There really isnt any reason to get one unless you have major modifications, cause the stock airbox like everyone states, does the same thing as a CAI, especially if you do the snorkelectemy... Spend the money elsewhere, like on some intercooler piping or on the exhaust.

 

Not to object to anyone. But Easy Street runs injen with all their packages. And we all know where Easy Street is in the books.

Nick

 

.....but even their most basic package is touting over 300 HP where an aftermarket CAI probably would help. I think what's in question is if it can produce appreciable gains on a stock car.

btw, I find it curious that ESX is bundling a BOV & CAI with their exhaust in the Stage 1 offering (not talking about their packages). Their description is: "Our Standard ESX STAGES are designed for those of you who want or need maximum performance with minimal modifications.". There's no details on that part of their website yet but I'd be really interested what sort of gain they claim by using an aftermarket BOV on a stock WRX (regardless of the much debated CAI).

- Kean

 

Talk with easy street. They are the fastest and they do use this intake. So it must be worth somthin to our motors.

Nick

 

.....I think you're missing my point. The car that obtained these "fast" #'s was heavily (very heavily) modified. I have no doubt that the stock airbox would not be adequate for that application. What I'm interested in is what the CAI does for a stock WRX.

On a side note, I found something odd in the basic kit they sell. If they claim to be all about performance, then why do they include a BOV with that kit? It doesn't come with any components that would require it. I know there are no details regarding these kits on their website yet so I don't want to make too many assumptions.

If I was interested in making a 10 second / 700+ HP monster, then I would probably be consulting these guys.

- Kean

 

Just givin some info on Injen. Just tryin to help, sorry if I missed your point.

Nick

 

....you are being helpful. Thanks. I would be very excited to have bolt-on perfomance like that. ......but I want to make sure it will give me the #'s some folks are claiming. Sorry if my posts sometimes come out blunt......no discourtesy intended.

- Kean

 

A lot of the info us bay area folks talk about comes from things we've heard from what shiv does at vishnu. over a year ago, there were some threads on nasioc talking about shiv testing incredible numbers of different combinations of parts to see what would give the best "bang for the buck." and also to find out which parts didn't do anything, as well as those which actually hurt performance.

i remember that bolt on intakes in general didn't give any performance gains whatsoever. i'm going to have to check on this, but iirc, to this day, shiv will not tune a car with an aftermarket intake. his stage 3 that will be coming out some time soon makes around 350 AWHP on his dyno which is like 900 (not really) on any other dyno still uses the stock airbox. for reference, txs st4 cars are doing very well if they make more than 250 AWHP on shiv's dyno.

 

Most of you are missing the point about why there is an argument against using a cold air intake. It really has nothing to do with whether or not the temperature of the intake air (not "charge", that refers to the intake cycle within the combustion chamber) is hot or cold, but rather the MAF sensor. Let's start at the beginning-

The factory ECU relies on the MAF signal to determine how much fuel to deliver during each combustion event (or series of events in some cases). It is basically saying "the MAF says there will be X amount of air in the CC, so it needs Y amount of fuel". This is the basis of crude engine management such as S-AFCs as well as a feature of more sophisticated systems like the Xede and stand-alones; it warps this signal to fool the ECU into adding or reducing the injector pulse time. I doubt that is news to any of you however.

What may be news is the fact that the actual MAF sensor is tiny, and is calibrated to read the exact flow for that exact diameter pipe in that exact configuration. If, for example, 300 cfm of air is flowing through, then it will see one specific voltage from the sensor, and it won't see that signal value for any other amount of air flow. The problem with changing that configuration causes the signal to be different for that 300 cfm of air- the ECU thinks it is seeing more or less air than it is really getting and calculates fuel accordingly. This is why some intakes can make horsepower on the dyno- they lean the car out in a very crude and dangerous manner, which almost always results in more power, but is far less reliable and safe than using tuning methods to do this.

