Talk:quattro (four wheel drive system)

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[edit] Adequately cite sources/clarify

The article suggests that the Q7 uses a Borg Warner system to provide AWD. There is no source cited for this. The specifications suggest that the center diff is a Torsen unit like other Quattros have (see http://www.audiworld.com/model/q7/07/Q7%20tech.pdf). The front and rear diffs are described as hypoid gears, which is identical to the arrangement on the other modern Quattro cars (see http://www.audiworld.com/model/). Perhaps citing a reference and clarifying what you're trying to get across would clean the article up a bit. Epinkert (talk) 04:26, 28 November 2007 (UTC)

[edit] AAM quattro center differentials

Teutonic Tamer: The link I have repeatedly posted (http://www.aam.com/file.php/729/AAM06_AR.pdf) is not an advertisement...it is a Fortune 500 company's annual financial report. Why do you doubt this? UrPQ31 (talk) 04:20, 30 May 2008 (UTC)

[edit] Subject Revision

I believe that a change does need to occur, regarding this article, 4motion, viscous coupling, etc. Perhaps re-evaluate all of these related articles. My idea:

1. Have a "VWAG Longitudinal AWD Systems" page (have "quattro" redirect here, but mention, for example, that the Audi A3 uses uses a "VWAG Transverse AWD Systems").
2. Have a "VWAG Transverse AWD Systems" page (have "4motion" and "syncro" redirect here).
3. Keep the "Haldex" and "TORSEN" pages, since they are their own entities, but edit to reflect the reorganization of the previous two pages.

The basis for my changes is that "quattro," "syncro, "4motion" are all BADGE names; they no longer definitively signify the type of AWD the vehicle has.UrPQ31 (talk) 20:50, 24 May 2008 (UTC)

[edit] Comparisons

Could someone make an AWD comparison page? I'm wondering how the AWD in my Subaru compares to that in Audi/VW and Mercedes. Thanks. - MSTCrow 00:04, 3 November 2006 (UTC)

Subaru AWD systems vary between Subaru models. There is an excellent overview at http://www.subaru.com, although you may have to dig for it. Subarus may use an electronic center differential, liquid coupling, sprung-clutch mechanism and a few others. A full discussion of this would tout the weight benefits of Subaru's systems over Audi's. —Preceding unsigned comment added by 216.162.217.10 (talk • contribs) 14:46, 26 November 2006
That's not really what we do here, honestly. What you're proposing sounds like either a significant amount of Original Research or, if such a thing has been published elsewhere (and I'm sure it has been), unnecessary duplication of content. Should you find an appropriate comparison elsewhere, however, you could certainly try adding a link here or on the AWD page.
User:Fox1 (talk) 22:49, 26 November 2006 (UTC)
I can't see a problem, as long as the article follows the wiki norm for 'comparison'. That is, a table template with a list of 4WD systems, and what features each of them have compared to the other. See comparison of file sharing applications. --Joffeloff 19:08, 9 January 2007 (UTC)

For a comparison of All Wheel Drive systems check out: http://www.autozine.org/technical_school/traction/tech_traction_4wd_2.htm. --[D. Evan Kiefer, 8 February 2007]

The last paragraph (the cons of the Haldex system) must be the WORST paragraph that I have ever read on Wikipedia... It sounds like it was written by an 8 year old!: "Full-time all wheel drive is better." <-- wow! that's not a broad, misguided, sweeping statement! "Some say Haldex system has less predictable behavior when cornering in snow than permanent all wheel drive systems. Other say there is nothing wrong with it; it is just a little different." Some say? Others say? Who says? The title to the last section "When Quattro isn't Quattro any more" is also extreme flamebait! --[T. Holm, 6 March 2007

The entire rewrite that added the generational format, the pros and cons, and the unencyclopedic tone needs to be re-rewritten. There was some good info added (generational format is fine), but style, NPOV and NOR went out the window.
I'd love to do it, but I'm a bit short of time.
Fox1 (talk) 19:11, 7 March 2007 (UTC)
Ok, I guess I had enough time for a quick run-through. I think I managed to make the article less awful, but I didn't have time to tip the scales over to "good."
Fox1 (talk) 19:18, 7 March 2007 (UTC)

[edit] Fair use rationale for Image:Quattro.jpg

Image:Quattro.jpg is being used on this article. I notice the image page specifies that the image is being used under fair use but there is no explanation or rationale as to why its use in this Wikipedia article constitutes fair use. In addition to the boilerplate fair use template, you must also write out on the image description page a specific explanation or rationale for why using this image in each article is consistent with fair use.

