questions for the supernerds... (Digifiz & nitrous)

[sfwilliams@comcast.net (Scott F. Williams)]

Scott Rose asked:
> Doesn't nitrous cool the intake temp charge as well as introduce
> a shitload of oxygen into the intake?

Yes, it does exactly that. There is certainly an intercooling-type effect.
However, what nitrous really does is permit the engine to burn more fuel and
thus produce more power. It improves the volumetric efficiency chemically
whereas a turbo (for example) does it mechanicaly -with a compressor. The
extra oxygen released by the nitrous oxide also radically accelerates the
burn rate of the available fuel. Cylinder pressures escalate along with
exhaust gas temperature. The likelihood of detonation increases as well. The
stakes are high along with the engine output. :^)

Typically, the ignition timing will be retarded at this point to avoid
trouble -much like that in a turbo car. In fact, if implemented very well, a
nitrous system should "feel" nearly the same as a turbosystem from the
engine's point of view. Again, the main thing that's going on is an increase
in volumetric efficiency.

So, my plan is to bump back the ignition timing via the method that I
described before. I'd love to have a nitrous-only alternate ignition map to
use. However, that is not a function that TEC-II supports.
--
Scott F. Williams
NJ Scirocco nut
'99 Subaru Impreza 2.5 RS
Mazda 323 GTX turbo "assaulted" vehicle
Golf GTI 16v "rollycar"
ClubVAC: "Roads found. Drivers wanted."