Wikipedia talk:WikiProject Automobiles/Conventions/Archive 4

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Suggest adding a note like the following to "Power" in WP:CARUNITS.

Beware of "RAC hp", "ALAM hp", "NACC hp", or "SAE hp" values

When checking sources for the power of an automobile or automobile engine from the very early twentieth century, beware of "horsepower" values given with notations such as "RAC", "ALAM", "NACC", or "SAE". (The "SAE" form is particularly misleading, since it may be confused with the later, much more reasonable SAE standards for measuring engine power.) These are not true measured horsepower values at all, or even reasonable theoretical approximations. They are computed using a crude rule-of-thumb formula:

"horsepower" = 0.4 × (number of cylinders) × (cylinder bore in inches)²

which only accounts for the number of cylinders and the cylinder bore, assuming that all engines will have the same mechanical efficiency, mean effective pressure, and limiting piston speed.

These assumptions might have been fairly reasonable for the very first automobiles, but they rapidly grew out of date, and the formula often gave very misleading values for many engines. For example, two related Chevrolet inline-4 engines from 1918 with identical cylinder bores were both rated at "21.7 NACC hp", but one had a longer stroke than the other, and their actual brake horsepower ratings on test were 26 hp and 37 hp. In fact, the issue of NACC horsepower (or similar terms) was confusing enough that inquiries were written to contemporary automobile journals asking about the difference.

Unfortunately, these are often the only "horsepower" values given in some contemporary sources, perhaps because they were often used to determine taxes by national or local governments. To make matters worse, some modern sources have blindly reported these values as actual power ratings. At least one set of sources, the various Standard Catalogs compiled by John Gunnell, compounds the issue by occasionally labeling them as "net hp (NACC)", even though no one actually measured net horsepower in those days. And because these values were calculated rather than measured, they were often reported to one or two decimal places, which might lead some people to believe that these were accurate measurements rather than precise but meaningless calculations.

To sum up, I'd say that if one of these figures is the only power figure you can find, look harder. :) If it's really the only power value you can find, either mark it clearly as a crude rule-of-thumb estimate, or better yet, don't report any value at all.

Caveat editor. :) --Colin Douglas Howell (talk) 00:26, 28 January 2018 (UTC)

Well, .... yes. The critical distinction, surely, is between Tax horsepower - a figure created primarily for the benefit of governments keen to devise and collect new kinds of tax, which needed to be easy to compute objectively, and which tends to turn up in the names given to cars (sometimes "adjusted upwards" by sales departments mindful that few people understood or cared about the maths) - and horse power which really does give an indication of the power reaching the back wheels (or the driveshaft after the engine accessories such as the muffler have been taken off in order to increase the gross power figure). As you say (write), way back when there was some sort of approximate correlation between the two, but by 1914 if not earlier, that correpation began to diminish. Both sets of figures are differently computed according to (1) where you are and (2) when the measurement was quoted. So ... what should we do about it when composing or "improving" a wiki-entry about a car? The important thing, surely, is to include in the text of any entry mentioning horse power clarification of whether the figure quoted is a tax horsepower figure or some kind of bhp. You can then help the interested reader by including a link to an entry on the type of horse power you have in mind.

Further suggestions welcome. Success Charles01 (talk) 09:35, 28 January 2018 (UTC)

Blindspots

Since you raise the subject, you do well to replace OSX's pictures as examplars which people should seek to copy when selecting pictures for illustrating wikipedia entries on cars. OSX uploaded some very good pictures, but he also uploaded a lot of rather mediocre ones. And he never seemed to know which were which. That's my opinion. Should you share it? Not necessarily. But since you clump around inflicting your own opinions - blindspots and all - with regard wikipedia car articles on an industrial scale, perhaps you will not mind if I share my opinion of your blindspots. This picture of a Honda illustrates one of your own frequently inflicted blindspots, and one that you did not, I think, learn from OSX. You seem to be unaware of reflections. Most pictures of cars have reflections. Doesn't automatically make them bad pictures. But a few of them have reflections real bad, and at that point the viewer begins to notice. And to wonder. This picture of a Honda is savagely compromised by the reflections in the paintwork. It is a particular pitfall when you photograph dark coloured cars - especially black ones, but it also works for the richer shades of blue - that are highly polished. On your picture of a Honda, which you are holding out as a "how to do it" picture, there is a bizarre street lamp reflection glowering at me from the back side window. Comic effect? Fine, but you are not holding this picture out as a joke. Curable with "photoshop" or sim and ten minute's careful work? Maybe. I know vanishingly little about photoshop. And on the flank of the poor Honda the reflections are so brilliant that I suspect I could identify the white car reflected in your Honda's paint work and - if I only knew the area - the block of flats opposite the car. Is it a bad picture? Hell no. There are many that are far worse. But if you insist on identifying this sort of picture as "high quality" you make yourself ridiculous. And - which we both should mind much more - you risk degrading wikipedia. Feel free to upload, for illustrative purposes, pictures that you think people should seek to match in terms of "high quality". But uploading pictures that you yourself have produced under those circumstances is simply asking for trouble. You and I are both, all too obviously amateur photographers. That's fine. No stigma. But surely you can find a better example than this Honda. When you do, please pay attention both to the reflections issue and to the angle of the car. In my judgement - which you do not need to share, but which please consider - the camber of the road is one of several factors which makes the angle of the car in this picture sub-optimal. A bad picture? No. But a picture that people should seek to emulate? How can I put this politely? No, sir.

