DiabloSVRacer

Hey guys,

so my buddy was taking off my front bumper to remove the headlights so they can get modified. he noticed that next to the battery in my 05 acura rl, the air tube that sucks in the air flows down into a bigger box (located right under/behind the driver headlight) and then flows back up into the air filter. so we removed the extra tubing and now my car sounds more aggressive and shaved some weight! what do you guys think about this? why did acura put all this extra tubing for?

-noob

T-jay

To get cool air from the front. All hondas have this.

VietGuy03

iTrader: (4)

It is usually referred to as the intake resonator. It cycles the air flow in a manner so that there is little to less resonance within the engine bay or within the cabin of the car. There are many people who have removed this and paired it with a K & N intake filter and received a more aggressive note with their intake. It is mostly purely subjective (can be a good thing) as there are not any if any noted gains that I know of.

rtr

Most likely it will make your car slower and make the air intake less effective

VQPower37

^ atleast it will sound cool doing it

23109VC

I think the intake is an area where there really is little area to improve. The old days of bolting on an I take or cat back and getting real gains you could feel are gone. Cars are so well tuned from the factory..it's not easy to squeeze more power from most normally aspirated cars.... Now a turbo car...you can mess with boost...but that's a whole different animal....

Mr Marco

^Exactly, 3hp? Are you going to spend $250 on an intake for 3hp? There is no doubt that more ponies can be obtained from under that hood, but it needs to be done with software.

T-jay

I see intakes are a sensitive subject around here.

rtr

Lol

RL Chi-town

really intake is not a bad thing...

tlmaster1

Yea i also removed the whole oem intake, and put in a k&n short ram for a 2004 tl.

037

I think the air might still be pushed into the intake tubing even with an aftermarket SRI.

not as much air as stock since it was push (from outside) and pull (from intake) but better than just having to deal with under the hood air alone, in theory anyway.

EL19

iTrader: (4)

I think you're right.

I just put in a drop in K&N filter and cut out the resonator. Used some 3" flexible tubing and connected that tube draws air from the front of the car to the tubing under the box. Its slightly peppier and has a deeper tone to the motor now. I like it.

rtr

Yea on the dyno you would see a change in your power curve not for the better when taking the stock air box and stuff out. Drop in K&N will do you guys just fine.

theNHBRL

long time no one has updated this but i have dont this on my previous tl and see that, one would get pedal happy, and push it but with the k&n air filter its much cleaner air and if you do the 3' tubing will get the cold air no matter what, just because its coming from front. now if you shorten it you will loss power because your sucking hot air. but sounds good. will do this on my rl.

dishwatercider

Installing a short ram intake, etc, in a car helps with the car's note, due to the pulling instead of pushing done by a cold air intake. You can actually see possibly increased hp (minor), and yet still have a much worse 0-60 time, as the car has to work more for its air. The note you are hearing is the car trying to gulp all that in. When you floor it, it may not be able to get air as fast and may have a poorer combustion cycle that is running very fuel rich, sounding pretty, but accelerating slower. Especially when coming from a standstill, where ambient airflow is basically nil.

The advantage to doing so, other than sound, is that in cycling in air that is already heated, you insert hot air into the combustion chamber. This allows for a more complete combustion cycle, and thus your fuel to be burned more efficiently (as long as its able to pull in enough air). So not only do you get a sweet note, it should encourage a better MPG and possibly a better acceleration rate when at normal operating RPMs.

I've been testing out the Takeda SRI in my RL, and I can certainly tell when its running well in my favor, and when I'm pushing it hard enough to actually be inefficient. You should be able to feel your car almost choke up. If you really punch it from a stop, it'll run really rich and you'll see your MPG drop. I think 037 can attest to that a bit. It seems to work better as a moderate performance boost, when you need to drop it a gear on the freeway to get around someone and have better airflow through/around the bay.

The only solution I could think of would be better passive intake ducts running up from the front of the car and just opening into the bay, making more forced air available to the engine as needed, at the risk of cooling the area down somewhat. Maybe if you had ones that allowed extra airflow at low speeds, but then closed up to keep the bay hot and get better MPG. I may have to play with this a bit...

We have any other engineers/mechanically inclined individuals who want to chime in?

oo7spy

My engineering expertise will not help in the mechanical realm, per se, but your idea regarding the temperature is interesting. There are a few aspects to take into consideration. For the same pressure, the engine intake suck, and volume, amount that can fit into the piping and manifold, your temperature and amount of air are inversely proportional based on PV = nRT, the ideal gas law. So assume that a CAI can pull in 60 degree air, and the SRI pulls in 120 degree air. Theoretically, you will get twice as much air with the CAI as you would with the SRI. The amount of air available definitely has a play in the combustion process. However, if the temperature of the air has an effect on the combustion efficiency, you need to find that sweet spot for optimal air quantity to air temperature in order to optimize your combustion.

Now, that SEEMS simple enough, but throw in your EGR system that takes some of the exhaust, mainly targeting noncombusted fuel, and routes it back into the intake manifold. This will do three things, save some of the noncombusted fuel, raise the temperature of the intake air, and also displace some of the available air in the combustion chamber which lowers the final temperature caused by combustion and reduces NOx emissions.

To find the best solution it is necessary to know what optimizes performance most, increased air temperature or increased air quantity.


Did you make it back to Austin? Did you go through the Appalachians or Tennessee? I was hoping for the prior and that you would have a camera for some awesome photos. What side of town do you live on? I wouldn't mind taking a peek at this ride if it were available.

dishwatercider

Air quantity is certainly very important as well, and the thermal expansion does decrease the volume of useful air reaching the engine. I think that's why the SRI is setup to be as open as possible, so it'll take as much air as it can from any direction.

My idea about the hot air making the combustion cycle more efficient comes from trying to increase the Carnot cycle efficiency, which is 1-(output temp/input temp), or roughly for our cars, (1-(ambient engine temp/combustion chamber temp)) The higher the difference between the two temps, the closer to perfect efficiency we get.

By using an SRI, we should do two things. First, when we cycle all that hot air from the bay in, we get closer to the 1500 degree temp that gas combusts at, albeit only slightly. Any little bit helps though. The second aspect is to pull all the hot air away from the area surrounding the engine, allowing cool air to come up under the car and create a cooler ambient environment. Both of these combined inch the overall efficiency of the cycle upwards.

However, as you noted, that doesn't do anything for us without a good air mixture, which requires a large volume of air, which the CAI is much better at providing. It really is an issue of finding a good balance between maximizing Carnot efficiency, and remembering the limitations imposed by PV=nRT.

And yes, the EGR does throw a fun wrench into things, fighting our attempt to increase temperatures by lowering peak combustion temperatures...

I am back in Austin, but only for a few days before the car wanders to Colorado for while. We ran through Tennessee, and didn't really get any good pictures, despite me bringing my little Nikon D40. It was more a mad dash to get back, as my travel date to the Springs moved up. I spend most of the time around campus, so I'm fairly central. If you or any other Austin area AZer's want to meet up, its gotta be tonight or during the day tomorrow... but I'm down.

db22

It seems like lot of effort for a debatable gain. Once the car is moving then the temp in the engine bay becomes close to outside temp, the only way to decrease the temp and therefore increase the density would be to use an intercooler. With addition oxygen you would require additional gas resulting in more power and less reliability. Honda can get about 850bhp from 2.4 liters but you cannot afford the engine rebuilds! Everything is a compromise.

oo7spy

Cider, too much going on right now. Surely the car will be around town sometime within the next year. I'm in no rush. Good luck in CO!