Please go to the image description page and edit it to include a fair use rationale. Using one of the templates at Wikipedia:Fair use rationale guideline is an easy way to insure that your image is in compliance with Wikipedia policy, but remember that you must complete the template. Do not simply insert a blank template on an image page.

If there is other fair use media, consider checking that you have specified the fair use rationale on the other images used on this page. Note that any fair use images uploaded after 4 May, 2006, and lacking such an explanation will be deleted one week after they have been uploaded, as described on criteria for speedy deletion. If you have any questions please ask them at the Media copyright questions page. Thank you.

BetacommandBot 05:32, 13 September 2007 (UTC)

[edit] torsen/haldex comparison dispute

I would suggest to either move the "longitudial systems" and "transverse systems" out of this article to the general awd article or an article about V.A.G. all wheel drive or have them rewritten to talk about Audi only. The comparison of torsen and haldex could stay in this article, but moved to a separate topic. Also, viscous coupling was never used on Audis and sold under the quattro badge - the "viscous coupling" topic does not belong here. the "haldex aftermarket application" should also be moved to the "Haldex" article.

Next, some technical aspects of the torsen/haldex comparison, as to my knowledge:
1. fuel economy of the Haldex system is a myth - decoupled axle and all other shafts rotate at all times, friction losses still exist. there is no proof automatic AWD is more fuel-efficient than full-time AWD.
2. haldex engine-braking issue is a myth - nothing prevents haldex from locking when engine-braking. the clutch gets locked when it senses the driveshafts are rotating asynchronously, either accelirating or decelerating.
3. haldex tyre identical wear issue is a myth - according to haldex-traction.com, haldex allows uneven tyre wear and works with mini-spares. This is torsen that requires all tires to be of the same size and wear.
4. and about torsen-based quattro weight distribution - the most important issue is missing is this paragraph: nose-heavy audis heavely understeer, this is why audi introduced 40/60 torque split to give more power to the rear and make it go around the corners.

Thanks. —Preceding unsigned comment added by Zello555 (talk • contribs) 22:24, 22 December 2007 (UTC)

What nonsense. Please cite your sources, and not from a forum.
Corrections to you unfoundeded tosh:
your point 1 - although Haldex shafts rotate all the time, when no torque is transmitted to the rear, then they are merely freewheeling. Simple phyisics states that a freewheeling object uses less power than an object which requires being driven.
Your point 2 - when braking, the Haldex DOES disengage torque to the rear axle. The Haldex works soley on electronics: it takes its rotational speed from the indivdual wheel speed sensors to calculate when to apportion torque to the rear. It also takes a feed from the brake light switch, and when the brake lights are triggered, the Haldex disengages fully.
Point 3 - Haldex DOES require all four tyres to be of identical wear, because it is NOT torque sensing (like the Torsen), but relies soley on the wheel speed sensors. The Torsen, being entirely mechanical, takes no readings from the wheel speed sensors, and simply relies on torque transmission, hence Torsen CAN accomodate differences in tyre wear.
Point 4 - modern Torsen Audis ONLY understeer when driven incorrectly. When driven correctly, a Torsen Audi will NOT understeer, and corners perfectly competently. Audi simply introduced the 40:60 Torsen to give it more of a rear wheel drive "feel".
Kind regards - -- Teutonic Tamer 19:47, 23 December 2007 (UTC)

Dear Tamer, 1. even if you can prove that a freewheeling object uses less power than a driven object, the benefit is almost non-existant. this is still the car's engine power that is wasted on the "freewheeling" parts. besides, audi has proved in 1980's that a driving tyre roll-resistance is lower than resistance of a driven tyre, thus permanent all wheel drive can be more fuel-efficient.
Now, please go back and read again:
2. the article is talking about engine-braking, where brakes (and brake light switch) are not involved. also, you must know, that clutch engagement mechanism is hydraulic. electronics are used to a) pre-tension the clutch b) disengage the clutch. please see haldex-traction.com
3. please visit haldex-traction.com and try to argue with those guys about this issue :)
4. torsen audis have been critisized for their unstable behaviour, changing from heavy understeer to heavy oversteer, depending on which wheels have more traction. a rear wheel drive "feel" was given on some purpose, which need additional investigation, but, perhaps, this issue is beyond this article.

