Originally Posted by madhat

I'm no expert... I could be totally off on this, but I'll give it a shot.

When you add nitrous to the mix, you're putting super dense oxygen to the cylinders, thus increasing the volume inside. Since diesel is compression ignited, the level of compression that is needed to ignite the fuel happens earlier in the stroke.

I've always been told to run less timing with spray.

Like I said, I could be off, so if someone knows better, please correct me.

Originally Posted by XLR8R

Propane injection is a fading fad, as it's now easier than ever to increase power through the ECM; besides the bulk and expense of the system, 'pane in significant flow rates adds too much timing to the engine - and the numbers just don't make sense if you try it for mileage purposes.

NO2 raises the total amount of cylinder pressure "under the curve" of the combustion stroke (just couldn't bring myself to say p***r-stroke ), but it's not spiky due to nitrogen buffering... kind of like stomping on the piston crown with your boot instead of hitting it with a hammer. Unless the quantity of nitrous you're using is large enough to tax the yield limits of the reciprocating assembly - running juice in modest amounts is easier on the engine. Of course, it's not practical for street use.

Water alone will help when it's needed... if the engine already runs relatively clean, cool & efficient - shouldn't make a big difference (although the carbon cleaning of the combustion chamber is always welcome! Otherwise, it's latent heat of evaporation helps to lower intake charge temp (increasing it's density), while lowering EGT as noted elswhere. Most of H2O's benefit is realized during the combustion process, where (insert long technical hydrocarbon chemical reaction analysis here) it delays the onset of cylinder charge ignition while accelerating the final stage of the combustion reaction (due to the catalyzing effect of the hydroxyl radicals).

Adding methanol increases power through intake charge densification (it has very high latent heat) and because of course - it's a fuel. When mixed with water up to 70%, it might cause timing rattle, but "shouldn't" promote pre-ignition, especially in light of it's extremely high cetane number. I know the 12Vs like to rattle pretty fierce with it though - and I bet the explanation isn't as straightforward as one would think.

These chemical supercharging injection schemes have been around since WWll, when they were used by Axis & Allies alike to improve the high-altitude performance of fighters, so the tech is pretty well proven out!

IDK what you've done to your '05, but I'd be comfortable squirting a 50% mix of H2O/CH3OH AND a 100HP (w/fueling to match) shot of NO2 (probably a #68 pill), using Hobbs switches to tune the stages for best spool & power with least smoke & EGT... just have all the right gauges and pay attention to them - especially the SOTP meter!