Quote:
|
Originally Posted by blue2000s
This is the WHOLE point. I wish I could connect these dots somehow because you're saying it right here.
If you change breathing on the engine, then you've changed the horsepower and torque curves and the game is a new one.
What he's saying is that redline isn't best in EVERY situation with an actual example, which, if you look back at my responses, is also exactly what I said.
Debate and discussion is a useful learning tool. If it remains on subject and avoids getting personal, all it can do is enlighten.
|
Here's the thing about the camero. Even tho it lost steam up top, it still will accelerate faster if you take it to redline. Making the car accelerate fast has more to do with being where the engine can accelerate than where it makes the most power over the logest part of the curve. Changing the intake manifold would have just made it more efficient and could beat the NSX but he should still shift at redline.
Lets say the Camero has a redline of 6000rpm. But makes peak power at 4500rpm which is probablly pretty close to the truth. Lets also assume the gears are long which they are so switching to the next gear will induce a drop of 2000rpm from whatever point you are at. Based on the curve of that engine it would probablly be best to shift at 5500rpm and land at 3500rpm where your in the greatest part of the curve. The problem is the engine will not accelerate as fast even though your in the strongest part of the curve.
Shifting at 6000rpm even though your way over the curve is better. The engine accelerates faster at 6000rpm with less hp than it does at 4500rpm with a lot more, thats what I'm trying to say. So shifting at 6000rpm and landing at 4000rpm is in a point where the engine will accelerate faster even though your not in the maximum part of the torque curve. It's all about how freely the engine can accelerate.
It's for the same reason many companies say you can't spray nitrous on a motor at less than 3000rpm. This is true most of the time but not all the time. The engine car freely rev in 1st and 2nd gear in most cars so you can spray them right at 1000rpm outta the hole in drag racing. You can't do this in 3rd onwards however because the engine ability to accelerate is lower so the stress on the motor with all that power is too high and will melt a piston.
This is the same way the engine works when accelerating at the top. It will accelerate more freely between 5500-6000rpm even tho it's making less power so acceleration will be greater even with less hp. I know this doesn't sound right, but a quick trip to the strip with that Camero would prove this, short shifting the engine into a zone down low where it doesn't accelerate is worse.
There is a trade off. You have 2000rpm you must accelerate in no matter what. What will accelerate faster? The zone from 3500-4000rpm or the zone from 5500-6000rpm? Look at this graph and you will see what im talking about. The Green zone is better because it will accelerate in the last 500rpm faster than the first 500rpm in the red zone. This is only true because its up higher in the rpm band where it's easier for the engine to accelerate. Even though it's outta the curve, the last 500rpm (5500-6000) is just a faster spot for the engine than 4000-4500rpm spot at the beginning of the shift.
What we are really debating is which 500rpm are better? The 500rpm frpm 4000-4500 or the 500rpm from 5500-6000. The rest of the rpm in the middle we are both in regardless.
Hope that helps,