I want to know if someone knows the air intake inlet temperature in the red line on the 3rd,4th and 5th gear on a Porsche 997 GT3?
Thanks

 

depends on ambiant temp

 

When the ambient temp is 90F
Do you measure it in other temps?

 

mdrums, means it will be relevant as there is a delta from ambient.

 

Which means?

 

It means the IAT is not an independent variable - the warmer the ambient temperature, the higher the IAT, regardless of what load is placed on the engine.

 

IAT in a GT3 is a non-issue, it comes straight from outside into the engine and is sucked in. I doubt it ever differs that much from ambient.

Where IAT matters lots is on turbo engines, where the pressurisation causes large rises in temperature, hence the need for intercoolers etc.

 

So,you don't have any temp numbers?

 

The other posts are on the money. The intake air temp will be very near ambient.

Now very near ambient sounds like I'm waffling and I am sort of. There are several issues with ambient temperature. What is reported as ambient for your locale may not reflect micro climates that exist and affect temperature.

IOWs while the ambient temperature as measured at the airport may be 90F, downtown in traffic it may be 100F. And if the road is in the direct sun and you are in heavy traffic the intake air temperature may be even higher.

Also, if you get in the car after it has sat a short time after running the engine the intake air temp will be rather higher than ambient because of heat soak which has raised the intake manifold temperature. For a time after engine start the intake air temperature will be elevated as it removes heat from the intake manifold.

By my observation from my 02 Boxster it can take more than a few minutes of steady driving at moderate speed before the intake air temperature gets as low as it can.

The Boxster engine air intake is located on the side of the car and in a particularly bad place regarding air intake temperature and dirt, too. This location has the engine ingesting hot air air that comes from out of the radiator duct ahead of the front wheel well and by my observation the very best I saw was a delta of 10F to 12F intake air temperature over that of ambient as measured using a digital thermometer sticking out of a slightly lowered driver's window. (My Boxster does not have an outside temp display.)

Added: for the worst case while driving in slow traffic in 116F AZ heat the intake temperature climbed to 135F. This is the temp at which the engine compartment fan comes on and it was on for what seemed like the whole time I was in AZ and that awful heat. Coolant temperature reached 226F and stayed there for what seemed like the whole time, too.

For the GT3 given its cold air intake system that collects air that flows over the car the intake air temperature is affected much less (if at all) by the heated air from the radiators.

In the case of my Turbo I have never bothered -- at least I can't recall -- paying much attention to the intake air temperature.

Even though the Turbo collects engine air that has come over the top of the car as another poster noted this is affected by the degree of boost and the efficiency of the intercoolers.

(Also, there is a lot more material to heat up and transfer heat to the intake in the Turbo's intake system.)

Additionally in the case of the Turbo (and this may be the case for your car as well) there is a fuel cooler which means that when fuel is injected into the combustion chamber this can (probably) work to lower the intake charge temperature which is nearly the same as lowering the intake air temperature.

If you really want to know for yourself what the intake air temperature is for your car in a variety of scenarios buy an OBD2 code reader/data logger test tool that allows you to view intake air temperature in real time.

Then you can observe and note any differences in the intake air temperature relative to say what the outside air temperature reading is on your car's dash.

 

Thanks for your answer.
I have I 997 s supercharger and I measured the air intake temp when the ambient temp was 90F the air intake temp was 150F after 5 times when I went 4times in the red line the 3rd,4th and 5th gear.
What's your opinion?

 

Do you have the link in order to buy the OBD2?

 

It would have been useful for you to describe your setup in your first post. Forced induction always increases IATs. Buy a Durametric cable and log your IATs and talk to your tuner about what he considers to be a safe temperature and if an intercooler will help prevent your ECU from pulling timing, boost, etc.

 

A dyno and road date logging session with your tuner is your best course of action.

You haven't mentioned whta problems if any you are having so we know why you need this information/advice?

bbywu hit the nail on the head, if you want help give us the facts. Having a supercharger changes the game totally.

Cheers
James

 

It is hot where you drive?

Seriously, man, a supercharger changes everything.

Obviously one of the changes is the supercharger raises the intake air temperature as it compresses it.

I vaguely recall there is a formula for calculating the increase in temperature arising from the amount of boost but I do not recall it well enough to attempt to use it to determine if the increase in temperature is on par with what it should be.

I strongly suspect though the increase in air temperature is about on par, but is probably too high. The Turbos if you recall use intercoolers to lower the intake air temperature after the turbo compressors have increased it.

But and this is probably what you want to know but I do not know how much the intake temperature is increased nor do I know how effectively the intercoolers lower this again.

What does the literature that came with the supercharger kit have to say about intake air temperature? Does it say anything about what to expect? What's too high? Does it suggest anything to decrease it? If not intercoolers maybe alcohol or water injection?

 

My Racekeeper data system I use at the track is also connected to the obd port and measure various temps and one is the intake temp. This varies depending in the outside air temp. I don't remember these stats and I am not near my computer to launch the rave keeper program to have a look but I remember something like 15-25 degrees from Florida winter ambient temps to more summer like temps.

I've been thinking of gold foil wrapping my air box and compare temps.