Cold Air intake on a EJ22

[SubaruLegacyWagon]

Older legacy 93' non turbo, would it be worth it to remove the airbox and replace it with a cold air intake? Or am I just asking for problems?

Edited April 24, 2022 by SubaruLegacyWagon

[laegion]

There really isn't much point unless you've done some other mods that require more airflow. There are lots of aftermarket filters made to fit most car's stock intake boxes. That's what I'd do if I wanted to upgrade my filtration. Plus a CAI introduces other potential issues unless it has it's own "box" surrounding it...such as moisture, and more heat than the stock intake, etc. I'm not sure about on yours, but on my '95 it has a little snorkel under the hood that scoops in cold air from the hood gap and feeds it into the airbox. That's far colder than any air in the engine compartment.

[heartless]

making sure you have a clean filter, and the air intake is clean and free of obstructions will do far more for you than any aftermarket crap will.

little story.. we tried an aftermarket cone filter on our Dodge Ram - it started having all sorts of issues with idle, acceleration and was definitely noisier than the stock setup..
put the stock air intake back on, and all the issues went away.

[el_freddo]

Stock air box and paper filter will move more air than your NA could ever need. 

What could benefit is making the intake hole into the air box larger, and scoop air from the front of the vehicle like later model cold air intakes do… how to achieve that on the older Gen1 is anyones guess atm - but I’m sure it’s been done before on an RS or other Gen1 turbo models that use the same air box  

Cheers 

Bennie

[1 Lucky Texan]

won't do anything unless you want more underhood sound/noise.

[el_freddo]

14 hours ago, 1 Lucky Texan said:

won't do anything unless you want more underhood sound/noise.

Have you seen the size of the air inlet on a Gen1 air box vs the diametre of the rest of the air intake between the air box and the engine? There’s a huge difference between the two, thus theory would have it that the air box inlet would be a restriction of some sort. How much for an NA? I don’t know and wouldn’t know how to test for that. 

But an air inlet to the air box matched to the engine air ducting between the air box and engine must reduce any restrictions in the setup. This includes deleting all the air ducting and boxes inside that front guard too. All of these changes will make things noisier, who doesn’t love a bit of induction noise? 

Cheers 

Bennie

[laegion]

9 hours ago, el_freddo said:

Have you seen the size of the air inlet on a Gen1 air box vs the diametre of the rest of the air intake between the air box and the engine? There’s a huge difference between the two, thus theory would have it that the air box inlet would be a restriction of some sort. How much for an NA? I don’t know and wouldn’t know how to test for that. 

But an air inlet to the air box matched to the engine air ducting between the air box and engine must reduce any restrictions in the setup. This includes deleting all the air ducting and boxes inside that front guard too. All of these changes will make things noisier, who doesn’t love a bit of induction noise? 

Cheers 

Bennie

Or they designed it that way on purpose...I'm not a fluid dynamics expert; but I imagine there are various effects created by having the inlet to the airbox smaller than the outlet to the TB...like creating a low pressure area in the airbox under sudden acceleration...either way, no engine is working at peak CFM often enough to make it have any kind of difference except at maybe the last few hundred RPM at redline while at WOT.

Unless there is some terrible problem with the design (and I'd say that Subaru engineers understand much more about fluid dynamics and flow restrictions and how they work to create a torque curve than we do) then I wouldn't mess with it unless you're doing major mods to the engine that would cause it to need more fuel and air.

Mostly what happens when people mess with their intake and exhaust without proven dyno tested setups is that you'll lose fuel economy (more air means more fuel to maintain the F/A ratio) and make your engine more peaky in it's power band. I wouldn't sacrifice low down power that's used every day in driving for a few hp at the peak of the power band that only gets used every once in a while personally, not even for a little more intake sound...

I think what's happening here is that people are thinking these motors (that are tuned very well to get good usable power from them considering their size) will respond the same to mods on intake and exhaust as an older, heavily restricted v8 (or stock turbo setup) would. It's just not the case. These aren't poorly tuned and detuned 70's V8's with heavily restrictive exhausts and intakes to comply with tightening emissions standards...(or a tiny stock turbo setup)

If you're looking for something with performance that responds to mods well, then buy a different car with a turbo...or spend the money to do a good quality turbo motor swap or something.

With a stock 4cyl motor a legacy just isn't a performance car. You'll need to do much much more than a CAI to make it one. but if you're just looking for some "street cred" or whatever it's called these days, or some more sound and you aren't concerned with the loss of mileage and low end performance then have at it...

Edited April 25, 2022 by laegion

[SubaruLegacyWagon]

The main reason I'd want to use a Cold Air Intake is for fuel economy, not expecting any kind of HP boost. But reading what you all wrote, and a little research, I decided not install one.

