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Nitrous Injection Point for Turbo Applications


JSM

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My experience is none, but what I've seen on most turbo applications is the Nitrous injection inlet is after the turbo, but before the throttle body. My question is why?

 

If the turbo compresses standard air, wouldn't it be better to compress the nitrous and air together at the same time? Does it simply not matter and there is no advantage anyway? Would there be any disadvantage in loss of cooling from the nitrous going this route? Would this harm the turbo?

 

Courious to anyones experimentation.

 

Thanks!

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Jeff, I'm going to take a stab at it. I looked through Corky Bell's Maximum Boost, but couldn't find anything directly relating to NO2. What I'd assume is that since nitrous is much more temperature voilatile and that most turbos are hot (i.e. point of having the intercooler); you loose the efficiency of using NO2.

 

From wiki:

 

"Nitrous oxide is stored as a compressed liquid; the evaporation and expansion of liquid nitrous oxide in the intake manifold causes a large drop in intake charge temperature, resulting in a denser charge, further allowing more air/fuel mixture to enter the cylinder. Nitrous oxide is sometimes injected into (or prior to) the intake manifold, whereas other systems directly inject right before the cylinder (direct port injection) to increase power."

 

Any other opinions/corrections are welcome.

Edited by tfreer85
Needed to do more reading :D and correct myself
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increases oxygen content and lowers air temperatures, increasing air density. it's not a fuel, but an oxidizer. Add an oxidizer to a flame, the flame gets bigger, not because of fuel, but because of oxygen.

 

I'd go with what tfreer85 said, in that it loses its ability to cool the intake charge if you put it before the turbo. put it after the turbo, and the density of the already compressed air would increase further.

 

I've heard of some drag racers setting it so the nitrous feeds directly into the compressor, but in that case, they use a small bottle and the nitrous is strictly used to spool the turbo up to full speed before they start (huge laggy turbo on a small engine) but that wouldn't be useful for anything else at all.

 

(One vw guy was able to go from 0lbs to 30lbs in an instant just by hitting the nitrous at the starting line.)

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I think that injecting before the turbo would be better, I'm going to quote TonyD(who was speaking in reference to water/meth injection) because he explains it much better than I do. I would inject the fuel after the IC though.

 

 

That's not true. In either injection point, there will be a change of state. The old spearco water injection was totally before the compressor simply because the pumping technology for impingement or atomization style nozzles didn't exist yet cheap enough.

 

Only on an intercooled car Bo.

In a non-intercooled car, the argument can be made for pre-turbo injection as a more efficient model as change of state at point of compression increases adibiatic efficiency of the compressor, whereas injecting it afterwards only gives you state change, with no resultant increase in compression efficiency.

 

I'm so happy my non-disclosure agreement with Cosworth has expired, I can say this happily, and with a clear concience:

 

If injecting methanol after the turbo wasn't any more efficient, CART teams wouldn't be using Counterflow Methanol Injection into the inlet of the turbines on the CART cars... I'm only parroting the engineers at Cosworth on their explanation to me on why the nozzles were in front of the turbine instead of elsewhere...

 

The cooling effect is one plus. But the compressor efficiency effect is one that goes unnoticed! Most of you guys know that the turbocompressor is a slave to it's thermodynamics. Cool that compression down and those "74%" islands on the map get fatter and fatter... And some other islands may well appear. And when those islands get bigger, that surge line moves left on the graph even further...

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With beginers that typicaly try to avoid extra costs such as a window switch or even just run a dry shot I would have to say yes. Nitrous being on of the cheapest ways to obtain power tends draws out the crowd that likes to cut corners.

 

I bought a used wet kit to put on my car. Well never did and we ended up puting it on a friends kouki z31 turbo. Well he had a habit of touching the revlimiter before shifting sometimes. He just got his motor put back together last week. With proper instalation and use nitrous can be used very safely and very often with no ill results.

 

Just inject a wet shot before the throttle body or even better a direct port kit. Nitrous has been around for like what, 60+ years at least. If it were better to spray before the turbo that is what everyone would be doing.

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It's all good. I was just curious. After thinking about where the injectors are placed in relation to how the air is mixed in the question seems to have no relevance.

In a “perfect world” scenario, having everything mixed together 100% proportionately would yield a cleaner, more powerful burn. Regardless, in this application it doesn’t really seem to matter.

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I have not run N2O on my Z, but I did run a 100 horse kit on a big block '69 Camaro I had, I once had a small backfire, more like a "sneeze" really, that made taco shapes out of the secondary throttle blades, shot a wicked fireball out of the cowl induction hood, right at the windshield and started the air cleaner on fire, well, flaming chunks of the air cleaner anyway... this was a plate kit and near as I could figure at the time, the fuel solenoid stuck for a split second and the engine got a big whiff of nitrous with no additional fuel. BOOOM! :shock:

 

I would think that having the compressor section of the turbo, all the plumbing, intercooler and intake manifold full of nitrous would make for a truely spectacular explosion if something similar happened.

 

James Thagard posted some photos of his awesome twin turbo stroker 240Z after a nitrous mishap several years ago, I wonder if they're still around?

 

 

***EDIT*** couldn't find 'em, but it was a good excuse to revist some of James' pics again, he sure does amazing work!

Edited by Chris240zTurbo
looked at some pitchers!
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I would think that having the compressor section of the turbo, all the plumbing, intercooler and intake manifold full of nitrous would make for a truely spectacular explosion if something similar happened.

 

Thats why I was hoping for pics after the explosion, lol.:burnout:

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Nitrous , is a great intercooler and produces great power on turbo motors when properly set up. However, I opened up a liquid/air IC like a can of tuna when a connector to the nitrous fuel pump failed, it also did very bad things to the motor.

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