Question about the intake...

BAVARIAN323i · 06-21-2002, 04:28 PM

I video taped the engine while reving it with the stock and ecis intake.
When the stock intake was in, two little doors simutaneously opened with the reving, on either side of the grill. With the ecis they did not open.
does anyone know why?

drewcon · 06-21-2002, 04:30 PM

no clue...so why did i even respond you ask, I'm not sure.:tongue:

Jspeed · 06-22-2002, 03:49 AM

I think I know what you're talking about. Those flaps open up when the throttle opens beyond a certain point. When you video taped the ECIS, was the hood open? If so, the heat-shielded area would not be enclosed and the vacuum wouldn't be great enough to open up any of those flaps.

KevinJ_2k1_325ci · 06-22-2002, 08:54 AM

Remember that the ECIS doesn't rely alone on the intake grill. It also is getting a fair amount of air from the front headlight below the bumper. If a great enough vaccum is created those little flaps will open but are negligable with the ECIS since it's getting more air from other areas.

Quote:

Originally posted by Jspeed
I think I know what you're talking about. Those flaps open up when the throttle opens beyond a certain point. When you video taped the ECIS, was the hood open? If so, the heat-shielded area would not be enclosed and the vacuum wouldn't be great enough to open up any of those flaps.

BAVARIAN323i · 06-22-2002, 10:45 AM

ok, the only thing is that I videoed it with the hood open for both the stock and ECIS. The doors opened for the stock, and not the ecis

Jspeed · 06-22-2002, 02:01 PM

Quote:

Originally posted by BAVARIAN323i
ok, the only thing is that I videoed it with the hood open for both the stock and ECIS. The doors opened for the stock, and not the ecis

Yes, but the stock airbox is self-enclosed, where the ECIS relies the hood to be closed to complete the enclosure.

View My Garage · 06-22-2002, 02:08 PM

Quote:

Originally posted by Jspeed

Yes, but the stock airbox is self-enclosed, where the ECIS relies the hood to be closed to complete the enclosure.

yup!

simsima325 · 06-22-2002, 03:58 PM

what if you got rid of these little doors? would you see an increase in power, even with throtle aplications that before would not have created the vacuum to open the doors?
-brendan

KevinJ_2k1_325ci · 06-23-2002, 12:26 AM

Since at low end RPM, the throttle is almost completely closed under 2500 RPM, there's very little need for air intake. Once speed builds above 25mph the doors will probably open letting more air in thus letting more air into the throttle. The RPM from 0-2500 relies purely on a small amount of air and more gas mixture for combustion which the ECU takes care of automatically. This is why you need your ECU tuned with a cold air intake if you want to take advantage of it at low end speed, otherwise all the benefit is mostly at the high end RPM.

Bottom line, you will get no benefit from opening the little doors. Get a cold air intake instead with a tuned ECU.

06-21-2002, 04:28 PM	#1
BAVARIAN323i Ballin' Join Date: Dec 1969 Location: Boston, Ma Posts: 2,504 My Ride: 1999 323i View My Garage	Question about the intake... I video taped the engine while reving it with the stock and ecis intake. When the stock intake was in, two little doors simutaneously opened with the reving, on either side of the grill. With the ecis they did not open. does anyone know why? __________________ *SOLD* 1999 e46 -Jim Confronti Shark Injector Software -18x8.5 Breyton Inspirations -Bridgestone S-03 Potenza Pole Position’s -H&R CupKit w/ M3 RSM & Z3 plate -UUC Pedals -European Lights w/ Silvervision Bulbs all around -DEI Shock Sensor

06-21-2002, 04:30 PM	#2
drewcon Bavarian Motor Slave Join Date: Dec 1969 Location: Boston Posts: 1,545 My Ride: 330ci View My Garage	little doors? no clue...so why did i even respond you ask, I'm not sure.:tongue:

06-22-2002, 10:45 AM	#5
BAVARIAN323i Ballin' Join Date: Dec 1969 Location: Boston, Ma Posts: 2,504 My Ride: 1999 323i View My Garage	ok, the only thing is that I videoed it with the hood open for both the stock and ECIS. The doors opened for the stock, and not the ecis __________________ *SOLD* 1999 e46 -Jim Confronti Shark Injector Software -18x8.5 Breyton Inspirations -Bridgestone S-03 Potenza Pole Position’s -H&R CupKit w/ M3 RSM & Z3 plate -UUC Pedals -European Lights w/ Silvervision Bulbs all around -DEI Shock Sensor

06-23-2002, 12:26 AM	#9
KevinJ_2k1_325ci Registered User Join Date: Dec 1969 Location: Alexandria, VA Posts: 3,083 My Ride: 2001 325ci View My Garage	Here's the deal Since at low end RPM, the throttle is almost completely closed under 2500 RPM, there's very little need for air intake. Once speed builds above 25mph the doors will probably open letting more air in thus letting more air into the throttle. The RPM from 0-2500 relies purely on a small amount of air and more gas mixture for combustion which the ECU takes care of automatically. This is why you need your ECU tuned with a cold air intake if you want to take advantage of it at low end speed, otherwise all the benefit is mostly at the high end RPM. Bottom line, you will get no benefit from opening the little doors. Get a cold air intake instead with a tuned ECU.

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06-22-2002, 03:49 AM	#3
Jspeed Registered User Join Date: Dec 1969 Location: Vancouver, BC, Canada Posts: 1,990 My Ride: '01 330i View My Garage	I think I know what you're talking about. Those flaps open up when the throttle opens beyond a certain point. When you video taped the ECIS, was the hood open? If so, the heat-shielded area would not be enclosed and the vacuum wouldn't be great enough to open up any of those flaps.

06-22-2002, 03:58 PM	#8
simsima325 'a certain moderator' Join Date: Feb 2001 Location: Hyattsville, MD Posts: 36,765 My Ride: Honda Civic View My Garage	what if you got rid of these little doors? would you see an increase in power, even with throtle aplications that before would not have created the vacuum to open the doors? -brendan