is running rich really bad for the engine?

[import_racer87]

i searched, i came up with many "im running rich" threads but none about why its bad


SO many turbo'ed cars seem to run rich ( the black ploom of smoke at shift points, the black shit on the bumper, the fireball in some cases) Now my question is, is running rich bad for the engine? i even see it a lot in tuned NA cars. if it is bad, please explain what it can mess up.

[wootwoot]

it isnt good but it is also not necessarily devastating. things it will do are foul your plugs, kill your cat, and cause a loss of power. most people complain about running rich because they are not seeing the power they should, and that simply pisses people off.

[TheSnail]

Its better then running lean. Running rich will layer you motor (valves) exhaust half with sut, it will foul your plugs and decrease the life of your o2 sensor, and clog your cat. But as far as destroying your engine, no.

[ghostuss]

It's ok for turbo car to run rich, sometime you want it to run a little rich but not too rich. It's for reliability issues. That's also why JWT ECU mostly run rich, JWT ECU is very conservative, it is tuned rather on the rich side and the timing is less aggressive. Running rich in N/A is bad, and there is no point to it at all but for some flame show off if you run a straight pipe.

[import_racer87]

hah, ok, ive heard people blame engine failure on running rich before, i guess its just because they are idiots and dont know what really happend. thanks for the help.

[kandyflip445]

It's possible it was running so rich that the engine flooded. Just not likely.

[blu808]

people only think that turbo cars run rich. They get that because when they let off, they loose boost to the motor without the maf knowing about it right away, therefor air is being let out while fuel is still being allowed. Making a black/blue cloud on letoff. Running rich on any motor will loose power. The objective is to run as lean as possible with as much iming as possible without detonation. usually no less than 12.9 afr.

Also running crazy rich will coat the cylinder walls with gas restricting the lubrication of oil causing the rings to wash out. At that point who cares that your plugs are toast.

[TheSnail]

Engine failure if you had 200lb injectors running at a 100% duty cycle for a minute with no spark. and hydro locked the engine some how. Other than that, I don’t see how it could be a threat.

[ghostuss]

Hey you broke 1000 post !! go snail, how come you not lazy now?

[TheSnail]

After a G, I am now lazy again, Mabe when I hit 1900 I will awake again.

[ghostuss]

Haha. You sound like a bear going back to a long sleep in winter.

[import_racer87]

Originally Posted by blu808

Also running crazy rich will coat the cylinder walls with gas restricting the lubrication of oil causing the rings to wash out. At that point who cares that your plugs are toast.

now for that to happen would you have to be running pretty fucking rich? past the point of a little black smoke or a fire pop every once in awhile?

[blu808]

Not really. If you are running rich all the time. then it can happen. You can also still run rich, and lean out the motor. If your curve is set rich at little boost, then when the boost hits it doesnt add enough fuel you will lean out.

[rps13_fastback]

actually, turbo car tunes are most definitely richer than NA car tunes, NA cars AIM for ~13:1, whereas turbo cars (on 91 octane) would wanna aim for 11.5-12.0 or ~12.5 on 93.

[blu808]

This is true, The ideal ratio on a turbo car is richer, but how can that be considered rich, if thats where its supposed to be?

[Steeles]

You can wash rings off your pistons running too rich (thats why My car is sitting right now )

[tErbo b00st]

Originally Posted by blu808

This is true, The ideal ratio on a turbo car is richer, but how can that be considered rich, if thats where its supposed to be?

That is what it is supposed to be for a car that you want running for awhile. When you actually drive the car the A/F doesnt stay exactly where you want it, it will fluctuate, so you tune the car a little rich (giving up a lil power) so that when it does fluctuate it will not go too lean and blow up your motor. NA cars have a much less possibility of detonating so they can tune a little bit more aggressive then we can.

I believe I am correct in saying that the "perfect" A/F is 14.7:1, but it is very hard to tune the car to stay at that A/F and not detonating is almost impossible w/ conditions changing constintley.

[blu808]

Originally Posted by tErbo b00st

That is what it is supposed to be for a car that you want running for awhile. When you actually drive the car the A/F doesnt stay exactly where you want it, it will fluctuate, so you tune the car a little rich (giving up a lil power) so that when it does fluctuate it will not go too lean and blow up your motor. NA cars have a much less possibility of detonating so they can tune a little bit more aggressive then we can.

I believe I am correct in saying that the "perfect" A/F is 14.7:1, but it is very hard to tune the car to stay at that A/F and not detonating is almost impossible w/ conditions changing constintley.

Of course the af ratio jumps around when you are not on throttle. It doesnt matter though because the motor is not under load, and cannot detonate. We were talking about the sustained afr. That is when the afr should stay constant on a properly tuned car, and 14.7:1 afr is still leaving a little room for error. Temp changes, alt changes, humidity and so on. That is a good afr for a street car. So all in all i think were on the same page here.