what is happening when running lean (not a noob question)
 

i ------- know what it means but when is it doing?

from my chemistry skills the only thing i can come up with is that the extra oxygen in the chamber is super hot and just wants to oxidize anything it can hit.
like how steel will rust slowly at room temp but if start tig welding without a sheilding gas it oxidizes like instantly.

dont tell me about 14.7:1 or ---- cuz i know that.
dont tell me to google it becuase every other fag out there has only 1 thing to say and that is what it is, not what is happening.

Re: what is happening when running lean (not a noob question)
 

Your question makes no sense and is in the wrong forum.

Re: what is happening when running lean (not a noob question)
 

when it runs lean it starts to detonate

Re: what is happening when running lean (not a noob question)
 

wrong mixture of air and fuel caused premature combustion. which is detonation. too much air and not nough fuel.

Re: what is happening when running lean (not a noob question)
 

this is the full answer.

when ruining super lean, you create more heat in the combustion chamber. this extra heat ignites the fuel before the spark plug does and... boom.

Re: what is happening when running lean (not a noob question)
 

You're question is worded poorly, and I dont think you will get an answer here. We are just a bunch of poor people that mangle together cheap turbo kits.

Re: what is happening when running lean (not a noob question)
 

Beat me to it. I agree with kain here.

Re: what is happening when running lean (not a noob question)
 

well its just that ive seen what happens to pistons when a motor goes lean and it like a hole is burned right through it. the hole is smooth almost like it is gradual.
but then ive seen pistons that were like totally cracked to hell with bent rods.
i just thought something else was happening

Re: what is happening when running lean (not a noob question)
 

The one's you saw with smooth holes burned in them were from running too lean without detonation (yes, it's possible). It acts like a blowtorch when you keep adding oxygen to the acetaline mix. The one's you saw that were cracked and broken were from detonation (could be caused from running lean or too much timing advance too). With them it's basically the mixture igniting too early as the piston is on it's up stroke, sort of like hitting it with a big hammer really hard while the piston is in motion coming up instead of where you want it on the downstroke.

Re: what is happening when running lean (not a noob question)
 

A lean mixture can also just cause a misfire and no detonation in vacuum with a light load or no load

Re: what is happening when running lean (not a noob question)
 

Holes in the Pistons are PRE IGNITION, very harmful stuff...not necessarily caused by running lean, but can be.

Re: what is happening when running lean (not a noob question)
 

yeah, what are we talking about as far as lean mixtures that can put holes in pistons? 18-19 a/f ?

Re: what is happening when running lean (not a noob question)
 

Depends on the cylinder pressures. More pressure = more heat on compression.

Re: what is happening when running lean (not a noob question)
 

would this be what is happening when you are hauling ass then let off the gas?

because i had to do that for a speed trap and i thought my ---- was going to blow.

full vacuum but like 21 afr.

Re: what is happening when running lean (not a noob question)
 

No, that's injector cut...basically the engine starts to act like a giant air pump when decelling and off the throttle.

Re: what is happening when running lean (not a noob question)
 

Pre-Ignition is NOT detonation. They are two entirely different phenomena.

Detonation is a second ignition after the spark plug has already initiated combustion.

Pre-Ignition is ignition before the spark plug has a chance to do it, which is WAY WAY more harmful than detonation. Pre-Ignition is a combustion event that totally works against piston travel, kind of like the worst case of advanced timing. It happens because when the piston is at BDC, the pressure in the cylinder is very low, thus any fuel inside is really easy to ignite, but has a slow flame propagation. Any hotspots in the cylinder could ignite the mixture.

Re: what is happening when running lean (not a noob question)
 

that bad?

Re: what is happening when running lean (not a noob question)
 

when the injectors cut off you get no fuel. vacuum volumes of air and no fuel, sound like a possibility for detonation to you?

it's normal.

Re: what is happening when running lean (not a noob question)
 

No, think about it.

You need fuel to have any form of combustion. Without fuel, you can't have normal combustion, detonation, or pre-ignition.


Fuel cut is a rather harsh way to cut engine speed though. Ignition cut is way way softer.

Re: what is happening when running lean (not a noob question)
 

you cut fuel every time you let off the throttle

Re: what is happening when running lean (not a noob question)
 

wrong. it isnt cut 100 percent. think about it, at idle, you engine is still delivered fuel.

Re: what is happening when running lean (not a noob question)
 

yeah but think about when your rolling down the road, the weight of the car keeps the engine turning.
my reasoning for this is the engine has no difference in sound or feel when i am coasting and then turn the key off and back on.

Re: what is happening when running lean (not a noob question)
 

In a OBD0 and 1 Honda, all fuel is cut during decel conditions. You guys are over complicating this.

Re: what is happening when running lean (not a noob question)
 

I agree 100% lol. Even my Evo cuts off fuel when I'm decelerating and off the throttle, it's normal so don't even worry about it. The timing get's pulled back so far anyway that for all practical purposes it should be firing on the downstroke anyway. The only time fuel cut is harsh is when it's used as a limiter when rpms are rising at full throttle, such as the "safe guard" that my Evo has for overboost...thank god I can raise that up ;)

Re: what is happening when running lean (not a noob question)
 

That had no bearing in this conversation. You are only confusing people.

Like I said before:

No fuel, no combustions events, normal or abnormal.

Re: what is happening when running lean (not a noob question)
 

so when engine is in decel conditions, not fuel, not spark even? only turns crank/rod and pistons up&down just w/ little air? or how it works then ? i say with little air cuz the cams are still working, i'd not say there isnt any % air on intake.

Re: what is happening when running lean (not a noob question)
 

yes, the distributor still sparks in decel...

the cams move, the valves open and if you are in gear you are doing what is sometimes called "engine breaking" because with the throttle closed...its hard for that big air pump to suck in air which is why you decelerate faster in gear

Re: what is happening when running lean (not a noob question)
 

ehh kind of. real engine braking systems is the jax brakes. they hold the exhaust valves open so that the vehicle cannot spark (diesel) which slows down your wheels dramatically. if you are just in gear the engine bracking effect is much less because you are still igniting fuel.

Re: what is happening when running lean (not a noob question)
 

Completely false. The reason why the Jacob Brakes work is because when you open the exhaust valve on the compression stroke, the engine is pumping twice as much air. Ie every revolution, instead of every other revolution.

Re: what is happening when running lean (not a noob question)
 

i see , so just spark is working without nothing in cylinders (just spark)? i was wondering for instance when dyno a car, car is decelering, theoretically there isnt should be to have any gas exhaust going out through exhaust, right? because engine just move without nothing in cylinders but i would not say that's right exactly.. or yes?

i always had this doubt but i thought just engine "idle" even when u decelerate, i means there is still fuel,little air with spark...

Re: what is happening when running lean (not a noob question)
 

your right man. haha im still learning.

Re: what is happening when running lean (not a noob question)
 

what jax and jacob means?

Re: what is happening when running lean (not a noob question)
 

It's a type of engine brake used on large diesel engines to assist in slowing them down. It's more commonly called a "Jake brake".

Re: what is happening when running lean (not a noob question)
 

Ok, what about this?

Re: what is happening when running lean (not a noob question)
 

I think you have it right. when you let off the throttle the injectors shut off. there is no gas going into the engine, but the plugs still spark. the only thing moving the engine is momentum.