Hello,

i thought that the essential advantages of a supercharger are the throttle response an the higher boost at low rpm.

But when i look at the technical specifications of e.g the TT-RS, we have 450nm at 1600rpm, the S4 has 440nm at 2900rpm.

Can anybody explain that?

Please excuse my poor english

I am not familiar with these 2 engines. Are they both four cylinders or six? Which engine is larger displacement? Don't forget, Audi's philoshophy (and many other MFRs) is to use smaller engines and forced induction to achieve equivalent power but less fuel consumption. So the SC version of the same car may have an engine with lower power output than a normal apirated engine with larger displacement.

For example, for the Q7, the outgoing engine is a 4.2 V8 normal aspirated with 350 hp, and the new SC engine is 3.0 V6 with 330 hp. But the torque output is same at 350 lb-ft. Quite impressive for six cylinders.

The TTRS has a turbocharged 5-Cylinder ,the S4 a supercharged V6, but with 450nm at 1600rpm the RS has higher boost at low rpms, so i dont unterstand why audi decided to put that SC on instead of a TC.

The TTRS has a turbocharged 5-Cylinder ,the S4 a supercharged V6, but with 450nm at 1600rpm the RS has higher boost at low rpms, so i dont unterstand why audi decided to put that SC on instead of a TC.

Good point - it may be simply consolidation of engine varieties to reduce costs - unfortunately.

The big advantage of a blower (supercharger) is responsiveness. Turbos are exhaust gas driven and even the best designs (BMW dual scrolls, very small quick spooling as in my VW GTI, etc.) still have some lag between hitting the throttle and boost coming on. Since the supercharger is literally connected with the engine via an actual belt there is no lag. The best of both breeds have gotten so good it's amazing but any turbo motor is going to have some delay coming off idle before you're up to full pressure. That's why you see drag cars with blowers rather than turbos. Some car mags also credited the Audi engineers wanting to 'try something new' and seeing what they could do with supercharging versus the typical turbo setup. I think they came up with a very well done product and it definitely works as a fantastic motor IMHO.

Sorry - meant to add above. Blowers also can have a packaging advantage - since it's living in the V of the engine, it takes up less room under hood and doesn't generate the heat load that a turbo would. Less engine compartment heat makes makes a difference. BMW with the N54 had several instances reported on their forums of owners under hard driving or extreme environmental conditions overheat their cars necessitating the use of an additional oil/air heat exchanger. More plumbing, more cost, greater complexity, one more thing to go wrong.

Drove the 3.0 V6T in a S5 Sportback this afternoon…all in all a Very impressive engine