This is very long and probably a bit confusing. Read it a couple times before you reply.
You guys (with one exception
) are forgetting one very important thing, GEARING.
Remember gear ratios x the final drive ratio affect how much force (torque) the drive wheels get. Higher gears equal less force (torque) at the wheels. The longer you can stay in lower gears the better, as this will allow you to accelerate faster.
HP and torque cross at 5252rpm after that HP increases with RPM, UNTIL the torque drops faster than the rpms are rising. Once torque and HP drop your rate of acceleration in that gear will decrease, so you'll shift. As we know already once you grab that higher gear the amount of force put down at the drive wheels will decrease.
So if you can figure out how to keep the torque curve on its "plateau" up to a higher rpm than you can rev higher while making more hp. That will let you stay in a lower gear for a longer period of time. Which will allow you to get more WORK done.
I took some numbers from a dyno chart of a 99GSX (dre). It's major mods are a stock 1G head, crower cams, stock bottom end, FP green, large spearco FMIC, usual fuel mods, PROefi stand alone. This pull was at 20psi on 92 octane pumpgas:
http://www.twingles.com/ideck/datalog/dyno092101b.jpg
Granted it's not the best dyno chart in the world due to something causing the choppy torque/hp curves, but it's enough to get our job here done.
It makes 345 foot lbs of torque at around 5000rpm and it starts to drop rapidly at around 6,800rpm. This netted 401hp at 6,800rpm.
Now let's say that dre did something to keep the torque curve from dropping until 9,000rpm (hard I know and the required mods would probably raise the torque peak, change it, and this is all going to be impossible on pump gas. Bear with me, this is all theoretical).
Horsepower * 5252
Torque = -----------------
RPM
If we plug in the numbers, 345 foot lbs of torque times 9000 all divided by 5252 we get ~591hp.
So we gained 190hp and allowed ourselves to rev another 2,200 rpm. That allowed us to stay in gear a lot longer, so it increased the total amount of WORK done in a given time frame (remember if you shift earlier you decrease the amount of force at the wheels, which will decrease the amount of work done than if you were in a lower gear).
Now let's make up some mythical numbers for our 2.4l engine. Let's say that with it our torque peaked around the same rpm, but a much higher torque value, 425 foot lbs. BUT we can't rev over 7,500 rpm due to the rod angles and piston speed of the 4G64 at high rpms, even though our torque curve might not be dropping.
When we plug in the numbers at our 7,500 rpm redline we get:
571hp. So in the end we are making LESS peak hp and shifting earlier, decreasing the amount of work we could get done in a given time period.
Less work in a given time period will mean it takes a longer period of time to move a mass a certain distance. If you do less work it is going to take longer to move 3000lbs a 1/4 mile.
So in other words our super torquey 2.4l will be slower than our hyper strung 2.0l.
Given the right valvetrain modifications the 4G63 can rev to 9k, although I do not have dyno charts to show if torque falls off well before that rpm or not.
A short word on torque vs hp though. Torque is all you feel when you drive, hp doesn't affect how hard your car "pulls" at all. The 4G64 powered car would feel a hell of a lot faster than the 4G63 powered car on the street, BUT it wouldn't actually be any faster. If you just want your car to slam your head into the seat the 4G64 would be worth it for sure, but if you actually want to be faster it might not be in the end.
Another thing to remember is that torque is multiplied by your gear ratio. 400 foot lbs of torque is going to end up being a shitload more going through your tranny in 1st and second than 345 foot lbs is. You're going to kill second gear syncros like mad.
I can't see this ever making the car faster in the 1/4 mile. Yes if our mythical 4G64 setup made 413 foot lbs of torque it's peak power would match that of the 4G63s. BUT it would still require you to shift 2,200 rpm lower and the amount of work done would still be less for a given time period.
You need to rev higher, not make more torque.
The replacement for displacement is HIGH RPM TORQUE AND GEARING!