Hell, I'm just glad it turned out to be beneficial for you :cool:

I'm interested in doing some logging on my car too. I JUST dropped my car off at Injen Technologies in Pomona, CA to have them prototype a CAI on my car. Paul had some insightful things to say about how they engineer the intake and also that they know about some of the stuff that they've seen on NASIOC, but more specifically this thread. I get it back Friday but dont know when I'm going to be back in reno.

That link doesn't work for me...

I think this is the page/thread he meant to link to.

http://forums.nasioc.com/forums/show...1776186&page=6

Note that the important thing to note on the dyno chart is NOT the HP/TQ, but the A/F... An intake alone should not change A/F, and if it does, and you run it without modifying the intake calibration table, you may get burned.

Try this anology... You are about to take a bungy jump off a bridge. Do you lie about your weight (tell him less than you actually weigh) to the guy who is setting the length of the cord so you just miss the ground?

Changing the intake causes the MAF to lie to the ECU unless you change the table to match the intake.

Am I looking at how it is leaner than stock after about 4150 rpms?

Lemme know if I'm going in the right direction with this... So the intake is allowing more volume of air to flow into the engine, but at the same velocity past the maf sensor. This makes the maf sensor think that there is less air than there actually is, since the maf doesn't measure the amount of air, it just makes an assumption on the amount of air based on how much the air cools the maf. Am I getting there?

FWIW, Paul also said that they actually engineer their intake to do that. Instead of changing the tables they modify the structure of the intake using different pipe diameters, filter diameters, etc...

Well if it does that, I would think it would be stock diameter, so the only improvement in flow over stock would come from the filter, so you could just drop in an aftermarket filter in your stock intake. Right?

Diameter alone does not determine the MAF's calibration. Sometime you can need calibration even if the shape of the tube is changed because the MAF sensor "sees" turbulence in the airflow as different flow amounts. The stock maps have been calibrated to the stock intake, so the turbulence in the stock intake is compensated for.

Along the same lines, it might be possible for a high-flow panel filter to create the same issues, but in practice on the Subaru I haven't heard of anyone having issues the way people have issues w/ aftermarket intakes.

So I believe you're saying that the only way to do what injen is attempting to do is via tuning the ecu, and cannot be done by adjusting any of the physical properties of the intake, since the maf is calibrated for the stock intake tract. Right?

Anything's possible, but using an intake to make power without tuning on a Subaru is like using explosives to propell a baby stroller. It may work at first, but Baby will eventually suffer an ugly death.

Even if you could safely lean out a rich area with an intake to make some more power, you're probably going to run lean somewhere else in the power band. You N/A guys can tune your cars now. Stop throwing rocks and bones at the motor in hopes of making power.

No, theoretically you could spend hundred of hours tweaking the new intake's design until the voltage coming out of the MAF matches the stock intake's voltage for every flow amount... but then you've just exactly duplicated the stock intake, so what's the point?

The only way to get the benefit of more flow w/o having potential issues w/ the tuning is to properly recalibrate the MAF table for the higher flow intake.

Lol!
Stop all of this and put a wrx engine in it already! I'll even lend a hand.
Step one: Go to msn money, they have 0% credit cards hehehe, that's how I financed mine :)

If there's one thing I've learned in the past decade... don't finance car mods. Just don't.

I would never finance mods. I'm just gonna buy an STi when I graduate. I've had the intake on since 2006, and if I change back, I'm gonna have to go to my parents' house and dig my stock intake out of the shed and clean it off.

Not that I don't believe you, but the one thing I can't get past is this: if it is so detrimental, why have I never hear of anyone having an engine fail due to their intake? And I've also heard that an intake is suggested with delta reground cams, because try actually do warrant the additional airflow capacity. I'm really not trying to argue with you about this, I'm just trying to learn

I've heard of people running lean and hurting turbo cars due to an intake. But I don't follow the N/A side much so I don't know if it's caused as much of an issue. Like it hasn't, simply because N/A cars are harder to blow up.

But that said, just because it may not blow up the car... if it doesn't actually do anything positive, and causes issues like idle problems. Why in the world would you want it on the car to begin with? Certainly if you get cams and suddenly the VE of the motor is increased, you'll want an intake to be able to make use of the extra power available (assuming the stock intake would be a bottleneck). But again, doing that without tuning for it is a waste... not only a waste of money on the intake, but a waste of money on the cams too.