Cheers, --Zello (talk) 23:49, 23 December 2007 (UTC)


Oh dear, you seem to have a hang up regarding Haldex!
1. Can I suggest you speak to a physics professor. Any object which is freewheeling requires less energy than an object which requires power to drive it. Get on a bicycle and try for yourself. OK, the benefit in terms of fuel consumption may be small on Haldex, but it is certainly measurable. Can you cite this research from Audi you quote? The only way that freewheeling tyre can offer greater resistance over a driven tyre is when you have a "directional" tyre, with an agressive tread pattern, which has previously been on a driven axle (the tread blocks "feather" in a different way between driven and non-driven wheels/tyres).
2. You are clearly very misguided. Audi programme their Haldex ECUs to fully disengage when the brakes are applied. This is specifically for the correct operation of the ABS. The "feed" from the brake light switch takes priority (in the Haldex ECU) over the readings from the front and rear wheel speed sensors.
3. Erm - Haldex-traction.com are simply a company website- who are trying to "sell" an inferior product. When you check with the actual manufacturer of the car with Haldex, ie Volvo, Audi, VW, etc - it is the vehicle manufacturer which rightly advises the vehicle owner of the absolute need to have matched tyres with matched tread depths. Indeed, in the UK, a few years back, a certain Volvo car failed to state this in the owners handbook, owners were running on tyres of unequal tread depths, and the Haldex units were burnt out. This very story made it onto a highly regarded UK consumer TV programme.
4. I really don't know where you are getting your info on the handling of Torsen Audis. Yes, some Torsen Audis WILL understeer when driven incorrectly, but put those same drivers in front wheel drive Audis, or even rear wheel drive BMWs and they will get the same understeer. Torsen Audis are actually praised because of their stability in corners. Maybe you are getting confused with the pre-Torsen Audis, which had the manually locking centre diff. When a centre diff is "locked", and cornering on dry roads, then the natural transmission wind-up can make the car twitchy.
BTW, I agree with you regarding moving the "Haldex aftermarket section". AFAIK, that is only really used on older VWs. Rgds -- Teutonic Tamer 22:31, 28 December 2007 (UTC)

2. do you know what is "engine-braking"??? --Zello (talk) 23:56, 28 December 2007 (UTC)

1. Here is the quote you were asking for: "This happens because, as vehicle velocity increases, the frictional losses for a freerolling wheel become greater than for an equivalent driven wheel." [1]
However, I agree with the current statement about "a slight increase in fuel economy" of the Haldex AWD and take this question off discussion.

2. According to haldex.com, in most cases, ECU indeed prevents the coupling from locking (i.e. neither it locks nor fully unlocks the coupling) when engine-braking and transfers very little torque to the rear. So the current statement about Haldex front-wheel-drive-like handling when engine-braking can be true, but it seem to depend on the vehicle.

3. Wasn't the Volvo issue you are talking about happening with pre-MY03 Volvos, which had viscous coupling installed?

--Zello (talk) 11:12, 8 January 2008 (UTC)

I read that an expert was needed for this page and I agree. I am not a drivetrain expert but hope I can help out on some of the discussions.

I will start with the Haldex vs Torsen dispute. To start the basic difference is that Torsen is a torque divider (needs one imput and two outputs) and haldex is a clutch (one input, one output) Basically it is a controllable clutch, meaning the amount (not percentage) of torque is passed through. Because it is electronically controlled, it can be programmed to act in almost infinitive ways). It could even behave like a virtual torque divider and that is (without knowing the algorithms) probably what it is doing in cars (probably different for different brands) I can not agree with the persistance of TT regarding the torque split. I will try to explain my thoughts in a simple way: Normally the front wheels are driven and the rear wheels through the Haldex. We can replace this with a rear wheel drive car that is driven on the left wheel and the right wheel is connected with a Haldex. If the clutch is closed, left and right wheel have the same speed and the torque split is depending on the road friction (the basic difference with a diff). If the left wheel (the driven one) is in the air, all torque goes to the right wheel. This is analogue in the (Audi) haldex: If the front wheels are in the air, 100% of the torque goes to the rear wheels. This can never be reached with a diff without mechanical lockup so the Haldex system really is not so bad. Robkraai (talk) 20:10, 11 June 2008 (UTC)

