Everybody is familiar with the conversation where you are trying to describe how powerful an engine "feels like" as far as low end grunt, right? Hopefully the point of reference is fairly reasonable, but admittedly it can be wildly subjective. The shape of the powerband means everything. I would consider the powerband shape of a GM Vortec 7400 as a good example of a "generic v8 engine"...medium rpm range and torque spread fairly evenly throughout that range. There's no real surprises...no shortage of low end torque, no overly hot top end, and a very mild rise in torque in the 3000-4000 rpm range. You don't have to "get to some rpm" to enjoy its best because it gives more or less the same amount of brute force no matter where you hit it in rpm. The Vortec 7400 is the quintessential example of a broad powerband v8 with real ruler flat torque output, imo.
So the exercise is how do modern performance v8 engines (yes, I included a Pentastar v6, just for additional perspective) compare as far as output between 2000-2500 rpm (pretty much what you would consider "low end torque" on most engines)? What does the engine "feel like" in that particular range? Does it feel like a 300 hp engine, 350 hp, 400 hp?... I'm not suggesting that 300 hp is actually occurring at that rpm. I'm suggesting this is about what you would expect out of a garden variety v8 engine that carries that rated hp number in that low rpm torque region.
The results are pretty much what I expected, but some may find surprising to see quantified here! Most of all, it really does illustrate how modern engines don't really "feel" like classic engines as far as horsepower values, unless you are expressly exploring some rpm's. If you are just rolling around town at modest rpm, these engines are more tame than their hp spec suggests. Also note that a higher hp spec engine isn't always going to feel "stronger", at least not right out of the gate. The ranking can surprise you.
On the low end,...
-a 320 hp GM Vortec 8100 feels like a whopping 383 hp engine
-a 390 hp Hemi 5.7 feels like a demure 312 hp engine
-a 415 hp Ford dohc 5.0 feels like a very nonathletic 265 hp engine
-a 305 hp Pentastar v6 feels like a very uninspiring 206 hp engine (not at all "v8-like power" as far as the 300 hp number)
Gearing is the key to how these modern engines even maintain a respectable demonstration of output on the low end. 1st gear is critical to let these engines quickly dig out to their respective and proper powerbands. Another way to think about it, is this (383/312/265/206 hp) is more like how these engines would be rated if they weren't being saved by the higher rpm liveliness (the Vortec 8100 being the exception to this and an example of just the opposite, for its clear lack of top end extension). Cams on modern performance cars are more high end oriented than they ever have, eh?
The point is especially poignant as far as the "305 hp" Pentastar v6. Unless you are frequently exploring 3500 rpm and above, it is not "v8-like" in the slightest. It is not far removed from any other "old school" 200-ish hp v6. That's not to say that nobody should ever pick the v6 engine tier for this car. If you seek a v6, then you should get a v6, but you don't get it because the hp rating seems v8-caliber as far as a hp number. It is just not the case, unless you are explicitly intending to keep the rpm on boil as you drive, and even then, it is only a modest example of v8 power, anyway.
Thoughts? Objections? Outrage?...
So the exercise is how do modern performance v8 engines (yes, I included a Pentastar v6, just for additional perspective) compare as far as output between 2000-2500 rpm (pretty much what you would consider "low end torque" on most engines)? What does the engine "feel like" in that particular range? Does it feel like a 300 hp engine, 350 hp, 400 hp?... I'm not suggesting that 300 hp is actually occurring at that rpm. I'm suggesting this is about what you would expect out of a garden variety v8 engine that carries that rated hp number in that low rpm torque region.
The results are pretty much what I expected, but some may find surprising to see quantified here! Most of all, it really does illustrate how modern engines don't really "feel" like classic engines as far as horsepower values, unless you are expressly exploring some rpm's. If you are just rolling around town at modest rpm, these engines are more tame than their hp spec suggests. Also note that a higher hp spec engine isn't always going to feel "stronger", at least not right out of the gate. The ranking can surprise you.
On the low end,...
-a 320 hp GM Vortec 8100 feels like a whopping 383 hp engine
-a 390 hp Hemi 5.7 feels like a demure 312 hp engine
-a 415 hp Ford dohc 5.0 feels like a very nonathletic 265 hp engine
-a 305 hp Pentastar v6 feels like a very uninspiring 206 hp engine (not at all "v8-like power" as far as the 300 hp number)
Gearing is the key to how these modern engines even maintain a respectable demonstration of output on the low end. 1st gear is critical to let these engines quickly dig out to their respective and proper powerbands. Another way to think about it, is this (383/312/265/206 hp) is more like how these engines would be rated if they weren't being saved by the higher rpm liveliness (the Vortec 8100 being the exception to this and an example of just the opposite, for its clear lack of top end extension). Cams on modern performance cars are more high end oriented than they ever have, eh?
The point is especially poignant as far as the "305 hp" Pentastar v6. Unless you are frequently exploring 3500 rpm and above, it is not "v8-like" in the slightest. It is not far removed from any other "old school" 200-ish hp v6. That's not to say that nobody should ever pick the v6 engine tier for this car. If you seek a v6, then you should get a v6, but you don't get it because the hp rating seems v8-caliber as far as a hp number. It is just not the case, unless you are explicitly intending to keep the rpm on boil as you drive, and even then, it is only a modest example of v8 power, anyway.
Thoughts? Objections? Outrage?...