(I'm pretty underwhelmed by your Mercedes picture too, but it does, for better and worse, echo some of the blindspots we associate with your friend OSX. Maybe I'll come back to that one after lunch.)

Sorry to write as I see it. Maybe others disagree. Do I have my own blindspots? I'm sure I do, but at least I don't clump around identifying my own more mediocre photographic contributions as "high quality". And ho ho. Best wishes Charles01 (talk) 12:04, 10 September 2018 (UTC)

Charles01, having a look at OSX's past images compared to mine and User:Vauxford, if we say look at the Aurion image not having one example that adhere to WP:CARPIX guidelines, due to the fact that the tires look dirty and the vehicle seems to be on dirt road which would kick up dust. Vauxford would be the best to ask in regards with higher quality images. – what I can do is I'll look over the image again and see if there are better alternatives. It appears that the Freelander was too bright therefore this illustrates an example of why OSX hasn't really carefully selected his image. He hasn't been editing for the past year or so, where I have been actively picturing cars in Fremantle and base the quality of the images on the basis of multiple attempts in one go.

I appreicate your commentary into this, but we should discuss this with User:Vauxford as he would be the expert in regards with high quality images --EurovisionNim (talk to me)(see my edits) 15:24, 10 September 2018 (UTC)

I had the impression from your respective talk pages that you had been "mentoring" Vauxford: not vice-versa. Either way, we should certainly welcome his thoughts on this. And those of anyone else with an opinion to share. Thanks for the quick reaction. But it must be the middle of the night in WA. Pls don't stay awake on my account! Regards Charles01 (talk) 15:30, 10 September 2018 (UTC)

Charles01, indeed I did. I was the one who gave him good suggestions, but that was based on my experience of car photography. I've done it for the past 2-3 years so I understand the concepts and i've pictured over 600 car photos so I know what is expected based on user's feedback. I used to use an iPad, but now I use a DSLR so its good. Vauxford has higher quality images along with me but I'm usually restrictive. Anyway goodnight everyone --EurovisionNim (talk to me)(see my edits) 15:37, 10 September 2018 (UTC)

Charles01, EurovisionNim Now, reflection is a pretty common problem when it come to photographing cars. I recalled Charles01 mention it to me a few times of how reflection can affect the picture. I must say, since our last talk on the Daimler 250 I begin to look at my pictures much differently, I never really thought about reflection before then and I thought people were just being picky. I didn't notice until now Nim changed the examples on the WP:CARPIX page, CARPIX is a good guide to know how to take a good photo but I no longer follow "by the books" since some parts of it seem to be rewritten to support OSX's way he took pictures. looking at the new examples, there must be better examples out there that could be used, as Charles01 pointed out, I could see a car, a street lamp and all sorts.

However some of these can't really be avoided, especially with newer cars (like the 18 and 68 Reg in the UK) that still has their showroom shine. You can reduce it in some situation such as avoid taking the picture when a oncoming car goes by and be cautious when the sun shines. I should really be lectured a thing or two with lighting to be honest, I always have room to improve.

One of my worst cases of this problem

Throughout the 2 years I been on here, the 5000+ photos I took are like stepping stones to me, I lean and adapt over time. I was inspired by photographers such as Rudolf Stricker, OSX and IFCAR and even Charles01 as a foundation of knowing how to take a good photos. As I progress and refine my skills I started to work off with what users such as OSX has left and start adding some of my style. Yes, I'm guilty myself for identifying my own photos as "High quality" while most said otherwise, most of the time I use that as a edit summary because it usually the first thing to come up on my Autofill.

My view of how should a quality image of a car should be is similar to what OSX wrote on WP:CARPIX; always photograph it at a 3/4 angle, avoid photographing ones covered in leaves, dirt, tree sap or bird droppings. although light cases like these can be easily patched on Photoshop, little obstructions such as 1/10th of a car is parked behind the subject which often happens in locations where people tend to park close to each other won't really compromised the picture of it quality, if possible, I try and digitally remove the car itself without making it too obvious, if not, it isn't the end of the world.

Back to Charles01's comment, it a good idea to reduce the amount of reflections on the car using Photoshop but I'm concern of the results being a blobby mess, reflection need to flow somewhere and just wouldn't look right.

For Nim's choice of examples. There definitely more better images out there that could be used as examples for CARPIX, perhaps we could rewrite some of the contents on WP:CARPIX to be less tailored to OSX style because of the "blindspots" Charles01's addressed. --Vauxford (talk) 18:32, 10 September 2018 (UTC)

I would not trust myself or the software to address generalised reflection issues using photoshop or sim. But occasionally for small things like a reflected street light it can be sometimes - not always - possible to cover the offending reflection with an adjacent piece of paintwork or window. (And there are folks out there who are able to achieve a whole lot more with photoshop etc than I am: but I still regard "photoshopping" with some suspicion.) My more general point about reflections is not that you should avoid them. Generally you can't. I can't. But sometimes the sun positions itself so that reflections are exaggerated and distract from the curves and creases on the panels that the car's designer(s) carefully incorporated and from the panel gaps. For me, that counts as a bad thing. Sometimes - not nearly often enough - the sun positions itself so that the reflections actually highlight the panel gaps and creases. That - at least on the planet I inhabit - counts as good! I'll try and find an example ....

On the Carpix bullet points more generally, they are for the most part fine as guidelines. But they don't tell you how to take a good picture. That is an altogether bigger question, and it's down to the phoographer's skill, experience and judgement. I do not think these things are intended as a set of "regulations". Or you will risk (1) some well intentioned bozo extending them over thirty pages to try and answer all the questions that might ever arise and (2) a series of identically composed images across the entire set of wikipedia articles which in the end just might become a little bit ... um ... monotonous. Regards Charles01 (talk) 19:27, 10 September 2018 (UTC)

And please do not hesitate to disagree with me!

