Would this work? individual throttle body filters

[GreasyGinzo]

Is the stock manifold a runner design or is it a breadbox? If its a bread box then I would imagine that you could pick up a decent amount of power with minimal loss in low end. On the other hand if the stock setup is has individual runners then you would lose massive low end. Bread box intakes are normally only used in a forced induction setups. Does anybody have more info on the car pictured in this thread?

EDIT: I noticed the website mentioned in vinyl and checked it out. They have a video of a grey e90 on the dyno (sounds dope) but they state they are not releasing any info just yet about gains or much else.

[aussiem3]

Looks revolting ... worm farm in action. No sense of taste whatsoever when it comes to getting out performance. BMW should sue this shop.

[kitw]

Originally Posted by aussiem3

Looks revolting ... worm farm in action. No sense of taste whatsoever when it comes to getting out performance. BMW should sue this shop.

BMW should just do nothing, since it is going to blow up as soon a bird flies in front of it... **SSSSHHHUUUUUUUPPPP* *gghghghgghahahaa* * BOOM *

[BMRLVR]

The OEM VANOS (variable cam timing) maps are tuned to work with the volume of the OEM manifold to resonance tune the engine. By using this fixed volume the cam timing is varied to use the sound/pressure waves to help fill the cylinders. You know the rattling sound that people hear with aftermarket filters? That is actually the natural resonance that the engine creates due to these sound/pressure waves being created in the intake plenum...... The fact that the torque peak is at 3900RPM and the noise is the loudest at around 3900RPM-4000RPM is no coincidence.... This is used to help fill the cylinders and tune the engine for maximum volumetric efficiency.

These sound/pressure waves are generated when the air is rushing into the cylinder past the open intake valves and the valves suddenly slam shut at the end of the intake stroke. When this fast moving air is suddenly stopped by the closure of the valves, a pressure/sound wave is created and it changes direction and heads back toward the plenum at somewhere near the speed of sound. This wave then ends up pressurizing the plenum and the other 7 runners/airhorns slightly so when the next cylinder is ready for the intake valves to open the positive pressure maximizes cylinder filling and therefore maximizes volumetric efficiency.

All engines (even older ones without any form of variable intake manifolds, or cam timing) have a point at where this effect is greatest and that point is almost always at the torque peak of the engine. The whole reason for manufacturers using variable length intake runners, Helmholtz resonators, and variable cam timing and lift, (no matter what manufacturer or name it has) is to take advantage of this naturally occurring resonance and to allow the engine to take advantage of this over a broader area of the rev range and maximize power and volumetric efficiency. With modern electronics manufacturers are able to take more advantage of this than ever before.

The reason why our wonderful S65 has such a flat torque curve is due to the fact that it is able to vary the intake cam 58 degrees, and the exhaust cam 48 degrees at a rate of 360 degrees per second. The S65's ability to do this is one of the main reasons (along with extremely precise spark timing adjustment, fuel injection control, a high compression ratio, and well designed cylinder heads) it is able to make the output it does from only 4000CC's (244CID). This extreme amount of adjustability and the rate at which it can occur allowed the engineers to tune the torque curve to be almost flat between 3500RPM and 7500RPM and have roughly 80% of peak torque available from 2000RPM to 8000RPM....... For a naturally aspirated engine this is basically unheard of (I know a lot of people criticize the S65 for having to little torque but realistically it has one of the flattest and broadest NA torque curves in the automotive world).

I know I got a little off of topic here but here is the point I was trying to build up to...... ITB's could most likely be tuned for good gains on the top end but the low end and midrange would most likely suffer due to the loss of your ability to resonance tune. Yes they would sound amazing but if you are one of the people that think the M3 has no low to midrange torque now you would hate an ITB setup. Couple this with the fact that it would be tremendously hard to properly tune software to work with this kind of setup makes it a useless mod for a street driven car...... If you were building a track car, it may be more worthwhile.

[Singletrack]

Good info! Thanks for posting.

[KGB7]

You still sucking in crap load of hot air, thus the engine will retard the timing and you will lose HP.

[J08M3]

BMRLVR - finally somebody who understands the pulse created in an engine. Thank you for posting. Same is true on the exhaust side of things, which is where most people are messing around on this car and with little understanding of what's happening.

[BMRLVR]

Originally Posted by J08M3

BMRLVR - finally somebody who understands the pulse created in an engine. Thank you for posting. Same is true on the exhaust side of things, which is where most people are messing around on this car and with little understanding of what's happening.

You are right, most people don't understand resonance tuning and the way new electronically controlled engines are able to maximize its benefit.

As for exhaust tuning, the principle is not exactly the same but is similar. Essentially in the exhaust side of an engine there are pulses as well but generally speaking a properly designed header and exhaust system uses suction to help extract the spent gases. This suction in combination with using the intake charge to push the exhaust gases out during valve overlap (which is also completely adjustable due to the adjustability of both the intake and exhaust cams).

As for the thanks you give me for posting this, I believe these forums should not only be used for entertainment but be used so that people with knowledge can share it with others.

You are completely welcome, and I enjoy contributing useful info to the community!

[raiste]

Originally Posted by BMRLVR

You are right, most people don't understand resonance tuning and the way new electronically controlled engines are able to maximize its benefit.

As for exhaust tuning, the principle is not exactly the same but is similar. Essentially in the exhaust side of an engine there are pulses as well but generally speaking a properly designed header and exhaust system uses suction to help extract the spent gases. This suction in combination with using the intake charge to push the exhaust gases out during valve overlap (which is also completely adjustable due to the adjustability of both the intake and exhaust cams).

As for the thanks you give me for posting this, I believe these forums should not only be used for entertainment but be used so that people with knowledge can share it with others.

You are completely welcome, and I enjoy contributing useful info to the community!

Great posts like yours are the reason I read this forum every day. Thanks!


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