We’ve known the RS4 is coming for a while now. There’ve been rumors in the press, assumptions based on market demand and the release of a new BMW M3 that raises the bar in the segment. However, a mention by quattro GmbH boss Stephan Reil during an interview caused us to come the conclusion that the model was in stone. So what of forced induction? CAR says the 3.0 TFSI in the form of an even more potent iteration that’d have to be at least 420-hp to match the outgoing model. While a turbocharged system was developed for this motor, we’re ruling out both forced induction options. We’re told specifically on the turbos there are packaging issues, especially in smaller applications of the MLB such as the A4 and A5 on which these two new RS cars are based. Without naming our source, we solidly believe the notion of one engine to be credible. A move to a forced-induction V6 in the RS5 as compared to the V8-powered S5 doesn’t make much sense. Given the news from a magazine as reliable as CAR, this just raised more questions for us. So we flat out put it to an executive over dinner and the answer was surprising. The RS4 and RS5 will get a high-revving engine like the outgoing RS4. The high-rev applications in the R8 and B7-generation RS4 have impressed Audi’s engine development teams and they wish to continue in that direction with the next-gen of Audi’s hottest models. First comes a high-revving V10 in the R8 this fall, then an assumed V8 in the RS4 and RS5.

The two running RS5 engine rumors prior to our trip to Valencia were either a supercharged 4.0 TFSI or a 450-470hp variant of the current RS4’s V8. We now believe a 4.0 TFSI turbocharged application is being readied for duty in the next-generation A8 based on our recent discussion, but that likely wouldn’t fit in the B8 chassis A4 and A5 applications.

This leaves the idea of an improved high-revving V8. Previous rumors put the updated high-revving 4.2 at 450-hp, though a recent news article from German auto magazine Auto Zeitung about the RS5 suggests as much as 50 hp more, putting the number at 470-hp. One thing is for sure, our contact tells us there will not be an increase in displacement.

So where doe does Audi plan to get the added power? The current engine is about as tuned as one might expect a production engine to be, so 30-50 more horsepower from a streetable ECU, intake or more aggressive exhaust doesn’t really add up. We’d asked drivetrain engineers in the past about Valvelift, though it had been suggested Valvelift wouldn’t spin as high as the RS4’s 8,000 RPM redline. We again raised the question of Valvelift and were told that it certainly does work within the rev range of the current RS4 4.2. If that’s so, this might explain the bulk of the rumored power jump, while other frictional loss is expected to be minimized as Audi has done in its V6 and 4-cylinder ranges. If our assumption is correct on this engine, don’t be surprised to see the R8’s base engine also get the same upgrades within that car’s own model cycle.

As of yet we’ve not heard of any RS4 models in testing nor have we caught any spy photos. While no RS5s have surfaced either, we have it on good word that at least one board member is driving an ‘S5 fitted with an RS4 engine’ and that there are at least two RS5 drivetrain mules known to be testing in America.

While in Valencia, we tried our hands at an S5 mule fitted with the 7-speed S-tronic box on a very small track outside of the city and were pleased with what we found. A full report will be out soon, but the incredibly fast shifting and intuitive Sport shifting modes we’ve experienced on earlier transverse S-tronic models were matched by the new 7-speed longitudinal box.

Another point of interest that very well could effect American versions of the RS4 and RS5 is that the as-of-yet European-only Recaro shell-style sport seats have been developed for airbag fitment and thus North American sale. The seat’s lighter-weight construction and more aggressive bolster design offer significantly greater sporting feel for track rats or simply those who like a good bear hug while driving. Given the B7 RS4 was the first such car from the Volkswagen Group to incorporate these seats, don’t be surprised to see them as optional fare on the RS4 and RS5.

Fourtitude created the illustrations you see here for the express purpose of helping to give a vision of what can be expected. Rather than guessing where we think the designs will go, we’ve carefully added current elements from the most recent RS6 - blister fenders, the latest RS style wheels and an aggressive fascia to show what an RS4 or RS5 released today might look like. We’ve gotten no official comment from Audi on how close these images are, though quattro GmbH boss Stephan Reil was impressed enough by the two images to request that we send him high-resolution copies.

With the S5 already on the market and the S4 set to bow at the Paris auto show, combined with our knowledge of test vehicles, expect to see the RS5 debut first. The RS4 should follow close behind the coupe – we’re guessing the RS5 could debut as early as next spring’s Geneva Auto Show and maybe the RS4 at the 2009 Frankfurt IAA. These launch projections are guesses but, given the importance of these two vehicles, they seem to be the most logical choices.

Nice! Too bad the price will likely be north of 70k.

What's most disturbing about Audi as of late is that all the cock and prick drivers who had flocked to BMW are slowly buying up all the Audi's now too!

Can you create BMW X3,X5,X6 forums while you're at it?
 
We can put them all in one for now and name it something like X-Bimmer or X-Series