Nitrous Oxide for those good time vibes

[NGOT8R]

Get yer kit installed WildHorse and “Let the Good Times Roll”.

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[markmurfie]

This guy is running the direct port plates 100 shot. I think you can do up to a 300 shot with them, possibly more. Like other nitrous kits it uses a TPS learn switch to trigger the system only when the TB is physically at WOT. He goes over looking at the fuel trims and tuning the solenoid timing, fuel jets, and bottle pressure to keep them all in line where you want them to be. Colder plugs would probably be a good idea, but at 100 shot probably doesnt matter.

This system injecting nitrous and fuel or a throttle plate physically interupts what the MAF would be sensing, so tuning anything in the ECU would be like tuning a major intake leak, combined with bad injector data if its a wet shot. ECU is not going to be seeing the full story of what is happening from the MAF sensor. Nitrous kits are external control and end user knowledge heavy to get it tuned and working correctly. As this guy did its up to the end user to bring the fuel trims back in line at WOT. You add 100ft-lbs of torque with out the ECU knowing anything about it. The bigger the shot the worst things that rely on accurate load and torque like timing and transmisson control get. Then because the ECU knows nothing about whats going on with the nitrous, theres nothing a tuner can do with logs, but guess at where these things should be. when you need a tune to start this guessing really depends on what you as the end user are seeing in the logs and other things you normally do for nitrous tuning and where you want parameters adjusted too. If even thing is happy great keep upping the jets, but just know you are the responsible tuner now. If you think you need to pull timing back a little IE: maybe 27* is kind of high for an engine making over 450ftlbs of torque, you will have to specify a maximum WOT timing with your parameter adjuster as they are no longer tuning. These 6r80 and 10r80 transmissions hold torque through gears pretty well so I wouldn't anticipate any adjustments needed to them, and I dont think people would tune their nitrous for full throttle nitrous powered shifts, but maybe some adjustments could be made to move shift points around to optimize them and hold gears a little harder with more pressure when you get to the bigger shots.

TLDR:
If you have to ask when you need a tune for nitrous, you shouldn't buy a nitrous kit.

 

[K4fxd]

Thanks for that Mark.

 

[NGOT8R]

I don’t know what all my tuner did to tune my car for nitrous on E85, but I specifically remember him having me log the car with the nitrous armed and the bottle closed first. Once he looked at that log, he told me to put the 100 hp jetting in and log again (with the bottle open this time). He looked at that log and then told me that it was safe to install the 150 hp jetting and log again. Once he reviewed that log, he had this to say:

“Log looks awesome! I think you may be running low on bottle pressure though. Nothing crazy just went 7% rich at the end. Can't beat those results though “

I mentioned it in my nitrous thread that I also run one step colder spark plugs and JMS BAP.

I also don’t/won’t ever hot lap my car on nitrous again (learned that lesson back in 2000). I now allow for a 30-45 min cooldown period between making runs with nitrous.

 

[engineermike]

This is why I would port inject it. If I were doing it on my car I'd plumb it under the intake manifold.

That would definitely fix the fuel distribution issue.

This is why I think a wet system is better. There will always be fuel for the amount of nitrous. It will still go lean but not as lean if the dry shot keeps sending nitrous and the ecm shuts off the fuel.

If you're running, say, a 125 shot and the PCM decides to shut off the fuel, then you're still getting 125 hp worth of fuel but 560 hp worth of air. In the dry shot scenario, the PCM will cut all fuel since there is no other entry point beside the injectors. Cutting all the fuel is better than cutting some or most of the fuel.

 

[engineermike]

Yeah no offence, but that's not the best way to do it.
Why put extra strain on the fuel system ?

Because the PCM should control all possible fuel injection points.

Also it'll be a wet plate system behind the TB, so the MAF will have
zero clue it's there. 50-75hp max.

The MAF will have zero clue and the PCM would have zero control. As a result, if you get a fuel cut for any one of 20+ possible reasons, you go super lean and bad things happen.

 

[engineermike]

The rear cylinders are going to be lean front cylinders are going to be rich. Wet fuel distribution in these manifolds suck. I would do like @NGOT8R and only trigger it above 4-4500 RPM.

Not that it matters because bad is bad, but I think the issue is that the liquid fuel droplets are carried to the rear of the manifold rather than making the hard immediate turn to enter the runners at the front. Gas changes direction easier than liquid. In the case I'm familiar with, the front cylinders ran lean and burned tips off of spark plugs.

 

[NGOT8R]

Because the PCM should control all possible fuel injection points.



The MAF will have zero clue and the PCM would have zero control. As a result, if you get a fuel cut for any one of 20+ possible reasons, you go super lean and bad things happen.

At the very least, I would add a Hobbs Switch. I had one on my 2004 Mach 1 and 2013 GT. They’re better than nothing, but I also realize they do fail too.

