higher b/c it has less stroke, but peak hp is the same.

Isnt low end torque almost always preferable in racing if hp is the same. I just cant figure out why Ducati went in that direction if in fact they did.

Geonerd · Apr 25, 2012

BarryMachine said:
Just out of interest, what version of Audacity are you guys using?

I have stuck too a version 1.3 Beta cos everything I got after that had a limit of about 1 minute for any processing of the waveforms. Not that this task needs 1 minute, I guess. But in the past I went ahead and processed a bucketload of stuff then burned all the waveforms to what I thought was going to be a usual full cd, instead I got a CD full of 1 minute cuts

That was when they went 1.4 so as I said I have stuck with 1.3 ( before they got all bigheaded and uppity and were happy to freely spread their good work around

The Windoze version is v2.0.0

Available from http://sourceforge.net/projects/audacity/files/audacity/2.0.0/

It looks like you Mac people get the same revision.

Pretty sure this is open source and 100% functional.

beefsupreme · Apr 25, 2012

Krop: I told you that you and the journos should call these bikes "81mm bore" bikes. That's not as evocative as "1000cc", but as I suspected last year, a lot more accurate.

Hopefully in a couple of years we can just say Moto1 and leave it at that.

Geonerd · Apr 25, 2012

gui22a said:
I think their true 1000cc engine is in development stage and the current one is just a stopgap. Maybe it was safer to go for a 930cc until the true 1000cc is ready. There are rumors about a lighter, tighter V new motor coming after Estoril.

Is the new ~1000cc engine part of their master plan, or a reaction to the demands of a certain grumpy-pants Italian?

Given that the bikes are either traction or wheelie limited for much of the lap, perhaps they thought 9xx would be plenty?

I tend to agree with Pov's notion that a smaller engine might produce better fuel economy at less than max power, where 90% of the race occurs. And when they need more oomph, just rev the .... out of it.

Krop's Quest shall be to corner Preziozi, a random mechanic, even one of the riders - anyone who will talk - and get answers!

Geonerd · Apr 25, 2012

mylexicon said:
This log frequency analysis appears to be hilariously accurate, and about 100 times easier than any wave period analysis I've ever done. These are not cherry-picked results either. I chose 6 pieces of quality footage, tested all 6 of them, and observed margin of error around 1%. I think it's safe to say that the Ducati is a 930cc or slightly less based upon the 17,500rpm, but here is an interesting twist in the plot:

Assuming mean piston velocity of 26m/s Ducati would need a stroke of 44.5mm to achieve the rev ranges we observed. What displacement is 81mm x 44.5mm? 916cc

I've seen that number somewhere before. Sounds like something Ducati would do, make the GP bike a 916 for a very superstitious rider.

Yea, I wish I'd tried Audacity earlier. The snap-to-peak is so much quicker and easier than hand analysis of the waveform itself. Cool Edit gets the same results, but at 5x the work. CE's frequency plot analysis shows only the strongest peak; if there's an odd harmonic, babbling commentator, etc. that is producing a signal stronger than the engine, you're screwed.

Your 916cc guess makes for a 'cute' theory. Hey, why not?

Jumkie · Apr 25, 2012

Two thoughts:

Ducati 9?? near all speed charts.

Ducati next engine and electronics will start from scratch...again.

gui22a · Apr 25, 2012

mylexicon said:
I tested a clip of the 800s to see how accurate Geonerd's method was compared to official onscreen data. Youtube says the footage was 2011, but the onscreen graphics are the 2010-spec, I believe.

The observed 16,XXX rev ceilings are consistent with an 81 x 48.5mm engine. Ducati revs higher b/c it has less stroke, but peak hp is the same.

The onscreen data I recall (those numbers showed during onboard footage) showed screamer Ducati reving as high as 19k, but I don't know how much truth is in there. After that, when they went to the big bang, it showed reving aha 18k. I think our audio measurements are a bit masqueraded by an unknown factor.

Geonerd said:
Is the new ~1000cc engine part of their master plan, or a reaction to the demands of a certain grumpy-pants Italian?

Given that the bikes are either traction or wheelie limited for much of the lap, perhaps they thought 9xx would be plenty?

I tend to agree with Pov's notion that a smaller engine might produce better fuel economy at less than max power, where 90% of the race occurs. And when they need more oomph, just rev the .... out of it.

Krop's Quest shall be to corner Preziozi, a random mechanic, even one of the riders - anyone who will talk - and get answers!

I'm sure it's a reaction, pure reaction, but I imagine it was indeed planned last year. They might go now to a low rev, more torque, instead of peak HP.

I would love to see Krop interviewing Prezi, but the man lives hidden from the press.

mylexicon · Apr 25, 2012

Geonerd said:
Yea, I wish I'd tried Audacity earlier. The snap-to-peak is so much quicker and easier than hand analysis of the waveform itself. Cool Edit gets the same results, but at 5x the work. CE's frequency plot analysis shows only the strongest peak; if there's an odd harmonic, babbling commentator, etc. that is producing a signal stronger than the engine, you're screwed.

Your 916cc guess makes for a 'cute' theory. Hey, why not?

The 916 theory isn't based on much. Mean piston velocity is not accurate enough to back into a displacement calculation with any degree of certainty, but when I saw the number, I had to post it. Ducati seem like the kind of people who would build a 916cc GP bike b/c it's in their DNA (or whatever).

Regarding the frequency analysis, I'm starting to realize the quality of the recording is everything. Dorna mics work really well, but I've been working on some other onboard vids with very inconsistent results. I'm analyzing an Alstare WSBK video which returns rev ceilings of 11,000rpm or 14,400rpm. Neither rev ceiling is accurate for that bike, and the recording has so much wind noise and reverb than peaks are difficult to identify.

