Autoblog

Those old cars were slow and unreliable in the days of Magnum PI (by todays standards). I really think that they only got interesting in the past ten years or so.

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Realitycheck, I think he was referring to the actual old days- like, way before Magnum PI. Lol. Try 30 years before, and you're closer to what he's saying. And I agree, nothing wrong with small V12s! Of course, I also love the F40, so it'd be just fine with me to do a V8 with turbos.

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Italians made some fantastic small-displacement engines with a high number of cylinders.

Alfa Romeo managed to squeeze 250HP out of a 2-litre V8 as early as the '60s - unmatched in roadcars, even by the Honda S2000. And the sounds, oh the sounds...

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The issue is that even with smaller displacement a V-12 will be much less efficient due to greater frictional resistance caused by more cylinders. Atop that the added complexity will add more weight to the vehicle compared to a forced-injected V-8.

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High HP requires a lot of fuel. You said it yourself. Going to turbos won't fix this. Turbos put in a lot of air, which means also a lot of fuel, which means a lot of CO2 out.

Don't worry though, the EU will NOT put Ferrari out of business.

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Except for... you never use all that power during the Euro test cycle. So, it'll have improved mileage and CO2 emissions during regular driving and cruising enabled by the smaller motor (I'm guessing somewhere between 3.6L-4.0L). But, when you want the power, the turbos are there for you. I'd guess around 600-700 from the factory. More HP is nothing but a boost controller away :) (well, maybe some bigger injectors, remapping, etc)

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The LS2 and LS7 say hi.

Gasoline turbo cars do not necessarily carry an advantage over a normally aspirated engine of the same power. This advantage is thinned further by HCCI.

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gas mileage is highy gear dependent though.... a 2.0L spinning 4200k rpms at 80mph (performance bias gearing) will use roughly the same amount of fuel as a 6.0L spinning 1400rpms at the same speed. Hence why the Vette gets such good hwy mileage.

Take a 4.0L turbo V8, gear it the same as the 6.0L V12 NA motor of equal power, and the smaller motor should get better gas mileage (and CO2 emissions) in 'normal' driving.

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Are you saying the Vette doesn't have performance bias gearing?

Why would one gear a 4.0L turbo V6 the same as a 6L V12? Even if you had the same gearbox, you should select a different gear in "normal" driving. This is because the turbo doesn't really work well at small throttle openings. Not only does the throttle plate tend to stop the air compressor impeller from working, but the reduced air into the cylinder means less comes out and so there is less exhaust to drive the turbo up to speed in the first place.

The turbo V6 is going to have to run more revs to get the same drivability as the V12. And this will increase the internal friction to the level of the V12 and thus knock down the mpg to similar levels too.

Hell, it's not like Ferrari spends a lot of time on mpg anyway. Their first steps probably aren't to design a whole new engine, but to see how they can improve the ECU programming and other small tweaks to their existing engines. Then design a new engine that incorporates these principles. Maybe it'll be a V12, maybe it'll be a turbo V8. Maybe it'll even be a turbo V6. Who knows?

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6th gear in the Vette is certainly not for performance. Not sure about the C6, but the older C5s use to top out in 5th gear because 6th was so tall for fuel economy reasons. Hey, I'm all for that because there's not a single race track in America where you're going to hit 180mph in a street car unless you're making insane amounts of power.

A 4.0L motor will only have to run ~8psi of boost to match the 6.0L motor. With properly sized turbos, you'll have that boost at 2k rpms. So, you'll essentially have the same torque and horsepower as the bigger motor from 2k rpms on up. Essentially same tq and hp curves mean the same gearing. No need to rev higher than the bigger motor.

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You cannot run appreciable boost at part throttle openings. Try driving a turbo car with a boost gauge some time. Unless the throttle is near wide open, you're not only not getting boost, you're running under vacuum. This means at part throttle you have to run higher revs than the turbo motor. And part throttle is where mpg matters, because no high powered car gets good mpg at WOT, because it takes fuel to make HP.

Note this (lack of a throttle plate) is yet another reason Diesels take to turbos better than gas cars.

No, 6th gear in Vettes isn't for the track. That leaves you with a mere 5 to work with. Oh, the humanity!

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You illustrate my point exactly with gearing and mileage. You can make a big motor get good mileage by gearing it down. However, the gearing in other cars such as the F430, etc are more performance baised with closer ratios, which also contributes to their ultra crappy mileage.

But you make no sense with your part throttle arguement and turbos. Considering I've driven a turbo car every day for the last 6 years, I know exactly how they behave and apparently you do not. With a properly sized turbo, ~1/3-1/2 throttle will create positive pressure. You will never be in boost while just cruising at highway speeds with any gas motor over 1.6L unless you're trying to power a F150 with it. I tried once to see how fast I had to go in order to require staying in boost at a cruise speed with my 2.0L Nissan, but slowed down after 110mph and never hit positive pressure. As long as you're not in boost, you do not have to run the rich A/F ratios that burn excessive gas.

So my statement stands, using a turbo motor of 4L that makes equal torque and power of a NA 6L, with the same gearing, the 4L will get better gas mileage in daily driving. I'll add that it'll most likely get WORSE mileage at the track.

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