studavis

But the important point being made here, is that you reach a point of diminishing returns with a normally aspirated plant. An internal combustion motor is essentially a giant air pump, and once you reach the volumetric point of no more, the only avenue that remains open is to compress the air, or go to a larger volume. Most of what Ferrari and Porsche have done, is to tweak portions of this formula to eek every last erg out of the given volume. Ferrari uses a five valve system, with the odd valve used to get waste air out. You can add a few more ergs by making the engine components out of lighter materials, or by varying ignition sequences, such as measuring the temp of the incoming air, and the available air mass at elevation. All of these changes allow for more power, but the physics of getting more air onto the chamber, just cannot be broken without compression. One only has to look at the GT3 RS and the Turbo. Essentially the same engine, 3.6 lt. The GT3 makes 115 hp/lt, with 300 foot pounds of torque (406.8 NM). The turbo, on the other hand, gets 133 lt/h and a whopping 460 foot pounds (623 NM) out of the same displacement. This translates to .7/10 a second faster to 60, and stronger roll on acceleration as well. The real answer here, is to figure out how to do reliably bolt on a Turbo and a Supercharger, add some glycol injection, and then we should see numbers up to the point of complete overkill, which is just about right?

Richard in NC

Besides volumetric efficiency (which is best measured by max torque per litre), one point overlooked is RPMs. Volumetric efficiency produces good torque, torque x RPM produces horsepower. High torque at high RPMs produces the most power. In the old days, cam shafts and intakes were tuned to produce max torque at low RPMs for heavy duty vehicles or high RPMs for race cars but not both. Today, variable valve timing and other tricks allow broad flat torque curves. The E39 M5 5.0 V8 was one of the best NA motors for a brooooaaad flat torque curve.

There is also the question of high RPM capability. That is what gives Ferrari, Porsche, & BMW their 100+hp/litre. A 400 ftlb motor that revs to 5000 RPM max makes less HP than a 300 ftlb motor that revs to 8000 RPM. Ferrari always had small displacement high RPM motors. BMW chooses to provide high RPMs but with broad torque curves. I prefer that over max high RPM power. I'm not saying Porsche and Ferrari can't do high power and broad torque but BMW can and mass produces their motors in cars that sell many times more than Porsche or Ferrari. Add the fact that most BMW motors can go 50k, 100k, or even 200k miles with minimal maintenance costs is not something that Ferrari can do nor possibly Porsche.

swajames

Porsche has a system called VarioCam (and VarioCam Plus) which does a similar job to the Valvetronic system on the E60, enabling a broader torque curve with increased torque at lower RPM. As for reliability and the cost of maintenance, I don't think either are a particular issue. Porsche says that oil changes are only required every 20,000 miles (or every two years) on the 997 and more than two thirds of the Porsche cars built in the last 50 years are still on the road. EVO magazine in the UK did a story earlier this year highlighting the true cost to own some exotics including Lamborghini and Ferrari (based on actual costs incurred by a fractional ownership club) where the cost for the Italians was in the many, many thousands of pounds for consumables such as clutch replacement. As a comparison, the cost for a 996 Turbo that was on the same fleet was GBP 390, probably just a couple of oil changes, and you'd have to suspect that the more vanilla 911's like mine would be even less (based on the schedules alone mine should be zero for the first two years)

pennetta

Another benefit to higher RPM is the better mechanical advantage you have before your change to the next higher gear, which reduces your mechanical advantage with each shift.

Russ1974

Is someone going to move this out of the E60 section? Anything slightly off topic from me and BOOM off it goes within 17 seconds

pukka

BMW does make cars this tuned with the M class. These cars require strict maintenance to be reliable. Of couse if you can afford one of these maintenance costs are not an issue.

CVTBenhogan

At least in the Ferrari case, don't forget about higher emissions and fuel economy.