CAI INstall Question...

[jbird88]

Is there a difference when installing a 3" and a 2.5" CAI?


Thanks,

Jbird

[2GTS]

A 3" will require enlargement of the hole next to the battery to get it to fit.

[jbird88]

Kind of a newb to this, what does that entail?

Thanks

[bmcb]

Sawzall by Milwaukee Tool Co. or Dewalt works best. :D
Or a BFH

[SWortham]

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.

[watson80]

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!

[Bnystrom]

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.

[AUTOBOT]

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.

[04 elantra cvvt]

Have any of you tried the K&N Typhoon system?

[AUTOBOT]

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.

[only1db]

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!

[04 elantra cvvt]

I am thinking about the K&N Typhoon kit for the accord. I like the way they are built.

[AUTOBOT]

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.

http://kandn.com/images/l/69-1208TR.jpg

[04 elantra cvvt]

That's true, but since I have to cut it for the MAF, I may be able to turn it around.

[Elantra2.001]

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.

[04 elantra cvvt]

That is my way of thinking. I'll get something at least.

[FordFasteRR]

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?

http://www.nitrousworld.com/ffpictures/2004-elantra/15-18.jpg

or this?

http://www.nitrousworld.com/ffpictures/2004-elantra/15-20.jpg

ohh wait... how about this..

http://www.nitrousworld.com/ffpictures/2004-elantra/15-22.jpg


:bowdown:

[XDGT03]

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.

[04 elantra cvvt]

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.

[FordFasteRR]

...... 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...

[04 elantra cvvt]

Well... vaccum is not measured in PSI, it's mesured in inches. At idle, our engines make about 26-28 in. of vaccum. As soon as you step on the gas, the vaccum drops. At full throttle, the engine is making about 2-5 in. of vaccum. The more load you put the engine under, the less vaccum you have. This is why hot-rods usually have to add a vaccum canister so they will still have brakes. The main factor in making vaccum is the camshaft. The lower the number on the lobe seperation, the less vaccum you will be able to make.

So, it's not really the force of the ram-air that works so well, but the added volume of air. A 45 lb. supercharger pushing air through a 1/2 in. hose will make less power than a 2 lb s/c pushing through a 6 in. hose. Making power is all about adding as much boost with as much volume as possible. I have actually seen a true ram-air trans-am make 1.5 lb of boost at 50 MHP and full throttle. As long as you can force the air in, it will make more power.

[Bnystrom]

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.
This is not true. For a given volume of air, the smaller the tube it flows through, the higher the velocity that it flows at. That's simple physics. If an engine is drawing X amount of air, it MUST travel at a higher velocity through a smaller intake pipe than through a larger one. That's why tuning the length and diameter of the intake will change the torque and horsepower output of the engine. This is something that's been done for decades to optimize engine performance. Whether a larger or smaller intake is desireable depends on what goal one is trying to achieve. A good general rule is that smaller diameter intakes are better at lower engine speeds and larger ones are better at higher engine speeds. BTW, the same principal is used in tuning the length and diameter of the intake runners between the manifold and the cylinders.


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.
A venturi is used to draw one liquid into the stream of another that's flowing past the venturi opening, as it a carburetor. It's not relevent to our intakes.


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.
While your comment about the throttle butterfly is correct, smoothing the airflow prior to the butterfly allows more air to flow through to it and is therefore beneficial.


Feeding the coolest possible air to the intake is what is important with SRI's.
Correct, but it's not the only thing.


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.
Granted, there are some wild claims being made, but you cannot lump all of them together and state that they're all untrue. Some manufacturers have legitimate claims.


Additionally, there are too many variables to "test" CAI vs SRI's. You have to think this one out.
Of course it's possible to test CAI's vs. SRI's. You simply maintain all other conditions stable and change only the intake. What's so difficult about that? It's the basis of the scientific method, as taught it grammar school science class.

