Boost starts building at ~1800rpm, 1500rpm is where I am out of stall,
ymmv on an automatic. More boost does mean you are burning more fuel
automatically because of the ALDA on those cars equipped with them, the
electronic IPs are a different beast altogether. Engine efficiency does
not equal MPG as does optimal not equal minimal. I am pretty sure fuel
is not increased on load as the bench tests dont involve load. Again on
the mechanical IPs. If fuel did increase on load you would not have to
move the pedal when you go up a hill.
I could be totally wrong on this part, the OP mentioned that a heavy
load ruined his axles, this is actually possible IMO, as it happened
with me (atleast this is my theory). As your rear sags (in my case I
lowered the car) the angle that the joints work at changes. Youve spent
a hundred thousand miles at essentially one angle. Then bam, you've
changed the angle, increased the load on the joint and the balls start
tearing into new metal. Then the trip is over and suddenly you are back
to the 100k wear mark but suddenly you have alot more area to move in.
-Rolf
On 07/29/2011 03:33 PM, Curt Raymond wrote:
Why 1500rpm? The turbo isn't kicking in at 1500 rpm... More boost doesn't equal
more fuel being burnt automatically, the load on the engine plays into that. I
don't know HOW but it does. The turbo makes the engine more efficient not less,
if you're not into the turbo you're not making optimal efficiency which is
where optimal fuel economy will come in.
An OM601 IIRC has its peak torque somewhere around 2500rpm so with my '85 190D
I used to endevor to keep it there. With the 5spd that was somewhere around
62mph in 5th. In later testing I realized it didn't make a whole lot of
difference to my fuel economy what the speed of the engine was, it was more on
the speed of the CAR. The sweet spot still seemed to be around 62mph, slower
than that and I went stir crazy, faster and the fuel gauge dropped faster than
I like.
-Curt
Date: Fri, 29 Jul 2011 13:56:07 -0400
From: Rolf<r...@winmutt.com>
To: mercedes@okiebenz.com
Subject: Re: [MBZ] Bearing kit and special tool? Now chaning a cv
shaft too...
Message-ID:<4e32f437.7080...@winmutt.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Remember the more boost the more fuel is being burnt. Ideally you want
1500 rpm at speed. I am at 1500rpm at 55mph in my 87 300d with the 5 speed.
-Rolf
On 07/28/2011 07:08 PM, Michael Canfield wrote:
I was thinking the 85 gears would get me better fuel economy at highway
speeds. Maybe at the cost of worse mileage overall if the turbo isn't
spooled up enough at average travel speeds.
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_______________________________________
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To search list archives http://www.okiebenz.com/archive/
To Unsubscribe or change delivery options go to:
http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