The tyre diameter topic I did not make up my mind about the torsen diff, it may be adjusted to a different ratio with unequal tyres. For sure it will cope with the wheel speed differences without a problem. The Haldex uses electronics and with software you can do anything! I cannot imagine that they did not build a routine for tyre size difference detection. I have been working in the past on DSA (Dynamic Stability Assistance) which also was based on wheel speeds and there one of the first modules was this tyre size detection. If Haldex states that it compensates for that (I did not read the stuff) I believe it until someone has a reason to beleif the opposite Robkraai (talk) 20:33, 11 June 2008 (UTC)

[edit] undoing quattro IV and V off-road behaviour

I changed the description of quattro IV and V off-road behaviour back to where it was prior to Dec 23, 2007 (partially undid the edit of 10:24, 25 December 2007 by Teutonic Tamer ).

Here is the proof that EDL cannot transfer enough torque left-to-right: [2]

Note that if this car would be on a slope, or towing smth, there is no chance the car would have moved any further.

Teutonic Tamer, you would do us a favor if you stopped vandalizing this article.

--Zello (talk) 22:39, 3 January 2008 (UTC)

What an absolute load of bollox!!!
You clearly don't know what you are talking about.
Is it just YouTube and internet forums where you learn all this mis-information???
Have you EVER worked on Torsen quattro systems??
Have you EVER owned any modern Torsen quattro cars??
You have been reported as a Wiki vandal. -- Teutonic Tamer 19:36, 4 January 2008 (UTC)
Ok, from an outside perspective - I don't think this is vandalism per se, but YouTube is pretty clearly not acceptable as a reliable source here. If Zello555 (talk · contribs) wants to reinsert this information, then please provide a more reliable source. Please don't simply reinsert the material or edit-war. MastCell Talk 20:39, 4 January 2008 (UTC)

MastCell, would making a video of my own Golf 4motion (with EDL) moving nowhere in the conditions I described in this acticle be a reliable source? I am afraid there will be no other source because no magazine has investigated this issue yet, if they care at all. But the problem is there and people are talking about it [3] and yes, some of them are posting videos to youtube.
Teutonic Tamer, when will you start actually READING what other people are writing? Where did I say anything about "Torsen"?
Regards, --Zello (talk) 23:16, 4 January 2008 (UTC)

Teutonic Tamer, because this was you who made changes to the original article (the changes I was trying to undo), I want you to support the changes you made with a reliable source. What you need to do is to get an evidence of a quattro IV Audi with EDL driving up a slope with one front and one rear diagonally opposed wheels in the air. Thanks. --Zello (talk) 11:25, 8 January 2008 (UTC)

[edit] dablinks and forced image sizes

WP:NAMB is clear about when dablinks are necessary. No user will get to a page called Quattro (all wheel drive system) by accident. If they type 'quattro' in a search box they will go to Quattro and be able to navigate there without a problem, and dablinks which do not include a link to Quattro shows a remarkable lack of concern for the readers' intentions. It is double redundant when every dablinked article (Audi Quattro and quattro GmbH) are linked to elsewhere on the page.

Articles are viewed by readers on many different screen sizes, and the facility is in every users preferences to force their own image sizes; that is why the recommendations at WP:IUP#Displayed image size exist. When people want to see the image at a greater resolution they can clickthru and see it full size. Again, that's the point of thumbnails. If YOU want to see the thumbnail at 300 pixels, set it in your preferences, but do not over-ride everybody elses choices. Iamaleopard (talk) 18:12, 2 May 2008 (UTC)

[edit] Title

I object to the title of this page. Quattro is not a system but a name used by Audi. In the definition it is used correct but also on several spots in the article the mistake is made Robkraai (talk) 20:20, 11 June 2008 (UTC)

[edit] EDL

I object to the usage of this name. In my opinion it is a name ivented by marketeers (AUdi only???) It suggests that it is electronically controlling the diff. In fact it is just an automatic brake system also known as traction control. Robkraai (talk) 20:24, 11 June 2008 (UTC)