Progressive PCM enriched dry nitrous update
Thread Starter
Racer
Joined: Aug 2009
Posts: 337
Likes: 6
From: Kanata ON
Progressive PCM enriched dry nitrous update
I finally got my custom progressive PCM enriched dry nitrous system going.
Dry nitrous and progressive controllers are nothing new but I am not aware of anyone who has done progressive dry nitrous using the stock PCM for fuel enrichment so I thought I would try it and share my results.
The good news is that the first pull with a very modest progressive 75 shot went great. On a pretty cold day with cold tires it struggled for traction through first and into second, pulled a low 5 second 0-60 and sat between 0.75 and 0.8 lambda the whole way.
The bad news is that the nitrous solenoid appears to have stuck open after the run. Since it only ran that way for a short time at closed/mostly closed throttle I'm pretty sure nothing is broken, though the extreme lean condition really confused the PCM. I eventually had to reset it to get it to run properly.
That plus a flaky starter, a failed alternator and snow
means I won't get any more runs until next spring. Still, I am happy that I was able to get it to work at all given the complexity inherent in teaching a very early MPFI computer how to drink the juice.
My goal for next year is to get the stock engine running a 200 shot. I'll keep posting results as I go.
Dry nitrous and progressive controllers are nothing new but I am not aware of anyone who has done progressive dry nitrous using the stock PCM for fuel enrichment so I thought I would try it and share my results.
The good news is that the first pull with a very modest progressive 75 shot went great. On a pretty cold day with cold tires it struggled for traction through first and into second, pulled a low 5 second 0-60 and sat between 0.75 and 0.8 lambda the whole way.
The bad news is that the nitrous solenoid appears to have stuck open after the run. Since it only ran that way for a short time at closed/mostly closed throttle I'm pretty sure nothing is broken, though the extreme lean condition really confused the PCM. I eventually had to reset it to get it to run properly.
That plus a flaky starter, a failed alternator and snow
means I won't get any more runs until next spring. Still, I am happy that I was able to get it to work at all given the complexity inherent in teaching a very early MPFI computer how to drink the juice.My goal for next year is to get the stock engine running a 200 shot. I'll keep posting results as I go.
Melting Slicks
Joined: Aug 2003
Posts: 3,438
Likes: 420
From: Lakeville MI
Just curious. Are you using the MAF to meter the nitrous or are you adding additional PE fuel (or bpw vs rpm fuel) proportional to the known or expected nitrous flow rate? No need to provide details.
I'd like to work up a MAF cal to support a fully dry system one of these days. I just don't know how the sensor really reacts to the spray. This would require some testing/experimentation, but it should be relatively safe if both the air and nitrous can be properly metered under all flow conditions and the ecm can fuel accordingly.
Keep up the good work.
I'd like to work up a MAF cal to support a fully dry system one of these days. I just don't know how the sensor really reacts to the spray. This would require some testing/experimentation, but it should be relatively safe if both the air and nitrous can be properly metered under all flow conditions and the ecm can fuel accordingly.
Keep up the good work.
Thread Starter
Racer
Joined: Aug 2009
Posts: 337
Likes: 6
From: Kanata ON
Just curious. Are you using the MAF to meter the nitrous or are you adding additional PE fuel (or bpw vs rpm fuel) proportional to the known or expected nitrous flow rate? No need to provide details.
I'd like to work up a MAF cal to support a fully dry system one of these days. I just don't know how the sensor really reacts to the spray. This would require some testing/experimentation, but it should be relatively safe if both the air and nitrous can be properly metered under all flow conditions and the ecm can fuel accordingly.
Keep up the good work.
I'd like to work up a MAF cal to support a fully dry system one of these days. I just don't know how the sensor really reacts to the spray. This would require some testing/experimentation, but it should be relatively safe if both the air and nitrous can be properly metered under all flow conditions and the ecm can fuel accordingly.
Keep up the good work.
I am modifying some table I found that allows changing the fuel at WOT vs. RPM based on the PWM of the progressive controller. So far so good, but given how coarse the table is there are definite limits to how close the PCM and progressive controller can be. I'll find out more about that in the spring.
Thread Starter
Racer
Joined: Aug 2009
Posts: 337
Likes: 6
From: Kanata ON
Another update: yup, definitely stuck:
Turns out I had pushed a little too hard on the barrel when tightening the fittings and had dented it enough to cause it to stick open the first time it activated. Good grief.
Anyway, fixed now, got a 0-60 of 5.0 s with a nice AFR all the way. Not a bad start, but nowhere near where I want to end up. Then the bottle ran dry
More to come.
Anyway, here are a few shots of the engine bay. See if you can spot any of the nitrous bits:
Turns out I had pushed a little too hard on the barrel when tightening the fittings and had dented it enough to cause it to stick open the first time it activated. Good grief.
Anyway, fixed now, got a 0-60 of 5.0 s with a nice AFR all the way. Not a bad start, but nowhere near where I want to end up. Then the bottle ran dry
More to come.
Anyway, here are a few shots of the engine bay. See if you can spot any of the nitrous bits:
Race Director
Joined: Sep 2001
Posts: 14,687
Likes: 753
From: NEwhere Ohio
yes, great idea.
My biggest issue with nitrous was how you always made more power on a full bottle than you do on a half bottle. Even when using a heater to spray at the exact same PSI!
Very frustating. Hot Rod even confirmed that phenomena. Has to do with less liquid nitrous flashing to gaseous nitrous with a half tank.
If you can figure a way around that phenomena. That'd be great.
My biggest issue with nitrous was how you always made more power on a full bottle than you do on a half bottle. Even when using a heater to spray at the exact same PSI!
Very frustating. Hot Rod even confirmed that phenomena. Has to do with less liquid nitrous flashing to gaseous nitrous with a half tank.
If you can figure a way around that phenomena. That'd be great.
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Thread Starter
Racer
Joined: Aug 2009
Posts: 337
Likes: 6
From: Kanata ON
yes, great idea.
My biggest issue with nitrous was how you always made more power on a full bottle than you do on a half bottle. Even when using a heater to spray at the exact same PSI!
Very frustating. Hot Rod even confirmed that phenomena. Has to do with less liquid nitrous flashing to gaseous nitrous with a half tank.
If you can figure a way around that phenomena. That'd be great.
My biggest issue with nitrous was how you always made more power on a full bottle than you do on a half bottle. Even when using a heater to spray at the exact same PSI!
Very frustating. Hot Rod even confirmed that phenomena. Has to do with less liquid nitrous flashing to gaseous nitrous with a half tank.
If you can figure a way around that phenomena. That'd be great.
The best solution is to leave the bottle temperature constant and use an external pressurization system. These NANO guys are the only ones I am aware of who sell a system and although I have never used their stuff the principle is sound and I expect it would work as they claim:
http://www.nano-nitrous.com/howitworks.shtml
I always wanted to get this system but the price is a bit more than I am willing to fork out until I have my unassisted setup well proven.
