Re: [AMC-List] AMC drivers

[adh@xxxxxxxxxxxxxxxxx (Sandwich Maker)]

" From: Matt Haas <mhaas@xxxxxxx>
" 
" 
" The sweet spot for gas mileage depends on the engine and what the terrain 
" is like around you. Smaller engines need more RPM but an AMC six or V8 
" (which make a lot of torque at low RPM) should be quite happy around 2,000 
" RPM at 65 MPH. If it's flat, you can get by with fewer RPM but you'd need 
" more in a hilly area.

it also depends on the cam.  you have to start to get 'on the cam' to
get good fuel efficiency, and the more radical the timing the more rpm
you'll need to find it.  i'm not talking about wringing it out, i'm
talking about approaching the torque peak.  [nb. engine performance is
also affected by advancing or retarding the cam]

'60s and '70s amc sixes officially developed maximum torque at
1600-1800 rpm.  you could get an american with 199, 3sp+od and 3.08
rear - and the od was set to engage at under 40mph.  cam duration was
only 244* 'on the ramps' [@ .005"]; i've never seen the equivalent
.050" measurement.  a jeep 4.0 would certainly pull these gears in
such a light car, but with 280* ['87-'95] it should get best mileage
at slightly higher rpms.

one of the reasons smaller engines are happier at higher rpms is that
they're often cammed more radically to make up for their displacement
lack.
________________________________________________________________________
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen
adh@xxxxxxxxxxxxxxxxx                       and think what none thought
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