Ideally, anything you do to the car should be tuned for. We live in an era of easily modifiable computer controlled engines. Hell, even in the "dark ages" of carburetors, people re-jetted and retuned for power mods.

Again, you may not be hurting anything, but the fact that you have to reset your ECU to make the car run well is very telling.

Go visit your parents, do some laundry and get the intake. They probably want to see you. ;)

Swap it back on and see how the car runs. If it doesn't change anything, then the issue is with your exhaust.

What exhaust do you have?

Do you still have the O2 sensor in, or did you plug something in its place? Cat or no cat?

Oh, the other funny thing with many intakes is that the cones actually have less surface area than the OE filter. I'm not sure, but I think the volume of the air cleaner box also acts kind of like a capacitor evening out the intake pulses...

It is definitely the intake, I remember having the issue after installing it. Although I think the mileage issue is due to my catless exhaust. I left the o2 sensor in, and I have a cel from it. I've read that the engine runs richer when you have the P0420 code, which I have seen to be true. Doesn't make much sense, if your cat is going out then running leaner would save the emissions, not richer. It is what it is tho. I think that is why my mileage improves, not the intake. It has to relearn that my cat is out, and slowly adjust to super rich again.

And I just saw my parents cuz yesterday was my birthday haha

Scott: everything I've read on nasioc says that these are fine without tuning. Obviously I'm leaing power on the table if I don't tune or my mods, but the car is supposed to be fine without tuning. There's a guy on nasioc (Matt Monson) that has everything I have, plus cams, and he's never been tuned and it still runs great. He lives in Colorado, and said that he dynos at the same power as a stock rs at sea level, which I believe is 20-25 over what he had stock

How'd he get the dyno from CO to sea level. ;)

Maybe he is getting more power, maybe it's even safe for the motor, but how do we know that your car is running safely and performing as well as it can until you get it tuned?

Since tuners are now able to use OS software, tunes are like $300. How much are you going to spend on those cams?

I plan on tuning after the cams. I figured it was pointless to tune before, since it's perfectly safe from what I've read. And yes, I know I could make more power from a tune, I just haven't gotten around to it.

He only knows what he dyno'd at, and what stock RSs generally dyno at at sea level. He compared it to what he's seen, not one particular dyno sheet. So I guess I meant around what they dyno, not at. Sorry.

Basically what I'm getting at is that with an NA motor, tuning is not nearly as necessary as it is for turbo'd subes, from everything I've read. I was wanting to learn how to OS tune myself, but I just never got around to it. And in order to make sure it's running right after a tune, I'd have to buy a bunch of gauges and pods for them.

At least you don't need a boost gauge. :P If you have a good tuner tune it, I don't think you need any gauges, personally, but that's just me. You can always add them down the road. Maybe grab an EGT next time you fuss with the headers.

I really don't know dick about N/A Subarus. However, I can tell you that my car would run fine on the stock map since it's a bugeye (well I'd probably want to ditch the MBC or never drive under partial throttle...), but I'd imagine that I'd be giving up like 30 WHP and the smoothness of a custom tune. I'm glad to hear that you intend to get your car tuned once you do the cams. Can't wait to see the results. :)

Are you going to get tuned for 91 octane?

Tune that thing for 87 and get NOZ!

So, to kind of bump this thread and maybe provide some relivant information, I didn't get my CAI. I got a call on the day I was supposed to pick it up saying that at max, they could only get 5 HP out of it. He didn't say why or what they tried, but I suppose that the stock intake was so well designed that there really isn't a good upgrade to it. So I picked it up from them and they'll continue the work at a later time (about two weeks) on a different car. They'll still send me one when they're done with it though...

Nice info to hear.^

Cody- I'd like to get a map for 91 tuned for max power, and one for 87 or 89 tuned for max fuel efficiency. That way, I'll have a fun map, and then I'll have a map for when I'm running out of money during school haha. I'm planning ongoing with ed at eq tuning, so I'll talk to him about all of that before I just do it.

And the guages comment was for if I tuned it myself. I figure then I'd want a wideband o2 and egt at the least.

Cool. Make sure you tell Ed to give you a dyno graph for each tune. It'll be interesting to see exactly what you leave on the table when you run the max fuel efficiency map.