I spent some time last night checking out the stock TL CAI. I found some interesting things and would like to share them. I didn’t compare it to other cars, find any rattle, or polish anything, so those looking for that please go to the next thread.

Let’s start at the filter box. The inlet is at the bottom of the box, and a baffle directs incoming airflow up through the filter towards the outlet. Subsequent pictures of the air filter show that this baffle is definitely doing its job.





Check out the next picture of the air filter. With 3500 miles on it, the dirt pattern clearly shows the preferred path for airflow. I had previously knocked the K&N because it had less than half the surface area of the stock filter, so how could it flow more? Seeing this airflow pattern has me considering a K&N for several reasons. 1) Despite the large filter area, the majority of the airflow is clearly occurring through a relatively small area. Since much of the filter is relatively unused, the filter D/P won’t change, but the air flow path and efficiency will change. I am taking the simplistic approach that any deviation from the path of least resistance reduces efficiency. 2) The stock filter pleats are oriented in a direction that would seem to obstruct airflow. The K&N pleats, according to their website, are oriented in the opposite direction. 3) As the preferred path through the stock filter is restricted, airflow through the filter box will change and become less efficient. Whatever element I went with, I would want to replace/clean it often. The K&N would save me a lot of money…



Next I found the intake silencer. Many cars have these and they serve the noble purpose of quieting down the rush of air into the intake. Many people like hearing that rush of air. Noise may not equal power, but disrupting airflow to quiet it generally does reduce efficiency. Intake silencers are widely known to steal a few horsepower in many applications. The silencer in the TL is pretty big so it may be better than others. It’s also pretty well hidden. At the inlet to the filter box is a rubber sleeve that connects the filter box to the silencer piping. Someone wishing to remove the silencer could disconnect it there. I suspect the incoming air charge at that location is just as cool as where the current inlet is…more on that later.



So, where is the air inlet? Good question, and the answer surprised me. Check out the shrouding around the battery in the next picture. This helps separate the CAI area from the ‘hot’ air around the engine. Check out that little triangular shroud in front of the battery.



Pull off the triangular shroud, and there it is!



When the car is in motion, air is forced up into this area by an opening in the front fascia.



There is clearly nothing cold about this CAI when the car is stationary. With the shroud in place it is pulling air through a restrictive path that is heated by the radiator. Acura claims a 15F drop when the car is in motion. How could you simulate this on a dyno? Just pull the triangular shroud and allow the intake to draw air directly from above. Could be wrong, but I’ll bet the colder air provides a nice bump on the dyno. I don’t think it makes sense to do this outside of testing, however. Removing the shroud would reduce the cold air benefits in a moving car (no real world power increase) and increase the chances of dropping something down the inlet that you might want back.

Conclusions - I'm going to get a K&N. I'll consider an aftermarket CAI, but I'd like to see a fair comparison to stock first. Because of it's inlet location, the stock CAI is at a huge disadvantage when stationary.

 

Aegir - Best post in this forum in weeks!!!! Thanks man!! This definitely helps out Norse and others!!

Seriously, keep up the good work!

 

nice deduction of the CAI. but why would performance be important to you when the car is stationary?

 

I never take it apart...

 

I'm thinking the point he's trying to make is: Company XYZ develops a CAI for the 04 TL. Company XYZ than pulls shiny new 04 TL into their Dyno Shop to measure the HP at the wheels with the OEM setup. This is performed with the TL strapped down, and not moving forward. Than they remove the OEM parts and adds their CAI parts and re-run the dyno test again to see the increase their product created.

The problem is, is that their test is flawed. The OEM setup requires the car to be moving (forward) to get the actual HP at the wheels.

So their test will show a greater increase with their CAI then you are actually getting...

 

Exactly, it's not important, but the most common method for evaluating cold air intakes is a stationary chassis dyno. I think unshrouding the stock intake on the dyno would better simulate the colder air the car would get when the car is in motion and provide a more representative baseline.

 

Exactly my point. I'm not saying that an aftermarket CAI wouldn't make more power, but if the difference is 3hp instead of 15hp, I'd like to know...

 

Sorry, I steal speedytl's picture out of fsttyms1

1. Due to install AEM Intake, you could see he relocated his battery (compare to Aegir's picture).

2. Due to Apex'i WS Exhaust, (if I'm right), he "seemed" to remove the 900-cell per-square-inch high efficiency converter mounts directly to the exhaust port of each cylinder head, and relocated the reserved tank of Radiator.

3. I think his sway bar is changed, too.

 

but on a chasis dyno don't they use these large fans and blow air at the car to simulate wind? wouldn't that effectively force cold air up the intake?

 

what are all those red wires for? it looks really strange hanging off the battery.

 

They should run dyno over the wind tunnel... it could get better (accurate??) results...

 

You didn't see this... right??

 

oops...didn't read the quote part. there wasn't a nicer way to install the electronics? its too intrusive looking in the engine bay like that.

 

Depending on the shop, the car may be facing the wrong direction. Generally, the fans can't simulate the effects of the car in motion. I'd be willing to experiment for the sake of science, but have no dyno cash...

 

Has anyone done 1/4 mile runs to see if there's a difference between stock CAI and, say, the Injen?

 

Hmmm, I'm wondering whether you can get to the area near the resonator by punching a hole throught the lower front fascia? That would help get cold air to an aftermarket intake.

 

Speaking form experence, I'd warn you to be sure not to let unfiltered air pass through your cold air intake, this will destroy your mass air flow sensor.

 

Don't ppl have tried some aftermarket CAI already? Besides the decent sound, do they really get the power they want?

If it's only 3-15hp for the engine, it may directly reflect to the performance with 2-10hp, how can human being feel it?

Sorry, I cannot.
:o


BTW, aegir, I really like what you shot... they're pretty detailed and good. I was just reading it again and compared to some materials/info I have... what you said is the useful knowledge, at least, for me. Thanks.

 

Aegir,

Excellent thread, thank you!

 

If we had one.

 

Like i said taking out that restrictor and add some tubing were the restrictor was cut out. And then bypass the back up resevoir so the flow is direct you would have your own CAI. Thats prety much what icebox does on the CL-S. i will be doing this an re dyno the car just have another project going after that i will start on the TL. GReat thread AEGIR

 

Bitium,

I take it the TL doesn't have a Mass Air Flow Meter? Interesting, how does the engine compensate then?

 

[QUOTE=rets]I never take it apart... really good. Thanks.



Looking at this picture....

What is the box below the filter????

From this diagram, why couldn't you just open up the path below the filter and not take the air up by the battery? It looks like that would do the same thing as an intake kit. Just put a KN in the air box and go.

 

 

Is not a water valve...come on guys is the resornator (silencer).

Check it out HERE

 

Glad you were aware of that. My younger brother's friend thought that by removing the stock air filter he would get more power. Thats a nice way of F'ing up your car. Using unfiltered air to combust in the cylinder. Destroying your air flow sensor, NICE. Also, another young moron thought he could redline out of the showroom with out breaking in his once new Integra GSR. Now his engine is doing funny shit cuz he never broke the car in properly. Just some of the spoiled young teens that don't know how to take care of something valuable like their car.

 

Our TL's have MAP (manifold air pressure) sensors, is pass the TB (trottle body) on the manifold, so if you remove your entire intake before the TB you will not mess with the MAP so is not part of discussion under this topic, but I could explain more when I have more time.

Because we do not have MAF sensors that is why on my other thread CLICK HERE when I install a duct from the bumper straight to the intake, I actually lost power, because the car couldn't compensate for the mass air flow.