Well, I'm not really racing other vehicles; I'm just trying to get close to the published quarter mile times at a local (SE Michigan) drag strip.

First visit got awful times; 14.135 was my best. Second visit I turned off ESP, got down to 13.675 & wrote elsewhere that I wouldn't drag again until getting to a dragway in Bradenton, FL, where my S4 was almost half a second faster than anywhere else. I don't want to drag too often without more input because for my 2000 S4 6-spd, several AWers advised against it. The S4 manual tranny is "not built for drag racing," they said
-- and costs about $10k to replace new. (My S4 tranny and clutch are fine, tho, after about 15 or so drag strip visits averaging about 4 runs each time...not that I set any track records!)

HOWEVER...now that it's turned colder (40s at night) my RS6 turbos seem determined to push me even farther back into my seat & launch seems quicker, too. So I'm thinking about one more visit to Milan Dragway before heading south for the winter, where cold weather will be hard to find (thankfully!).

THE ISSUE: I still want to avoid abusing my car, but I wonder: Does anyone know if the RS6 ZF Tiptronic is better suited to the strain of drag racing than my chipped S4 6-spd?

Also, how much (if any) difference do you think the cold weather will make? Figure temps of low 40s F now compared to upper 50s F before.

I'm sure you can get away with a lot as long as you don't totally trash the car. If anything breaks the bill's on Audi.

but as <i>CarbonFibre</i> says, it's under warranty so I shouldn't worry too much.

In my opinion, any Audi with an S or RS designation (or in fact any with the word Sport in it's description) should be capable of being driven in a sporting manner on a regular basis with self-destructing, or it's falsely advertised.

I doubt you will have a problem. Several cars in Europe have been chipped and drag racing without transmission problems for some time now.

Saw that in an Audi Sales video somewhere. It's more than capable of taking the strain.

Some time ago, <i>AUJ</i> posted <a href="http://www.sovereign-publications.com/auto-art-2.htm">this link</a> on the A/S6 forum.

The tables in there show some tranny/converter combos. The 5 HP 24 seems to match the published RS 6 gear ratios, and in combination with the W280 converter provides handling of up to 520Nm of torque, which again matches up fairly well.

Did I convert wrong or did you make a mistake somewhere? Is this a misunderstanding?

You're converting from the chart that shows 420-520 Nm of maximum engine torque, right?

Just wanted to make sure before I ask: What is the conversion rate for Nm (whatever that means) to lb ft? I have conversion tables for distance, volume, area, weight -- but not torque or anything that looks similar.

Every Nm is equal to about .73756 lb. ft. of torque. I get the conversions from a bookmark I recently had to update here:<ul><li><a href="http://www.forcecontrol.com/conversions.htm">http://www.forcecontrol.com/conversions.htm</a</li></ul>

In any case your data are correct, if The Brit and his URL chart are correct. The chart shows a maximum engine torque allowance of 520 Nm for the tranny specified by The Brit. 520 x .73756 = 384 lb ft, just like you said.

Why is that? Maximum torue from the RS6 engine is rated at 415, and 384 is 31 below that. What gives? Can anyone explain?

If you read the linked artice's section 4.3, it states "<i>Extensive measurements on public roads were evaluated. These showed that current traffic conditions do not allow long periods of full load running, enabling the test times of the high torque range to be significantly reduced</i>".

To me, this indicates that the stated torque rating is a continuous rating, not a peak rating. Given that the RS 6 produces 560Nm (413lb. ft) peak torque, this would tie in with the 'allowable' peak over the stated torque rating.

However, although ZF don't think peak loading is likely to happen often, I think everyone overlooked the fact that the RS 6 has such a wide peak torque band - I think it's entirely possible to run the transmission on an RS 6 at peak loading for considerable percentages of it's drive-time.

It's been said that MTM trashed several gearboxes on their test RS 6 while bumping up the torque, and there have been several reports of stock RS 6s gearboxes failing (my business partner is one of them) - does this suggest that the stock RS 6 runs the box close to or slightly over it's maximum rated value enough to expose any weakness in the gearbox build? Does this mean a weak gearbox <b>will</b> fail if the host car is tuned? Possibly.

Before anyone starts pointing to RS 6s that have been tuned well above 413 lb. ft and haven't broken their gearboxes, just remember that ZF's stated vales are probably calculated to give a &lt; 5% failure rate or something, meaning that the vast majority of 5 HP 24 boxes will accept more peak torque to a greater or lesser degree, and for a greater or lesser duration.

Just some food for thought...

will Audi please build a tranny with some decent headroom, please.

And given that the A8 4 litre diesel V8 doesn't produce much horsepower (274hp) but kicks out a stunning 650Nm (480 lb. ft) of torque, the A8's 6-speeder box must be able to comfortably handle that kind of torque, which makes it possibly a 6 HP 32, or a slightly over-torqued 6 HP 26.

Now, either we need an A8 gearbox in an RS 6, or an RS 6 engine in an A8.

I did find the link below (posted separately as it made the page too wide!), which indicates even lower input torque values. If Audi are starting to use the 6 HP range, the allowable torque does appear to be higher across the range, which is good news.

<ul><li><a href="http://www01apps.zf.com/kst827/ZF_ProduktDB/view_produkt_prod.asp?lang=en&amp;bgcolor=0&amp;langID=2&amp;d oSendAnwend1=1&amp;anwendID=18&amp;doSendBereich=1&amp;bereich ID=null&amp;doSendFelder=1&amp;geschaeftsfeldID=null&amp;doSen dPr

I got a spartan-looking page, clicked on a couple of places that were clickable, but got no useful info

ZF have some sort of session state that gets broken in a posted link. You can go to ZF's homepage (<a href="http://www.zf.com/">http://www.zf.com/</a>) and click on Products For, then Systems, then Cars. After that scroll down and there's link to 4/5-spd transmissions.

After all that effort, all you get is the following table &amp; some German language PDFs.

Type Type of prime mover speeds(forw.) Input torque(Nm)
4 HP 20 Front 4 330
4 HP 22 Standard/Heck 4 340
4 HP 24 Standard/Heck 4 450
5 HP 18 Standard/Heck 5 300
5 HP 19 Standard/Heck 5 300
5 HP 19 FL Front 5 310
5 HP 19 FLA Front Allrad 5 310
5 HP 19 HL Heck 5 310
5 HP 19 HLA Heck Allrad 5 310
5 HP 24 Standard/Heck 5 420
5 HP 24 A Front Allrad 5 470
5 HP 30 Standard/Heck 5 560
6 HP 26 Heck 6 600
6 HP 26 A Heck Allrad 6 600
6 HP 32 Heck 6 750
6 HP 32 A Heck Allrad 6 770