first off, a disclaimer: I'm goig to talk about petrol(gasoline)-fuelled non-turbo-charged engines here (mind you, about a half of cars in Europe are turbo-diesels but I want to limit down the spectrum so we don't get lost in too many variations)
fallout ranger wrote:A 4 cylinder will usually be somewhere between 1.5-2.5 liters in capacity. Knowing that and assuming an average HP/capacity ratio of 85hp/liter across the board (for NA variants), a 4 cylinder can be assumed as having ~130-215 horsepower.
A 6 cylinder is normally 3-4 liters and has an average output of 75hp/liter, this would give it power in the range of 225-300 hp.
An 8 cylinder is usually between 4.5-6.5 liters, and has 65hp/liter. Assuming these capacities and ratios, an average V8 would have ~300-425hp.
4 cyl---130-215
6 cyl---225-300
8 cyl---300-425
I don't know that much about America (I guess Gore can handle that), but I can write a bit about Europe.
I think now we want to discuss what's widely used and not some super-powerful units so I'll use examples of some of the most popular cars in Europe;
1 very popular German make, 1 French, and 1 Japanese: a small model and a big/mid-size model from each. (data is probably valid for cars not from the latest generation)
Volkswagen: Golf, Passat:
4-cylinder units: 1.4L/75hp - 2.0L/102or115hp (53.5hp/L - 57.5hp/L) average 55.5hp/L
Renault: Clio, Laguna:
1.2L/60hp - 2.0L/140hp (50hp/L - 70hp/L) av. 60hp/L (1.1L is rare)
(mystery here: 2.0L is 140hp but 2.0turbo is 135hp )
Toyota: Corolla, Avensis:
1.1L/60hp - 2.4L/163hp (54.5hp/L - 68hp/L) av. 61hp/L
although typically (1.1 and 2.4 are rare) :
1.3L/75hp - 2.0L/147hp (58hp/L - 73.5hp/L) av. 61hp/L
Altogether, for
popular European cars,
4-cylinder non-turbo petrol engines have
1.2-2.0L displacement (or even 1.1-2.4L) and
60-147horsepower (or even 163hp),
hp/L ratio ranging from
50 to 73.5hp/L.
Average hp/L ratio for this group (I chose to add the 6 ratios and divide by 6) is
60.5hp/L
So basically what I calculated doesn't look like what you wrote, F.ranger
The point is that displacement is assumed when talking about cylinder counts, and when you assume displacement you get some sort of guess as to power
as you could notice (see some of my posts before for example), displacement-power ratio alone is quite varied. Then if you make allowances for cylinders'number-displacement ratio being so very different for different models (and you
should make), talking in terms of cylinders' number to indicate power is far too fucking vague, imprecise and a wee silly