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What air/fuel ratio is dangerous for N2O?

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Old 02-10-2016, 07:11 PM
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What air/fuel ratio is dangerous for N2O?

Hello, I have 345 rwhp N/A and I am adding a 100 shot. I was wondering at what AFR does it become dangerously rich and dangerously lean to the point where there is either lifted ring lands or severe detonation?

Thank you.
Old 02-10-2016, 09:26 PM
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Re: What air/fuel ratio is dangerous for N2O?

Thats a loaded question. Depends on few factors...such as ring gap, timing, combustion chamber burn rate, and cam valve events for starters

But in general, small shots on typical small blocks that are in good running condition, i would stay high 11's air fuel on gas. Pull timing and run colder plugs
Old 02-11-2016, 08:12 AM
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Re: What air/fuel ratio is dangerous for N2O?

Originally Posted by Orr89RocZ
Thats a loaded question. Depends on few factors...such as ring gap, timing, combustion chamber burn rate, and cam valve events for starters

But in general, small shots on typical small blocks that are in good running condition, i would stay high 11's air fuel on gas. Pull timing and run colder plugs
Is low 11 AFR rich enough to hurt something?
Old 02-11-2016, 09:29 AM
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Re: What air/fuel ratio is dangerous for N2O?

Eh i dont think but its alot richer than needed imo

But plug inspection should be the method to determine it.

I track tuned mine, starting at mid 10's air fuel. 150 shot. Moved to low 11's picked up 3 mph. Dropped to high 11's, picked up 1.5-2 more and i stopped there
Old 02-15-2016, 11:16 AM
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Re: What air/fuel ratio is dangerous for N2O?

What about n20 with boost I got a wideband to install here promptly and on the 5-7 psi I figured to shoot for around high 11 first depending where its at now. But I do believe I'll try 100 shot. The kits been on the car but I haven't used it yet just BC I'm afraid of hurting something with not knowing AFR. I'd like to have 2seperate bins once tuned for the boost I'll copy bin and tune one at the track for N20. Already should have cold enough plug in car.
Old 02-15-2016, 11:37 AM
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Re: What air/fuel ratio is dangerous for N2O?

Similar low mid 11's or so on typical pump gas. Race gases may like leaner

Main thing is making sure timing is low. Pull more when adding nitrous on top of the boost pulled timing
Old 02-15-2016, 01:40 PM
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Re: What air/fuel ratio is dangerous for N2O?

Is 12.4:1 AFR with 26* total timing dangerous enough to cause engine damage? I think I will be using that as a starting point on the dyno. Thanks
Old 02-15-2016, 02:05 PM
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Re: What air/fuel ratio is dangerous for N2O?

All engines are different

Find what it likes for max power na before spraying

If its 12.8:1 and 36 deg timing all motor, then i would pull 4 deg maybe 5 for a hundred shot and put in the recommended jets and get a baseline pull. It may be perfect it may not be. Be careful with it

Then add 1 deg back in once you get air fuel somewhat in line to what it wants. If it starts at 11:1 afr the slowly jet it leaner and watch power. Sneak up on 11.5 and leaner to see how power reacts. Big jumps in power will happen if overly rich but as you approach optimal, power will not change or just make tiny changes in hp/trq. Once you reach that point, add the timing back 1 deg at a time til you see little power gain. then back off timing again 1-2 deg, and jet it richer slightly before taking to track
Old 02-15-2016, 02:05 PM
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Re: What air/fuel ratio is dangerous for N2O?

I have alot spark added in PE I can back it off and also I have boost timing master for now. Code 59 is on hold till I figure out what I'm doing memcal wise. I'm trying to figure out the BPW vs. Load table on 32b mask at this moment. Runs real rich all the time. Then at idle in closed loop pw goes very low, But runs good then. Bought LC-2 on amazon for 149.99 a few weeks ago. So we'll find out.
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