grnaudi96

I am a frequent on the 12V forum but I have an opportunity to purchase a 2002 A6 w/ the 4.2 and was wondering if a conversion to the bi-turbo style was even possible. With the RS6 running generally the same engine, the parts would be there. I realize this sort of undertaking would be like converting my 2.8 12V V6 to the 2.7T of the S4, but I was curious if anyone had done it. I searched the forums to no result. Thanks for your comments in advance!

Thumbmaster

The RS6 uses many forged and custom parts to withstand the additional power and torque. Also, the transmission of the 4.2 will likely not fare well with RS6-level output. I believe some time ago someone here had access to a complete RS6 engine and asked about dropping it into a 4.2 body. The concensus was that it will most certainly be a waste of time and money. The 4.2 is already a very powerful cruiser. I wouldn't jeopardize its reliability by adding turbos to it. However, the jury is still out on the supercharger kit that's to be released (any day now).

meatwad/beefcake

the stock internals will handle 500 hp maybe 600 but the compression should be lowered with headgaskets.

AudisAPlenty

The engine, body, electrical system, and fuel tank assembly,are entirely different from the 4.2 A6, not to mention the bumpers are pricey peices as well as the side rocker covers The radiator alone cost almost a thousand bucks. To make matters worse, RS6's are still going for a substantial sum of money at the salvage yards, as most that are salvaged are repaired. I have only seen one wrecked RS6 go for less than 15K and it was damaged to the extent that using it for a donor would be cost prohibitive.

ruknd

iirc, the RS6 engine is a cosworth design and a totally different engine all together

XM_Rocks

When will you be starting this project?

AudisAPlenty

Not really true, I did a side by side comparison, blocks are the same, as are the crankshaft. The pistons have a bit more dish than the N/A engine. Heads are physically the same, but I think I remember seeing somewhere that the internal cooling passages are different. The valvetrain is the same as the S6. I think cosworth just bolted up some turbos and engineered the other stuff around an S6/S8 engine.

baskinblack4.2L

The RS6 has lower compression and audisAplenty is right there are different passages

Toxicity

even with different passages wouldn't it still be possible to atleast use the RS6 turbo headers etc. as a starting point in turboing a 4.2 thus saving you the problem of having those parts made custom

alpinab7

Like any motor: Use forged rods, new pistons to lower compression. 034motorsports sells manifolds. Get software, injectors, intercoolers and all related plumbing, clutch kit, tranny, etc. People say the internals are not the same but any good turbo project starts by beefing up the lower end. Even us guys with turbo cars (1995.5 S6) have beefed up internals once we get past a certain output. Yes it can be done. Figure $15k or more if you do a lot of the work. But why build an RS6 when you can build a 800hp monster by just using bigger turbos?