Power drill + airbox = great induction sound

[exbmwdude]

Well, I finally did it...

I broke out the power drill and put about 50 1/4" holes in the top of the air box yesterday. I removed that silly little extra air intake on the top of the air box while I was at it. I also removed the foam on the front side of the box which is there to reduce intake noise. I've done this mod on every fuel injected car I've owned in the past 20 or so years and I've been happy with the results each time. At idle and part throttle, it sounds exactly like it did stock - quiet. But when you get on it, you are rewarded with a nice throaty roar from the motor - as it shoud be .

I'd recommend this to anyone who wants to hear more motor, without the expense and potential headaches of a CAI system. There are absolutely no downsides or potential warranty issues here as the stock air filter is still used.

exbmwdude2006 M35S

[maxnix]

So now you are drawing heated air from underhood? Must sound great while going slower.

[exbmwdude]

That's a myth that I disproved with a G-tech about 10 years ago.

Believe what you want - factory airboxes are restrictive to reduce noise. What you lose with "heated" air you more than make up for with reduced restriction. And the holes are on the top of the box right behind the grille to the side of the radiator. They are exactly where that goofy little extra air "scoop" is on top of the airbox.

Try this - look at the airbox of the previous generation G35 sometime (which - not concidentally - has a nice throaty growl). You'll see a big open hole in the box where our M has that silly/tiny scoop.

exbmwdude2006 M35S

[Boon]

So now you are drawing heated air from underhood? Must sound great while going slower.

To be honest, while moving, the air that is coming under the hood where the airbox is located is the same temp as the air coming in from the outside, the minute difference is not enough to bother performance to a point where you would notice. Also the plastic around the air intake conducts more heat then anything, luckiy air is not affected that much as it is rushing in so fast.

All in all this is more of a sound mod then performance. It should not effect anything other then the resale value of your nice car being that the airbox is all chewed up. Might want to obtain a replacement before you do this. Also your gonna want to change your filter more often as it will get dirtier faster.

[jbillion]

To be honest, while moving, the air that is coming under the hood where the airbox is located is the same temp as the air coming in from the outside, the minute difference is not enough to bother performance to a point where you would notice. Also the plastic around the air intake conducts more heat then anything, luckiy air is not affected that much as it is rushing in so fast.

All in all this is more of a sound mod then performance. It should not effect anything other then the resale value of your nice car being that the airbox is all chewed up. Might want to obtain a replacement before you do this. Also your gonna want to change your filter more often as it will get dirtier faster.

Can you please post pics of what you are talking about.

[auditech10]

I did this to my chevy caprice when i was in high school and verified a few extra ponies ON THE DYNO with a before and after test, so I can vouch for it. If you do it decently enough, nobody will ever know unless they pull the box out and even then if you do it cleanly its hard to notice.Cheers

[maxnix]

1,) That's a myth that I disproved with a G-tech about 10 years ago.

2.) Believe what you want - factory airboxes are restrictive to reduce noise. What you lose with "heated" air you more than make up for with reduced restriction.

1.) How, pray tell? It is a know fact teha under hood air is hotter and thus will produce less power as there is less O2 per unit volume. Unless you have the ability to transcend the laws of physics, I have to suspect your "proof."

2.) Yes, they are quieter than ricer-boy add ons, but they are not restrictive if done right like Infniti. Infiniti incorporates water traps and harmonic resonances to enchance certain velocity of airflows for a more uniform torque curve.

Very few readily available after market manufactures spend the hundreds of thoussands of dollars to model and test the intakes like OEM generally do.

[maxnix]

I did this to my chevy caprice when i was in high school and verified a few extra ponies ON THE DYNO with a before and after test, so I can vouch for it. If you do it decently enough, nobody will ever know unless they pull the box out and even then if you do it cleanly its hard to notice.Cheers

Here's the problem with dyanmometers, there is no airflow and thus no air resistance, and the hood is seldom closed so temperatures cannot increase with operation like the real world.

And don't think for a minute that Chevy spends 1/10th as much per unit as Nissan when it comes to induction design.

[exbmwdude]

1.) How, pray tell? It is a know fact teha under hood air is hotter and thus will produce less power as there is less O2 per unit volume. Unless you have the ability to transcend the laws of physics, I have to suspect your "proof."

Apparently you don't know what a g-tech is. It's a very accurate in-car accelerometer that looks like a radar detector. I owned one for several years and used it in many of my cars as well as those of my friends. It was great for learning how to launch cars properly as well as determining if mods did any good (or harm).

Personally, I don't give a %$#% if you believe me or not. I can tell you that I have drilled out about 20 airboxes over the past 20 years. About half of those were mine and half were those of friend's cars. Everyone always liked the extra sound/roar from the intake and the g-tech never once saw a power loss. If your car is moving (duh, it's a car not a statue) then you have plenty of air moving in and around the airbox since it's right behind or next to the grille, and the main scoop over the radiator is still intact. It's more about the sound getting out than any extra air getting in. I'm not claiming this is a mod to extract 20 more HP - it's just a zero dollar way to hear more of what an enthusiast likes to hear...the motor!

exbmwdude2006 M35S

[infinitiandbeyond]

Okay. As this relates to yet another car, a Porsche, here goes.

My last one was a 964, Carrera 2, RS America. This web link depicts the same air box I had and nearly the same modification I did myself.

http://www.porsche964.co.uk/te...d.htm

This is a very popular and easy owner-induced mod with 911's from the early 80's into 2000 or so. It does make a difference in performance and certainly sound.

I see it both ways. I still ponder a CAI for my M but I might do this instead.

Maxnix' point about the filter is true. I had to clean it/oil it often. A better flowing gauze-based filter like a K&N would be nice for the M.