In my opinion, it doesn't matter. Its a tube with a filter...one is longer than the other. There is enough air circulation under a hood while driving to get a good temperature coming in and a bigger part is how well our intercooling systems working.

 

If you want to be technical, the CAI is much better. You have cold air all the time vs having to take a few seconds to get the air cooled down.... and even then, air under the hood is hot, each 10 degrees lower equates to 1-2 hp I believe.

 

Thats all very hypothetical but you're also assuming that the temperature outside the engine bay (which the filters aren't really far from the engine bay) are colder in temperature and then you factor in that it still has to travel through an alluminum tube which gets heated and stays heated and having a longer traveling path slows down air velocity.

This is all nitpicking but no one will every dyno a before and after switching intakes. Hence, it doesn't really matter especially on a turbocharged vehicle like ours where the intercooler plays a bigger part in that post turbo air flow.

 

I got the CAI because it is quieter than the Cobb.Also it is cheaper.

In principle it is easier to clean the CAI which is a dry filter than the Cobb SRI which is oiled.

In practice ,although I haven't cleaned mine yet,it may be quite difficult to take the CAI off to clean it while the Cobb is relatively easy to dismantle.

 

I still like to pose the argument that in theory a SRI is better because when you're moving the under hood temp is practically ambient (I've logged readings from my IAT sensor), and when you're stop and go the hotter air allows the fuel to atomize better, improving fuel economy (search "hot air intake" on fuel saver forums).

Basically, you're not losing any power when you would want it, and you've got better mileage when you don't need/can't use the power. Not to mention the propensity of CAIs to hydro-lock the engine.


Dyno testing is moot because it in no way simulates real world air flow.




..and begin the debate.

 

There has been a million discussions on this topic.:deadhorse:

My .02.........The lower the IAT sensor readings the better for performance. Mainly due to the fact that the ECU has timing and fueling compensations tables based on IAT readings.

 

For me it comes down to mapping and filtering.

An intake that results in less efficient filtering than stock should not be on the car.

An intake that doesn't require a re-map isn't worth putting on the car.

An intake that requires a re-map isn't worth putting on the car.

Between those three criteria the intake choice is simple.

 

Stock

 

My car has a Short ram intake and i like my car the best so in short the Short ram Intake is the best.

Just kidding around but honestly, you will get opinions of both sides and no one really has any hard proof. the CAI goes into your fender. right? well the COBB intake with the box installed takes air directly from the fender and the filter is sealed off from the engine bay. Plus you have the intake duct taking more air into the fender well. So guess what, the COBB intake with the box is a short ram and cold air intake. Makes sense to me :dontknow:

 

there is a difference but as far as hp gains its pointless to get either. i bought a CAI and it didnt help the power hardly at all. im sticking with my factory airbox until i go rotated turbo.

 

There are plenty of data supporting the correct intake. Those that lack "hard proof" to use your wording generally are those that sell intakes they market as better than Subaru's yet when asked to produce UOA data showing how much Si is in the motor there aren't any, or it's not relevant etc.

I'd buy an intake that generates statistically significant data showing reduced Si and wear metals in the oil without hesitation.

 

there is a difference but as far as hp gains its pointless to get either. i bought a CAI and it didnt help the power hardly at all. im sticking with my factory airbox until i go rotated turbo.

What turbo?

My .02.........The lower the IAT sensor readings the better for performance. Mainly due to the fact that the ECU has timing and fueling compensations tables based on IAT readings.

Agreed.

 

What turbo?

I doubt it really matters.. when you start changing placement of things then there becomes a legitimate reason to change intakes. One of the big advantages of going rotated is that you can run a large diameter straight intake instead of having to cram it under the intake manifold.

I couldn't run the OEM intake if I wanted to.. FMIC pipe is in the way.

 

I doubt it really matters..

I disagree; respectfully, or course

Any turbo VFXX or larger has enough power gains from an intake that it's worth the cost. 10whp gains should be easily doable on that size turbo. While there may not necessarily be peak gains of 10whp (injector-limited @ StageII), you should see solid gains throughout the powerband.

For a car that's not injector-limited @ StageII power levels:
2011 Subaru STI stage 2 plus intake. Before/After intake test. - NASIOC

I'm aware that there wasn't a comparison of StageII+injectors vs StageII+injectors+intake, but Mike addresses that later in the thread.

 

I disagree; respectfully, or course

Ehh.. I was just saying if he's going rotated it doesn't matter what turbo he's going to use, he's going to need a new intake.

 

I haven't had my STI on a dyno, but I really think adding the intake made a difference. Of course the EWG and turbo sounds much louder which is nice, but my butt dyno also says the car really does better at higher RPM with the intake than it did without.

I just got back from a day at the track and I was keeping up with 911 996 (2001-2005) Turbos through most of my rev band. They were much quicker on the low RPM range, but at high RPM I was about dead even. Stock 996 Turbos have about 350 WHP/WTQ, but they weight significantly more than my car at 3700 pounds. The ones I raced against today had an instructor in the passenger seat too, so add another 200 pounds, while I was solo in my car. I'm probably around 300-310 WHP/WTQ with my stage 1, muffler delete, and intake, and probably 3400 pounds versus 3900 for the Porsches.

 

I'm probably around 300-310 WHP/WTQ with my stage 1, muffler delete, and intake, and probably 3400 pounds versus 3900 for the Porsches.

Sorry, but there's no way you're at 300-310 whp with a StageI reflash.

 

Very possible. Takes a lot of stickers and some AutoZone chrome "vents".

 

one word..... dynojet

Dynojet or not. 60-70whp from a StageI base map? Not happening.

