what is "running too lean/rich" mean

apparently running lean is bad, but why
can someone run TOO rich?

how do i make sure i do not run lean

 

Running lean/rich has to do with the amount of oxygen per one part fuel. This is basic chemistry really.

For example, the perfect burn, at standard pressure/temp/etc. would be 14.7ish afr, which is air/fuel ratio. I know its 14.xx for sure. This is where ALL the fuel is combusted leaving the least amount of bad emissions.

If you run rich, that means your mixture is rich with fuel, and the oxygen is less per part, for example. Rich = 10:1 afr. 10 parts O2 per 1 part fuel.

Lean means theres not enough fuel, so oxygen would be higher.

Like 20:1 afr.

If you run lean, theres a large chance of detonation, or preignition which can easily blow up the engine, thats why running lean is bad. If you run rich, your car will just bog down with fuel, and sometimes explode fuel out the exhaust port and stuff which can happen with nitrous if you spray accidently with the bottle closed. LOL. I did it to test the fuel solenoid once and it just bogs down the car, and sometimes stalls it.

Now that thats out of the way, what does this have to do with nitrous?

Well with nitrous kits for the cobalts, youll want a "wet kit" which means there will be fuel along with n20 sprayed. THe fuel is to keep the air to fuel ratio at good conditions to control detonation becuase nitrous adds a lot of O2 to the cylinders.

If you run lean with nitrous, theres a good chance of detonating, but colder plugs, high octane gas, and safety precautions will prevent this.

To not run lean, make sure you use correct sized jettings in the fogger. Make sure the fuel line has enough pressure, make sure the fuel solenoid works, make sure you run high octane gas. 91 minimum. 93 minimum if available.

EDIT: Most of that is right but its late so im sure some information is off. Just know this, NITROUS IS PERFECTLY SAFE IS USED CORRECTLY.

 

If you dont feel like reading.. Lean is running with not enough fuel (too much air) and rich is running with too much fuel.

Good write up btw

 

A quick writup of shot sizes and what is the safe limit for premium gas.

50-75 on 1.6 - 2.4 liter engines

75-100 on 2.4-4.8

100-125 on 4.8 - 6.0

150 6.0 +

That is a very generous measurement. genearlly on teh upperside mizing in race fuel is a good idea.

Also runnign rich can foul plugs. Not that big of a deal. Running lean melts pistons.

You can run rich millions of times, but you run lean once.

 

SpecialK right on, good write ups fellas

 

thanks.

but i kind of dont agree with his post. you can run higher shots of nitrous on the engine, it just depends on what setup you have, single fogger or direct port.

If its a single fogger hes talking about sure, that works i suppose. But its because the fogger cant atomize that much fuel and nitrous at once and its not distributed evenly into the intake manifold and has a greater chance of puddling which means a blown intake.

I would do 100 shot direct port on stock stuff, maybe not clutch stock, because 100 shot would blow it up lol. But 100 shot on stock stuff will be distributed evenly among the cylinders ensuring a far safer shot.

You might have to change timing a bit though.

But generally speaking <75 on the stock 2.2 before you have to change timing, and upgrade to direct port. Might even be able to pull a 100 shot on the 2.2 with direct port no timing changes.

But yea, premium is the way to go for any nitrous on a street car. higher = better.

Like he said, running rich isnt so bad, because while it can foul plugs, it usually will burn it off unless youre constantly running rich.

 

I run a 125 with a direct injection system with a LSX intake, I know on teh conservitive side but then again I'm a bit cautious with the stuff realising that if I go nuts I WILL break rods. I'm at that point with my T/A.

Either way the best bet is to start with a light shot and get used to the hit, then go up and tune for the increased shot. Going right out with a 50 might make you end up in a wall.

But yes valid points on a direct injection setup for the above reasons. I however am a solid believer in the dry shot and using larger injectors to compensate for the extra ox in the system because of the nitrous seperating. I've seen too many hoods/scoops land in the bleachers cause of a nitrous backfire.

 

Looks liek you guys know what youre talking about. I have asked this before and never got a straight answer. I have a dry shot ZEX kit from my cavalier. Is it safe to run that on a SC. Or should I get the wet upgrade? Thanks guys

 

The dry wont' hurt it. Older SC/s a wet system would damadge it. Also consider the cooligin effect of nitrous into the intake before the SC. There's a few guys running small shots for that reason alone so they don't detonate on hot days at the track. Hell there'es even anti lag systems for turbochargers too.

But as far as experience I'm no spray god. I only have three bottles through my T/A so far. And I've had the system on for a year nearly. Sad two of them were on the dyno to tun the cantankerious brat.

 

Ok I think I'll try it, so the spray thru the SC wont hurt as far as you know?

 

It's NOT going to hurt, I hate when people say that, I've posted this before, I have many many bottles through it, and every time I pull off the spuercharger it looks no different than new...older superchargers yes, new eaton on the s/c, no...

 

Rgr, sorry I am just being cautous. Thanks for the tip

 

I don't blame ya, the first time you use it is quite an experience, get some type of air/fuel meter though, preferably wideband...

 

Rgr I had it my cav and it was awesome I cannot imagine this one. Cannot wiat. Gonna tr to put it on this weekend

 

I didn't say it would. Just said it hurt older ones cause they were never ment to have fuel run through them. Well... not totally true. Cause we've all see huge blowers with dual quads stacked atop them with a big ol scoop.

 

Special K, i ran through 2.5 bottles in less than a month. I dont see how you can be so conservative to use only 3 bottles in a year! But your car will last longer lol.

Narrowband is virtually uselesss when dealing with F/I because its not accurate like you need. Wideband will do the job. in the future im getting the AEM wb02 hopefuly for around 250.

 

I was just making sure got all the info before I stuck this thing on and blew up, lol. Never had any problems on my Cavi just wanted to make sure the SC could handle it

 

From ZEX.com

Q: What is better, a "wet" or "dry" kit?
A: It all depends on the application. A "wet" kit is ideal for both normally aspirated applications as well as forced induction applications. It can require a little bit more installation time than a "dry" kit, but is easier to tune if greater than stock HP settings are to be experimented with. A "dry" kit is excellent for normally aspirated combinations that have a return style fuel system. They are very easy to install and are a great "first time" nitrous system. It is not recommended that "dry" systems be used on forced induction engines.


Now I'm lost, lol

 

Get the wet kit, I'm telling ya...supercharged=wet kit, n/a=dry kit, lol

 

N/a = wet kit.

If you put a dry kit on a 2.2 or 2.4, its going to run lean and blow up. Unless you have some modified injectors that pump more fuel when youre spraying, but tahts not the case.

WET KIT WET KIT.

 

true true...if monitored though I think dry kit will be ok, they run rich anyway, i just meant if you are going to use a dry kit at all then it should be on n/a...thanks for the correction/idea

 

Only that many bottles cause I only use it on the track. Using that shot on my stock tires would probably kill me on the street. That and the track I go too really hates my cageless car. 11 sec slips and no cage = boot.

And yes, it would be very wise to get a Wideband. Nothin like running 14:1 and not knowing it till a piston melts. O.o