Charles01, Well I don't mean a full revamped just some correction that suit (almost) everyone that can follow it as a rough guide. Reflection can be unpredictable, I reduce the sticky situation by photographing in dull weather rather then sunshine. --Vauxford (talk) 19:59, 10 September 2018 (UTC)

"Examples of what to avoid" gallery

Hi, I removed the "Examples of what to avoid" gallery yesterday as I disagreed with the gallery,

Like I said in the edit summary it all comes down to common sense - You would use the very best image,
It's also worth noting "okay" is subjective - What I might find to be the best image someone else may not and what someone may find the best image I may not .... so it's all subjective,
(For instance I would find this image, this image, this image, this image, this image, this image, this image, this image all to be okay and usable in any article - We need to remember we're an Encyclopedia not a showroom/car dealership)

My other issue I had with the gallery is that the majority were Vauxfords images - Now if you look closely you could find fault with probably every image on here/Commons and so I thought it was very unfair for his to be the majority - Vauxford isn't the perfect photographer but neither is anyone else,

I appreciate we all want the best for the Encyclopedia but like I said it's all common sense.
Cheers –Davey2010 ^{Merry Christmas / Happy New Year} 11:25, 28 December 2018 (UTC)

Archive changes

Just a heads up I've moved the archives around so instead of for instance 2008 being in 3 seperate folders they're now all in one folder,
I've removed the years from the archive table tho as we shouldn't need to keep updating this every few years - They're all in year order so like any other talkpage it's simply a case of trawling through and finding whatever you need to find, Thanks, –Davey2010^Talk 18:06, 29 December 2018 (UTC)

Slight update - I've removed the table and replaced it with the standard talkpage header, Cheers, –Davey2010^Talk 18:23, 29 December 2018 (UTC)

EurovisionNim's bad pictures section

Thank you for removing that bit, Vauxford. Here is the edit note I was about to attach to the same edit. (But you got in first and did the edit...):

This is silly. If the problem is EurovisionNim and Vauxford dumping all their worst pictures on wikipedia then the solution is for those guys to restrict their uploads to their least bad pictures. If one looks hard enough they have both already uploaded pictures - not enough - that have few or no major issues. Some even moderate to good IMHO. Inflicting more that even EurovisionNim thinks are bad on the rest of us again, as here, doesn't begin to tackle what has become a significant quality problem.

Regards Charles01 (talk) 09:30, 28 December 2018 (UTC)

I agree with Davey2010 removing this section (and AlgaeGraphix added 'Category:Wikipedia naming conventions/Transportation'. On 30 June 2020, {@|Gonnym}} removed it from 'Category:Wikipedia naming conventions/Transportation'.

Does anybody object to making this an official guideline of the automobile project?  Stepho  talk  22:24, 30 June 2020 (UTC)

The way these conventions are currently written would need to be made consistent first. For example under Units the first paragraph talks about using the units of the relevant market first, then the rest of it says metric should always go first. I'm not sure I understand the logic behind the second option anyway. We should list the unit that's original first, eg using HP or PS for older cars, or Cubic inches first for older American engines, in line with MOS:UNIT (unless you want to argue that these are "scientific articles". A7V2 (talk) 00:31, 1 July 2020 (UTC)

Yes, should be an official guideline if it is possible. And yes, maybe we should also improve the conventions where possible. Best,  Mr.choppers | ✎  03:29, 1 July 2020 (UTC)

I think that the "Units" section has some flaws.

• The first sentence is „We use the local standard first when making judgments on localized units and terms. The unit order follows a vehicle's major market.“ → That sounds reasonable to me. But there are markets – (for example East Germany) – that had units that are not listed anywhere in the Units section as appropriate or aceptable units. And this may sound like a weird question, but how is the local standard defined?
• As far as I can tell, there is no difference between MKS and SI in the Units section, both are referred to as metric. Maybe that is precise enough, but maybe it isn't. I believe though that most readers (and Wikipedia authors) possibly don't know how to deal with it "correctly". So we might end up with articles on vehicles that use MKS whenever SI should be used, or vice versa.
• In the general conventions section, the first sentence is „We use the standard International System of Units (SI) describing automobiles, and will generally follow the SI writing style.“ → This rule is ignored in most articles on motor vehicles, and for example, the "Displacement" section doesn't follow this rule either.
• The "Displacement" section describes how to deal with the discrepancy between "marketing displacement" and "actual displacement", but it does not describe how to deal with "tax displacement" and "actual displacement". (Tax displacement uses $\pi =3.12\lor \pi =3.1416$, but not $\pi =\pi$ in the displacement formula.)
• The "Power and torque" section doesn't include MKS units for torque.

Best regards, --Johannes (Talk) (Contribs) (Articles) 13:03, 1 July 2020 (UTC)

The first sentence can be removed. We already state that we follow WP:UNITS, which says that we use metric by default but allow for some exceptions for US and UK articles. But many people don't follow the links, so it would be nice to reiterate it as the last bullet point.

MKS, metric and SI all refer to the same thing from our perspective.

You are right that many articles ignore this convention. Therefore we need to fix those articles.

Can you clarify where the displacement section violates the units section?

