Renault PU vs Honda PU?

[R_Redding]

I readed somewhere they use sonic waves to get a better picture of the competition's power.

The old YMEC site is usually quoted when the topic of acoustic analysis crops up..

http://www.ymec.com/hp/signal2/carf4.htm

The software itself is hideously expensive,maybe out of date now ,but it does show methodology ...which can be replicated in other software.

Rob

[Brian Coat]

Thanks for posting that - very interesting.

If anyone wants to play about with this ... MATLAB is also a good tool and there are good free/common tools like Sonic Visualiser; Tony; Excel/VB which can just about do the job.

Like many of us, I have eclectic engine tastes and I've also used this method on NHRA Pro Stock runs to see what mean piston speed they shift at (>33.5 m/s)

[Cold Fussion]

Surely the sound analysis is only useful to derive the car velocity/engine rpm, however since the teams already have access to GPS data then surely they wouldn't need to do any audio analysis for this. Reca has a few posts where he derives car velocity using audio analysis.

[NL_Fer]

If they'd measure the first part of straights' acceleration. Just after tyre grip is not an issue and before aero drag kicks in. They can see the cars pure acceleration right?

[hollus]

It is not that easy, NL_Fer.
Tire grip doesn't just stop being limiting in a black and white way, it is a bit more gradual and the driver might or might not nail power application.
Aero drag is there at any speed and it might or might not change with speed following the usual drag equation, certainly vortexes won't.
The attitude of the car will change depending on acceleration and speed, and with it the drag.
The power needed to run the compressor varies with speed.
The rpm level has an effect on power, albeit smallish.
Electric power might be applied in a million different ways, certainly it is not all or nothing.
Engine parameters are changed from lap to lap and even from corner to corner.
The car's weight can only be know to a certain degree of accuracy (by the competition).
And then there is the external wind speed.
Then there is whatever else I am forgetting.
It is not so simple and it takes a lot of data and a lot of corrections to reliable measure the other's power.

[basti313]

Well...natura non facit saltus...so you can have a quite clear picture if you monitor the acceleration in different gears, maybe two straights during a Q3 run. A manufacturer can easily calculate the gear ratio and with their own data they have more or less a number on power vs RPM. The rest is a function of the drag, which is...more or less...still v^2, and the max power.

For me it is not a question if they can do it, but why they should do it. When the V8s were frozen and Renault was complaining about the power deficit, they needed the numbers. But at the moment everybody is just trying to get more power...no matter what the competitor is doing.

[hollus]

Sorry, my bad, I meant to say that what we, fans, can do with the info available would yield a blurry picture of power levels at best (although Reca did do a pretty good job of it in the past). I should have paid more attention of NL_Fer's choice of words.

I guess that teams do regularly go through this type of analysis and they all know each other's power levels to within a few HP. But likely they use a lot more info that a section of a straight to do that. My gut feeling is that aero is everything but a function of v2 these days, with the crazy rake, vortexes everywhere and, some of us suspect, designed to stall surfaces and underfloors.
In any case, I do believe you when you say that they know each other's gear ratios

[Cold Fussion]

Surely the way the teams do it is they would take the GPS data and using their simulation models they would continuously alter the variables until the data fit. Even if downforce and drag isn't exactly v^2, it should at least be consistent so with a large amount of cornering data they will eventually be able to build up a downforce vs speed map.

For an outsider like us, we could only realistically use the qualifying laps since tyre wear will continuously skew the picture and we can only infer it's affects if we know the rest of the variables.

[PlatinumZealot]

Drag might have other effects on the air as the car punches through it.
A higher drag car has a more turbulent wake. Maybe this turbulence can be measured by sound too?

The Exhaust gas temperature could also be analyzed against the other readings too. Colder temperatures could mean better energy usage inside the cylinder for a given GPS+engine rpm+turbulence reading??

[NL_Fer]

I still think about the driver, exiting a corner, gradually pressing his throttle until it's floored. If we look at the accelaration graph, accelaration must be increasing, reaching a peak when full throttle is reached. Then with increasing speed, drag comes in to play. But the peak of acceleration, when full throttle is pressed and speed is still low, can be measured.

Weight during qualifying is just a few kg above the minimum.

Sure teams must have nice models, but some things are not that complex to figure out.

[PlatinumZealot]

That is an excellent point. Measuring acceleration before aerodynamic effects get increasingly significant is a clever idea. There are less variables to deal with. Clever man.

[gruntguru]

Problem is, these cars are traction limited up to a very high speed (150 kph seems to ring a bell for me) and aerodynamic drag is definitely a major factor by then.

Aero drag can be calculated by looking at the acceleration at two different (non traction limited) speeds and calculating the "acceleration power" required at each. The difference is the increase in "drag power" which has a V^3 function.

[Cold Fussion]

At Spa, the Mercs were traction limited to what looks like 170-180 km/h, so you can't just ignore drag since it will be significant at 200 km/h.

http://www.dailymotion.com/video/x33udx9

Even if you say there is some lag in the graphics, it is at-least 150 km/h.

[hollus]

Juzh just brought an awesome post to the table in the 1.6L formula thread:
http://www.somersf1.co.uk/2015/11/power ... right.html
That settles how teams measure each other's performance. Triangulating changes in car attitude from the position of white lines in onboard videos is a bit more sofisticated than I had in mind! And even then:

Drag and horsepower are possible to distinguish but not perfectly...

And two more quotes regarding Honda in particular:

For example, when the Brawn team had to buy engines for 2009, they changed to a more powerful unit which did their championship hopes no harm at all.

...at BAR we were always told the car had too much drag. Later we learned, when the team changed engines, that there was a significant power deficit.

On behalf of Honda: Auch!

[NL_Fer]

Weren't Button and Barichello raving about the Merc pu. Praising it's power delevery and drivability, compared to Honda.