My 2019 Bullitt has a Fuel Pressure Sensor and Nitrous Pressure Sensor incorporated into system and they’re both adjustable via my ProMax controller and are monitored on the fly. The nitrous will shut off if any of the preprogrammed (low/high) parameters aren’t met.

https://nitrousoutlet.com/products/...HX2k4iMNlcuZ6v_lg41mzYbC_DTB-QPFrd6HvO0MGxKsD

https://nitrousoutlet.com/products/...gMMpjWDyaKA2XahFr6AtLtL73i1Svp_pIsGDSW4Z4MUQQ

 

[NGOT8R]

Not that it matters because bad is bad, but I think the issue is that the liquid fuel droplets are carried to the rear of the manifold rather than making the hard immediate turn to enter the runners at the front. Gas changes direction easier than liquid. In the case I'm familiar with, the front cylinders ran lean and burned tips off of spark plugs.

Factory plugs or colder plugs?

 

[engineermike]

So I'm assuming for sure a dry shot of 50/75 HP will definitely need a tune, correct ?

I would never embark on this adventure, but if I did I would start with a 25 dry shot and inject as far ahead of the MAF as possible, probably just downstream of the air filter. I'd log injector duty cycle and fuel trims and see how it reacts. Ideally, the fuel trims would not change appreciably because the MAF should account for the additional flow and add fuel before anything needs trimming. If the fuel trims react unfavorably, start trying different nozzle aim and locations until you get the result you want. I've seen people even point the nozzle upstream so the flow is more homogeneous by the time it reaches the MAF. If the fuel injectors have sufficient overhead and the fuel trims do not change, then start bumping it up until you reach the target hp level or injector duty cycle gets too high. I'd also explore a TPS safety interlock since we don't have direct control over the throttle blade.

 

[K4fxd]

I would never embark on this adventure, but if I did I would start with a 25 dry shot and inject as far ahead of the MAF as possible, probably just downstream of the air filter. I

I have thought of this but would the MAF sensor itself be able to withstand the sudden temp change? The AIT will be in the 90's then suddenly drop to some degree below zero.

In the case I'm familiar with, the front cylinders ran lean and burned tips off of spark plugs.

It was a long day and I got it backward.

Cutting all the fuel is better than cutting some or most of the fuel.

I was only thinking the ECU would cut *some* of the fuel. I can see the flaw in my thinking.

I'd also explore a TPS safety interlock since we don't have direct control over the throttle blade.

I would set the system like the video and only let it arm when throttle is 100%

inject as far ahead of the MAF as possible,

Would this require some modification to the maf period due to the extra O2 in nitrous?

 

[engineermike]

....You add 100ft-lbs of torque with out the ECU knowing anything about it. The bigger the shot the worst things that rely on accurate load and torque like timing and transmisson control get. Then because the ECU knows nothing about whats going on with the nitrous

This is basically the crux of the matter. The PCM is in full control so subverting that by fooling it or bypassing it only creates a ripple effect through all of the controls. The fuel and throttle control came to mind for me initially, but mark brings up the transmission. Just last week I was logging transmission data and found that they modulate the clutch pressure as a function of torque input. At 3000 rpm a 100 wet shot adds 175 ftlb of torque that the pcm doesn't know about and, thus, can't increase clutch pressure to account for it.

I see the dry shot working much better in this regard (assuming a TPS switch is in place) because, in addition to the PCM fuel control advantage, the load and calculated torque should increase and the rest of the logic can adapt to it. If this is the path, it would take a bit of tuning but the tune would work the same as a basic supercharger tune. You could actually use the timing tables to pull timing at loads over 1.1, extend the torque tables out to higher loads, etc. It would interpret the nitrous as an increase in manifold air density.

 

[engineermike]

All of your points are valid concerns....hence my dislike of it overall.

I have thought of this but would the MAF sensor itself be able to withstand the sudden temp change? The AIT will be in the 90's then suddenly drop to some degree below zero.

With a 125 shot I don't think it would be that cold. Quick and dirty math says if you inject far enough ahead of the MAF to let it mix and become homogeneous, the average temp would be more like in the 40's.

I was only thinking the ECU would cut *some* of the fuel. I can see the flaw in my thinking.

Well, the Ford logic does allow for "enleanment" but Ford essentially quit using it in the early 2010s as far as I can tell. I have seen aftermarket tuners turn enleanment back on since then, probably due to misunderstanding how the SAI logic works. Currently, it will actually cut fuel to individual cylinders if it wants partial torque reduction but ran out of spark retard to get there. But again, it cuts all the fuel to that cylinder in that cycle, so no fuel = safe.

Would this require some modification to the maf period due to the extra O2 in nitrous?

Possibly but I think any error there would fall out in the wash when finding the best position of the nozzle.

 

[WildHorse]

If you have to ask when you need a tune for nitrous, you shouldn't buy a nitrous kit.

How do you learn if you don't ask ? But thanks anyways.

 

[WildHorse]

And just to clarify, NO E85 . This will be on 91 E10 w/ VP racing octanium .

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