knock, knock! Who's there?

[Tess McMillan]

Right, I remember the vacuum pump; that sound was more "Audi-sounding" 
than the knock I am experiencing now. We removed the pump from my car 
about two years ago. 

This knock is happening at 3800 rpm, when the engine is working hard 
(more so going uphill, for example). But I think I remember when I went in 
for my track inspection in April, they leaned me out a bit. It's been 
since about that time, maybe May or so, that I've started to notice this 
issue.

And to be completely truthful, on a daily basis I'm only commuting to 
school and back and with so much schoolwork I am not getting out to do 
Italian Tune-ups on the weekend. 

Thank you for the education, guys!

Tess

On Sun, 22 Jul 2007, Tony Hoffman wrote:

> And, to add to that, because it's pre-detonation, it tends to hapen
> more at lower RPM's or where the "dynamic" compression is higher. As
> an engine turns faster, it actually pulls in less ari per RPM. This is
> because the valves, intake system, exhaust, etc, is not a limiting
> factor for airflow at lower RPM's. But, that becomes an impedence at
> higher RPM's. Which is exactly where bigger cams, bigger exhaust, high
> flow air intake systems, ported heads, etc all come in.
>