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I read this also but never read any rationale why they would have gone through so much trouble and expense. IMO this is simply marketing BS put out there by Audi (and similarly, all of the other manufacturers) which the journalists eat up, hungry to fill their columns/blogs/videos or whatever.
Case in point is the V10, developed by Audi for the Lambo Gallardo. When it showed up in Audi sedans and the R8 (in a different state of tune, of course) it was supposedly a "different" motor also. Now the V10 in the new R8 and the Huracan have identical output and Audi admits they are the same motor.
The 4.2 V8 has been Audi's big engine forever. They tune it up for use in the RS4 (and then the R8) and then suddenly decide to develop an all new 4.2 V8 for a limited production run of the RS5 based on the V10? Highly unlikely! I'll bet the real story is the Lambo/Audi V10 was originally developed from their 4.2 V8, and the RS5 simply has a less restrictive exhaust then the R8 - end of story!
Here's straight from the horse's mouth. It has almost nothing in common with the old 4.2l V8, save for the displacement:
Stephan Reil, R&D Chief in charge of all Audi RS and R models, explains:
The engine for the RS5 was practically developed from scratch. It develops more power and torque than the outgoing unit, yet it uses twenty percent less fuel. Although the redline was pushed up to 8500 rpm, maximum torque, an identical 317 lb-ft is now available between a less hectic 4000 and 6000 rpm. Engineering highlights include a two-mode intake manifold with tumble blades, variable intake and exhaust timing, and a multimode exhaust system. To trim parasitic losses, Audi reduced piston friction, lightened the DOHC valvetrain, and fitted a variable-output oil pump. A regenerative braking system increases alternator output during deceleration and reduces its output during normal driving.
and
The high-revving, normally aspirated V8, whose cylinder head covers are painted red, is built by hand at the plant in Györ, Hungary, and has much in common with the V10 from the R8 high-performance sports car.
The V8 weighs just 216 kilograms . Its crankcase is manufactured using the low-pressure die casting method, which ensures particular homogeneity. The aluminum-silicon alloy combines low weight with high strength. Its high silicon content makes the cylinder barrels extremely durable. The forged crankshaft, the forged steel connecting rods and the pistons forged from a high-strength aluminum alloy are all also extremely lightweight, yet strong.
The crankcase is a bedplate construction. The lower bearing bridges for the crankshaft are integrated into a common frame for maximum rigidity and optimal vibration behavior. The cast iron bearing bridges reduce the thermal expansion of the crankcase and thus keep the play at the main bearings of the crankshaft within tight limits.
Here's straight from the horse's mouth. It has almost nothing in common with the old 4.2l V8, save for the displacement...
I hear you but I'm still saying it's marketing BS! Not up to researching right now, but I bet a 430hp 2010 R8 V8 has identical components and nearly all of those features except maybe the "two-mode intake manifold with tumble blades"!
I hear you but I'm still saying it's marketing BS! Not up to researching right now, but I bet a 430hp 2010 R8 V8 has identical components and nearly all of those features except maybe the "two-mode intake manifold with tumble blades"!
Well....it seems to be a bunch of marketing BS.
The motor in the RS5 and R8 have the same bore, stroke, displacement, bore centering and so on.
They said of the R8 motor: the new V10 was bred out of the 4.2L V8
Then they said a few years later...the V8 was bred out of V10.
The motor in the RS5 and R8 have the same bore, stroke, displacement, bore centering and so on.
They said of the R8 motor: the new V10 was bred out of the 4.2L V8
Then they said a few years later...the V8 was bred out of V10.
Total BS......
Yes, it has the same 4.2 liters of displacement (just like about a dozen motors Audi/VW make), but other than that its an entirely different motor. So there's that. The R8 has the old RS4 motor and the RS5 has a totally redesigned 4.2 liter based on the V10. Both are high revving V8s, but the RS5 motor and the R8 V8 don't share any major components.
And of course Audi leverages what they learned on previous generations of their engines, but it doesn't mean they're the same motor just because it's a 4.2L.
I hear you but I'm still saying it's marketing BS! Not up to researching right now, but I bet a 430hp 2010 R8 V8 has identical components and nearly all of those features except maybe the "two-mode intake manifold with tumble blades"!
Except for everything else, like an entirely different casting process, different pistons, different crankshafts, different crankcase, different bearings, different valves, different oil pumps, made in a different factory….other than that, they're identical.
I drove my 5.2 for a few years - even had it out in the snow with the stock tires - excellent car in every respect. I had the Stasis ECU tune, Stasis Exhaust and BMC Carbon Air Filters on mine (still have them if anyone is interested, also have my stock exhaust as I sold it with the Stasis Exhaust). I also had a full Premiere Satin Guard wrap on it that was stunning. The car was extremely capable and the sound was fantastic. I do disagree with some here in one respect, I didn't feel as emotional connection to it as I did with my previous Porsches. I thought that with the Porsches there was more drama when I wanted it. That can be a good thing or a bad thing depending on how you like your motoring experience. I sold it for something a little more "practical" that my whole family could enjoy - an APR tuned RS7. It's running 674hp/700lb-ft on 93 octane and when I can get 100 it makes 728hp/744lb-ft of torque. Very different cars. The R8 could be driven with extreme confidence at high speeds on twisty roads. The RS7 is a total sleeper that is more like a muscle car - 0-60 in around 3 seconds and will run the 1/4 mile in 10.6 sec. It can also haul lots of cargo and carry 4 people. That being said, I have a deposit down for an allocation slot for the 991.2 GT3 RS if Porsche develops one. I think that car may be the ultimate road going motoring experience for me.
09-10-2015, 10:05 PM
