Tuning low ect's

[Ghetto_CB7]

Hello, I was just curious as to what other people tune a/f ratio's to on cold engines. By this I mean before reaching normal operating temperature.

Most of the tunes I have seen, and the one I am running seem to lean out the engine under cold temps, I am assuming this is to increase combustion temperatures in attempt to raise ECT's quicker.

My current tune leans out my low load and low rpm a/f to midd 16's I was just curious what the other more experienced people were doing, especially since it is getting cold again.

[rexload]

You said tunes SEEM to lean out the engine under cold temps

Could it be possible that they aren't really tuned for colder temps? and it just runs leaner because it's cold.

I personally don't think it is a big deal as long as you are in the high13-16s range. But the logic I was following was cold engine = needs just a tag more fuel to run smoothly. Correct me if I am wrong.

[gdout90accord]

If your cold temp is lean, u need to tune your cold temps ECT, IAT Etc.

[Ghetto_CB7]

hmm weird

Well I guess I might be wrong then. I figured that the higher low load low rpm leaning out was to increase combustion temps.

I guess I will have to fix that, and I guess they use cold idle to put more energy in the motor. Huh I would have though that having it lean at idle and low load and rmp was what others were doing.

OK, well thanks

[LoDollar92LX]

i try to tune warm up afr's a little richer then operating temp afr's. if its too lean, the combustion temps could make the piston expand faster then the cyl and cause issues. Same idea why you dont beat on a motor till its warmed up to temp.

[dbsharp]

i try to tune warm up afr's a little richer then operating temp afr's.

Agree

if its too lean, the combustion temps could make the piston expand faster then the cyl and cause issues. Same idea why you dont beat on a motor till its warmed up to temp.

Disagree.

From my understanding, the main reason for running rich when the engine is cold is because the fuel does not atomize as well on the cold engine parts, and because the fuel need to be in the gaseous state, or very near it, to burn properly you need more fuel to have proper combustion.

[dbsharp]

bump for a modified post

[Ghetto_CB7]

Good information

Thanks guys, good info here. If I have any other question I will post them up, I don't think this subforum gets used as much as it should.

[wed3k]

Agree


Disagree.

From my understanding, the main reason for running rich when the engine is cold is because the fuel does not atomize as well on the cold engine parts, and because the fuel need to be in the gaseous state, or very near it, to burn properly you need more fuel to have proper combustion.

dont you know anything about coefficient of thermal expansion?

[dbsharp]

The amount of thermal energy released by the burning fuel mix at the loads engines usually see while warming up is not going to cause a piston to wall interference issue on a properly built motor.

If don't believe me, do the research yourself, but just to get you started, here is the piston temperature readings from a 2.2l motor at WOT. You should know that max piston temps are usually around 300-350 deg Celsius, and the gradient is about 150 deg Celsius to where you are actually measuring piston to wall clearance. Next you need to investigate the actual amount of expansion the piston and the wall will under go. Also don't forget the thermal energy transfer from the piston to the cylinder walls and to the oil slinging against it from below.

[Ghetto_CB7]

Ready Fight!

Round 2... Ready Fight!

Mortal Kombat FTW

[wed3k]

i was thinking boosted for some reason.

[dbsharp]

no bodys fighting anyone. This is more about learning IMO.

[Ghetto_CB7]

twas a joke, hence the mortal kombat.

I think by the time people get to this forum they are tired of yelling and fighting with people.

[98vtec]

Agree


Disagree.

From my understanding, the main reason for running rich when the engine is cold is because the fuel does not atomize as well on the cold engine parts, and because the fuel need to be in the gaseous state, or very near it, to burn properly you need more fuel to have proper combustion.

this is correct.