Airbox modification..

[denward]

good idea

 

[babyface]

two main reasons why you won't feel much.

The hole you opened up might be stalling. Think sticking your head out the window of a moving car, the faster you go, the harder it is to breathe right?

You need something that can effectively scoop the air, like a velocity stack

The other is, if you were able to properly ingest more air, the ecu is probably not compensating for it enough....you can only determine if it's being effective by checking the plugs for more of a lean burn...or installing a wideband O2 sensor to see if the AFR at speed is changing.

After reading your post, i decided to build a plate to cover the areas around the velocity stack. This allowed only air to pass into the the filter through the velocity and i must say, the rev higher rpm is noticablly smoother and progressing in power, rather than fluctuating power. The intial hole was exactly how you described it, like it was getting chocked with too much and not enough direct air.

 

[moon*]

if u ever plan to do open pod; u can try my CAI intake

i kinda drill a hole; n had a hose tat goes directly underneath my airfilter.

 

[Tmus]

well we've finally done it, took only a few hours but it's done.

Overrev Tuned homemade CAI

debris catcher removed for increased volume & resonance

is there a performance increase from removing the paddings? i thought it was just for noise reduction.

 

[OveRReV]

is there a performance increase from removing the paddings? i thought it was just for noise reduction.

i haven't got a dyno but the principle of removing the padding is to increase the volume of the airbox & to let the resonant frequency inside the airbox to go undamped which can help increase power. this is why motorcycle manufacturers spend millions in R&D to develop airboxes in their high performance sportbikes, they want to stuff the biggest airbox they can fit in a sportbike & use the noise coming from the intake to stuff more air inside the cylinders.

even F1 engines have sealed airboxes over the row of velocity stacks, the principle is like that of the 2stroke exhaust pipe where you use sound (resonant frequency) & pulse waves emanating from the exhaust port to pull the charge out of the transfer (intake) ports & use the returning pulse wave to stuff the over scavenged charge in the exhaust port back in to the cylinder like a supercharger/turbocharger does.

engines with small intake plenum can benefit from a bigger airbox, engines running ITB can be fitted with a bigger plenum much like an airbox for a sportbike, airboxes can resonate in different frequencies depending on shape, volume & material used this is why custom airboxes are made of solid/rigid material to enhance the resonance effect.

 

[Ash-EK9]

if u ever plan to do open pod; u can try my CAI intake

i kinda drill a hole; n had a hose tat goes directly underneath my airfilter.

that looks good ware can you get one of those covers for the air filter, on the other hand making one would be easy peasy

 

[thingee]

@ haitch

were did you get the cf tube? cant find one anywhere!

 

[haitch]

My Spoon lookalike tube is actually plastic and was part of a mates cheap IK for his E39 ( - but you can get the same from Merlin Motorsport, I have one just have not swapped it over yet, I thought the link is on one of the pages

 

[haitch]

45 Degree 76mm Hose Joiner Elbow from Merlin Motorsport

 

[bRedcoupe98]

just wanna share...my simple cheap OEM airbox mods

 

[haitch]

Am I missing something or have you just removed the filter?

 

[olly ek9]

Am I missing something or have you just removed the filter?

far as i can see he`s drilled a hole in the side of the airbox and inserted another venturi type intake tubimiythingy in there.

 

[haitch]

My eyes! I see it now

 

[thingee]

My Spoon lookalike tube is actually plastic and was part of a mates cheap IK for his E39 ( - but you can get the same from Merlin Motorsport, I have one just havnt swapped it over yet, I thought the link is on one of the pages

ye. saw the link. but lookin 4a cf tube. any ideas?

 

[stevenEK9]

well we've finally done it, took only a few hours but it's done.

Overrev Tuned homemade CAI

debris catcher removed for increased volume & resonance

OEM intake tube cut & welded shorter

K&N drop-in is used for filtering, can you say Mugen CAI rep.

up next we'll replace the stock rubber tube to a solid PVC tube, gonna scrounge the local hardware stores for the right size tubing.

i am such a cheap bastard.

Really like the idea of how you've removed the lower resonator and welded the velocity stack style end onto the pipe! Very similar to how most aftermarkey systems take their cold air feed (mugen/comptech to name a couple)

Recently been thinking of doing the same thing to my airbox as after long hard drives you can feel how hot the air is in that corner of the engine bay where the air is being brought in from!!

Anyone got any feedback on removing the lower resonator, not concerned about "oh it sounds way better" etc, but has throttle response or low/mid/top end pull been increased etc?!

Cheers

 

[haitch]

Mine feels slightly sharper, more pull through the revs. One thing is for sure with both resonators removed and a decent CAF the engine doesnt feel so strangled, especially noticeable on track.

 

[stevenEK9]

Cheers for that!

Mate has the old lower resonator with piping from his Jordan as he fitted an AEM not long ago, see if he fancies selling it so i can hack it up

 

[Gee]

Do these cold air intakes REALLY work?

I have just done my B18C conversion and the EK9 box and resonator are still in place at the moment and I think it may be restricting the engine.

I have a DC2 airbox and resonator to go on, but have no idea how the resonator would fit so was just going to fit the DC2 airbox and hook up a cold air feed with some ducting from the front bumper.

However, I have read that they can make the car sluggish lower down the rev's as the resonator stores air so there is a constat supply immediately to the filter.

Not sure what to do now?