New Saab Engine Tech

[Doug Dayson]

Saab's concept is this...best engine efficiency (power and mpg) is obtained at
the highest possible compression ratio which of course varies with load and
combustion chamber temps...as well as intake charge temps and timing etc...

So with that in mind at low load and part throttle the engine can support much
more compression without detonation than it can at high load and WOT.

So much for a rigid block structure eh...(:>)

How to they balance this thing and curb vibration etc?

Interesting eh?

Doug

nacelp wrote:
> 
> My (dumb guy) way of thinking about it is:
> It takes x amount of Energy, to move y weight, z distance. Second two items
> are fixed, so the only variable is the engine.  So as long as the engines
> say both make 10 HP with 2 lbs of fuel, the mileage will be about the same.
> Some theories, don't mean a hill of beans in the practical work, of
> measuring real performance.   Like using lots of EGR and/or wide throttle
> openings for cruise.  I have yet to get better mileage or throttle response
> than tuning for a min TPS value.  Your results may vary.  For highway
> mileage it's about finding the engines sweet spot tune wise.  Guy I know is
> getting 31 MPG (C/K Pick-up) with a 5.7 vortec being run by a 747.
> Grumpy
>    Speciallizing in simple explainations (least trying too <<g>>), cause
> that's all I can understand lately.....
> 
> > I've certainly heard this a bazillion times.  Can someone explain to me
> > why I get the same mileage now in my S-10 Blazer with a 5.7L TBI engine
> > as I used to get with the stock 2.8L TBI engine?  Granted the 2.8 was an
> > '86 calibration and the 5.7 is a '91 calibration.  And I have to admit
> > that highway mileage is a little worse, but city mileage is the same.
> > The 2.8 was a wimp in that truck, which weighs in at over 4000 lbs.
> > Believe me, that engine rarely suffered from "pumping losses".  I've
> > also heard plenty of times that the more vacuum you have the better your
> > fuel economy is, despite the fact that vacuum=pumping loss.
> >
> > anyone?
> >
> > --steve
> >
> 
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