Intake pipe and filter vs just an air filter on a turbo setup

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..

Spooleddohc wrote: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..

I understand that you want colder air entering, but obviously the closer to the throttle body the hotter its going to get. I'm in no way taking one side over the other. The only reason i deleted my intake pipe was because I thought it was going to hit my intercooler pipes. And the only reason i keep bring up what ifs is to get your minds thinking because this is a very interesting topic, and I'm sure a lot of people will find this thread very informative. Sunday night i will be performing my test. I will be using a stock 2g rubber intake and a k&n fipk filter vs. my k&n on my turbo. It sucks I wont have an aluminum pipe to test but maybe i can find one for testing another time.

just run some pvc into the fender well and put on a filter, and just be dne with it...

Id rather not have a cheap half assed looking engine bay lol. I like the look of the filter on my turbo, but that's not the point of this thread. I think this thread is going in a different direction than i planned, this isn't supposed to be about my car, its supposed to be an argumentative debate with facts and opinions on why one way is better than the other. For example someone says no filter and pipe is better on the track because..... an intake and filter is better on the street because...

Yes that does make sense. But also just because the pipe is warm does not mean that the air inside it is. I wonder if you could somehow insulate an intercooler pipe if you could keep the air ice cold when entering the throttle body. Like take a regular metal pipe and somehow put styrofoam or something that would keep the exterior heat away from the air inside. Kind of the same concept of a cooler. Im gonna have to experiment with this a little bit. Who knows if it works, it could take off and I could get rich! HAHAHAh of course I would deffinately give a percentage of profits to ESD.

Exhaust wrap is what your talking about

That would work as well. But Im talking about something inside the pipe that would still let you have the nice looking piping on the outside. Exhaust wrap works well but looks like crap.

92tsifwd wrote:That would work as well. But Im talking about something inside the pipe that would still let you have the nice looking piping on the outside. Exhaust wrap works well but looks like crap.

I think Exhaust wrap looks sexy... like you know what your doing by putting it on.

Lol to each his own.

I hate exhaust wrap. I want to run a pipe to the fender and put a filter on it, I think that will see that most gains

I have a friend that ducted air to a air tight, well designed box located where the maf would be. Huge, but he was happy with the results after logging. IAT temps dropped significantly.

I dont see much of a difference with a filter being on the turbo vs having an intake pipe with a filter. But having a filter on the turbo vs a custom CAI setup would show a bigger difference.

Update. I have an extra upper intercooler pipe for my car. It has a 45 degree bend on it and is 2.5" in diameter. Well, this will work perfect for putting a filter right in the bottom of the bumper on the passenger side, getting fed by air through the cresecent moon in the bumper. Problem is, it has a blow off valve flange on it. My father in law is bringing it to work Monday so it can be tig welded shut. So I will have a 2.5 intake pipe with filter being fed fresh cold air from the bumper, I can't wait to test and see the results.

This just got even more interesting.

My brother has his Cold Air Intake filter down there only its on driver side because its 420A. Looks good too.

Bottom line is, the colder the air in, the colder the air into the combusion chamber. The cooler the air enters the turbo, the cooler it will enter into the IC, the cooler it will enter the throttle body (TB), the cooler it will be when it goes into the combustion chamber.

Why is the air going to be cooler entering the turbo using an intake pipe?

1) The longer of a distance air travels, the cooler it will get. Heres an example. If i stand 3 feet in front of you and blow air in your face, it will be cool. Now if i stand within inches from you and do it again, the air will feel much warmer. Same concept is applied to an intake pipe. For many reasons. Which brings me to...

2) Heat.
A) Using just a filter on your turbo, you are sucking air that is within inches of your 1300 degree exhaust manifold.
B) The turbo itself already creates heat from compressing the air going into the turbo.
C) The air entering through the front of the car while driving will be also heated up by the time it reaches the turbo. Why? Because it passes through the FMIC (if you have one) and the passes through the radiator. Which will heat up the air.

So where the hell are you finding any "cool" air at all to the turbo if using a filter directly onto the turbo? You AREN'T!

Ok so maybe this isn't a big deal. Say if you have a filter on your turbo and sucking in warmer air. When the air passes through the IC, the air will heat up even more. The hotter the air is when entering the turbo, the hotter it will be when entering the IC. Which heats up the IC even more than what it already is and it continues to do so. Your IC then loses is abuility to soak up the heat. You know what this is called? Heatsoak. Heard of it?

Maybe the power gains arent that big of a difference. The rule of thumb is for every 10* lower the temperature of the air that enters the combustion chamber, you gain 1% of HP.

(10* intake temp = 1% HP)

1% may not seem like much right? Think about it. The air you would be getting by using a filter directly on the turbo is MUCH warmer than the air in the stock filter location or in the SMIC location. Say the temp of the air at the filter in the turbo area is 50* warmer than the temp in your inner fender well (SMIC area) if using a CAI setup. Using the above formula, thats 5% of HP. On a stock DSM with 200HP, thats 10HP! Now imagine what 5% would be on your car Cris or on any highly modified DSM with some higher HP. Cris, that would be 20-25HP on your car.

Now this is referring to a street car in which you run it for hours at times depending on where you are going. So the engine bay and engine parts have plenty of time to heat up. If you have a track car, you may only run it for 10 minutes at a time once every 2 hours and only a few seconds of hard driving. Thats why you see the open turbos in the track cars.

Again, this is a big deal on a street car. If you are sitting in town at a red light, the turbo is just soaking up all the warm air. So, you are still at the red light, light turns green, and you launch the car. Oh hey, dsmlink is showing some knock. And you wonder why? Filter on your turbo, turbo sucking in all that warm air, well no wonder why you get knock. I have heard from several people with this issue.

I am not pointing fingers at anyone. Cris is the only one here using the filter on his turbo. He made a thread so we can debate, and i like proving my point. This could be useful for everyone in the future. I just dont see any pros to using a filter on the turbo. Unless maybe you literally cannot fit an intake pipe in your engine bay for whatever reason. Or maybe you like having that clean look. Only performance thing i can see anyone benefiting from this is you have less restriction. But in my opinion, its not something i would want to do.

When you say how the air temperature being 50* warmer near the turbo as opposed to the stock side mount location can cause knock, due to warmer air entering the combustion chamber, then wouldn't that mean whever summer rolls around we would all have to re-tune our cars due to the warmer air?

I'm no tuning expert, but I know temperatures fluctuate up to 70* from winter to summer, and going by your logic that would mean we would all have more knock in summer due to warmer air coming through the engine bay, rather than cold air in the winter.

I guess what I'm trying to get at, is do people need to re-tune for summer?

I dont know if retuning your car seasonally is a nessecity but most people i know do retune their car a few times a year because of the temp differences. If you are modifying your tune frequently (daily, weekly, monthly) like most guys with dsmlink do, you generally wont have to make a big change because you are always keeping up with your tune.

Hope this makes sense. But yes, temp changes between summer and winter will make a big difference on your tune. As will elevation.

With speed density on link you'll always have to do a little tweaking. If you stay on top of it you won't have to make significant changes.

Update: me and turbo4awd custom made an intake for my car. We used 3" piping and it runs all the way to the passenger fender. As soon as I put it on and did a wot pull my afr went lean to 12.3:1. It's definitely getting more air. Have yet to do some logs.

A hard intake pipe just makes the air flow entering the turbo smoother... less turblance in the air stream the better. The intercooler is what really cools the air.

Yea flow is key. This was a really interesting topic.