What are the benefits of having a higher redline such as in an SR20, 3sgte, K20 etc. etc.? I'm having an argument with a domestic buff who won't listen to reason. I've given him all the basics and yet his whole defence is, "i've got the torque at 2000rpms, you don't get yours until 4000."
So waht else can i slam into his face?
Benefits of having a higher redline?
Tell him if high RPMS arent great, then why do Indy cars and F1 cars rev to 15k?? you make more power at higher RPMs, or at least have more potential. torque is good for drag racing and daily driving, but for a road course, most of the cars have freer flowing engines that rev up a lot higher because they can make more power that way.
EDIT: Tell him smaller displacement engines rev up that way to make more power for their size. Since they're not outlandishly huge and slinging around pistons the size of a paint can, they need to rev up a little higher, which means they have a different powerband, but perform better with a different transmission because they can do more work. If hes smart, he'll know how to do the equations for the work an engine makes and if hes dumb, he'll probably just say, "see, no replacement for displacement" without actually looking into it.
EDIT: Tell him smaller displacement engines rev up that way to make more power for their size. Since they're not outlandishly huge and slinging around pistons the size of a paint can, they need to rev up a little higher, which means they have a different powerband, but perform better with a different transmission because they can do more work. If hes smart, he'll know how to do the equations for the work an engine makes and if hes dumb, he'll probably just say, "see, no replacement for displacement" without actually looking into it.
-
Nismo_Freak
- Posts: 10314
- Joined: Wed Jul 24, 2002 10:42 pm
- Car: 89 Nissan 240SX
You have to apply gearing as a factor as well, a car with a higher redline (well mainly powerband) can take advantage of a quicker gear ratio.
Plus the higher the RPM the higher the potential for power production. The engine is an overglorified air pump in a sense.
Theoretical Ex.
2.6L @ 8200 RPMS10660L of Air Moved
5.7L @ 6200 RPMS17670L of Air Moved
Now we know that the 2.6L is turbocharged, this nets a rough peak 71% more airflow at 10psi.
This gives it 18228L of air being moved, which dictates the RB26 should make more power than a LS1. When in fact it doesn't. The fact that the RB26 is a turbocharged engine reduces it's ability to make the most of every L of air injested because of heat, pressures, restrictions, etc.
There is no replacement for displacement, but efficiency and higher rpm operation sure come close.
Plus the higher the RPM the higher the potential for power production. The engine is an overglorified air pump in a sense.
Theoretical Ex.
2.6L @ 8200 RPMS10660L of Air Moved
5.7L @ 6200 RPMS17670L of Air Moved
Now we know that the 2.6L is turbocharged, this nets a rough peak 71% more airflow at 10psi.
This gives it 18228L of air being moved, which dictates the RB26 should make more power than a LS1. When in fact it doesn't. The fact that the RB26 is a turbocharged engine reduces it's ability to make the most of every L of air injested because of heat, pressures, restrictions, etc.
There is no replacement for displacement, but efficiency and higher rpm operation sure come close.
-
C-Kwik
- Moderator
- Posts: 8070
- Joined: Thu Aug 01, 2002 9:28 pm
- Car: 2013 Chevy Volt, 1991 Honda CRX DX
It's easiest to think of this by looking at torque at the wheels. An S2000 is usually a great example to use as a high revving motor. Find a 240 HP V8 and start doing some torque multiplication with the gearing each car comes with. You'll find they will put down similar average torque numbers.
And then if you would like bring up the Porsche Carerra GT. It uses a 5.7L V-10 that puts out 605 HP and 435 lb-ft of torque with a 8400 RPM redline. A competition Viper puts out 520 Hp and 540 lb-ft of torque. Both cars are within 50 pounds of each other. Both nail a 1/4 mile in 11.2 seconds. The Porsche traps at 132 and the Viper at 130. The Viper is a HUGE 8.3 Liters. While there is a bit of a HP difference where the Viper would seem slower on paper, the larger displacement is likely tuned with a a very broad torque curve. The area under the curve is likely huge. Not to mention the Viper competition test I am using as a reference used Hoosier Slicks and the Porsche used Michelin PS2's. But in any case, the Porsche does the same thing the Viper does with a smaller motor. I couldn't find a direct comparison, but the Viper hit 60 in 3.1 seconds 100 in 7.0 seconds and 130 in 11.2 seconds. The Porsche does the same in 3.5, 6.8 and 10.8 respectively. Clearly the Porsche is beginning to show it's horsepower advantage at higher speeds. Yet, on the next page of the magazine I am using as a reference, there is a 690 HP Viper(modified consumer Viper) and only clicks off the 1/4 mile in 11.4 seconds at 128 MPH. Despite being a heavier car, the HP to weight ratio of this car is better than the Viper Competition and the Porsche. Race tires would likely help a lot here, but even then it's not catching up to the Porsche at higher speeds either. Aerodynamics may be a small factor here, but it's still an interesting observation. Another contrast to consider is that the Corvette Z06's 5.7L V-8 only musters up 405 HP and 400 lb-ft of torque. It pushes nearly the same weight through the 1/4 mile in 12.4 seconds at 116 MPH. In any case, this is very convincing proof of how high RPM's can replace displacement.
I used the June 2004 issue of Car and Driver as a reference for the Porsche and the 2 Vipers and did a search on the Car and Driver website for the figures on the Z06.
And then if you would like bring up the Porsche Carerra GT. It uses a 5.7L V-10 that puts out 605 HP and 435 lb-ft of torque with a 8400 RPM redline. A competition Viper puts out 520 Hp and 540 lb-ft of torque. Both cars are within 50 pounds of each other. Both nail a 1/4 mile in 11.2 seconds. The Porsche traps at 132 and the Viper at 130. The Viper is a HUGE 8.3 Liters. While there is a bit of a HP difference where the Viper would seem slower on paper, the larger displacement is likely tuned with a a very broad torque curve. The area under the curve is likely huge. Not to mention the Viper competition test I am using as a reference used Hoosier Slicks and the Porsche used Michelin PS2's. But in any case, the Porsche does the same thing the Viper does with a smaller motor. I couldn't find a direct comparison, but the Viper hit 60 in 3.1 seconds 100 in 7.0 seconds and 130 in 11.2 seconds. The Porsche does the same in 3.5, 6.8 and 10.8 respectively. Clearly the Porsche is beginning to show it's horsepower advantage at higher speeds. Yet, on the next page of the magazine I am using as a reference, there is a 690 HP Viper(modified consumer Viper) and only clicks off the 1/4 mile in 11.4 seconds at 128 MPH. Despite being a heavier car, the HP to weight ratio of this car is better than the Viper Competition and the Porsche. Race tires would likely help a lot here, but even then it's not catching up to the Porsche at higher speeds either. Aerodynamics may be a small factor here, but it's still an interesting observation. Another contrast to consider is that the Corvette Z06's 5.7L V-8 only musters up 405 HP and 400 lb-ft of torque. It pushes nearly the same weight through the 1/4 mile in 12.4 seconds at 116 MPH. In any case, this is very convincing proof of how high RPM's can replace displacement.
I used the June 2004 issue of Car and Driver as a reference for the Porsche and the 2 Vipers and did a search on the Car and Driver website for the figures on the Z06.