Tax displacement might have to wait for another day. I suspect it will differ according to region. I'd like to see some solid references before tackling that.  Stepho  talk  11:51, 2 July 2020 (UTC)

@Johannes Maximilian: Hi Johannes. What is (please) this tax displacement? I can see it uses a slightly different formula. Where is tax displacement used? Thanks, Eddaido (talk) 11:59, 2 July 2020 (UTC)

• I'd argue that there is a difference between MKS and SI, most notably, that MKS has no force (kN), it only has weight (kp) and mass (kg), with weight being defined as mass times (earth) gravitaional acceleration. There are vehicles that were designed with MKS figures, and we have to be careful not to confuse mass with weight.
• The units section reads "We use the standard International System of Units (SI) describing automobiles, and will generally follow the SI writing style", but in the "Displacement" section the text reads "Engine displacement should be expressed in (…) cubic centimeters (display as cc)"; according to the SI writing style, cubic centimetres must not be displaced as cc (SI-brochure, page 147), instead, cm³ has to be used.
• Thank you for asking that question about the tax displacement, I will try to briefly explain it — this is (was) a typical German thing. In Germany, car (=vehicle with a mass of less than 3500 kg) tax depends upon the engine displacement, the emissions behaviour, and the engine operating principle. So determining the displacement was (and still is) important for taxation. The forumla for the volume of a cylinder includes Pi ($(0.5D)^{2}\cdot \pi \cdot s\cdot i$) and is thus difficult to use without a calculator. Therefore, Pi was defined as 3.12 in the German StVZO (Straßenverkehrszulassungsordnung). Using 3.12 instead of Pi in the equation will result in a less precise figure, but that was acceptable back in the day. The displacement was (and still is) counted in 100 cm³ "steps", and each "begun" 100 cm³ of displacement cost money. Therefore, most manufacturers designed their engines with large cylinder bores and short strokes so that they would have (significantly) lower tax displacement than effective displacement. For cars that were made before 1989, manufacturers usually gave two displacement figures, the tax displacement, and the effective displacement (for example, BMW E28, PDF pages 151 and 152, section 6—06 and 6—07) Since 1989, a new formula with Pi= 3.1416 has been used. The difference between Pi and 3.1416 is negligable, which is why manufactuers have stopped calling it tax displacement. I'd recommend sticking to effective displacement, because that is much more relevant than obsolete German displacement taxation. Best regards, --Johannes (Talk) (Contribs) (Articles) 15:31, 2 July 2020 (UTC)

• I agree with the proposal to classify it as a guideline. There is always room for improvement, but I think it is still suitable to be a guideline. Cheers, 1292simon (talk) 12:25, 29 July 2020 (UTC)

Pferdstarke (PS) units

Mr.choppers recently changed the conventions so that cars that were originally measure in metric horsepower (PS) would have the PS first. I support the idea that PS is important and that conversion to kW should be based on PS and not hp. However, kW should still be displayed first, as per MOS:UNITS. The way that I normally solve this is to use PS as the input parameter to {{convert}} or {{cvt}} but adjust the output order. Eg {{cvt|280|PS|kW hp PS|order=out|0}} gives 206 kW (276 hp; 280 PS).  Stepho  talk  22:14, 7 November 2020 (UTC)

• Hi Stepho-wrs. I agree that kW should be first, since the primary consideration should be the unit that is most widely understood amongst readers, rather than whichever historical unit was used when the product was introduced (e.g. we don't measure the height of the pyramids in whatever length unit was used in ancient Egypt). Wikipedia regards SI units to be the most commonly understood. Thank you for sharing with us the method by which the kW figure can be listed first without causing any rounding errors from the PS conversion.

  Therefore I disagree with the recent addition of "For older metric cars, where the original unit is in metric horsepower (PS) use this unit first..." to the Power & Torque section. Regards, MrsSnoozyTurtle (talk) 05:43, 4 January 2021 (UTC)

I also agree, PS is important but conventions that conflict with the MOS are not useful. Toasted Meter (talk) 06:16, 4 January 2021 (UTC)

Having a conversion from PS to kW with kW displayed first is sometimes not ideal, but, in general, a reasonable method of informing the reader. The problem with "older metric cars" is a definition problem: What is a metric car? What is an older car? What about motor vehicles that aren't cars? It would be very difficult to reasonably define all of this without having either inaccuracies or endless details. Also note that the SI system wasn't introduced in all counties at the same time; so generally putting kW first no matter what era the car was made is acceptable and better than a vague "older metric cars" rule. Best, --Johannes (Talk) (Contribs) (Articles) 09:33, 4 January 2021 (UTC)

To me it becomes very weird and factually incorrect to write 221 kW (296 hp; 300 PS) when "300" is clearly meaningful as being a nice round number, probably prominently used in marketing. Fiat marketed their cars as "Uno 75" for instance, so leading with kW is strange. In 1962 the Mitsubishi Minica's power increased from 13 to 13 kW (17 to 18 hp; 17 to 18 PS), yet another occasion when an ahistoric application of SI units becomes absurd. When Opel claimed 75, 90, 100, and 110 PS for the engines in the Opel Rekord, then clearly these are the meaningful numbers. European cars before 1972 should absolutely lead with metric hp, as that is how they were designed and measured by their manufacturers. When the Japanese manufacturers agreed to limit power to 280PS, that is the unit they used - leading with kW is misleading at best. When the car is of more recent origins or there is any doubt about which unit to use, then by all means use kW first - I am not suggesting that we lead with PS for the Golf TDI 140, although clearly VW didn't call it the TDI 103. As a matter of fact, I do not think that kW is more understood than horsepower as of yet (note AutoBild not even including kW); it is certainly not something we can take for granted. Outside of Germany and Australia I do not see car enthusiasts ever using kW, but I am not here to try to get rid of kW so don't let us get sidetracked. Interesting how Nm was universally adopted much faster, it seems that only the Japanese are holding on to the kgm.

