NOS... What would happen?

[Bearded_Dragon]

I've seen that discused. Apparently it's pretty common to spray in front of the MAF on the LS1 engines, but... one of the more interesting techniques I've seen is to spray after the MAF, and hack the IAT table in the PCM:

"The IAT trick essentially gives you two separate tunes. The PCM includes tables that modify spark advance and fuel enrichment in response to changes in intake air temperature. We take advantage of the fact that the range of these tables extends beyond normal operating temperatures and therefore parts of the tables are normally unused. We can modify the IAT tables in these normally unused areas to reduce timing and add fuel as needed during nitrous injection. When nitrous is activated, a relay in the IAT sensor circuit, forces the PCM to read a false temperature that falls in the modified areas of the IAT tables. Normally, intake air temperature is measured by a thermistor (IAT sensor) in the mass airflow sensor (MAF). When nitrous oxide is activated, a relay switches a fixed 300 ohm resistor into the IAT circuit in place of the thermistor. This forces the PCM to read a temperature of approximately 85 degrees Centigrade. The modified table areas then take over. The highest true intake air temperature I’ve seen is 59 degrees C, well outside the modified table areas. When nitrous is disabled the modified areas of the IAT tables have no effect and the normal timing and PE tables are used."

Link: https://ls1tech.com/forums/nitrous-oxide/1741872-most-you-ve-sprayed-front-maf.html

Hmmm...

But again, that's 20-year-old tech. I have no idea if our engines can be similarly hacked.

Any car with MAF can take a small dry shot. Dry nitrous is spraying before the MAF and are smaller shots. I'd bet all gas engines in a JL could take a 50 shot no problem, maybe even 75. Since no car manufacturer runs fuel injectors at 100% duty you always have a little wiggle room with small dry nitrous shots.

Wet nitrous sprays after the MAF but before the intake manifold, and are larger shots but require a more complex setup with fuel solenoids. Usually this requires PCM tuning because you're bypassing sensors and spraying larger shots. Running stock timing and fuel trims, while injecting extra fuel that had bypassed the MAF, means bad idea.

Direct nitrous is a type of wet system but injection happens at the fuel injector ports.

Chances are if you setup a 50 dry shot on a window switch (a device that allows nitrous to spray at set RPM range), you probably wouldn't even feel it in a heavy vehicle like a JL.

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[BDinTX]

Ohhh interesting! Wouldn’t it really benefit the 2.0T with the cooler intake charge? Somebody needs to try this.

 

[Charger68]

"I live my life 17.5 seconds at a time"

 

[old mike]

Gosh, I can't be sure what it would do to your engine; but, the idea sure makes an old man like me just puke and throw codes ...kinda like taking 1,200 pounds of coca leaves and boiling them down to a single snort up your nose.

All seriousness aside, there's a difference between horsepower and torque and, at least for offroad Jeeps, this idea is aimed at the wrong end of that difference. Maybe for a lawless approach to mall crawling, but really not even for that.

 

[Retrograde]

Any car with MAF can take a small dry shot.

Hrmmm....

 

[MayThe4x4BWU]

A bit of this:

Plus a bit of this:

Resulting in something like this:

Probably...?‍

 

[AFD]

Any car with MAF can take a small dry shot.

Iirc, someone here pointed out to me that none of the JLs have a MAF sensor, but instead have an air intake temp sensor where the mass airflow sensor would usually be, and then instead, have a manifold absolute pressure sensor to calculate volumetric flow.

No idea if that would make a difference in your statement though, as they're kinda-sorta measuring the same thing, but in a different way and in a different location.

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