So it has been a week since the reveal...
05-03-2017 | 05:06 PM
#125
Suzuka Master
Joined: Sep 2006
Posts: 7,674
Likes: 2,600
From: Raleigh, NC - USA
Gearing is a torque multiplier. Both engines have the same output at the crank but the 3:55 gearing is a better torque multiplier. More effective torque better acceleration. Back in the day of the Muncie rock crusher the cool kids got the sexy 2:20 1st gear close ratio box. The guys going to Englishtown got the wide ratio 2:56 first gear box for superior torque multiplication & better acceleration.
05-03-2017 | 05:25 PM
#126
Team Owner
Joined: Jun 2014
Posts: 30,487
Likes: 4,416
From: In an igloo
I think there's some misunderstanding of what Saintor's said. He said,
"Prove it. The "295lb/ft of torque at 1600rpm right up to 5200rpm" is good for test benches, but rarely conclusive for acceleration."
I don't think he's arguing that having low end torque is useless. He's saying that having a lot of low end torque does not automatically mean it's gonna accelerate fast. If it is, then the BMW 335d should be much faster than the BMW 335i. The thing is, with modern boosted engines, manufacturers set their ecu so that the peak torque is LIMITED and stays the same through out. What this means is that, the car would still feel very lively in low rpm because of all that torque, and likely to feel more lively than a NA engine with the same horsepower rating. But as the S2000 has shown us, even if you don't make a whole of torque at low rpm, you can still get decent acceleration, and it's hp that determines how fast a car can accelerate.
As you mentioned, hp is a function of torque, so, you NEED torque to get hp.
Again, the torque curves gives you an idea how the engine would feel when you are driving it. With something like the Q50 silver sport, or any modern turbocharged cars, you don't need to be shifting constantly to get moving. In fact, shifting to a lower gear might not help that much. Whereas in a car like the S2000, if you don't always keep the engine in high rpm, you will be going nowhere fast. But ultimate, the S2000 can still accelerate like any other cars with 240hp at 2800lb.
So your comment,"Honda engine can keep making HP into the high revs, but that's simply due to- you got it- the high revs, as by about ~4500-5000rpm, torque starts to drop," is not 100% correct. Honda NA engines can make hp into the high revs because even at those high revs, the engine is still sustaining the torque output - not dropping. In the case of the S2000, the torque actually GOES up once it's at 6000rpm or so, and maintains it all the way to 9000rpm.
So here's an example, if the torque of the S2000 starts to drop at 6000rpm, say, just 120lbft by 8500rpm, the horsepower would be: (8500RPM x 120lbft)/ 5252 = 194hp@8500rpm
On the other hand, if the S2000 maintains 150lbft at 8500rpm, we would have (8500rpm x 150lbft)/5252 = 243hp
The S2000 is an extreme example, but if you look at a non high revving NA k24, or J35, a similar trend can be seen - that the torque curve is quite flat and doesn't start dropping off until 5500rpm or so.They might not make peak torque from 1500-5000rpm, but they still maintain 90% peak torque from 2000rpm to 6000rpm or so.
Also, most modern turbocharged cars have small turbochargers. They are good for minimizing lag, and more importantly for this discussion, are designed with making peak torque as soon as possible (ie, 1x00 rpm). The downsize is that they can't keep that boost up after 5000rpm or so. But for regular consumers, they don't really care about power after 5000rpm.
"Prove it. The "295lb/ft of torque at 1600rpm right up to 5200rpm" is good for test benches, but rarely conclusive for acceleration."
I don't think he's arguing that having low end torque is useless. He's saying that having a lot of low end torque does not automatically mean it's gonna accelerate fast. If it is, then the BMW 335d should be much faster than the BMW 335i. The thing is, with modern boosted engines, manufacturers set their ecu so that the peak torque is LIMITED and stays the same through out. What this means is that, the car would still feel very lively in low rpm because of all that torque, and likely to feel more lively than a NA engine with the same horsepower rating. But as the S2000 has shown us, even if you don't make a whole of torque at low rpm, you can still get decent acceleration, and it's hp that determines how fast a car can accelerate.
As you mentioned, hp is a function of torque, so, you NEED torque to get hp.
Again, the torque curves gives you an idea how the engine would feel when you are driving it. With something like the Q50 silver sport, or any modern turbocharged cars, you don't need to be shifting constantly to get moving. In fact, shifting to a lower gear might not help that much. Whereas in a car like the S2000, if you don't always keep the engine in high rpm, you will be going nowhere fast. But ultimate, the S2000 can still accelerate like any other cars with 240hp at 2800lb.