Horsepower will one day be as extinct as the rod or the centner, but it cannot yet be compared to those nor to the royal cubit. I am all about the metric system, but I don't think we should apply it so as to obscure reality or provide misguiding numbers.  Mr.choppers | ✎  15:07, 4 January 2021 (UTC)

Also, there is no conflict with MOS:UNIT as it does allow leeway for using "conventional units" when apt (bolding mine):

the primary units chosen will be SI units...or such other units as are conventional in reliable-source discussions of the article topic (such as revolutions per minute (rpm) for rotational speed, hands for heights of horses, etc.).

 Mr.choppers | ✎  15:17, 4 January 2021 (UTC)

But that is just personal preference. A meaningful figure is one that allows comparision. If, for instance, a power figure was measured according to let's say the DIN 70020 standard with three significant figures, then a 150 PS figure converts into a 110 kW figure, which can then be compared against other DIN 70020(!) figures. It would not be reasonable to have a 110.325 kW DIN figure (such accuracy simply doesn't exist), but that is not the case here (there are several motorbike articles that state "real wheel horsepower" with four or even five significant figures, but no standard. That is an example of completely meaningless figures). Marketing is basically whatever the manufacturer or the sales division believe is best for sales – an Unimog U 70 does have an engine rated at 70 PS, but an Unimog U 1300 L surely does not offer 1300 PS. Image a Claas Mercator 75 with a 75 PS engine; it would perform underwhelmingly; the engine power output is much closer to 75 kW, but I believe that 75 was choosen rather arbitrarily and has nothing to do with engine power. (Regarding VWs with EA 189 engines: I don't think that they were marketed as TDI 140, at least not in Austria or Germany). I could make zillions of examples like this; you get the point. What marketing wants us to believe is not very relevant for Wikipedia anyway. You state that you do not think that kW is more understood than horsepower as of yet – I'd say that people understand neither of them. Power is the product of the crankshaft's angular velocity and the engine torque; but, who knows this? Most people simply see a PS figure and can then tell whether that's much or not (which is why PS works), but I do not expect people to know how to put a PS figure into context. Doing so is a nuisance which is why virtually everybody who knows how to do that tends to use SI instead. In cases such as the Minica engine upgrade, using SI first is not ideal (see my 09:33 reply), but in such cases we can explain this using text. I mean your idea of using PS for "older cars" is not bad, and I like using it because it makes clear what the sources say. But this method also has its drawbacks (as explained above), and with Stepho's method, the problem of "not writing what the sources say" can be avoided. (I could talk about even more details for ages, but I don't want to cause too much discussion). Best regards, --Johannes (Talk) (Contribs) (Articles) 17:52, 4 January 2021 (UTC)

• Also, the concern of "provide misguiding numbers" is covered, since the method posted by Stepho-wrs above provides an accurate conversion from PS into kW. Regarding how well recognised the units are, I believe that casual readers (i.e. those without a specific interest in cars or physics) outside of France/Germany are more likely to recognise that kW or hp are units of power, compared with PS, ch, etc. Regards, MrsSnoozyTurtle (talk) 22:37, 4 January 2021 (UTC)
  • MOS:UNIT does not say to use the unit used historically/in context. As pointed out above by User:Mr.choppers, we should use the units conventionally used to discuss the topic in reliable sources. I'm no Egyptologist but where I've seen the height of the Great Pyramid written down with any precision it's in metres, not cubits, so it makes sense here to use metres, as do reliable sources. In many cases, especially for older cars as outlined by others above, this will either be PS or hp. A conversion to kW should still be given, but I think it best to lead with the unit which is actually being used. And of course we should not be giving numbers more precise than are used in reliable sources when doing such conversions. A7V2 (talk) 23:13, 4 January 2021 (UTC)

A few responses: @Johannes Maximilian: obviously examples of things not named after their horsepower are irrelevant, but the Unimog 70 and the Uno 75 (like most Fiat products of much of the 1980s) were named for their approximate horsepower output. I am just trying to show that leading with the metric hp is sometimes clearer than kW. I have always seen the various VW Group diesels differentiated by their horsepower outputs, but I don't have any period brochures handy. It is not my personal preference, it is the preference of the manufacturer of the item that I am trying to illustrate. Also, only listing kW outputs in the table of Unimog 406 is a perfect example of the kind of obfuscation that should be avoided at all costs. Even your example of the Unimog 1300 is clearly named for its power (around 130PS, I have some old INUFAs in the basement so that I can check for sure).

@A7V2: - well said. As for rounding, the habit of rounding to 0 works well, excepting cases of approximations.

@MrsSnoozyTurtle: - PS/ch/cv etc are nothing more than abbreviations of horsepower in various languages. I am unsure of how and when WP decided that "PS" would be the abbreviation used for a metric hp (why use German??? Is it just because Japan also uses that abbreviation since the 1960s?), but that's an editorial decision that should not have to make it impossible for us to refer to the output of a 1960s vehicle in the unit used by the manufacturer. (I also don't have a better proposal for how to clearly differentiate imperial hp and metric hp.) Literally every country in the world used horsepower to measure automotive power until SI started taking hold in the 1970s, and the changeover seems likely to remain incomplete until the end of the internal combustion engine. What about a 1950s Opel with 60PS? Do we lead with kW there? What about the Bugatti Type 35's 140cv? Again, PS is not some kind of esoteric specialist unit. It is a horsepower, plain and simple, it just so happens that countries using the imperial measurement system picked a slightly different definition of hp than did the civilized world.

