Performance Filter

mickob16

Ive been looking at these filters and according to their manufacturers they improve the performance and economy of your car and even the BHP.If they are so good why arent they fitted as standard on all cars.If i put one in would it be considered a modification therefore requiring me to inform insurance company?

Matt Simis

See: http://www.boards.ie/vbulletin/showthread.php?p=71460522

n97 mini

Surprised you didn't mention removal of resonator box in your post Matt. From experience aftermarket filters have added noise and reduced economy.

tossy

Of course the have reduced economy,the purpose of an uprated air filter is to allow more air in,more air equals more burnt fuel.

ShiresV2

n97 mini wrote: »

Surprised you didn't mention removal of resonator box

http://www.brighthub.com/engineering/mechanical/articles/84316.aspx

The purpose of the Helmholtz resonator is to improve the volumetric efficiency of the engine and also to help with engine sound attenuation

Gary ITR

What car is it? I spent a lot of time choosing mine, in the end I decided to go for a replacement airbox with a foam filter inside.

I went for an ITG Maxogen, really pleased with it so far

Matt Simis

n97 mini wrote: »

Surprised you didn't mention removal of resonator box in your post Matt. From experience aftermarket filters have added noise and reduced economy.

My e31 has "chambers" that could be considered resonators, but without any real data I left them alone but put a direct feed in after them. My logic was the chambers will provide more air if needed but my newly routed direct feed would be the primary Air source.

The Audi S8 on the otherhand, despite being much newer doesnt seem to have anything very interesting going on in the air intake.

Although both cars have stock filters they both have modified air intakes... I cannot tell any noise difference, but they both feel "peppy'ier" after the intake mods.

Gary ITR

Matt Simis wrote: »

My e31 has "chambers" that could be considered resonators, but without any real data I left them alone but put a direct feed in after them. My logic was the chambers will provide more air if needed but my newly routed direct feed would be the primary Air source.

The Audi S8 on the otherhand, despite being much newer doesnt seem to have anything very interesting going on in the air intake.

Would an airbox for the E31 be found easy enough? If you got one you could test your modding on a dyno

Matt Simis

Onkle wrote: »

Would an airbox for the E31 be found easy enough? If you got one you could test your modding on a dyno

I still have the stock airbox installed, I could just block the alternative ducting off to do such a test. My concern is I dont think even the big fan at Urban would have the same focused ram effect (air volume) as 70mph and above open road driving, which is the airflow speed requirement to actually make "ram air". So while it would do "something" I dont think it would really replicate real world air intake performance.


On the e31 forums they consider the e31 (V12 model) intake to be "perfection" but before my mod the Air box was "luke warm" after a drive, after the mod its "chilly cold". It definitely cools down the intake if nothing else. I was fortunate as the e31 has two stock "trumpet" ram type intakes that are routed direct to the front brakes. I intercepted this air with rubber ducting and routed about 50% of it into the Air Box. What I loose is water/air seperation, noise suppression (cant tell any diff) and any intake frequency harmonics if they existed but gain a focused stream of high pressure cold air.

PS: To answer the initial question, the E31 has a totally custom air intake system that costs a fortune, so no, finding another wouldnt be easy outside a scrapped 850!

mickob16

Onkle wrote: »

What car is it? I spent a lot of time choosing mine, in the end I decided to go for a replacement airbox with a foam filter inside.

I went for an ITG Maxogen, really pleased with it so far

BMW 525D.I dont know anything about them so welcome all advice given.

-Chris-

I wouldn't bother, you'll probably get 2-3bhp out of it.

Save your money and remap.

mickob16

-Chris- wrote: »

I wouldn't bother, you'll probably get 2-3bhp out of it.

Save your money and remap.

Wasnt looking for extra horses just if it helped the car run better like they claim but goin to give it a miss and get remap done.

Matt Simis

mickob16 wrote: »

Wasnt looking for extra horses just if it helped the car run better like they claim but goin to give it a miss and get remap done.

Just ensure you have a clean, new OEM paper filter and get the remap, much more impactful.