[19Nova72]

When your accelerating like a sane human being on a public road, what exactly causes the motor to have that 'loaded up' sound. Especially when going up hills or when you are in too high of gear and accelerating. I've noticed 1st gear in my Nova doesn't ever really put a load on the motor I assume because of the gear multiplication, but 2nd and 3rd will. The part that gets me is that if your accelerating @ a fairly constant rate, on flat ground, what all of the sudden changes??? Timing curve? A/F ratio?

 

[RedSS454]

I'll throw in what I think about this, but it sure is no scientific answer. The fact that it doesn't sound like that in 1st is probably the gear multiplication. Similar to the way that Deisel trucks don't use first gear if their not loaded.

And in 2nd and 3rd, the gear ratio changes, so the car is working harder to push the car to that given speed. Working harder would give it that 'loaded sound'. Similar to how the car sounds a little different when you rev it in nuetral/park then when you drive it at that same RPM.

Chris

 

[19Nova72]

I think your right, it's definatley working harder and is ineffecient when it gets louder. I'm still confused as to why it gets louder. Maybe it's because the gas is being burnt to late on the compression stroke and more of the sound travels out the exhaust? Whatever it is drives me nuts not knowing why it does that.

 

[Jerry70]

If you're running an open element air cleaner the sound will be more noticeable than with a snorkle type. What changes is the pitch of the sound. As you change gears (up) engine rpm drops and so does air velocity, both intake and exhaust. Put some 4.88's in it and the sound difference won't bug you as much .

 

[Randy Mosier]

How is the power output at lower RPMs vs higher RPMs? Does it seem to pick up power as the RPM climbs? I had a 74 Cheyenne pickup years ago that really bogged down bad until the RPM built up, and then it took off like a rocket! It turned out to be a timing chain that was so stretched, it had actually jumped one tooth out of time. When camshaft timing is delayed, an engine picks up a lot of top end power but loses power on the low end. The opposite is true when cam timing is advanced. An engine will pick up a lot of lower end power but will lose power on the top end. That's how I was able to eventually diagnose my problem in my pickup.