So how is it possible for 300 cfm to give a 250 or 350 cfm signal? Simple. As a gas passes through a tube at a given pressure (atmospheric pressure in all cases, as we are talking about the intake air prior to reaching the compressor) its velocity is dependent on the diameter of said tube. Increase diameter, decrease velocity, and voila- incorrect readings.
But it gets better. There are also currents in the intake tubing that come into play. Notice how the factory intake tubing is all bent up and corrugated and convoluted? That causes little eddies and cross currents that affect the way the MAF reads the signal of X cfm of air passing through it. While these make theoretical computation of the exact airflow over any given point within the intake tract impossible, they are stable and repeatable. Thus, the factory ECU can be calibrated to rely on them.

Then there are those who say the factory intake is "restrictive". Bull****. WRC cars make well in excess of 300 horsepower, and they are breathing through a restrictor that is 32mm in diameter. That's barely an inch and a quarter! So what is restrictive about the 2-1/2" tubing of the factory intake? Granted, it isn't the most efficient shape possible, but it works fine. This inefficient shape is often why aftermarket tuners look at the engine and say "gee whiz, I think I can make a better one of those!", and so they do. Only not really. Because by changing the air flow/signal relationship, they screw with fueling. You can indeed flow more air through an aftermarket intake, but that's just one small part of making lots of safe, reliable power. The tricky part is making it burn efficiently.

By now, many of you are putting 2+2 together and thinking that a more efficient intake plus good engine management able to properly calibrate the signal will increase horsepower. Well... no. Funny thing about turbocharged engines- they don't seem to really care what's happening upstream of the compressor, up to a point (slap that WRC restrictor in there and you'll see what I mean). This is why the WRX needs absolutely no recalibration to go from Death Valley to Mammoth Lakes, an 8,000 foot vertical journey. The MAF signal allows it to automatically adust fuel for the amount of air being ingested by the motor. This is relevant because the lower atmospheric pressure at high altitude has a similar effect to inefficient tubing.

As for Shiv not tuning intakes- he does, but only on the dyno. He won't allow off-the-shelf maps to be run on cars with intakes because the fuel tables will be wrong. If you bring it to him to custom tune, then he can work around it. And yes, he's tested many many intakes on many many WRXs, and none of them have shown significant power gains (significant meaning 5+ repeatable, consistent horsepower) over the stock intake, and some even lose power. Particularly the short ram intakes. This is why you can't buy a Vishnu intake- we could certainly produce one, and certainly Shiv could make off-the-shelf maps for it, but it's pointless because no intakes make more power than stock. We could sell it, and people would buy it, but it wouldn't make anybody's car faster.

 

'nuff said. Stock intakes work!

Don't fix what ain't broke!

--
0==WW==0
"…axles of evil…" - george w. bush

 

well from what i have heard, injen intakes make the combustion

dangerous in the long run, other than that running is not so bad

unless your constantly running high rpm's such as in a auto x

event. ANother thing is it make the engine run lean. But my injen

intake has served some good purpose i make long trips from so

cal to nor cal about 5 times a year. When i first purchased the car

i would get about 300 miles per tank, after i purchased the intake

on mobile 91 octane i would get about 330 so i mean i guess in

the long run it paid for it self, but i am not sure how reliable this

intake is. Other than that, i have sent in my ecu to Cobb tuning

and George from Cobb said my car will be fine after the reflash,

cause i was worried about running to lean. Cobb's custom tuning

will provide stock specs for your maf sensor, in other words ur

ecu will think it is running stock but actually sucking in more cold

air. George ensured me my car would run safely for many years.

other than that if you guys are interested in purchasing a injen

cai, it makes cool spooling noises. when u shift it makes a subtle

but noticable bov noise. and it has some sound to it. i am thinking

about getting a blitz sus.

 

You have a custom-tuned engine management to compensate for your Injen intake - that's the way to do it. Don't use an intake to lean out the air/fuel ratio for better fuel economy, though!

OT - what's with the double-spacing in your post? It's awkward reading it...

--
0==WW==0
"…axles of evil…" - george w. bush

 

so it doesnt strain yours eyes..... *cough cough* cause reading BAN SUVS post was difficult and so small, also when i first joined the admin hassled me about it =) anyways i didnt buy it to lean out my engine thats the last thing i want but the custom map made it normal to the engine if you can understand, i know what i am talking about in my head just cant say it out right =\