www.dodo-upgrades.nl

The is a big issue that few people bear in mind. The length, the size and the shape of our induction kit do matter in the performance of our engine. This happens because by changing the intake tube we affect the velocity and the volume of the air coming into our motor. It's not just that however. All these affect the resonance of the intake and exhaust. This is the secret to make power out of an N/A engine. Have a look at Junior WRC and you will understand how 1600cc engines can perform 240+hp with great amounts of torque.
So one thing we can do is not to mess with our intake tube and just remove the resonators and add an performance filter in the box. D14 owners are unlucky here as our intake is a mess. So we get rid of it. Instead, we can get a stock airbox with the stock tube from a d16zy/y8 engine or even better the best probably dc2R airbox (it has a cone filter inside).
If we do that we keep the same length of the intake tube which is a good factory option.
Then we could buy a decent aftermarket kit. Good companies are supposed to rnd the size of their tubes.
Another option is to customize our own piping. This is what i have done.
At first i had an aftermarket intake tube which was 76mm(3inch). I always thought this is too big. i had the feeling that the car wasn't so good at low and mid revs |(maybe the too big tube reduced the velocity of the intake air) So i made a custom one 55mm width. i thing this is better. Noone can tell for sure of course, if you don't go to the dyno for the exact results.

So today i received my apexi intake which has a short intake tube to be added in the stock ek4/9 in.tube. So i am thinking of getting a used tube like that

My car had the stock tube, linking airbox to IM. I upgraded it to EG VTi intake tube, which is larger and has the exact same length.

I noticed significant improves, and I'm not using EG VTi TB. I'm waiting for the D16 head to be on, and then I will decide whether to buy and edelbrock IM, and use B16 TB, or if I'm going to polish my D16Z6 IM and portmatch it to the polished head.

Many doubts run through my mind, I hope all ends well and with ECU tune I can reach 100whp, I would be very happy

Can someone measure the b16 and d16 intake sizes? I mean the width of the rubber tube i uploaded. Thanks!

the b16's inlet intake tube diameter, is about 68mm
it couldn't fit to b18's tb i put

Thanks!!

Will a inlet tube and air box from a Y8 engine fit on the throttle body of an A4?? I am going to be doing the Y8 inlet swap and dont want to have to buy and inlet kit yet.

you need to change the intake manifold in order to do that.

Yea i will be doing the Y8 manifold swap so cool, thanks.

What would you guys is a max and min value for intake tube diameter?

Tough question! I would just say that the majority of kits meant for d16 and b16 engines are too big for d14.
I would say something around 60mm tube.

I use EG B16 intake tube on my D14, and it runs much faster than with the stock D16 one (my car has D16z6 full intake).

I'm sick, guessing the flu got me, but as soon as I'm ok I will measure stock and B16 intake internal diameter.

Sorry, should've done it before