Cold Weather=More power. Why?

[Mikem53]

Originally Posted by Suberman

Does the BRZ have knock sensors? If it does then the engine won't make more power in cold weather.

Turbo engines do if they are intercoolers.

That's all wrong.. Knock sensors are there to sense knock and retard ignition should knock occur. Cold air is denser and supplies more air in the same volume of space for more complete combustion and therefore makes more power.
The engine timing will be the same unless there is knock. So the colder the intake charge, the more complete the combustion will be and more power will be made. Knock sensors don't come into play unless there is detonation to some degree.. Then timing would be pulled and less power made. It works the same for NA or FI, cold air packs more air in a given space for better combustion which in turn creates more power.

[Suberman]

Originally Posted by SpeedR

And why would you bother if colder air dose not make more power?

and now were done troll

There are other ways to cool the intercooler. Mitsubishi Evo have used water/methanol sprays for example. You're confusing two different effects.

If you can cool the compressed air then gains are possible. If you merely start with cooler air and then compress it there are no significant gains to be had in a modern knock limited engine.

Intercoolers cool the compressed air from very high temperatures before it goes into the combustion chamber. Direct fuel injection cools compressed air inside the combustion chamber, again from a very high temperature. Both reduce the tendency to knock and therefore develop more bmep and more power. Starting with "cooler" air doesn't make enough difference to the temperature of the compressed air. At least that's what I say. I'm too lazy to do the Boyle's Law math and I don't know what the ignition advance mapping actually is in these engines. I predict no power differences between this engine at plus 40C and at minus 40C but I'm open to the idea. My actual point is it isn't as simple as colder air = more O2 per unit volume = + more fuel injected = more power. In the olden days, probably before you were born, you could feel this difference. Now it is imaginary.

You need to appreciate the difference between intercooling and CAI "cooling".

NOW we're done, unless you have any interesting ideas.

[Suberman]

Originally Posted by Mikem53

That's all wrong.. Knock sensors are there to sense knock and retard ignition should knock occur. Cold air is denser and supplies more air in the same volume of space for more complete combustion and therefore makes more power.
The engine timing will be the same unless there is knock. So the colder the intake charge, the more complete the combustion will be and more power will be made. Knock sensors don't come into play unless there is detonation to some degree.. Then timing would be pulled and less power made. It works the same for NA or FI, cold air packs more air in a given space for better combustion which in turn creates more power.

Dyno tests anyone?

You need to read up on end gas detonation. Then you'll understand how knock sensing actually works and you'll agree with me, instead of being wrong.

[Suberman]

Originally Posted by Rayme

Say it in simpler terms, are you saying the ecu pulls timing when it sucks in colder air? Are you saying the ecu doesn't use the colder air charge to extract more power out of it?

It sounds like if you are saying is true, the opposite also should be, the warmer the air intake, the more ignition timing it advances then, right?

EDIT:
You know what, fuck it, you're just a troll on here. You go one about the car's handling again (which seems to be the only thing coming out of your mouth) in this thread which has nothing to do with making more power in colder weather anyway.

You were doing so well before the edit.

[Mikem53]

Originally Posted by Suberman

Not only that but the compressor doesn't run at all in cold weather because the evaporator would freeze up. Plus 3C or about 40F is the lowest temperature at which the AC can operate. There's an anti frost switch which opens at that temperature and disconnects the drive pulley from the compressor.

Evaps freeze up because they lack airflow or are low on freon not because of ambient temps .. The reason the AC doesn't run below a certain temp is to protect the compressor. The thick cold freon/oil can damage the compressor and internal valves..

[Mikem53]

Originally Posted by Suberman

Dyno tests anyone?

You need to read up on end gas detonation. Then you'll understand how knock sensing actually works and you'll agree with me, instead of being wrong.

I think we all learned enough from you already to know who is wrong..

[Mikem53]

Originally Posted by Suberman

You need to appreciate the difference between intercooling and CAI "cooling".

NOW we're done, unless you have any interesting ideas.