[heartless]

4 hours ago, SubaruLegacyWagon said:

The main reason I'd want to use a Cold Air Intake is for fuel economy

bumping up your tire pressures just a little bit will do more for fuel economy than a CAI will, lol
example: if you normally run 35psi, bump it up to 40..

tires in general can have a pretty profound affect on fuel economy.. the formula used (hard/soft), tread design, type will impact fuel in one way or another.

driving style will also be a factor.. if you tend to be an aggressive driver.. jumping off the line at lights, not slowing before stop signs (ie waiting as long as possible to brake) will eat up a fair bit of fuel economy.  average speed, too. if you are one to routinely run 10-15mph over the speed limit on the freeway.. try dropping down to only 5 over...  the faster you go, the more fuel you are using.

basically, there are lots of little things you can do that dont cost anything at all to improve your fuel economy. on that car, i would expect around 27mpg overall.. you might get it up to 29 if you are lucky.. that was the best i had ever gotten out of my 90 Legacy wagon... same basic car with a few cosmetic changes.

[SubaruLegacyWagon]

I speed everywhere, even more aggressive since I got the rear sway bar put in. I've been averaging about 250miles per tank before the light comes on. Had the gas light come on at 210 the other day, thought somebody siphoned the gas.

[el_freddo]

You need to quote distance to fuel put in the tank until it was full. 

For example, our family bus just got 1254km to “a tank” (two actually). Breaking that down we put 158L of diesel into the main and aux tanks. That further boils down to 12.6L/100km 7.9km/L). Not too bad for a 2.5 ton vehicle that’s 18 years old with 380,000km on the clock. 

Put that up against my Brumby. It got something around 450km “to a tank”. It’s fuel usage was 8.6L/100km (very stoked - 11.6km/L). But it’s got a 55L tank vs the 170L of the family bus, and I don’t run either of them dry as that would be very inconvenient :p 

Cheers 

Bennie

[heartless]

9 hours ago, SubaruLegacyWagon said:

I speed everywhere, even more aggressive since I got the rear sway bar put in. I've been averaging about 250miles per tank before the light comes on. Had the gas light come on at 210 the other day, thought somebody siphoned the gas.

yup, that right there is your problem. You should be able to get closer to 300 miles to a tank full... (roughly 10.5-11 gals of the 14 gal tank)  I am going to guess you are under 25 yrs old, right?

driving like that is not doing your car any favors - wearing things out faster. Sure, it can be fun - in the right setting - but daily driving on city streets, not so much.

[SubaruLegacyWagon]

16 hours ago, heartless said:

yup, that right there is your problem. You should be able to get closer to 300 miles to a tank full... (roughly 10.5-11 gals of the 14 gal tank)  I am going to guess you are under 25 yrs old, right?

driving like that is not doing your car any favors - wearing things out faster. Sure, it can be fun - in the right setting - but daily driving on city streets, not so much.

Gonna set a goal to hit 300.. I just can't stand driving like grandma.

[GeneralDisorder]

MAF sensors are extremely sensitive. So sensitive that I can't even begin to illustrate it to you. You should endeavor to replicate the EXACT conditions of a factory intake and MAF sensor as much as possible......

The ECU has a VERY CAREFULLY defined MAF sensor scaling table. ANY changes to the filter box, bends near the MAF, or the MAF housing itself WILL result in incorrect and non-linear scaling. 

The ECU on a '93 is not capable of flash programming and thus not capable of ANY adjustments for MAF scaling. 

You will ALWAYS be best served by EXACTLY replicating the factory intake and it's air filter. Make sure all connections are clean and tight. 

There is NO PERFORMACE to be had without tuning of the MAF scaling. Which is not possible without a stand-alone ECU. 

LINK ecu does make a plug-and-play compatible ECU for this application. It is speed density and you can toss that manufacturer specific MAF and it's housing. 

GD

[heartless]

7 hours ago, SubaruLegacyWagon said:

Gonna set a goal to hit 300.. I just can't stand driving like grandma.

lol, you dont necessarily need to drive like Grandma, but you do need to chill just a little.

make an effort to slow down a little.. for a couple of reasons.. 1. your fuel mileage will increase, and 2. you wont end up getting ticketed

when pulling away from a stop, dont stomp on it, just ease into it - you are not at the drag races, so stop pretending you are. there are no prizes on the streets, only tickets.

I live in the country, so for me, backing off the throttle before i get close to a stop sign is quite useful.. about a 1/8 mile or so.. let the car slow down a little before using the brakes.. brakes will last longer.

it is not about driving like Grandma, but it is about making multiple small changes that do add up.

[1 Lucky Texan]

pretend there is an egg, that must not be broken, between the top of the gas pedal and the bottom of your right shoe.

[el_freddo]

9 hours ago, 1 Lucky Texan said:

pretend there is an egg, that must not be broken, between the top of the gas pedal and the bottom of your right shoe.

So remove the throttle return spring??

Cheers 

Bennie

[1 Lucky Texan]

lol, one of the first cars I drove regularly had a sticking throttle, being a dumb teen, I took to driving barefooted so I could use 'toe grip' when need to pull the pedal back up. When my sister told my Dad, he just came out and lubed the linkage to fix it.

ah...good times, good times...

 

[heartless]

lol, my first car would do that on occasion, but rather than driving barefoot, i learned to stick my toes under the pedal and lift it, lol