Re: Dakota R/T vs. GMC PSSSSyclone

From: Rader (
Date: Thu Jun 18 1998 - 12:07:29 EDT

> A turbocharger has a completely different effect on a Diesel engine than
> a gas engine.


> Secondly diesiels don't
> grenade with one on as they are very low RPM engines. Since they are low RPM
> they can use much heavier duty conecting rods and pistons (14:1 or HIGHER
> Compression)
> because the reciprocating weight of the motor is no big deal with a 4000 rpm
> redline,

  Well... while these details are all essentially true, I think there's something
missing. The reason diesels don't grenade under pressure is because they are
built according to their fundamental design as a compression ignition engine.
Because of this, they must be able to withstand cylinder pressures far beyond
the design spec of most gasoline (spark ignition) engines. Therefore, they must
use much heavier-duty components, which ends up as a much higher reciprocating
mass. That, along with the fact that the power curve of a diesel is naturally
torquey at low RPM, limits their effective RPM range.

  Given the fact that diesels must be designed around the cylinder pressures of
compression ignition, the extra pressures involved in turbo- or supercharging
are much less of an issue in diesels than they are in gas engines.

  So we agree on the basics, we just tie them together in a different order.


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