One thing that can't be ignored is that most of the claimed power are simply marketing numbers. One Swedish magazine used to do very very careful testing of maximum power, and the discrepancies between brands and models were simply staggering. Mazda's 150hk was nothing like BMW's 150hk. Do we really believe that BMW's 2002, 2002 ti, and 2002 tii produced exactly 100, 120, and 130PS? I don't. They're nominal figures, like 2x4 for a piece of lumber. If I was at a cocktail party for WP car nerds I might suggest that converting these nominals is as useless as converting 2CV into 1.47 kilowatts.

Anyhow, I firmly believe that European cars built before 1972 (Germany was an early adopter) should always lead with the unit they were designed in (i.e., either kind of horsepower), but I think the date ought to remain flexible. Not sure what the various national laws stated, but French and Italian and other manufacturers absolutely used hp (metric) as their main unit until the 1990s at least - as evidenced by some of them literally naming their products after this power (cf. Fiat, Venturi).

I do not believe in trying to work out a set of strict definitions for this, it will only cause complications, but my rule of thumb is that if whichever kind of power output (kW or PS or hp) of a range of cars mostly ends in 5s and 0s is likely the leading one. I do not feel the need to do this to 2000's and newer cars and I want to make abundantly clear that I am not trying to apply PS everywhere or to unwind the metric system in any way. Quite the opposite; I work as an architect in NYC and every day I have to deal with the miseries of feet and inches that even Americans themselves do not know how to use. For a true headache, check out the scales we have to use. Ever try to figure out how big to make something so that it appears 3/32" tall when reproduced in 1/8" = 1'-0" scale? Don't even get me started on paper sizes.  Mr.choppers | ✎  00:54, 6 January 2021 (UTC)

FWIW, BMW prefers PS when describing their own cars from the mid-70s.  Mr.choppers | ✎  02:52, 6 January 2021 (UTC)

…but how would we know whether or not the Fiat Uno 75 was named after its engine power output in PS? What if the engine is rated 75 PS (CUNA), which is then 72 PS (DIN 70020) and 51 kW (ISO 1585)? What about the Audi 60, which has a 55 PS engine? We cannot know for sure what the names were/are supposed to tell the customers. We only know that we should not rely on marketing claims. In case of the Unimog U 1300 L: Its name is not an indicator of its engine's rated power output: The type 435.115 (model U 1300 L) was offered with 96, 100, 115, or 124 kW engines (1). So, I understand why you'd argue that PS is "clearer", but I disagree: we are not supposed to deliver clear, nice, even or appealing figures, we are supposed to treat figures without interpreting them. If there is evidence for a "PS naming", then we can express this using extra text, exempli gratia "Fiat named the Uno 75 because of its power output in PS", but as long as we don't have any such evidence, we should avoid assumptions, even if things are (or appear to be) obvious. You state „Anyhow, I firmly believe that European cars built before 1972 (Germany was an early adopter) should always lead with the unit they were designed in (i.e., either kind of horsepower), but I think the date ought to remain flexible.“ → at first glance, this is not a bad idea, however, imagine the date remained flexible: This would cause zillions of useless discussion on whether or not PS should be used first in several different articles, and the discussions would always be the same. I mean, you have handed it to me on a plate: „When describing their own cars form the mid-70s, BMW uses PS“. Describing is different from being mandated to use. BMW can describe their own cars however they want – what if they describe their newer cars with PS, too? Would that be a reason to use PS first? You and me, we both know that it would not be too reasonable to do so, but what if one day a new editor shows up who (mis)-interprets "the date ought to remain flexible"? Best regards, --Johannes (Talk) (Contribs) (Articles) 15:12, 6 January 2021 (UTC)

It is not the end of the world if BMW E28 leads with kW and BMW E30 leads with PS. I do not see a hard rule being applied in this matter to German WP, and allowing flux and editorial judgement seems to create less debate than trying to create some sort of byzantine rule which will then lead to problems, misapplications, and judgment questions. Are you suggesting that the names of the Fiat Uno 45, 60, 70, and 75 do not refer to the approximate metric horsepower output??? The fact that certain submodels of the Unimog 1300 range were added to include other engine options does not change the fact that "1300" refers to ~130PS, just like how the "8" in Mercedes 208 refers to ~80PS. Whether or not Fiat referred to CUNA or DIN or ECE does not change the fact that the name refers to the horsepower produced by the car. One metric hp converts to 735W, whether it is measured by the DIN, JIS, CUNA, or any other standards. Again, I am trying to show that horsepower is not irrelevant, it is used by the manufacturers themselves. Manufacturers do still use PS to describe their cars in many markets, but it is no longer the dominant form and so no one cares. I would say that from 1972 to about 1995, most European manufacturers are in a transition period; Japan and others switched even later. And in the end, there is no conflict: it is painfully easy to see which unit is "conventionally use in reliable sources," because it is the units that are used to write about these cars in reliable sources.  Mr.choppers | ✎  14:32, 7 January 2021 (UTC)

We're not writing for people that live in the 70s. We're writing for today's and the future's readers. And today US readers primarily understand hk and kW, UK readers primarily understand BHP and kW, Australian readers primarily understand kW. Readers from other countries primarily understand kW or whatever horse power is called in their languages. The only unit that is somewhat universally understood is kW. ⛐Boivie (talk) 15:17, 7 January 2021 (UTC)

