The question many people ask me is if there is a replacement for displacement. I have had this discussion at length multiple times recently. With all the new CAFE requirements and the public’s demand for better fuel economy, some people are worried about fun cars.
While it is true things need to change to achieve better gas mileage numbers, that does not mean the fun will end. New technologies are making different things possible for this new age. The use of direct injection and forced induction will likely play a large role in the future of the combustion engine Many automakers are already downsizing their engines and starting to implement these technologies.
Ford is utilizing twin-turbo charging in combination with direct injection to create more power from smaller displacement engines. They are calling this technology EcoBoost. Using two turbos spooling up at different times, it reduces the old problem of turbo lag. Achieving maximum torque under 2000 rpm’s is one benefit from using this set up. Even better is that the torque curve is flat! Ford is getting 365 horsepower and 355 pound feet of torque out of a EcoBoost V-6 displacing only 3.5 liters! The engine could undoubtedly handle more boost and produce much higher numbers than that, but long term durability would be called into question at some point. Some theorize that the 3.5 liter EcoBoost could have an output of 450+ hp and 450+ ft-lb.
I mentioned earlier that many companies are downsizing the displacement of their engines. Ford’s EcoBoost powerplant is just the beginning. In the 2010 Audi S4, a supercharged V6 is used. This replaces the 4.2 liter V8 found in the previous generation S4. Many worried about the hp and torque ratings of the car when the smaller displacement engine was announced. The fact is, the 2010 S4 with its supercharged V6 has more torque and only slightly less hp than the V-8. The gas mileage has improved greatly and the driving dynamics are still intact. The only real loss was the deep burble from the throaty V-8. Problem was, that V-8 was thirsty.
Mercedes has also announced they will start downsizing their engines and will begin to offer more forced induction on future models. Mercedes’ performance arm AMG will be following suit with downsizing and forced induction as well. BMW has already started this with the latest M models, which utilize twin-turbo V8’s instead of naturally aspirated V10’s.
All this talk about forced induction is great. Downsizing is definitely going to play a role in the future. However, that is not to say you can’t get decent gas mileage out of a big, naturally-aspirated engine. A base model Chevrolet Corvette is rated at 26 mpg on the highway. That is 26 mpg from a 6.2 liter V-8, producing 430 hp! That isn’t terrible – in fact that is down right great! No direct injection, no turbos, no superchargers – just good old American muscle. The 2010 Ford Mustang 5.0 V8 achieves 25 mpg on the highway. Again, naturally aspirated, with no forced induction.
Back to the original question, is there a replacement for displacement? It really can be answered either way. Yes, you can get the power of a naturally aspirated V-10 out of a blown V-8, or V8 power from a technology-infused blown V-6. And now, we are just starting to see V-6 power from inline 4’s with direction injection and turbos. What you do lose when you try replacing displacement is the sound and feel of the engine. A turbo V-6 just doesn’t have the same rumble when you start it up. Everyone’s opinion will differ on this topic. In the end, mine is that you can replace the power of a larger displacement motor and even get some better characteristics, but in the end you can not replace the feel and experience of a larger, naturally-aspirated engine. It will always be different, but not necessarily worse.