[Shovelman]

One thing that defines a car for me is how much air it moves thru the cylinders. It's not as telling as power to weight but it speaks to me about the character of the drivetrain. To calculate the basic number, multiply the rpm at 60 mph by the displacement.

*230i 2200 rpm x 2.0 l = 4400 liters per mile.

Cobalt 2400 rpm x 2.0 l = 4800 l/m

Impala 1800 rpm x 3.5 l = 6300 l/m

Beatle 3000 rpm x 1.2 l = 3600 l/m

*turbocharged

Of course this is in high gear, and it assumes that air moved equals displacement which is not even close. It is an interesting starting point. Any numbers to share?

[petegtsv10]

Viper: (guessing at rpm) 8.4(1200) = 10080
ZO6 (supercharged, and guessing at rpm because it's raining now) 6.2(1200) = 7440

[Sportstick]

Originally Posted by Shovelman

One thing that defines a car for me is how much air it moves thru the cylinders. It's not as telling as power to weight but it speaks to me about the character of the drivetrain. To calculate the basic number, multiply the rpm at 60 mph by the displacement.

*230i 2200 rpm x 2.0 l = 4400 liters per mile.

Cobalt 2400 rpm x 2.0 l = 4800 l/m

Impala 1800 rpm x 3.5 l = 6300 l/m

Beatle 3000 rpm x 1.2 l = 3600 l/m

*turbocharged

Of course this is in high gear, and it assumes that air moved equals displacement which is not even close. It is an interesting starting point. Any numbers to share?

Interesting, and reminds me of a chat early in my career with one of our powertrain engineers that an engine is just an air pump. Had not thought of it that way before then.

But, with your analysis, what is the implication? Does Impala "win" for pumping the most air at the lowest rpm at 60mph, presumably creating more torque (?), or does your "Beatle" (would that be Paul, Ringo?), um, Beetle, come out best for being the most efficient for the least air to achieve the speed, and the least fuel to go along with that air?

[bimmerfile]

Back in the '70's I had a '73 Pontiac Grand Am with a 7.4 liter V8, so at 2400 RPM (using the formula) I guess that must have kicked out 17,760 LPM?
Does that win me a chicken dinner?

[3.0L]

Clearly, the Impala will need more frequent air cleaner replacements.

[Gabrola]

According to Bugatti, the Chiron gulps up 60,000 liters per minute

[Sportstick]

Originally Posted by Gabrola

According to Bugatti, the Chiron gulps up 60,000 liters per minute

That takes my breath away!

[morphomeman]

If we measure liters per dollar, the Bugatti is clearly a big loser.

[Maynard]

Somebody needs to go back to shop class (math is intact). On a four stroke engine it is 'suck squeeze bang blow' - in other words, only half the cylinders are sucking air each revolution, the other half are sealed up making power on the downstroke. So your numbers are double the potential volume. The Turbo adds another twist, really a big wildcard, because they are pushing in more air. This will make turbo-to-normal aspiration an unfair comparo, biased against turbos. You could dig out the standards and convert boost pressure to volume, or make an engineer's day and email BMW asking them for the Kg mass numbers (I think the only simple way to quantify gasses at variable heat).

In principle, you are right that the % filled - volumetric efficiency - is crucial, and it used to be almost synonymous with power and tuning before turbos. Good race engines could move >100% of their volume by using well tuned manifolds, and the engine becomes more like a musical instrument than a simple air pump. Now simpler (for me) to use hp/litre as a measure of how heavily boosted a motor is, and how long you are likely to go before you learn who made your turbo and how much they want for a new one - i.e. some Merc's and Audi's are pushing over 300hp from the same 2L size, and racers can get well up into the 500's, but with 'substantially reduced service intervals'. For street cars I think Honda is the current NA champ, with the s2000 putting out about 120/L IIRC (1060's F1 type numbers, but don't think they had VANOS/VTEC).

[Shovelman]

Ouch! that's an embarrassing math error. Of course you are right (with the exception of the ancient Saab 2 strokers). I did put an asterisk by the turbo because it makes a big difference.

[3.0L]

One bit of good news: Air (for now), is free. It's just the fuel you have to add to it that might be a problem. Or not, depending on the size of your wallet.

[Gabrola]

Originally Posted by morphomeman

If we measure liters per dollar, the Bugatti is clearly a big loser.

The Bugatti is the worst value for money car anyone could buy; it's pretty much a big loser at anything per dollar

[Maynard]

^^^^That, except resale value. Theoretically, since they seem to appreciate, and a lease is financing of the depreciation, then a lease option would have the dealer paying me to drive it, right? right? Yeah, the guy on the phone at Braman Bugatti was laughing too (and no, I even afford to change the washer fluid, let alone the brakes or tires - I think it eats what my car is worth in about 2k miles).

[EuroDude]

You forgot the "e" at the end of breath, breathe. I thought this thread was about asthma and COPD