The main factor in making vaccum is the camshaft.
The main factor controlling the vacuum in the intake is the position of the throttle butterfly. The more open it is, the lower the vacuum, as it allows more air to flow and fill the cylinders more completely.

[XDGT03]

Yes, I should have been more clear about the velocity issue. You can increase the velocity but you simultaniously decrease volume. Less air molecules. Manufacturers tune runners for optimal balanced performance. That is why some have gone to variable intake runners. But, it still constricts air volume (less molecules) but yes does increase volocity.

Air entering the IM on a fuel injected engine is thoroughly disrupted once inside. Plus, on our car, it is entering on one side of the IM not the center like on some port fuel injected, and carburated engines with the IM in the center of the cylinder banks.

THe reason for the inability to truely test ( I guess in theory it could be done) a CAI vs SRI is that you have to provide an ever increasing volume of air to the CAI as engine revs increase and the volume of air would have to correspond to what the speed would be at a given rpm and gear. Under the standard conditions of testing as done by most companies selling SRI's, SRI's come out with higher HP output numbers than CAI. But how can they really tell with their testing methods. They just blow a constant flow of "shop" air into a CAI and test the SRI with the hood open. THe kind of objective controled test that would need to be done, so far as I know, has never been done. Because, I believe, there are too many vairables to try to control. And since there is less tube for air to travel through on an SRI, if you can feed it cool air, it will be better than a CAI.

I have seen a bunch of stuff out there (not specific to Hyundai) talking about the Venturi effect of intakes. Tho i don't think I have ever seen it on Hyundai forums, it is out there on plenty of others. I just wanted to dispell any ideas that this is a factor. I think even Stillen promotes a Ventrui effect on his tapered intakes. BS

I think i heard the hand out the window arguement before. But Ford is right about the pressure and rpms. Actually, Random posted the total volume of air at WOT once on the old board. I will try and find it. And there is some difference when dealing with caburated motors and fuel injected.

[jameswing]

If you wanted to do a true test of CAI vs SRI, have a setup using each on the same car, and do a dyno test with each one on. If a dyno test is cost restrictive do 5-1/4 mile runs with each driving the same, and compare the average times.

[04 elantra cvvt]

The main factor controlling the vacuum in the intake is the position of the throttle butterfly. The more open it is, the lower the vacuum, as it allows more air to flow and fill the cylinders more completely.

This is true to a certain extent. If you watch a vaccum gauge, as you open the throttle, the vaccuem will drop, but if you hold the trottle at the same position, as the engine reaches it's maximum speed at that trottle position, the vaccum will start to increase again. The main thing that determines the amount of vaccum is the lobe seperation of the cam.

And since there is less tube for air to travel through on an SRI, if you can feed it cool air, it will be better than a CAI.

IF you use a SRI, you are picking up the air from under the hood which is much hotter that the air that the CAI picks up from in the fender.

[XDGT03]

IF you use a SRI, you are picking up the air from under the hood which is much hotter that the air that the CAI picks up from in the fender.

Yes, which is why I said

if you can feed it cool air, it will be better than a CAI.

WeaponR makes a SRI that is cold air fed. That is the best setup I have seen. RShack has one.

Plus, if you add hood spacers and remove the cowel seal, that engine bay air will escape. We haven't really determined how it will escape tho. There is some question whether it will flow up and out at spead or down along the firewall. But nevertheless, the engine bay will be vented.

I hope to do some temperature testing sometime soon. I member over at the EGT Club has some equipment to do the testing, hopefully we can hook up at an autocross event in August and do some testing. (outside of the race)

[Bnystrom]

Yes, I should have been more clear about the velocity issue. You can increase the velocity but you simultaniously decrease volume. Less air molecules. Manufacturers tune runners for optimal balanced performance. That is why some have gone to variable intake runners. But, it still constricts air volume (less molecules) but yes does increase volocity.
From a practical standpoint, we're not talking about diameter differences that would result in appreciably less air reaching the intake manifold.


