Lean engine + N20 = bang (explain?)
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Intermediate
Joined: Nov 2001
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From: Houston TX
Lean engine + N20 = bang (explain?)
I've been reading a number of posts lately that have been telling that running nitrous when an engine runs lean (such as when hitting the rev limiter) can lead to, well, bad things! I'm not currently running nos, but I'm curious why this happens. Just looking for a small education if anyone can help out :seeya
Le Mans Master
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From: Burlington ON
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Re: Lean engine + N20 = bang (98TXcoupe)
Running lean causes detonation, which when combined with Nitrous can be deadly to your engine. If you install an RPM Window Switch that tells the Nitrous System what RPM range it is allowed to be sprayed in, you never have to worry about hitting rev limiter on a missed shift.
Also, if you install a TPS based Wide Open Throttle Switch, it will detect whenever the computer tells the car to go to less than 100% throttle (ie. Traction Control) and it will stop spraying nitrous, which in turn saves your engine.
With most optioned out Nitrous Kits, a Fuel Pressure Switch is included which keeps an eye on your car's fuel pressure so that if it drops, the Nitrous will stop spraying, which avoids possible detonation while on the juice.
This is a reason that these simple electronic switches are such an important part of a safe and reliable Nitrous System.
[Modified by MattG, 10:27 AM 3/20/2002]
Also, if you install a TPS based Wide Open Throttle Switch, it will detect whenever the computer tells the car to go to less than 100% throttle (ie. Traction Control) and it will stop spraying nitrous, which in turn saves your engine.
With most optioned out Nitrous Kits, a Fuel Pressure Switch is included which keeps an eye on your car's fuel pressure so that if it drops, the Nitrous will stop spraying, which avoids possible detonation while on the juice.
This is a reason that these simple electronic switches are such an important part of a safe and reliable Nitrous System.
[Modified by MattG, 10:27 AM 3/20/2002]
Melting Slicks
Joined: Jan 2001
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From: Aloha, Oregon
Re: Lean engine + N20 = bang (MattG)
leaning out is a condition by which you end up with more O2 than available fuel to maintain a healthy A/F ratio.Nitrous, a natural oxidizer, works by providing that extra oxygen to combine with more provided fuel to produce more power. so, if you are spraying n2o but somehow come up short on the fuel, you go lean. going lean means burning VERY HOT. it is these elevated temps that have torch-like effects on the pistons or valves. i've seen the heads of valves that look like someone took a cutting torch to it. the moral of the story is to ensure you have a healthy fuel delivery. a key to this is all the safety and monitoring devices that MattG mentions above. I use a laptop to scan the motor + have a recalibrated A/F gauge and full sweep electronic fuel pressure gauge on the A pillar pod, + i run a mixture of Toluene or xylene (whatever the paint store has on special) to bring up octane (which helps with detonation), + the MSD window sw + WOT switch. cant be safe enuf. all of these precautions allows me to push my nitrous shot to over 200.
Drifting
Joined: Aug 2001
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From: Thousand Oaks California
Re: Lean engine + N20 = bang (98TXcoupe)
Fuel is a cooling agent for the incoming charge as well as the burning mixture. The temperature of the incoming charge is one of the variables reponsible for abnormal combustion. And while the mixture is burning, the less excess fuel, the more likely that other sites in the chamber will self-ignite. Interestingly, too lean a mixture may be safe from abnormal combustion as the charge won't even ignite and the thing will miss.