So your comment,"Honda engine can keep making HP into the high revs, but that's simply due to- you got it- the high revs, as by about ~4500-5000rpm, torque starts to drop," is not 100% correct. Honda NA engines can make hp into the high revs because even at those high revs, the engine is still sustaining the torque output - not dropping. In the case of the S2000, the torque actually GOES up once it's at 6000rpm or so, and maintains it all the way to 9000rpm.
So here's an example, if the torque of the S2000 starts to drop at 6000rpm, say, just 120lbft by 8500rpm, the horsepower would be: (8500RPM x 120lbft)/ 5252 = 194hp@8500rpm
On the other hand, if the S2000 maintains 150lbft at 8500rpm, we would have (8500rpm x 150lbft)/5252 = 243hp
The S2000 is an extreme example, but if you look at a non high revving NA k24, or J35, a similar trend can be seen - that the torque curve is quite flat and doesn't start dropping off until 5500rpm or so.They might not make peak torque from 1500-5000rpm, but they still maintain 90% peak torque from 2000rpm to 6000rpm or so.
Also, most modern turbocharged cars have small turbochargers. They are good for minimizing lag, and more importantly for this discussion, are designed with making peak torque as soon as possible (ie, 1x00 rpm). The downsize is that they can't keep that boost up after 5000rpm or so. But for regular consumers, they don't really care about power after 5000rpm.
I own a 2006 3.2L V6 TL, mated to a 6MT, with mods on it (better tires, exhaust, intake, intake spacer, etc).
I also own a 2012 2.0T I4 Sonata (wifes car)
after an extensive overhaul of the TL, the wife and I just so happened to be driving home together- her in the sonata, me in the TL. We were stopped at a red light with an empty road in front of us. We decided to open the cars up, off the line.
The TL was more than handily beat. Every time I shifted, she kept pulling on me. We called it quits by ~120km/h. She beat me by a bit more than a car length. You can suggest I need a driver mod, but I've been driving manuals for a decade now and have developed some very fast shifting skills, amongst other things such as rev match downshifting and heel-toeing- not something the average manual driver can do. Once again, she beat me without even trying, in an automatic, completely stock car, to boot.
Argue what you want, but you're making a lot of generalizations, and the mighty, bigger engine with two more cylinders had its ass handed to it, by a smaller, less cylinder, turbo unit. I also looked into the weight differences and they were at about ~175 pounds of each other, when considering the amount of fuel and other shit in the cars (The TL being slightly heavier).
05-03-2017 | 05:47 PM
#127
Banned
Joined: Feb 2001
Posts: 2,905
Likes: 124
From: MTL, Canada
Gearing is a torque multiplier. Both engines have the same output at the crank but the 3:55 gearing is a better torque multiplier. More effective torque better acceleration. Back in the day of the Muncie rock crusher the cool kids got the sexy 2:20 1st gear close ratio box. The guys going to Englishtown got the wide ratio 2:56 first gear box for superior torque multiplication & better acceleration.
05-03-2017 | 07:49 PM
#128
Suzuka Master
Joined: Sep 2006
Posts: 7,674
Likes: 2,600
From: Raleigh, NC - USA
Ok, But you are still talking about variation in gearing, not variation in engine torque. Instant force applied on the wheel is a different beast than engine torque. Static engine torque alone means not much, except for its ability to sustain a load. For accelerating, you need more like its ability to create the most effect from both sustained torque and RPM variation (i.e. movement) in the least time which is in check with the definition of power. This is why engine power is what matters most at any RPM, not engine torque.
For cars in a 1/4 run will gain most of there terminal speed in the first 1/8 mile. Using my 335is as an example. First 1/8 mile 8.06 @90mph + second 1/8 mile 4.5 @ 24mph = 1/4 12.5 @114mph. Torque multiplication runs out & horsepower pulls you over the line.
05-03-2017 | 08:28 PM
#131
Banned
Joined: Feb 2001
Posts: 2,905
Likes: 124
From: MTL, Canada
Here is an hint for you.... with a given gearing, an engine torque of 300lbs-ft at 1000rpm won't give you the same applied torque [force] at the wheel as 300lbs-ft at 5000rpm. Yeah I know, now it is more obvious....