Air entering the IM on a fuel injected engine is thoroughly disrupted once inside. Plus, on our car, it is entering on one side of the IM not the center like on some port fuel injected, and carburated engines with the IM in the center of the cylinder banks.
It certainly isn't the most efficient design.


THe reason for the inability to truely test ( I guess in theory it could be done) a CAI vs SRI is that you have to provide an ever increasing volume of air to the CAI as engine revs increase and the volume of air would have to correspond to what the speed would be at a given rpm and gear. Under the standard conditions of testing as done by most companies selling SRI's, SRI's come out with higher HP output numbers than CAI. But how can they really tell with their testing methods. They just blow a constant flow of "shop" air into a CAI and test the SRI with the hood open. THe kind of objective controled test that would need to be done, so far as I know, has never been done. Because, I believe, there are too many vairables to try to control. And since there is less tube for air to travel through on an SRI, if you can feed it cool air, it will be better than a CAI.
You don't have to "feed" anything to a CAI or an SRI. You install them on a car and run it on a dyno. I think that what you're trying to say is that for the test to be valid, there should be a stream of air to the front of the car to simulate the normal airflow that the engine would see on the road. While this could be done with fans for low speeds (perhaps up to 30-40 mph, you'd need to do it in a wind tunnel if you were looking for the results at highway speeds or top speed. However, the results for lower speeds would still provide a valid comparison, since they can still be run at the full range of RPMs.


I have seen a bunch of stuff out there (not specific to Hyundai) talking about the Venturi effect of intakes. Tho i don't think I have ever seen it on Hyundai forums, it is out there on plenty of others. I just wanted to dispell any ideas that this is a factor. I think even Stillen promotes a Ventrui effect on his tapered intakes.
Tapering will increase the velocity of the incoming air and lower the air pressure, which technically IS the venturi effect. That may be beneficial at a certain point in the engine's power band, which will depend greatly on the air demands of the engine and the initial size of the intake. With an EGT, perhaps there would be a benefit to starting with a 4" intake and tapering it gradually down to the stock intake size of 2 3/4" at the MAF (just speculating). However, I doubt there would be any advantage to tapering down to less than that, since the air would be allowed to expand again between the MAF and throttle body.

On cars without an MAF, there might be an advantage to tapering smoothly down to the size of the throttle body. Higher air velocity at that point may help get more air into the intake manifold. Has anyone done any tests of this?

[XDGT03]

Yes, here is the definition of venturi effect

"Bernoulli's theorem implies, therefore, that if the fluid flows
horizontally so that no change in gravitational potential energy occurs,
then a decrease in fluid pressure is associated with an increase in fluid
velocity. If the fluid is flowing through a horizontal pipe of varying
cross-sectional area, for example, the fluid speeds up in constricted
areas so that the pressure the fluid exerts is least where the cross
section is smallest. This phenomenon is sometimes called the Venturi
effect, after the Italian scientist G.B. Venturi (1746-1822), who first
noted the effects of constricted channels on fluid flow."


But the usfullness of this effect is in the part where it states:
the pressure the fluid exerts is least where the cross section is smallest

So we agree i guess. lol

Yes, there is probably no appreciable loss in the number of air molecules since there are no more molecules entering with the so called ram air setup, but there is the additional drag on the motor by it having to create the "venturi effect".

Yes, Yes, Yes, to the valid tests. SRI's out perform CAI's on dyno's. The test is conducted with the hood up and a fan blowing. Big deal. This is not a true controled test. Now maybe it seems I arguing both side of the issue here. No. My belief is that an SRI, fed by cool air, and hood spacers with the cowel seal removed is better than a CAI. Hopefully i can at least prove that the underhood temps are significantly lowered with this set up. I will not be doing any dyno's since no one around here has a dynojet (can you believe that in the Motor City? Maybe they got stolt lol) and no one will except less and basically eeking out 1 hp at 4200rpms one way or the other really doesn't matter to me. I'm happy with what I got.