Proper Air Fuel ratio for N2O
01-16-2007, 06:42 PM
#1
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Proper Air Fuel ratio for N2O As the title states....whats the target A/F that everyone suggests....
I have run 12.9 AF spraying a 125 shot with no knock....logged in HP tuners....my car has never run richer than 12.5 AF on the hose and has had about 2 1/2 bottles through it....
Is it just a matter of time? or is it ok to run it as long as it doesn't knock....
I have run 12.9 AF spraying a 125 shot with no knock....logged in HP tuners....my car has never run richer than 12.5 AF on the hose and has had about 2 1/2 bottles through it....
Is it just a matter of time? or is it ok to run it as long as it doesn't knock....
01-16-2007, 09:18 PM
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That's pretty lean. A lot would depend on how much timing is in the tune. The brittle factory pistons are not going to survive much detonation being that lean. I'm assuming this is on pump gas as well. Your walking the line, get it down to at least 12.0-12.2. 11.8-12.0 is considered the max for safe power.
01-16-2007, 09:26 PM
#4
On the smaller shots the clyinder pressures are going to be lower, so a slightly leaner mix will not be an issue. With that said, 12.9 is still kinda of high, imo. I would opt for low 12's at a leanest point. Then remember, if you go bigger then the 11.5 to 11.8 area would be safer. Then if going real big, sometimes as rich as high 10's can be benificial. It's mostly what your comfortable with, and of course no KR.
Robert
Robert
01-17-2007, 07:39 AM
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I'm not sure what the total timing is, ie: I can't remember....I'll have to ask my buddy that tunes the car...Cablebandit on here....I'll get him to push it back to around a 12.0....thanks for the replies.....
PS...I wanted to clairify this is a 5177 kit with 38lb injectors and a walbro pump....
PS...I wanted to clairify this is a 5177 kit with 38lb injectors and a walbro pump....
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01-17-2007, 05:26 PM
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Originally Posted by Nitro Dave's Nitrous Outlet
Go to 11.8 af. You are to lean.. 12___ is still to lean even for smaller shots.
Dave
Dave
This is purely educational for me, just looking for a bit of insight....thanks for the help....
01-17-2007, 07:28 PM
#11
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Originally Posted by b1er
Just for the sake of argument.....why go to 11.9 if 12.9 isn't getting knock retard....?....(theory)if the motor didn't knock at 14.7 and ran right (no knock) why would one richen the mix....?
This is purely educational for me, just looking for a bit of insight....thanks for the help....
This is purely educational for me, just looking for a bit of insight....thanks for the help....
01-17-2007, 08:38 PM
#12
Yea, I agree, it's a safety net. On shots up to 100hp, the clyinder pressures aren't too bad, so if one wants to push it a bit low 12's or high 11's are fine. Just use the highest octane pump gas. I choose to run high 10's on my 250rwhp shot for added longevity, yes some power is lost, but hey it lives on a stock longblock (mucho higher clyinder pressures).
Robert
Robert
01-18-2007, 08:50 AM
#14
Do not be fooled by watching for knock retard. Sometimes the beginning of detonation may not even be picked up and read as knock yet. Reading the spark plugs is the real tattle tale. using tunning software and watching for knock is a great tunning tool but can be misleading sometimes.
Phoenix64 and Robert pretty much covered the rest pretty well. The very small amount of power increase is not worth the added risk you are taking by running a raged edge tune at a lean air fuel.
Dave
Phoenix64 and Robert pretty much covered the rest pretty well. The very small amount of power increase is not worth the added risk you are taking by running a raged edge tune at a lean air fuel.
Dave
01-23-2007, 05:52 PM
#15
Originally Posted by Nitro Dave's Nitrous Outlet
Do not be fooled by watching for knock retard. Sometimes the beginning of detonation may not even be picked up and read as knock yet. Reading the spark plugs is the real tattle tale. using tunning software and watching for knock is a great tunning tool but can be misleading sometimes.Dave
One of my good friends lost a piston and most of his plugs running a large nitrous shot in the standing mile. We logged the run and it only showed like 2 degrees of KR at the time it blew! The knock sensors can fool you into a false sense of security.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
01-23-2007, 06:17 PM
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What would be a good starting point for your A/F NA for a wet shot? Im using a NX kit and never sprayed before. My A/F hangs just above and below 13 and at 3k it dips down to about 12. Would the recommended jetting from NX richen it enough so it doesnt blow?