A one-second search shows this not to be the case [1]. And again, I don't want to apply horsepower to new products, just to historic ones. And I do not want to omit kW either, but to avoid obfuscation. When we write about the Volvo PV it is absurd to lead with kW.  Mr.choppers | ✎  17:24, 7 January 2021 (UTC)

• One article from a website (in a language other than English) is not proof that PS is more commonly recognised than kW. Especially since most English-speaking readers would equate "horsepower" with imperial horsepower rather than metric horsepower. MrsSnoozyTurtle (talk) 06:49, 8 January 2021 (UTC)

I've been letting this mull over in my mind for the last few days. Mr Choppers raises some excellent points that cannot be dismissed easily and I certainly respect his intent and integrity. Yet, I cannot help feeling that PS and hp are rooted in the past. Fossil that I am, I still think in terms of hp, even though Australia has used kW for decades. But the new generations (at least in Australia) use kW intuitively.

It is true that many cars were named after a nominal, rounded power figure. I treat this as marketing and mostly ignore it for actual power figures. If the actual power figure is not available then any conversion to kW and hp should make use of |round=5 or similar to avoid false precision. The British liked naming cars for nominal power figures. Some even had 2 figures like Austin 18/24 for 18 tax horsepower and 24 "real" hp. This is similar to a discussion about the Ford 302 cu in engine. Ford in the US badged the cars as 5.0 L but for WP we put 4.9 L in the infoboxes because 302 cu in is actually 4,949 cc, which properly rounds 4.9 L. The Americans weren't happy about this but we eventually persuaded them about the difference between badges and measurements. Marketing and engineering need to be clearly separated.

It is also true that manufacturers were rather liberal with the power figures. It was a figure that could be read off from a dyno and that could be replicated as desired. But they did things like removed/disconnected the water pump belt, most of the oil, the alternator, the air conditioner, and any other parasitic drag. This means that any figure given should be treated with a rather large amount of salt. But none-the-less, if it is presented as an engineering figure (rather than a marketing figure) then we report it as such.

Oooh-la-la!

The literature of the time naturally used the units of the time. As mentioned above, that's like reporting the height of the pyramids in cubits. However, modern enthusiast magazines and books about older cars still tend to use the older figures. Even here in Australia, modern magazines about classic cars from the 1970s use hp - but those magazines are mostly aimed at like-minded fossils. And of course, British magazines for classic cars will use hp to their dying day, so it's hard to dismiss German magazines for using PS. WP:UNITS says 'such other units as are conventional in reliable-source discussions'. It's tricky to interpret this. For their example, horses are still measured in hands in modern horse racing. For cars, modern literature talking about modern cars always uses kW (US excepted, who are determined to ignore the metric system). But modern literature about classic cars still holds on to the old units. Out of all the points raised, this is the only one that really makes me think. Is it a strong enough point?  Stepho  talk  08:46, 8 January 2021 (UTC)

Thank you for hearing me. This is not the kind of interaction one expects on the internet. Perhaps we ought to use a more clear cut example than 1990s BMWs (a very blurry place and period for this question): what would you do about the Berliet T100? Literally no one has ever talked about this vehicle in terms of kW. The nation that built it, the manufacturer, all period and modern sources only ever refer to horsepower. The truck carries a giant 600ch. or 700ch. badge in its grille. What about the 1931 Audi 15/75 PS? We use hp when describing the Ford Falcon (XA), as Australia wasn't metric yet (that article could use a couple of conversions, btw). I would like the same sort of respect for machines built in pre-SI metric countries.

The difference from cubits is that horsepower is not dead yet (I don't say this in a gloating nor a prescriptive manner), and it's not only fossils who use it. Even in Germany, an SI bastion, current articles are published which exclude kW entirely. BMW themselves use only PS when describing their own pre-SI 1970s products, changing to kW/PS for cars from the late 1970s. Obviously Auto Bild using PS only might be the result of being published by the heavily right-leaning Axel Springer SE; I have a feeling that a lot of euro-sceptics want to "keep their horsepower safe from Brussels bureaucrats" or somesuch, but that is not what I am after. Please don't mistake me for some sort of reactionary. Also, do note that "metric language" Wikipedias do not feel the need to only use kW - perhaps because they don't have to struggle with some people insisting on using stones and drams and other absurdities - I randomly looked up Renault 21 in French and ch is used nearly exclusively, switching to kW outputs for parts of the Laguna I article and then switching back to only horsepower for the Laguna II. There is not a single kW output even at the current Renault Talisman. Same thing in Italian, in Spanish, Swedish, and so on.

Why has the same thing not happened with kgm? Is it simply that no one has an emotional attachment to their cars' torque figures? I can recite the maximum power of every car I have ever owned, but I couldn't tell you the torque of a single one.  Mr.choppers | ✎  05:31, 10 January 2021 (UTC)

MrsSnoozyTurtle has ignored the discussion here and uniilaterally reverted my proposed changes. This user has not responded directly to the comments I have made nor to direct quotes from MOS. What should be done next?  Mr.choppers | ✎  06:32, 2 February 2021 (UTC)

That is an unfair accusation from Mr.choppers at me. What happened is more like: Mr choppers made an edit to give Pferdstarke more prominence. Soon after, Stepho-wrs started this thread identifying some concerns with the change. Eventually, others (including myself) joined in and various aspects were discussed. After 10 January the discussion had petered out without consensus for the original change, so on 15 Jan I restored the previous version, which was reverted on 2 February by Mr. choppers.

