I am thinking of purchasing an audi, either S4 2.7t or A6 2.7t. Is there a difference in these two drivetrains (i.e.engines or trannies or final drive ratios, Quattro systems, etc)? Which ever one I get, I plan on doing the basic mods to get the most out of the stock turbos/ injectors.

thanks,

David

 

If your modding I would say just go for the S4. it is easier to find things for it. If you thinking Chip/exhaust you can also just get the A6. really depends on what you want. the A6 is more of a boat or luxury car, the A6 is more comfy on long trips. the S4 is much more stiff and more sporty feeling.

 

The S4 has more HP and Torque than the A6 2.7t. Even though it's the same motor, they're set up differently. The only thing that makes the S4 2.7T more powerful than the A6 2.7T is the ECU. Unfortunately you're not able to interchange the S4 ECU to the A6 due to a protective device in the S4 ECU.
Another thing is that the engine code is different between the two but other than that the engines are similar.
I would shoot for the S4 also if you're planning on modding but if you can't get an S4, the next best thing is the A6

 

The A6 and S4 2.7T both have250 HP and 258 ft/lbs torque. 2000 thru 2002 A6's and S4's both use engine code APB. 2003 thru 2004 A6 sedans and 2003 thru 2005 allroads have engine code BEL. Check the factory spec sheets at http://www.audiworld.com/model/. Any engine performance mods for the S4 can also be done to the A6. The exhaust on the A6 is different but upgrades are available for both A6's and S4's from APR and other vendors. I had no problem finding springs, sway bars, etc for my A6. There is a lot more room in the A6 and it only weighs about 160 lbs more than the S4 so the performance is comparable. Which ever one you get you will enjoy it!
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I called APR and they concurred they are the exact same drivetrain. I guess it just coes down to driving both and figuring out which one I like better. I have 3 kids so the wife is definately puushing me in the A6 direction, but they are rarely in my car so I don't see how it really matters much.

 

[align=left]This is from the Audi PDF in regards to the 2 motors. Some of the info out there is misleading and it's what most people are led to believe is that the S4 and A6 are the same. Please see below.[/align][align=left]Engine[/align][align=left]The 2.7-litre V6 biturbo[/align][align=left]This engine will also be used in the Audi S4[/align][align=left]and Audi A6.[/align][align=left]The engine used in the A6 has a comfortoriented[/align][align=left]setup, which means that it has[/align][align=left]different torque and power output.[/align][align=left]This effect was principally achieved by[/align][align=left]modifying the software configuration of the[/align][align=left]engine control unit.[/align][align=left]A tuning protective device prevents[/align][align=left]the S4 engine control unit being[/align][align=left]installed in the A6![/align][align=left]This prevents misuse, which can[/align][align=left]result in damage to the drivetrain![/align][align=left]An auxiliary heater is not available[/align][align=left]as an option for the S4 and the A6,[/align][align=left]due to the constraints on space.[/align][align=left][/align][align=left]The technical data[/align][align=left]•[/align][align=left]Configuration:[/align][align=left]V6 engine with 90° V-angle and twin[/align][align=left]turbochargers[/align][align=left]•[/align][align=left]Engine code:[/align][align=left]S4: AGB[/align][align=left]A6: AJK[/align][align=left]•[/align][align=left]Output:[/align][align=left]S4: 195 kW at 5800 rpm[/align][align=left]A6: 169 kW at 5800 rpm[/align][align=left]•[/align][align=left]Torque:[/align][align=left]S4: 400 Nm at 1850 to 3600 rpm[/align][align=left]A6: 310 Nm at 1700 to 4600 rpm[/align][align=left]•[/align][align=left]Maximum speed:[/align][align=left]6800 rpm[/align][align=left]•[/align][align=left]Compression ratio:[/align][align=left]9.3 : 1[/align][align=left]•[/align][align=left]Displacement:[/align][align=left]2671 cm[/align][align=left]3[/align][align=left]•[/align][align=left]Bore:[/align][align=left]81 mm[/align][align=left]•[/align][align=left]Stroke:[/align][align=left]86.4 mm[/align][align=left]•[/align][align=left]Weight:[/align][align=left]approx. 200 kg[/align][align=left]•[/align][align=left]Engine management:[/align][align=left]Motronic ME 7.1[/align][align=left]•[/align][align=left]Firing order:[/align][align=left]1-4-3-6-2-5[/align][align=left]•[/align][align=left]Fuel type:[/align][align=left]S4: 98/95/91 RON[/align][align=left]A6: 95/91 RON[/align][align=left]•[/align][align=left]Compliant with emission standard:[/align][align=left]EU III-D[/align][align=left]Figures obtained using 98 RON[/align][align=left]unleaded premium fuel to[/align][align=left]89/491/EEC.[/align][align=left]Figures obtained using 95 RON[/align][align=left]unleaded premium fuel to[/align][align=left]89/491/EEC.[/align]

 

The Audi info you quoted is from the Audi self study guide for the European models that was used for training Audi techs in the UK http://www.s4-mtm.com/images/Audi_S4_engine_english.pdf
These specs do not apply to Audi A6 & S4 cars sold in North America. The only2.7T engine available in S4's in North America was engine code APB as stated in my previous post. The same APB code engine is also in the2000 thru 2002 A6's and Allroads.
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^^True...As for the original post I would get the A6. It's pretty much a wide-body S4 and it only weighs 200lbs more than the S4. So you get almost the same performance, more room, and a beautiful body.

 

I totally agree. Great value for the money, and has the same performance potential when youmelt the VISA card doing mods...

 

def the a6...much more room and way better looking...and once chipped, a very powerful car...if you get the 6 speed