Lol.. You seem to make things more complex than they are so you can talk down to others. But the facts are:
Cooling is cooling.. Period. It creates a cooler more dense intake charge which in turn creates a more complete combustion cycle.. Whether it's intercooled or CAI.
Blah blah blah.. Cold dense air creates more complete combustion which in turn creates more power.. Hence the use of ICs in FI applications and the reason sube/toy designed the stock CAI pickup. Maybe you should write and argue with the engineers who designed CAI and ICs so they can learn something as well..

[strat61caster]

Originally Posted by Mikem53

Maybe you should write and argue with the engineers who designed CAI and ICs so they can learn something as well..

Wait those are designed by engineers? I just assumed they had a guy borrow someone's car and make a tube that gets as close to the fresh air as possible, at least that's how every single one I've looked at appears.

Edit: I misunderstood thinking you meant the cheapo aftermarket intakes synonymous with ricers, I understand now that your post was likely intended to talk about OEM systems which are obviously designed, analyzed and tested.

[Suberman]

Originally Posted by Mikem53

Evaps freeze up because they lack airflow or are low on freon not because of ambient temps .. The reason the AC doesn't run below a certain temp is to protect the compressor. The thick cold freon/oil can damage the compressor and internal valves..

Pure nonsense.

[Suberman]

Originally Posted by Mikem53

Lol.. You seem to make things more complex than they are so you can talk down to others. But the facts are:
Cooling is cooling.. Period. It creates a cooler more dense intake charge which in turn creates a more complete combustion cycle.. Whether it's intercooled or CAI.
Blah blah blah.. Cold dense air creates more complete combustion which in turn creates more power..

Pure nonsense.

Completeness of combustion is not the phenomenon. All emission controlled engines burn clean.

A cooler and therefore denser air/fuel charge can indeed produce more power due to the simple chemistry of fuel combining with air. More of both produces more power.

However, the point you are missing is that engines burn fuel while spinning at high rpm. The timing of the combustion event is relevant. Because of timing issues the knock sensor equipped engine can extract as much power out of the warmer air as it can from the colder air.

[asphaltkyle]

[mike the snake]

What about at max power though? Colder air will allow more timing and will knock later, so the engine should be able to make more max HP.

I know when it's cold out, my engine is more perky, I can definitely feel the difference. It's slight, but very noticable with what little power this car has.

There should be no argument that colder, denser air can cause an engine to make more power.

Modern electronics kind of "even the playing field" under normal driving conditions by compensating with timing and throttle and fuel adjusting abilities.

Originally Posted by Suberman

Pure nonsense.

Completeness of combustion is not the phenomenon. All emission controlled engines burn clean.

A cooler and therefore denser air/fuel charge can indeed produce more power due to the simple chemistry of fuel combining with air. More of both produces more power.

However, the point you are missing is that engines burn fuel while spinning at high rpm. The timing of the combustion event is relevant. Because of timing issues the knock sensor equipped engine can extract as much power out of the warmer air as it can from the colder air.

[Mikem53]

Yeah.. We all feel the improvement in power when it's cold out..which is why the OP started the thread.. But the pseudo internet scientists must tell us we are all wrong and try to explain.

Originally Posted by mike the snake

What about at max power though? Colder air will allow more timing and will knock later, so the engine should be able to make more max HP.

I know when it's cold out, my engine is more perky, I can definitely feel the difference. It's slight, but very noticable with what little power this car has.

There should be no argument that colder, denser air can cause an engine to make more power.

Modern electronics kind of "even the playing field" under normal driving conditions by compensating with timing and throttle and fuel adjusting abilities.

[Suberman]

Originally Posted by Mikem53

Yeah.. We all feel the improvement in power when it's cold out..which is why the OP started the thread.. But the pseudo internet scientists must tell us we are all wrong and try to explain.

Ah yes, the notoriously accurate butt dyno.

It's probably just the lower rolling resistance of those summer tires in the cold.....

If there is an effect from ambient temperature then the effect should be even more noticeable with higher elevation and lower air temperature. A simple winter v summer acceleration test in Denver should establish the power gain. If the same test in San Francisco produces no acceleration advantage in cold weather then the question will be answered.

Or somebody could ask a dyno operator what they do about adjusting for ambient sir temperature and barometric pressure when they calculate your ( probably phantom) whp gains from your CAI.

There's nothing pseudo about the Internet.