Re: 304/290/200R4 - now V8 Fuel Mileage

[adh@xxxxxxxxxxxxxxxxx (Sandwich Maker)]

" From: Tom Jennings <tomj@xxxxxxx>
" 
" On Mon, 9 May 2005, Sandwich Maker wrote:
" 
" 
" > 'lugging' it is not a good idea.
" >
" > generally, your engine will be most efficient near its torque peak.
" > if you want great highway mileage, you want a cam that moves that peak
" > down toward your highway rpm.
" 
" As I see it, there's three things in tension: lower RPMs keeps
" frictional losses low, but you must have enough to makde decent
" torque and HP.  1600 rpm sounds great, but it's impractical to
" make HP there. 2000 - 2500 is probably a good target RPM for
" torque peak, probably line up all the hard parts
" (trans/OD/axle/tires) then have a cam ground to put it spot on the
" target RPM/MPH.

all the amc sixes excepting the 4.0 at least -claim- torque peaks in
the 1600-1800 rpm range.  my 199 sure drives like it; i can pull top
[3.08 axle] from almost idle when the car's warmed up, and it feels
like it could shift again about 45.

i don't think you could move a v8's peak down that low even with the
mildest cam; they breathe much better than sixes.  but it's moot if
you get comparable off-idle and low rpm grunt.

" But first you can take really big hints from what the factory did;
" little americans with manual trans and steep axles, see where
" those cams are ground and start there.

3.08 + od was a factory option in americans even with the 199.
________________________________________________________________________
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen

adh@xxxxxxxxxxxxxxxxx                       and think what none thought