cjoenck

As fall approaches in Chicago with cooler morning and evening air temperatures, I notice the car is driving better - read better acceleration and smoother - than in the summer when ambient temps are in the 80s or 90s. I understand that cooler air is more oxygen rich but shouldn't the engine management systems compensate for that? So question is why is the engine running better with cooler ambient temps.

Thanks for enlightening me.

Spyerx

They can’t compensate enough. Higher octane fuel helps.
Even my gt3rs is much better in cool weather. You can feel it on track.

SRM11

Hearing that makes me want to pull it out of the garage.. not like I **really** need an excuse if it's not raining.

cjoenck

So was the engine originally tuned for the Northern European climate in Germany where summers are rarely above 90? Is there a way to adapt for warmer climate? What exactly does the temp sensor in cylinder 3 drive? Obviously not influenced by ambient. Is there a temp sensor in the AFM or does the barn door only measure volume throughout? So many questions.

Spyerx

carlskisWP

Yes, it has to do with colder air being more dense, so for the same volume of air in the cylinder there is more oxygen on a mass basis. I don't think there much the ECM can do to compensate. I guess thats what turbo chargers are for

Navaros911

I notice the same... and the difference is drastic in this climate.

In my case I even feel a power difference... and I feel it across all cars, even the Cayenne S.

It is just a fact of life. Humidity is very, very high here in the summer nights as well. That affects it too.

I have no choice but to live with it.

-nick

LM964

This

cjoenck

So cooler air is denser and more oxygen rich. Apparently the Porsche engineers thought about it too. Has anyone seen or used the RS Intake


It takes the air from the spoiler inlet, i.e. much cooler theoretically than the air in the engine bay.

Another solution apparently is this:


Not sure what happens with water getting into the air scoop though

Goughary

If you use one of those and intend to drive in rain, you just drill a small hole in the bottom of the air box for drainage. Easy enough. I thought about going that way, but with all the rain and snow my car sees, doesn't make sense.

Bigsix964

^Interesting. I feel like that would worry me. There's no real chance for error there with some H2O induction? I was surprised to see a hot air intake the first time I looked at one of these engines. Practically I guess there are few alternatives, but the difference is always noticeable when the temps drop.

JasonAndreas

The RS has the same intake as the non-RS models.

The 993TT intake trumpet (used to funnel air from above rather than through the intercooler) has two drain holes on the bottom.

cjoenck

Interesting. I have never seen an RS engine bay and was going off the description of the funnel on the vendor's website. They come out of the UK for about GBP 100 plus shipping.

JasonAndreas

For the NA engines it only makes a difference to air intake temperature while the car is stationary.