ORIGINAL POST:
"Saw a thread on another forum that interested me. As most of you know I
run speed density and got rid of my maf and intake pipe. I just have a
filter attatched to my turbo. Basically the point of this thread is to
consolidate facts and opinions on whether its better to run a pipe and
filter or just a filter or no filter at all. Apparently just running a
filter will damage both the turbo and engine being your sucking in hot
air behind the radiator. I put 6k miles on my car and haven't noticed any damage to the turbo. So, let the debate and fact war begin I guess."

I would do some logs with a pipe and without and see at least if there is performance gain with a pipe. Ive heard the same thing in regards to using a filter directly on the turbo could potentially cause failures. But it cant be any different than driving in warm summer conditions.

I dont believe it is unsafe but i can see a slight performance decrease without an intake pipe. For obvious reasons. The air entering the turbo is going to be warmer where as using a pipe would suck in air from a cooler area. Performance gains may not be huge at all but logically there has to be at least a small amount.

My personal opinion is that the colder the air is the better. I know with pipes comes air flow restriction but I've crunched numbers on hp based on different temps and its huge. Any physics expert will tell you that cold air compresses more than hot air (heat expansion) and since turbos are to increase amount of compressed air the more you can compress the better. IMO... and that is just my opinion... a exterior forced air induction is the best setup but that is just my 2 cents... debate still open!

PS I can provide equations numbers and also I doubt your turbo and engine would be damaged from the heat (as long as you stay in range, you monitor exhaust temps right?) but it would be better to lower intake temp...

I think it wouldn't matter. My friend has an intake pipe on his car with the same fmic I have, and his intake temps are the same as mine. Never goes above 74 degrees. So, I think as long as you have an efficient fmic it wouldn't really matter.

I agree to a certain point. You are comparing two different cars. I bet if you either, one, put an intake pipe on your car and log the changes or, two, have your friend go speed density (unless he already has) and put a filter on the turbo removing the maf and intake, log the temps, I guarentee there will be changes.

As i said in my first reply, the changes may not be very much but there almost has to be some change. Now if you duct air into the engine compartment through the headlight or make a CAI then the changes will be much larger.

Regardless, the temps are going to be higher the closer you are towards the exhaust system. If the filter is directly at the turbo, the air entering the filter is all the warm air that is near the exhaust manifold. Now if you have an intake pipe with the filter where the MAF would be, the air entering the filter would be cooler air that travels through the pipe to the turbo. The further away you get from the exhaust manifold, the cooler the air is.

I can also say the intake pipe will be by the exhaust also, being it attatches to the turbo right under the manifold. so that will have temperature effects. Correct?

I'm just playing devils advocate here. Obviously for daily driving it.might hurt the car but full drag cars don't even run filters at all. Trying to see it from both sides of the debate.

No problem good points made by all. My opinion is best option is to pull air from outside the engine bay as it is almost impossible to tell how hot the engine is in spots while at speed. AJ's post had the best answer and that is to try it both ways and track the numbers.

I have a stock 2g intake pipe, ill try it with that and take a log and compare. But, if I were to permanently put a intake pipe on it would be in the passenger inner fender well.

onefast2gdsm wrote:I can also say the intake pipe will be by the exhaust also, being it attatches to the turbo right under the manifold. so that will have temperature effects. Correct?

The intake pipe will be near the exhaust manifold, yes. But thats why there are aftermarket hard intake pipes. Hard, aluminum intake pipes reflect the heat. Rubber OEM pipes absorb the heat which will create higher temps for the air inside the pipe.

Hard pipes are hot to the touch (depending where on the pipe you touch and whats near the area you touch) but they keep the heat out of the pipe. The air traveling through the pipe will stay much cooler in a hard pipe because of this.

With a hardpipe, you are taking the air from a further distance away and directing it into the turbo. No hard pipe, you are taking the air directly from the area where the turbo is and this air will be much warmer.

Like Shake Zulla said, its impossible to accurately measure the temp of air in these areas under driving conditions.

Like I said I'm playing both sides of the fence. Any what ifs is what I'm trying to bring out. I will be doing some logs and report my findings.

Sounds good. This is an interesting topic.

PS: text me!

Running filter or pipe to filter will not damage anything, nor will you see any real perfomance from it either, however running a pipe to a horn to either the front or side of your car will give a "ram air" effect which will yield denser air...i had a screen covering my turbo inlet just for leaves and crap and it ran no diffrent from when i had a filter on it. A "short ram" vs. a "cold air system/long ram" has shown a diffrence in engine performance showing the short ram with the decrease of engine performance ie:engine reading hotter air.. however by the time the air reaches the intake chambers its within so many degrees on all cars, unless you live in a warmer or colder area, then it would be colder and or hotter...

I think it really wouldnt make a difference what the temperature of the are entering your turbo is. Thats why we use intercoolers correct? To cool air going into the combustion chamber? Also half of the air intake on a turbo'd car is recycled exhaust right? We all know hot air comes from an exhaust so whats the difference what the temp of the intake air is? Like I said its what the intercooler is for.

The intercooler is deigned to cool off air, but why make it work harder? if cold air is entering it, then colder air SHOULD come out. Of course any air thats being entered will get cooled off, but common sense says the colder the air entering, the colder the air leaving, and engines perform better with cold dense air. Thats why it seems like driving a turbo car in winter makes it seem a lot quicker. Regardless, I can touch my intercooler pipe right by the end tanks and the pipes are ice cold. touch it by the throttle body its luke warm. So i honestly dont think it makes a difference because the pipes are under the hood in a very hot engine bay.

Hot air isnt recycles from the turbo, intercoolers are in place to cool the air that is heading to.the engine due to the fact that turbos get/hold heat, cris is right that u want denser air at all times, and the colder the air in the combustion chamber the better, so it makes a big diffrence what the temp is..