Cool climates vs. hotter climates

Just curious if anyone notices a improvement in running and performance in cooler climates vs. hotter climates. Seems to me my 996 runs better in the fall and spring then the summer months. Perhaps not ........maybe it's my imagination? Cheers and safe driving.

Not your imagination I notice it at night v. the day. I would guess because we have crappy 91 and the car is meant to run on 93 so it retards timing when it's hotter so it doesn't detonate

You'll notice it A LOT with a NA car. Turbos will notice much less, but yes, it helps Turbos too because you won't get to a heat-soak situation.

cars always run better with cooler dense air. especially F.I. cars because air gets hotter as its compresses.

I thought I was nuts and was the only one noticing it. Definitely better dring the cooler months.

who cares about the slightly better feeling performance in cold months, its all about the top down experience, and in winter... ugh... its coming

Malcom Macdowell is giving me the creeps-He's been a Crockwork Lemon since that movie!!

Why would you notice LESS in a F.I. car? When winter hits here in Phoenix I swear it feels like I have an extra 20whp in my WRX. Colder air is colder air, period.

This thread reminds me of the great paradox which once got an acquaintance in trouble in a 930 some years ago. He came around a corner one fall morning, jumped on the throttle, just like he had many times before with no problem, and spun off the road. The reason for his off-road excursion, of course, was that it was the first really cool morning of the year. Engine horsepower is up, tire traction is down, and the same maneuver that was no sweat before resulted in the car breaking loose. Not as much of a problem these days with PSM and the like... And personally, I love the extra kick in the pants that I feel on a crisp fall morning. caf '02 Targa

Im ready for winter, if you can call it that here, it just cools off enough where you can wear shorts and not get sweaty lugging the Xmas tree inside. You guys must go through hell having the P-cars locked up in hibernation all winter in the less friendly climate regions.

The reason is because the F.I. cars will cram closer to the same amount of oxygen in the engine regardless of temperature. So, when it's hot, it will have close to the same amount of O2 to burn as when it's cold. This is also true for elevation as well. Now, I didn't say it isn't noticable at all. Just LESS than on an NA car. Yes, being colder helps the intercooler, etc. but ultimately it comes down to oxygen burned and on FI cars, the ECU controls how much is pushed into the engine to burn and an F.I. car gets about the same amount in regardless of temp. (notice I said "about" the same) When at higher elevations, a NA car could lose 10% performance while an FI may only lose 3-4%. Yes it affects both, but the F.I. LESS (notice less is a relative term) than an NA car. This is also true when hot and cold air. Both affected, but one less than the other...

The volume of air being sucked (or pushed) into the engine isnt a function of air temp at all. Anyways you're still talking about volume. Volume of air is not eqaul to density of said air! You can cram all the air into a cylinder you want, but as even you mentioned its the oxygen in the air thats going to make the power. We all know it already but, colder air means more oxygen. The reason F.I. cars are less susceptible to increases in altitude is because you have positive pressure forcing air into the cylinder as opposed to just atmoshpheric pressure, which decreases with altitude. But when were we talking about altitude.

What I said is still true. Relatively speaking, an FI car feels and benefits less than NA. I think you are missing my entire point.... it's the word "relative". yes you feel faster in the cold weather with your FI car, but RELATIVE to NA, you'll feel it less.

I still dont see any valid point in what you said. Can anyone else chime in on this?

hehe Maybe you and I are the only ones who care? Just accept that I'm right.

What I am realizing is that there are a bunch of highly educated and technically inclined individuals on this chat network who seem to know alot about porsche mechanics. Thanks for your repsonses, and getting us educated. Cheers and safe driving.

Ok...time for my 2 cents. The reason that cars perform better in the cold weather is because of the increase in O2 in the combustion chamber. It is a fact that cold air (and cold water for that matter) contain higher levels of O2 than warmer air. The colder the air, the more O2 goes into the engine. The SAME increase in O2 levels go into a FI cars as carb cars. Nitros performance is a direct result of increasing O2 levels in the combustion chamber. You are completely wrong to say that a FI car does not get the same increase in performance as a carb car does. An increase in O2 will increase power in all combustion engine. The colder the air, the more O2 in the volume of air in each chamber. This air will combust the same weather is is combined with fuel from a carb or an injector.

I would have to say you would notice it more in a forced induction vehicle. I don't have dyno proof to proove it but, put an ice pack on the intake of an NA car and put ice on the intercoolaer of a turbo car and see which one picks up more power.

Ugh, how about no. Its gonna take more than just "Im right" and a smiley face to change my opinion. Lets go through your post again. You said... As I already mentioned air volume consumed by an engine isnt related to air temperature at all. Imagine you have a 500cc cyclinder. On the intake stroke, the piston moves to the bottom of the cylinder and creates a volume that is 500 cc's. Assuming 100% VE to make numbers easy, you will always have 500 ccs of air in the that cylinder, regaurdless of air temp. Density WILL change though, and thats what were talking about here. Wrong. Hot air has less oxygen than cold air, no matter what engine its going into. Therefore for an FI engine to see the same amount of oxygen hot as it does cold, it would have to see more volume to make up for the lack of density. Air temperature does not change the amount of airflow into an engine! How is this possible? Does having a turbo suddenly change the the fact that hot air has less oxygen? Im sure theres a chart somewhere that shows oxygen content vs air temp, and the matter of fact is ALL cars abide by it. Actually we weren't debating fuel injected engines vs carburated, but Naturally aspirated vs Forced Induction.

SPR: You can get Sunoco GT (100 unleaded) at Cosby Oil on Fairmont. Ten gallons of 91 and five of 100 gives a tank octane of 94. I've noticed the car runs stronger, particularly above 5000 RPM. If you get a race gas card from them you can pump 24/7.

PTEC, you missed my intention yet again. My smiley and accept that I'm right was a joke. The net fails to show those things I guess. Anyway, we can agree to disagree until there's real proof one way or another. The one item you're not taking into account is that inside the intercooler, the ECU controls how much air is being compressed. As it does, it gets hot. Whether it starts at 100 degrees or 50 degrees before it gets compressed... it ultimately gets close to the same density and temperature before being burned. The it takes more work when it's warm than when it's cold, but the results are closer than without this process as in an NA engine. The variable that helps is the temp of the intercooler itself and its ability to stay cooler and not get heat soak. So the starting air temp helps some... but ultimately, the O2 getting burned is going to be about the same. Again... agree to disagree. This is pointless until we get some real proof.

What are you talking about? The ECU has no control what so ever over the intercooler. Zip, zero, nada. The intercooler is not a boost control device, its a simple heat exchanger, nothing more. Plus I believe the DME doesnt change boost pressure relative to air temperature, though it will change timing to prevent detonation. We know that compressing air raises the temperature but if you start with cooler air you are going to end up with cooler air. An NA car doesnt have to deal with this but it also doesnt have the intercooler. Plus if ambient air is cooler the intercooler is only going to be more efficient. Theoretically, colder air is going to allow more air to be compressed into the cylinder before the compression causes the air to heat up to the point where detonation will occur. This is an advantage that NA cars will never have.

If anything my NA engines seem to run better when it is hot.