Therefore, I believe it is best for the previous wording to remain at the moment. As for the question of "What should be done next?", perhaps a revised wording could be proposed here and discussed? Regards, MrsSnoozyTurtle (talk) 05:06, 6 February 2021 (UTC)

No, the discussion never decided to revert my change. Stepho-wrs has come around to leading with PS when dependable sources mainly do so. No one has agreed to remove any and all mention of metric hp, as you are trying to do across a number of BMW articles.  Mr.choppers | ✎  05:51, 17 February 2021 (UTC)

Looking through the above discussion, there is no consensus amongst the 6 other people for the changes that you made. Therefore the accusation of Mr.choppers that I "ignored the discussion here" is unwarranted and unfair, and I ask that he withdraw it please?

If you would still like a change to how Pferdstarke is treated, I suggest creating an RfC with specific wording proposed. In the meantime, adding PS units to articles such as a car built from 2012 to 2015 is not in line with the Conventions. Regards, MrsSnoozyTurtle (talk) 22:01, 19 February 2021 (UTC)

Now that you have explained how you see it, sure, I will withdraw that comment. I also didn't see any agreement to revert my changes. As for removing PS entirely, as you are doing on numerous BMW articles, I have not seen much support. Particularly when PS is the unit used in reputable sources. As for the car built 2012-2015, I recommend comparing to the German entry. Including PS as well serves to protect against the constant swapping back and forth between hp and metric hp outputs which leads to so many errors, and causes no harm that I can identify.

You also have not responded directly to most of the comments I have made. For instance, the insistence on calling it Pferdestärke shows that you either have not read anything I have written, or that you are deliberately othering metric horsepower to make it seem an obscure unit. Again, I am not the one who chose to use "PS" as the abbreviation for metric hp, which is simply horsepower as defined by the majority of the world's population. And there are many editors who still prefer PS even for new cars: Very recently, I swapped kW to become the leading unit at a few Hyundai pages, which led to protests on my talk page.  Mr.choppers | ✎  22:22, 19 February 2021 (UTC)

Hi Mr.choppers. This situation is a case of WP:BRD but as a courtesy your changes were left in place until the discussion died out. So it doesn't seem fair to use this courtesy as an argument for accepting the changes when there hasn't been a consensus. As previously suggested, perhaps you could create an RfC with specific wording as a way to focus the discussion?

The reason I refer to the unit as Pferdstarke is that in articles the unit appears as "PS". This is a concern because the casual English language reader is much less likely to know what PS means, compared with hp or bhp.

The issue of errors caused by swapping between hp and PS sounds like something that could be solved by adopting the method proposed by Stepho-wrs above. However, perhaps there are situations where it is a problem, so could you please point us towards examples of Revision Histories where this has been an issue?

Describing Alawadhi3000's discussion as "protests on my Talk Page" does not seem accurate; IMHO it was simply a question that was asked and then resolved without drama following your explanation. Regards, MrsSnoozyTurtle (talk) 07:01, 21 February 2021 (UTC)

Again, there is no real good reason that we use the abbreviation PS for metric horsepower. If you do not abbreviate PS, then it reads "metric horsepower" and that is the unit we are discussing. The choice of abbreviation is a problem, as it makes the unit seem more obscure than it is and makes it look somewhat inappropriate when applied to Swedish, French, or Italian cars. In horsepower it is abbreviated "hp (m)" in one place, which is not much less awkward however.

Alawadhi3000's protest just shows that there are plenty of editors who prefer using metric hp, just as there are plenty of manufacturers and others who still do. I am not suggesting that PS become the de facto unit used, but when reliable sources and manufacturers all refer to metric hp then it should at the very minimum be included. As for vehicles built before the official adoption of SI, we absolutely ought to lead with the unit used by the manufacturer, whether that be an imperial or a metric hp.

The reason I argue for using PS when appropriate but do not argue for leading with kgm for torque in similar situations is because kgm is an obsolete unit, horsepower is not. I would argue that even after fifty years of SI, kW remains more obscure than horsepower outside of Australia and South Africa (they leapfrogged the customary metric units whereas those have provided "stickier" in nations that were already metric, maybe the situation is similar in other Commonwealth nations?). On another note, why do we still apply cubic inch conversions to modern cars as a matter of habit? I rarely see even Americans use cubic inches, aside from when discussing older cars.

I will write up a new proposal when the kids allow me an hour of peace.  Mr.choppers | ✎  18:46, 21 February 2021 (UTC)

Hi, just to clarify a few things, my post on Mr.choppers talk page was more of a question rather than a protest and I forgot to chime in on this debate so I'll do it now.

As a person who almost only edit Korean based cars, they use PS for power and kgm (or more precisely kgmf) for torque, I don't really have any preference regarding power units, I always put in the units which the manufacturer use and use the convert tool to KW and hp for power and lbft and Nm for Torque, I think this is the best practice.

If the majority of editor agree on the fact that the leading unit should always be a certain unit, I have no problem with that as long as the base of the conversion remains the original units used by the manufacturer (like what Mr.choppers did on the Kia Optima page), but I really really suggest using more appropriate units, it seems that hp and nm are the most units used worldwide for power and torque respectively, so those units should be used instead of SI units. Regards, Alawadhi3000 (talk) 21:41, 21 February 2021 (UTC)

Should "General Motors" be preferred over "GM" in relevant article titles?

I have started a discussion to that effect at Talk:GM A platform (1925). Essentially, having article titles be of the form "General Motors XXXX" instead of "GM XXXX" is more professional, more consistent, and slightly more in line with policy. Thank you!  – John M Wolfson (talk • contribs) 18:25, 12 May 2021 (UTC)