 

happens all the time.. here in town we have two major Subaru shops, both with Mustang dynos. Less than a month ago a STi put down 680whp on one dyno. A few days later went to other shop, car only make 510whp.

 

happens all the time.. here in town we have two major Subaru shops, both with Mustang dynos. Less than a month ago a STi put down 680whp on one dyno. A few days later went to other shop, car only make 510whp.

I don't believe DJs have an adjustable CF, do they?

On the topic of MDs, I'm disappointed that the "local" shop gave in to the pressure of applying a CF :sadwave:

 

I'd like to be right at 300-320... but i've asked 4 different tuners now and all 4 have given me 4 different responses ... some similar... some adding stuff that isn't even necessary IMO anyway. If that link is true and that place got 280 whp on a mustang dyno with those few mods then that's the way to go IMO anyway.

Those numbers were from when the dyno read low. Stock '08 STI didn't break 200whp

 

Bah. All you guys and your "experience" and "researched" advice. I've found my modification bible.

Five Steps to Making More Power in Your Subaru WRX - Gearbox - Car and Driver



:zing:

 

Ok guys... I heard back from Phil at Element tuning... very honest guy it seems like... this is what he had to say about the meth injection as well as a full exhaust, etc...

"Yes with a stock turbocharger there aren't huge gains with the water/meth like we get with the larger turbochargers where gains can approach +100 whp.



At 280-300 whp you're not going to see huge gains on certain parts because at that power level you aren't really asking that much from the exhaust system or the intake. On 600 HP cars we've seen gains as high 80 whp with the right exhaust. So for now a good DP and a tune is really where your money is best spent. A little here and a little there does add up to some gains but at a large expense. They will pay off later when you go to a larger turbocharger etc.



Now 300 whp with those mods sounds like a lofty goal to me and I will be up front I don't tend to tune the factory ECU and engine very aggressively. I prefer to tune it in a way I know you can beat on it and it will be safely tuned. "

 

Ok guys... I heard back from Phil at Element tuning... very honest guy it seems like... this is what he had to say about the meth injection as well as a full exhaust, etc...

Phil is a completely stand-up guy, and truly one of the best tuners in the country. I never heard back from him when I sent him a message on doing the OpenECU/UTEC tune a while back.

 

I think I will go with them over the other local guys I have spoken with, just because he is honest, does the opensource tuning, and i've heard basically all good things about him.

 

holy dyno numbers batman this is a in depth intake thread...just my .02 i dont understand how anyone can say a aftermarket intake isnt better than stock. the stock intake on any car, or any motor are so restrictive due to carb,dot, and all the other crap manufactures or forced to comply with. how does a panel filter in a encloser get as much air as a open element? more air=more power on any combustion motor. for ex. my quad is known to have the least restritive intake out of any sport model. remove the air box, put a filter on the stock tube and its dyno proven 1.5 hp. even with stock air box and k&n style filter is over 1 hp. replacing the whole intake tube and open filter 2.5 hp peak and 4. something in mid dyno proven on stock motor...another thing to consider is our cars obviously have the hood scoop so it might bring more fresh air to a short ram vs trying to get air through the bumber/fender.dont know if there is any research on this or not but just a theory.

 

OK this is IMO an interesting topic; here are my views:

holy dyno numbers batman this is a in depth intake thread...just my .02 i dont understand how anyone can say a aftermarket intake isnt better than stock.

Because the aftermarket intake isn't better than stock.

The stock intake on my car is also fitted on a car that makes 23% more power, stock from the factory. This means the stock intake on my car is not limiting power output.

the stock intake on any car, or any motor are so restrictive due to carb,dot, and all the other crap manufactures or forced to comply with.

Where are the data to support this? See above. Your car may vary, but the stock intake on my WRX is outstanding.

how does a panel filter in a encloser get as much air as a open element?

I don't see the relevance.

Here's something relevant: Show my one "open" filter or one imitation (the "tuners" call it "aftermarket" but if it's not an authentic part, it's imitation...) intake that filters air better than stock. Used oil analyses showing reduced silicone in the oil compared to stock would do fine for this.

for ex. my quad is known to have the least restritive intake out of any sport model. remove the air box, put a filter on the stock tube and its dyno proven 1.5 hp. even with stock air box and k&n style filter is over 1 hp.

Except we're not discussing the quad, and the quad is likely atmospherically aspirated. It is also unlikely to be expected to survive the same time/miles as a good road car. Since dirt in the motor translates to wear on the motor, good filtration is crucial, at least for my motor. And, since my stock intake is not reducing output, I have nothing to lose by keeping the authentic part and not using an imitation.

 

your right you dont have anything to lose, and the stock wrx intake is excellent thus me giving an example of my quad which also has a excellent intake. its also designed to be a cheap, mass produced part to comply with above agencies. just like the downpipe, and exhaust. changing you mufflers out may not give you dyno hp numbers, but it will give you better flow, as the stock cbe is pretty good on the newer cars. i personally, and fam, friends etc having been ridding for 20+ years in the desert and dunes with k&n style filters and not once have had a problem due "lack of filtration". im pretty sure those conditons are far worse than the car would ever see. i have had k&n intakes on all three of my cars with no issues. i have had it on my titan for 4 years, go offroading and all, no issues. i just cleaned my tb and intake tube last week and i was even suprised how clean it was.

 

the data to support that a aftermarket intake is better is all over for several cars. i personally dont have data on all cars and so forth cause that would be rediculous lol. judging by your number of post im sure you have way more knowledge on these cars than i ever will, just adding my .02 is all

 

judging by your number of post im sure you have way more knowledge on these cars than i ever will

Post count means absolutely nothing when it comes to knowledge. That said, Spiros is a vast encyclopedia of knowledge, both Subaru and random.