Nitrous to increase turbo efficiency

[kilrbee]

Turbo-diesel application. Under augmented boost, around 34 psi at discharge, I am experiencing severe loss in compressor efficiency. Discharge temps right at 600 F. Calculated around 60% efficiency.

Part of the problem is that IAT is caught up in a thermal feedback loop, and can rise as high as 200 degrees, 100 over ambient. With a CAI this can be minimized. AND

I had considered WMI pre-compressor to cool ambient, and help raise the efficiency of the charger, also pre-cooling air for the CAC (I know, I know... but the truck will overheat because the CAC, which is in front of the radiator, is heating the stack ambient to 200 degrees, and overheating the vehicle)

I am concerned with blade damage. Will Nitrous be a better medium to cool charge pre-turbo? What kind of cooling value will it have compared to water?

 

[dcasto]

Any thing that will boil lower than water temperature is better, but get you checkbook out.

I don't think you are seeing an effiency loss, the compressor puts up a constant head or it will throw the gas up in the aira fixed number of feet. To convert feet into pressure you multiply the density of the fluid times that number of feet and divide by 144 to convert from PSF to PSI. The warmer the air the lower the density so by cooling the air it gets cdenser and the discharge pressure goes up.

They make CO2 sprayers will help as would Nitrous, but CO2 is safer and cheaper.

 

[kilrbee]

For grins, we can assume 800 scfm, at 160 F. What would a "safe" nitrous quantity be, and how much will it cool my 800 cfm?

 

[Majik]

So are you trying to cool the IAT unit with water or cool the incomming air into the engine with water?

I would never recomend injecting a hydralic like water into a 18:1 compression engine. Nitrous and diesels have a unique relationship that hinges on self destruction. Sure diesels don't run "lean" but they do melt pistons. Have you considered a water to air IC instead? or some kind of CO2 cooling IC or CO2 cooled compressor housing.

 

[kilrbee]

I think it is 12:1. What ever I put in there, at 600 degree potential, it will never be a liquid after it passes through the compressor.

Yes I have considered a W2A.

You say nitrous and diesel is a problem? Timing issue? EGT?

 

[Majik]

what kind of engine is it? 12:1 seems low

Nitrous and diesel have worked well for some of our customers such as spraying a 40-70hp dry shot into a 7.3L powerstroke running 20lbs of boost. when they step upto more than that we get pictures of pistons that have melted. depending on your engine whether electronic or mechanically injected. Timming is locked in by the injection pump. not something easy to retard when nitrous is on.

 

[kilrbee]

duramax

I can change timing at will with software.

My objective is to cool more than it is to augment power. I just figured maybe the nitous would absorb a lot of heat for a small charge. Maybe I should look at atomizing diesel across the compressor

 

[dcasto]

If you cooled the air down from 160 F to 60 F, you could put in 20% more air in the cylider. It would take about 800 lb/hr of CO2 to cool the amount of air proposed above. It would take abouut 1200 lb/hr of nitrous to cool the same air. The CO2 or Nitrous would NOT be injected but would be vented and lost.

 

[boatmotorgod]

you are pushing 34# of boost and you are not interested in augmenting the power with a cooling medium? you are pushing that poor turbo way past its efficiency curve, and that IAT is dangerous for the engine. If you are really not interested in the power boost then turn the boost back down to a safer level and the IAT will come down with it. Or, you could turn down the boost slightly and make some really sick power by injecting propane as a cooling medium. If you installed a larger turbo on the engine; you could make 34# without pushing the turbo so hard and the IAT would drop dramaticly by way of better efficiency.

 

[kilrbee]

I agree with the turbo swap, but that is not going to happen.

How does propane affect optimized timing?

 

[Majik]

The duramax is 17.5:1 and latemodels they lowered it to 16.8:1. I don't think you'd have enough compression to light off a diesel with 12:1 unless you've got some custom piston in there. Never the less. Keep that in mind when throwing water in there. Try a different turbocharger

 

[kilrbee]

That is way easier said than done.

 

[boatmotorgod]

I believe the propane accelerates the burn rate as well as adding fuel to the fire. I have seen kits that only operate @ WOT & add 100 to 200 HP. Thats enough torque to twist the driveline off.

 

[kilrbee]

It is a tough drive combo. 100 HP is mot too bad on it as long as it is not in 5th.

The effect on combustion delay and burn rate is my main concern. I don't want to cause MEP spikes at TDC. Some kind of timing retard would be prescribed. But I can only guess what that would be.