[W126 Coupe] Engines

[Jim Nowak]

Talbir,

"Yes, absolutely, you can extract plenty of power
without supercharging!"

No where near what you can get from a supercharger. 
With forced induction you can achieve over 100%
efficeince rate from an engine.  There is no
comparison with power returns per dollar spent on a
forced induction motor vs a NA motor.   

"NORMALLY aspirated V8 and shoves out 510hp and more
importantly 630 NM of torque !!!!"
  
I hear what you are saying.  However, the AMG 5.5L
supercharged motor already has much more torque at 700
NM and just about as much hp as the 6.3 L.  The
factory rates the E55 hp at 476 but it is more like
500+ from the dynos I've seen.   Not to mention, the
supercharged 5.5L motor is easily modified for 550 to
600 + hp and can take the E55 AMG to the 1/4 mile in
the low 11 second range.  The 6.3L engine will be very
difficult to modify and will be twice as expensive to
extract the same amout of power as the   blown 5.5L.  

The only real positive I see from the 6.3L motor is
the displacement and weight savings.  You can swap the
piston for lower CR and boost away.  There is no
replacement for displacement.  Of course, given every
thing else is equal. 

"But if you're prepared to get involved, then get down
to the bare M117 and work from there...higher lift
cams, revised pistons, unpgraded injection and
ignition control systems, revise the exhaust manifolds
etc etc...you'll have a super engine with plenty of
power. And one that will have longevity, smoother and
more responsive, without the detonation risk that a
forced induction engine carries."

The supercharged street motor will be more reliable
given the same fuel and ignition changes.  A
supercharged street motor is only under boost for
possibly 2% of the time.  For the remainder of the
time, that engine has much less wear and tear than a
similar high compression motor.  A high compression
motor is always under that same stress but the blown
motor gets a break when you are not at WOT. 
 
"If you compare to boxing, bhp is about how FAST you
can punch...torque is about how HARD you can punch !"

HP is a measure of torque.  HP = torque * RPM/5252 
You can't have hp without torque and rpm.  If you keep
the torque higher in the rpm band, you will have more
power.  It's rather simple.  

"Do the Aussie spec SEC's have an even lower
compression ratio of 8:1 ? They'd be PERFECT for
turbocharging, provided an intercooler is worked into
the process."

I'm not sure but the US motor is just about perfect at
9:1 CR for supercharging.


Jim  

 


--- Sharan Bains <sharanbains at hotmail.com> wrote:

> Yes, absolutely, you can extract plenty of power
> without supercharging !
> 
> Just look at the latest engine released by AMG....
> 6.2 litre (labelled 6.3) 
> NORMALLY aspirated V8 and shoves out 510hp and more
> importantly 630 NM of 
> torque !!!! And that's the most crucial statistic,
> torque. If you compare to 
> boxing, bhp is about how FAST you can punch...torque
> is about how HARD you 
> can punch !
> 
> Now the 5.6 isn't too far off in terms of
> displacement - the increased 
> displacement mainly provides more torque.
> 
> This latest engine gets it's massive power from a
> high compression ratio of  
> 11.3:1....that's almost like having a US spec 9:1
> compression 5.6 M117 
> running at 10 psi boost ! And then the sophisticated
> fuel and ignition 
> control units maximise the power further.
> 
> Supercharging is fine and works well if you don't
> want to get technical and 
> want easy bolt on power. And the power gains are
> big....more than you'd gain 
> from a normally aspirated M117.
> 
> But if you're prepared to get involved, then get
> down to the bare M117 and 
> work from there...higher lift cams, revised pistons,
> unpgraded injection and 
> ignition control systems, revise the exhaust
> manifolds etc etc...you'll have 
> a super engine with plenty of power. And one that
> will have longevity, 
> smoother and more responsive, without the detonation
> risk that a forced 
> induction engine carries.
> 
> All I did with my Euro 560 was change the camshafts
> to AMG spec ones - and 
> the performance increase was very significant. I'd
> say in the 20-30hp range, 
> with ease....and those cams do make a real
> difference in the Euro engines. I 
> fI ever find a set of AMG spec pistons, I'll be well
> chuffed ....
> 
> Do the Aussie spec SEC's have an even lower
> compression ratio of 8:1 ? 
> They'd be PERFECT for turbocharging, provided an
> intercooler is worked into 
> the process.
> 
> 
> talbir
> 
> 
> 
> 
> 
> 
> 
> 
> >From: David Fatovic <coloradocroat at yahoo.com>
> >Reply-To: Mercedes Coupes Mailing Lists
> <mbcoupes at mbcoupes.com>
> >To: Mercedes Coupes Mailing Lists
> <mbcoupes at mbcoupes.com>
> >Subject: Re: [W126 Coupe] Engines
> >Date: Mon, 18 Jul 2005 10:26:12 -0700 (PDT)
> >
> >So once you strip off all the control stuff, you
> have
> >an engine to do whatever you want with it correct?
> >Somewhat?  I feel you can get much more horsepower
> out
> >of the engine other ways than supercharging it.
> >
> >Thanks,
> >
> >David
> >
> >--- Jim Nowak <jjnowak_32503 at yahoo.com> wrote:
> >
> > > David, that is correct.  I'm looking to do that
> to
> > > my
> > > SEC and I already did it to my porsche 928.
> > >
> > > Jim
> > >
> > > --- David Fatovic <coloradocroat at yahoo.com>
> wrote:
> > >
> > > > I have a question.  An engine is an engine is
> an
> > > > engine once you strip off the controls right? 
> So
> > > is
> > > > it possible to take a 560 engine from a 91 and
> > > strip
> > > > off the the vacuum controls and the mechanical
> > > fuel
> > > > injection, basically get down to the bare
> engine.
> > > > Then build up the 5.6L to have new fuel
> > > management,
> > > > new air intake etc.
> > > >
> > > > Also what is the latest MB tranny (year) that
> you
> > > > can
> > > > mate to the M117 engine?  I would think that
> the
> > > > later
> > > > trannys would work better, better gearing and
> 5
> > > > total
> > > > gears too.
> > > >
> > > > Any ideas?
> > > >
> > > > David
> > > > The MB Coupes Website!
> > > > W126 SEC Mailing List
> > > > Postings remain property of MB Coupes, L.L.C.
> > > >
> > >
> > > The MB Coupes Website!
> > > W126 SEC Mailing List
> > > Postings remain property of MB Coupes, L.L.C.
> > >
> >
> >The MB Coupes Website!
> >W126 SEC Mailing List
> >Postings remain property of MB Coupes, L.L.C.
> 
> 
> The MB Coupes Website!
> W126 SEC Mailing List
> Postings remain property of MB Coupes, L.L.C.
>