ITG vs BMC - put to one test

[M5pilot]

Alot of people ask me which is best - ITG filter or BMC filter with it's carbon box.

Well, I decided to put it to the test today.

Got hold of the Alpina C2 again which has a BMC on it already.

Went for a drive - a very long one! Yes it sounds very nice, really deep reverberating noise at lower rpm's upon full load turning into an even louder deep bass noise at higher rpm's.

So on went the ITG making sure the inlet track was exactly the same length.

Went for another long drive and here's what happened:

Firstly gone was the deep bass note which was replaced by a whistling/sucking noise on part throttle.

Throttle response vastly improved on part throttle and especially when putting the engine under sudden load. With the BMC throttle response was a little whooly.

There WAS more bottom end grunt and the engine revved up much smoother and harder. Top end pulled much better and this was much more noticed in 3rd gear than 2nd (2nd is over in a flash in this car so it;s hard to tell). 3rd gear pulls to around 90mph and with the BMC the power started to tail off after around 5500rpm whereas with the ITG it just kept pulling harder.

The biggest difference was between gear changes. With the BMC everytime I changed up (driving to just before the limiter under full throttle) the car bogged down and then the power built up slowly again.

With the ITG this just didn't happen. No bogging down at all, acceleration continued.

It is amazing how much difference a different filter can make.

Anyway, question answered.

On a high powered 2.7 running Stand Alone management the ITG improved the car quite some bit.

The sponge with a trumpet is the way forward.......unless of course you want the deep bass note and bling looks of the BMC.

Sal

[Geoff]

Sal i was always on the understanding that foam filters were not as good as cotton gauze filters? I know this is a different sort of filter but in an old test at Bexleys, on panel filter elements, ALL the foam elements were down on torque and bhp as opposed to cotton gauze elements.

Is the BMC cotton gauze?

Re-reading this post probably has no relevance but i cant be bothered to delete it!

[M5pilot]

All depends on the foam Geoff.

From experience the ITG filter element over say a standard element showed gains in BHP and torque on the dyno tested on an E30 M3.

Other foam filters like Pipecross are not the same at all. They are well known to deterioate very quickly and fall apart. Supercharger's have been destroyed by these sub standard filters. Again, not offered by the Zone shop because of these very reasons.

With the BMC Carbon Airbox it's more than just about the material used. The box totally deletes the trumpet whereas as the ITG retains it as part of it's housing. If you look inside a standard airbox from any BMW, even all of the M cars, they have a trumpet inside the airbox. Remove it and you lose torque and throttle response. Even the GruppeM intake systems for alot of exotic supercars all have internal trumpets retained.

It is this retaining of the trumpet in some form is what's probably making the difference. Directional airflow is extremaly important.

I hope someone with a much better understand of autmotive engineering/air flow dynamics comes along and explains this in a little more detail.


Sal

[Geoff]

Cheers for the info update.

[Andy335Touring]

Out of interest how big is the air filter in one of those BMC's ?

I've not seen one(air filter element) in the flesh but i get the impression that the air filter is on the small side ?

[M5pilot]

No, the filter is quite large inside the BMC.

It's just the overall design which is quite funky inside and probably doesn't work so well for airspeed.

Sal

[pnd]

How does the itg panel filter compare with a k+n? Also are there no hot air issues with the full replacement system?

[M5pilot]

K&N's are not something I like for many reasons.

Badly made and distort over a short period of time. Their newer stuff for newer cars is much better.

As a basic filter the ITG is definately better.

If someone wants a K&N system then you;d need to make your own kit as the one sold for the E30 is pants.

There are no hot air issues in an e30 engine bay unless your sitting in traffic where it's very unlikely you'll be needing full power.

Sal

[Bob_S]

Am I right to assume you are talking about the cone filter and not the element?

[ianeire]

How would a driver of a 325 feel the added gains of the ITG?

Would they be as prominant as the gains felt on the more powerfull car with regards throttle response and top end urgency?

Surely the two cars to test the kits on would be the 318is and the 325is, the cars many people have...

Sounds like a great piece of kit all the same!

[M5pilot]

It's not the element I was talking about here.

On a 325i, everyone has felt the improvments in top end grunt and throttle response. The other benefit of this setup is that it doesn't make a horrendous amount of induction noise and is still quite refined.

Why haven't you bought one yet!

Sal

[ianeire]

Why havent I bought one... the list of things I want to buy for the car grow longer by the day... as do the list of things I NEED to do!!

itg, bbtb, arbs, exhaust, wheels, polybushes... I could go on and on!! Unfortunately the wages dont stretch nowhere near far enough! Petrol tax insurance and social life also strike me down!!

Ive a plan in mind for friday night though, I'm going to win the euromillions, its a banker!

[cliffybabe]

the ITG zone filter is a wicked mod the sound was wicked, I have lost that noise now the 6 branch and scorpion systme is on the motor

I did re-fit my stnadard box and K&N element a little while back and it didnt feel as responsive as when the ITG was back on