I think that was the problem with the 10:10 sample at Indy in my last post. The wall and grandstand were reflecting sound everywhere, and wreaking havoc on the sound recording.

mylexicon · Apr 25, 2012

gui22a said:
The onscreen data I recall (those numbers showed during onboard footage) showed screamer Ducati reving as high as 19k, but I don't know how much truth is in there. After that, when they went to the big bang, it showed reving aha 18k. I think our audio measurements are a bit masquerade by an unknown factor.

I'm sure the GP7 probably did rev to 19,000+

The 800s changed when the reliability rules were introduced. The engines were detuned, de-revved (slightly), and cooled down with bigger vents and radiators.

I don't think the numbers are off by much at all. Geo's manual calculations of the Dorna footage matched the stroke-calculated-values. When I used the Audicity frequency analyzer to check our readings against an official Dorna rev limiter, error was 1%-2%. For high quality recordings, I think the readings are very accurate.

mylexicon · Apr 25, 2012

I don't want to throw a wet blanket on this project, but I have some concerns now. I realized that the control data was not really control data b/c I didn't test any Ducati samples. I found some Ducati onboard footage from the 800cc era, and the frequency analysis has not reflected the onscreen data. In fact, it's has been almost 1000rpm too high at every sample.

http://www.youtube.com/watch?v=0RuBNdIVceQ

Sampled clip at 6:41.8 seconds (size 8192) and observed 151hz (18,120rpm) compared to 17,072rpm on screen.

Sampled clip at 5:41.3 seconds (size 8192) and observed 153hz (18,360rpm) compared to 17,471rpm on screen.

Sampled clip at 7:25.3 seconds (size 8192) and observed 155hz (18,600rpm) compared to 17,628rpm on screen.

Sampled clip at 8:29.6 seconds (size 8192) and observed 157hz (18,840rpm) compared to 17,780rpm on screen.

The analyzer works great for Yamaha and Honda, all numbers mesh, match, and make sense. However, the Ducati appears to have an engine note that causes the analyzer to estimate revs about 1000rpm too high (according to onscreen graphics). Assuming Ducati are using the same big-bang firing order, it appears as though the Duc is turning about 16,300rpm-16,500rpm. If the rev ceiling is low-to-mid 16's, the Ducati is a 1000cc motorcycle. Intuitively speaking, that was the only displacement that made much sense, so I'm not surprised at the results, though I am disappointed that we may not have any interesting information. Good story to tell, though.

Check my work. I hope nothing has gone to press just yet. I'm going to continue looking for Ducati samples.

Jumkie · Apr 25, 2012

I doubt Kropo would publish during a race weekend, but u might want to PM him ur doubts just to be safe.

Geonerd · Apr 25, 2012

Look at the Duc waveform. The peak-to-peak indicates 17k

mylexicon said:
I don't want to throw a wet blanket on this project, but I have some concerns now. I realized that the control data was not really control data b/c I didn't test any Ducati samples. I found some Ducati onboard footage from the 800cc era, and the frequency analysis has not reflected the onscreen data. In fact, it's has been almost 1000rpm too high at every sample.

http://www.youtube.c...h?v=0RuBNdIVceQ

Sampled clip at 6:41.8 seconds (size 8192) and observed 151hz (18,120rpm) compared to 17,072rpm on screen.

Sampled clip at 5:41.3 seconds (size 8192) and observed 153hz (18,360rpm) compared to 17,471rpm on screen.

Sampled clip at 7:25.3 seconds (size 8192) and observed 155hz (18,600rpm) compared to 17,628rpm on screen.

Sampled clip at 8:29.6 seconds (size 8192) and observed 157hz (18,840rpm) compared to 17,780rpm on screen.

The analyzer works great for Yamaha and Honda, all numbers mesh, match, and make sense. However, the Ducati appears to have an engine note that causes the analyzer to estimate revs about 1000rpm too high (according to onscreen graphics). Assuming Ducati are using the same big-bang firing order, it appears as though the Duc is turning about 16,300rpm-16,500rpm. If the rev ceiling is low-to-mid 16's, the Ducati is a 1000cc motorcycle. Intuitively speaking, that was the only displacement that made much sense, so I'm not surprised at the results, though I am disappointed that we may not have any interesting information. Good story to tell, though.

Check my work. I hope nothing has gone to press just yet. I'm going to continue looking for Ducati samples.

Let's not throw the baby in the dumpster just yet!

I can't think of a good reason the revs wound be a constant 1000PRM too high. If there was a problem, you'd expect a proportional scale factor issue, not a static offset. Curious.

I looked at the last sample, at 8.29.6 and got this:

13485:8296Duc.jpg]

Manual analysis backs up your frequency sniffer - the spreadsheet says 18,866 RPM.

Either the video has been sped up, or the Dorna RPM-O-Meter is wacky. I don't yet see a proven problem with either the manual analysis or spectrum-peak-HZ methods.

Run the Audacity sniffer on the attached WAV file, and please manually look at the peak-peak time interval.

Geonerd · Apr 25, 2012

P.S.

Laptop booting ....

(I haven't yet installed Audacity on the desktop - am trying to keep it clutter-free for as long as possible.)

OK.

This sample in the previous post is short, so the peak HZ jumps about a little as you change the FFT size, but I'm seeing 153~156Hz, which matches the above manual calculations above as well as can be expected.

You do bring up a valid point! Some of the engines with irregular firing orders produce odd harmonics that may mask the signal we're looking for. Most all of the numbers I've posted in this thread were generated with manual waveform measurement.

For now, I'll stand by my work. The math is correct, but we are obviously at the mercy of the videos being used as data. If they are being played back at anything other than normal time, we're borked.

For the moment, I'm inclined to disbelieve the Dorna tachometer.

Keep digging!

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