View Single Post
Old 01-20-2009, 10:43 PM   #12 (permalink)
ConnClark
DieselMiser
 
ConnClark's Avatar
 
Join Date: Jun 2008
Location: Richland,WA
Posts: 985

Das Schlepper Frog - '85 Mercedes Benz 300SD
90 day: 23.23 mpg (US)

Gentoo320 - '04 Mercedes C320 4Matic
90 day: 22.44 mpg (US)
Thanks: 46
Thanked 232 Times in 160 Posts
Quote:
Originally Posted by Christ View Post
I had to point this out... while 4kRPM might be 90MPH in high gear, in low gear it might be the equivalent of about 10-20 MPH, and is completely do-able.

What this means: You could potentially drive around town "cleaning" your Diesel Particulate Filter.
Driving around in a low gear and reaching 4000rpm does not require the amount of torque it does as going 90mph. Hence it won't require the same amount of fuel to be burned and thus raise the exhaust gas temperatures as much as going 90. Also the shop manual expects the accelerator to be floored while being held at 4000 rpm on the dyno. So unless I can find a hill to drive up thats steep and long enough to sustain 4000 rpm with my foot to the floor for 20 minutes my DPF will not be cleaned driving at 10-20mph.
__________________
  Reply With Quote