whats up guys, what is the best intake for the wrx? im trying to stay away from the injen cai intake because i purposely think cai's really don't make more power than a regular intake for turbo cars, first off b/c the pipe is so long that the air flow takes is decreased, second the colder air is gonna get hot because of the turbo. so what i want is a short intake with maybe a heat shield. so are there any on the market, so far all i've seen is the blitz. and how those the kn filter and removed silencer compare to the gains off a conical intake?

dennis

someone dynoed the k&N drop in at like 3-5 HP. I don't know of any other intakes so far. But if u look at most of the faster cars (like the ones in SCC last month) a majority of them have the stock air box, including Alex (imprezer) who ran a 12.8 . Thats not to damn bad with a stock airbox:) I think the intake money should go to something more worthwhile...look into a short shifter, (www.kartboy.com) or some tires. stock wrx tires SUCK! :D
Good luck
Keith

Originally posted by datdudedennis
. . .i purposely think cai's really don't make more power than a regular intake for turbo cars, first off b/c the pipe is so long that the air flow takes is decreased, second the colder air is gonna get hot because of the turbo.
dennis. . .

first, induction of air into the engine is heck of a lot more complicated than "shorter is better". Since air is a fluid with mass, it has inertia. When it's moving it tends to stay moving and when it's still it tends to stay still. Compare this to electrical inductance if that helps. In theory, a longer tube (of sufficient diameter) will give you a greater inductance effect and therefore tend to allow higher volumetric efficiencies in the intake manifold at high rpms. A shorter intake will provide a quicker acceleration of the air in the pipe so you'll get quicker 'response' but perhaps less ultimate high-end power.

Second, it doesn't matter how hot the air gets after the turbo, if it starts out colder, it will end up colder after the turbo. Simple thermodynamics! Lower the initial temp, more heat required to raise the temp to a certain level.... I can promise you though that a cold air intake (such as the Cobb/APS version) WILL definitely improve your car's power, response, and sound over the stock airbox. The peak hp may not be affected much but it is definitely noticeable at lower rpms. Have a good one!

nhluhr,
i know that when the air starts off cooler but lets say the air is 50 degrees cooler than the engine bay, when it gets passed the turbo its not going to be 50 degrees cooler than the air that has been heated in the engine pay, its not a linear effect. sorry i didn't if you were implying that it would be the same amount coooler or not. and there is no doubt in my mind that the cobb or injen cai makes more power than the stock airbox but i meant compared to a short intake like the spo intake. and how i got the info about intakes is from the experiecne iwth my brothers car. his civic has a supercharger, we put an aem cai and notice very nice low end but the highend just lagged, then we put a short intake and the highend felt better but low end wasn't as strong. so that is where i got my info, who knows if its correct though.

so does anyone know the gains of the cai's by cobb and injen? my salesman specificially pointed out the warning to stay away from 2wd dynos, so do most car shops have 4wd dynos as well as 2wd?

feedback greatly appreciated.

dennis

save your money and replace the restrictive hose that goes to the turbo inlet. It should be available soon in the vender classifieds for around $250+

I took my wrx to the track and installed the ingen cai. The first three runs without the cai I got a 14.9, 14.7 and 14.7 I then installed the ingen cai and got into the 14.6 and 14.5 range so I think it may have helped. It could have also been that I was just getting the hang of thangs but anyway it sounds a lot cooler when you install the intake anyway.:cool:

Originally posted by datdudedennis
nhluhr,
i know that when the air starts off cooler but lets say the air is 50 degrees cooler than the engine bay, when it gets passed the turbo its not going to be 50 degrees cooler than the air that has been heated in the engine pay, its not a linear effect. sorry i didn't if you were implying that it would be the same amount coooler or not.

correct.. if the CAI draws air that's 50 K colder than from the engine bay the air won't be that same 50 K colder after the turbo, simply because when the air is colder, the diffusion of heat happens more rapidly but it's still going to be on an exponetially decaying curve... Start lower on the curve, end up lower.

Either way, a 'short ram' or a CAI will both be a huge improvement over stock.