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Discussion Starter · #1 ·
Is there a difference when installing a 3" and a 2.5" CAI?


Thanks,

Jbird
 

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Discussion Starter · #3 ·
Kind of a newb to this, what does that entail?

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Countersteer forever
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For the most part a 2.5" CAI will give you better performance than a 3" anyway. A 2.5" creates higher intake velocity as the air enters the engine. The optimal size depends on the engine, but 2.5" or 2.75" seems to be about right for our cars. But if you can find a 2.5" that's what I'd recommend because they're also the easiest to install.
 

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Hyundai Dealer
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i just bent the edges of the hole down a lil bit with a set of pliars. I only needed to tweek it a little bit and it slid right thru!
 

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SWortham said:
For the most part a 2.5" CAI will give you better performance than a 3" anyway. A 2.5" creates higher intake velocity as the air enters the engine. The optimal size depends on the engine, but 2.5" or 2.75" seems to be about right for our cars. But if you can find a 2.5" that's what I'd recommend because they're also the easiest to install.
Does anyone sell a 2.75" CAI? That's the diameter of the stock intake on an '04 EGT. I can see the logic in not going any larger, but I find it hard to believe that there would be any advantage to going smaller.
 

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Bnystrom said:
Does anyone sell a 2.75" CAI? That's the diameter of the stock intake on an '04 EGT. I can see the logic in not going any larger, but I find it hard to believe that there would be any advantage to going smaller.
There are other parts of the intake itself that is more restrictive then just the pipe. But in addition, the stock intake has all sorts of crazy bends and changes shape in several places.

I would think of an intake similar to an exhaust.
First off, you want as few bends as possible and you want them to be as gradual as possible. Now, you want to be able to move as much air as quicly as possible. The smaller, the faster it will travel but the less air it will get. The larger, the more air it can take but the slower it will move. Generally speaking, your choice in size is 2.5" or 3". Both sizes will work fine and although you will have to modify the hole a little to fit the 3" it isn't that much harder to do the install (not enough to worry about). Also, just like an exhaust, if you go with the smaller piping, you will usually feel more of the gains in the low end and with the larger piping, the high end.

I have a 3" intake, and although the car does not suffer in the low end, it screams after 4k rpm.
 

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04 elantra cvvt said:
Have any of you tried the K&N Typhoon system?
No I have not nor has anyone else that I know of.
When I got my intake, I figured if I was going to modify an accord one, I wasn't going to spend the money on an expensive one. The only reason I modified an Accord one was back then, there were no Elantra ones. Now, i would probably just buy the Evofusuion one and put a k&n filter on it.
 

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turbo envy
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the evofusion intake is 2.75....nice gains and nuch nicer sound....its a nice piece i enjoy everyday :D

to enlarge the hole...i used a flathead screwdriver and a hammer...couple hits and your home free....just use a little silicone afterwards and you are good to go!
 

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Just keep in mind it doues have an extra end for a breather hose. On the accord, it would face down but on the Elantra, we use it bacwards and it will face up. Not a biggy to performance, but it will look a little odd.

 

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With out some more serious NA mods, you wont be able to feel much of a difference. 2.5 or 3, just get something, anything is better than that convuluted stock setup.
 

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SWortham said:
For the most part a 2.5" CAI will give you better performance than a 3" anyway. A 2.5" creates higher intake velocity as the air enters the engine. The optimal size depends on the engine, but 2.5" or 2.75" seems to be about right for our cars. But if you can find a 2.5" that's what I'd recommend because they're also the easiest to install.

right.. 2.5 inch is better than 3 ??? thats why i ran a best of 15.1 with a 3 inch CAI and a cat-back...


(gtech time).

so, can you explain this?



or this?



ohh wait... how about this..




:bowdown:
 

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Super Hero
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There is no way you can increase velocity of air by restricting its delivery. The shorter the tube the better. If you could put a filter on the end of the TB, that would be best. There is no venturi effect in an intake. If you want to understand a venturi effect there is a ton of stuff on the internet about it.

There is no benefit to "smoothing" the air flow in the intake tube either. By the time the air enters the intake manifold, through the obstructed TB's butterfly, the air is so turbulant that any possible positive effect is negated.

Any air flowing through any tube is slowed by the friction created by the molecules colliding with the tube. Powder coating helps this but still.

Feeding the coolest possible air to the intake is what is important with SRI's.

This is not some ranting off the top of my head. I thoroughly researched this. The only people making claims of increased velocity of air are the ones selling intakes. Additionally, there are too many variables to "test" CAI vs SRI's. You have to think this one out.

Also consider: in effect companies claiming increased velocity want you to believe that it is forcing more air into the IM creating a ram air effect. This is complete BS. Ram air is only benefical at speeds above 150mph. There is plenty of OBJECTIVE resources on the net for this too.
 

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I will agree with everything but the ram-air issue. A blower works the same way. Though the volume of air is not the same with the ram-air, but at 30 MPH, you will be making about 1-2 lb ob "boost" if that's what you want to call it. To test this, stick your hand out the window at 50. There is some force. I thought the same thing you did untill I put a funtional cowl-indution hood on my old Camaro. I noticed an immidiate differece at 35 +. And the cowl does not work on ram-air, it works on drag. So, if you were able to put a true ram-air system on the car, you would notice the difference right away.
 

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04 elantra cvvt said:
...... So, if you were able to put a true ram-air system on the car, you would notice the difference right away.

What you notice is the (cold air) gains from the fact that ram air and cowl induction are both feeding cold air into the intake...

"ram air" is totally different and you really do have to go super fast to overpressurize the intake due to the fact that the engine itself is creating a very powerfull vacuum..

ie.. if you have -30 psi of vacuum ... you have to go fast enough to overcome 30 psi .. and even at that.. you still have ZERO psi of boost... to make boost by just moving forward you have to surpass the vacume ... and at 6800 rpm redline of the beta2 engine... i have no damn idea what the vacume actually is.... lol

so i cant tell you at what speed you will actually make boost using "ram air" ... and of course you will need a fully sealed ram air induction box for it to work too...
 
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