Open Box on Intake

[NFAM3]

Has anyone left the airbox open? Does it do anything? Better sound or better performance?

[robb7979]

I did one better. Left my hood AND the air box open.

[SROC3]

tried using straws.......didn't work too well

[NFAM3]

I tried the hood open thing but didn't work too well, I got pulled over while I was driving. Then I actually did try the straw thing, the jumbo straws at that but really didn't see any difference. My next option was just leaving the air box open but I wanted to ask the experts like you two first. Maybe I'll just leave the airbox closed and try the straw INTO the open hood, see if that works. Thanks for the answers.

[robb7979]

As a serious response; don't do it. You'd be sucking in hot engine compartment air. Hot air= less density=worse performance. That's the least of what your problems would be, since the air filter is designed to work with a seal. I.e. with the air intake closed. I don't believe anyone can fault you for not searching, if that's any consolation.

[NFAM3]

If its any consolation, I'm using the app and it doesn't have a search button. But thanks for the serious answer.

[robb7979]

Originally Posted by NFAM3

If its any consolation, I'm using the app and it doesn't have a search button. But thanks for the serious answer.

Honestly, sorry for the satirical response. I'm not one of the search Nazis. leaving the box open will allow all sorts of dust and dirt to enter your intake. It might sound great because of the greatly diminished restriction, but it won't be good for your engine. Even in the short term.

[Singletrack]

Originally Posted by robb7979

I did one better. Left my hood AND the air box open.

LOL.

Originally Posted by robb7979

Honestly, sorry for the satirical response. I'm not one of the search Nazis. leaving the box open will allow all sorts of dust and dirt to enter your intake. It might sound great because of the greatly diminished restriction, but it won't be good for your engine. Even in the short term.

Honestly, the air being ingested normally through the lower bumper scoop is just as bad, or worse, than the air under the hood. In terms of contaminants...

You will get hotter air (not just at idle), more detonation, less timing, less HP. You will also lose whatever benefit there is to the hood vent design with the upper airbox cover.

[Ateam]

The sound however would be incredible! Some people are willing to live with the loss of 15-20hp at the most for an incredible sound. All about what you really find important on a day to day basis and what makes you happy. A sweet sounding car can be worth some hp loss to some but not others. You could also think of it as an m3 with only 380hp but that sounds even more incredible

I personally do not or would not only because I personally believe in getting the most power squeezed out of a performance engine which to me means putting race gas/pump to get to 95-96 octane etc. Even if it only helps a couple hp I feel I am getting the power and performance that the m-engineers designed.

[JCtx]

Originally Posted by NFAM3

Has anyone left the airbox open? Does it do anything? Better sound or better performance?

Common sense dictates that with a big a$$ hole in front of the bumper feeding the airbox, there will always be more air available than the engine would ever need. That's the reason for the hood vent, to 'bleed out' excess pressure at speed.

The issue is usually to change the air filter or not. A racing filter allows more air to pass, but the engine is unlikely to need any more than it can get with the stock filter. The only exception could be at the very top of the rpm band, BUT for a measly few HP at best, it's just not worth it allowing more dirt ALL THE TIME, especially if you live in a dusty environment.

Finally, I don't understand how people could like cheap induction noise; leave that to lesser engines that sound like crap otherwise (and still, I prefer engine sound over intake noise), but not on a V8, especially a gem like the S65, which sounds like no other IMO. But yes, to each his own. Good luck.

[Singletrack]

Originally Posted by elp_jc

The issue is usually to change the air filter or not. A racing filter allows more air to pass, but the engine is unlikely to need any more than it can get with the stock filter. The only exception could be at the very top of the rpm band, BUT for a measly few HP at best, it's just not worth it allowing more dirt ALL THE TIME, especially if you live in a dusty environment.

Macht Schnell meets the same filtration standard as the OEM filter and has been shown to add power.

Reducing the drop in pressure across the intake will increase power and response across the entire usable RPM range. Now whether you can feel it, or measure it on a dyno is a different story.

[SROC3]

BMW has the design down pretty well for max intake power and velocity. I'd try the Macht SNell system. PRetty bad ass. Get the Stage 2. It would be kinda cool though if they created some "cold-intake system" like I had on my Honda civic in the by-gone days of yore......ahhh yes, the reverse periscope design into the bumper housing. Had a nice little HKS filter on it too. That greased out, green colored one

[NFAM3]

I have the AA Green Filter in the car. I just remember on my older cars, I'd remove the airbox and put a K

[flipm3]

How's this.....