Just an update. Not so lately I added an AEM intake to my car. Here are my before and after results.

I decided to go with this intake instead of my ARC box since the AEM was CARB legal. That was the main attraction of the AEM. I do not know how much the sticker is going to help if I get pulled over given that a) I have an illegal exhaust and b) the sticker is hard to see below the hoses and the stock snorkel.

I wanted to make a before and after test on the impact of the intake on my tune w/o any changes to the tune. So I made a number of runs on Sat and a number of runs today. The weather was almost the same for both test sessions:

Temps for test with stock intake with K&N drop-in: 17* C, 61% humidity, 102 kpa pressure

Temps for test with AEM intake: 16* C, 54% humidity, 102 kpa pressure

My car has the following mods:

JIC Downpipe
Invidia Exhaust
Resonated 3 inch TP
Nisei LICP
K&N Drop-in

The first thing that I noted is that I hit the boost cut limit at the top end. I run a stock boost cut form 4500 rpm to redline. When I did my first log, I hit the boost cut at 5500-6000 rpm. I was expecting that and it was not a surprise. So I pulled over and raised the limit by 10 load points from 4500 rpm to redline. That solved the problem. The lesson here, is that if you have a TBE and plan on using this intake w/o a tune, then you will hit the boost cut. So please plan to get your tune or at least lift the boost limit on your Evo.

Second, is obviously the boost increase at the top end. This is the way the boost profile looked like before and after the AEM intake. The boost was slightly lower at the low end and between 0.5 psi to 2 psi higher from 5500 rpm to redline. The car was holding 21.63 average psi by 7000 rpm with the AEM intake vs. 19.44 average psi with the K&N drop-in. For those who have an MBC, this is very helpful since you can hold ~ 19 psi by redline vs. the ~ 17 psi with the MBC alone.



Third, the AFR was also impacted by the intake. The AFR richened up all the way to 5500 rpm and remained almost the same from 5500 rpm to redline.



Fourth, the airflow with this intake increased at the top end (5500 rpm +) and decreased at the low end (below 5500 rpm). It could be that the richer AFRs had something to do with it. I will see how these numbers change once I tune the AFRs back to the way they were before the AEM intake.



Fifth, the intake air temps dropped with this intake during WOT operation was less than I expected. Perhaps it was the lower IATs that I began the test with. Despite similar ambient temps, the IATs during WOT operation for the AEM intake dropped ~ 4*C vs. 8*C for the stock intake. And yes, I was running the stock snorkel. Maybe an RMR hood scoop is in order. But that sucker costs about $350.



Finally, the before and after power curve looked like this:




The power gains are concentrated above 5000 rpm. Below that the car lost a bit of power, especially torque. The average HP gains from 5500 rpm to 7500 rpm were 16 hp and the average torque gains were 15 ft-lbs. The peak HP gain was 19 hp.

Clearly the car gained power from the increase in boost. If I re-tune the boost to the way it was with the baseline log, the power will most likely disappear. Which raises the question, is this intake really worth it given that I can raise the boost by similar amounts to what the intake added and get the power gains that the intake gave me? This question comes with the caveat that with the stock intake box I could not hold more than 19.xx psi by redline.

 

Nice gain on the top end. I'm sure that the turbo is working more efficiently with the improved airflow. I'm surprised that IATs were lower for the AEM setup.

 

The Temp starting point was lower for the AEM but like nj says the delta was higher on the drop in.

 

i agree, the filter would have to be getting fresh air from some other source, or maybe humidity or temps were a bit lower that run.....