various long post(trying to catch up)

[Edward C. Hernandez]

> Gentlemen, OEMs use exhaust gas to supress detonation, right? 

NO, we use it for NOx control because it reduce peak combustion
temperatures(reducing NOx formation). It has a side effect of reducing
burn rates(because it significantly dilutes the mixture), which means
you need more spark advanvce when EGR is on. Problem is, EGR heats up
the inlet air, shortening the fuse. Water can do this without heating up
the air(arguably, cooling it) and without diluting the mixture to the
same extent. I'm having second thoughts about water's effect on burn
rates now...

>I have read that the big reason for four valves is to get the spark
>right in the center.  Flame front has much shorter distance to travel,
>meaning higher compression without detonation.  You could probably get
>the same effect with four spark plugs per cyl.

Yes for all three sentences. There has been research on the last.

Edelbrock Vari-Jection is no longer offered.

One possible source for spec sheets on sensors would be a certain kind
of service manual from the dealership. I've seen exerpts from such a
manual that we used to diagnose faulty sensors a few years back. Can't a
imagine a dealership without one of these manuals. If  they won't sell
you one, maybe you can convince them to give you an outdated one.

Short term knocking is okay, but the longer or more severe it is, the
greater chances of scuffing bores and breaking ring lands and losing
crush in the rods bearings. Personally, I try never to knock. I don't
always succeed, but I wince when I hear it.

dn, is there a FAQ for some of this stuff? I don't know if you have a
site or just a digest. I can't get over the firewall here. I would
consider writing a FAQ or two for your site so the same questions don't
get asked over and over.

Ed Hernandez
Ford Motor Company
ehernan3 at ed8719.pto.ford.com