[p1zaul]

not sure exactly what to call it and it has been discussed before but has anyone tried a fix for the helicopter effect, (like when you only open one window in a normal car) on the e93 with all windows and top up going around 50 or 60. was thinking of trying to spray some foam in the trunk lid, not sure if anyone had tried that or if it's a bad idea.

[p1zaul]

no one else ever had this?

[GixerEd1]

New to this Forum, but on some other Forum, Bimmerfest or Bimmerforums, I remember reading about how someone used spray-foam or some other sound-deadening/cushioning type of material between the rear seatback and the trunk. If I'm mistaken, sorry for the misdirection, but I am fairly certain that I did read about this issue/remedy. Let us know if you find that DIY and if it worked for you. Thanks!

[milkmaster]

NOT SEEING THIS ON MY 2008 e93. SO FAR IT HAS BEEN GREAT.

[roadkillrob]

There was a service bulletin for this back in 09 or so, the fix from BMW was to fill the trunk lid with spray foam, but my SE said it was a crap fix and wouldn't do it and the real fix was to replace the tires from the crap bridgestones that it came with. The dealer replaced my tires with Michelins at about 10k miles on the bridgestones and have never had the issues since, they said it was the way the tires wore made the issue worse.

[roadkillrob]

Maybe try this also https://www.e90post.com/forums/showthread.php?t=1120405

[roadkillrob]

Here is the official service bulletin

SI B54 04 08
Special Roofs April 2008
Technical Service

SUBJECT
Wind Buffeting/Pressure Noise at Highway Speeds


MODEL
E93 (3 Series Convertible) produced up to 12/2007


SITUATION
When driving at highway speeds, typically between 55-65mph, and the Retractable Hardtop (RHT) fully closed, a pulsating pressure sensation can be felt and heard.

The intensity of the noise increases when driving over coarse surfaces.

Driving outside this speed range will fully eliminate the noise.

This noise is most commonly compared to the noise heard when one of the rear windows is opened slightly on a 4 door vehicle.

CAUSE
A resonant frequency is reached at this speed which causes the convertible top cover (forward of the trunk lid) to vibrate, altering the acoustics inside the vehicle.

CORRECTION
On a customer complaint basis, the following steps should be taken:

Match balance the rear wheel and tire assemblies.

Increase the rigidity of the convertible top cover.

Modify the way in which the rear axle carrier is mounted to the body of the vehicle (does not apply to all models).

PROCEDURE
Balancing Wheels

Match balance the rear wheel and tire assemblies using approved tire balancing equipment.

NOTE: Optimizing the tire-wheel assembly will minimize any vibrations and contribute to the overall effectiveness of the repair.

Convertible Top Cover Rigidity

Park the vehicle in a location where this work can be performed and the vehicle can be parked for at least 24 hours. After the structural foam is applied, the vehicle must not be moved during the 24 hour curing time.

Perform the following procedure for the left side of the storage lid. It will later be performed for the right side.

Follow all applicable safety precautions when performing the following repair.



Use a marker to make a mark on the tube at a distance of approximately A=6cm from the top of the cartridges.



Remove the fastening nut and sealing plug from the cartridge. Next, install the mixing nozzle (1) onto the cartridge and secure it with the fastening nut (2).



Install the included extension tube (1) over the end of the mixing tube (2). Use a permanent marker to mark a line (3) at a distance of B=10cm from the end of the extension tube.


Due to the high viscosity of the 2 part structural foam, it must be warmed in order to flow out of the cartridge properly, and into the void it is intended to fill. Place the cartridge to be used under Hot running water or in a large pail of Hot water to heat the cartridge thoroughly. This should take 15-20 minutes.

Cut a rectangular piece of covering film to 40mm x 60mm.



Open the RHT until the roof panels are in the stacked position and the convertible top cover is fully open. Install the rear module supports (Cartool number 54 0 240) to hold the storage compartment lid in the open position.



Structural foam will be installed in the area (1) shown in the illustration. The left side is shown and is a mirror image of the right side.


Mask off the inside of the luggage compartment as well as the sides of the rear quarter panels to protect them from being damaged during the repair.

Remove the cartridge assembly from the hot water and immediately install it into the applicator.

Connect the recommended pneumatic applicator to a shop air supply. A pneumatic applicator is recommended as a manual applicator can make it difficult to fully fill the necessary cavity.

Pull the trigger and apply a small amount to a piece of scrap material to see the rate at which the foam will come out of the applicator, and then immediately wipe off any excess material on the end of the flexible tube.

If necessary, adjust the regulator on the applicator so that it dispenses at a fairly slow and consistent rate.



Feed the flexible tube into the lower outer-most hole in the cover (1), up to the line drawn previously at 10cm.


Fill the cavity with approximately 60% of the cartridge. When the plungers in the cartridge have reached the line drawn previously on the outside of the cartridge in Step 4, 60% has been applied. The red indicator on the side of the applicator displays the position of the plungers.

Remove the flexible tube from the panel and wipe off any foam that is on the outside of the tube.

NOTE: If any foam spills onto the outside of the cover, clean it off immediately with a clean cloth. Do not use any solvents or cleaning products to remove it.

If the foam was flowing very slowly prior to removing the tube from the panel, it may need to be warmed again before the remainder is applied.



Insert the tube into the larger hole (1) toward the inside of the panel as shown in the illustration. The tube should be inserted until it reaches the outside edge of the hole used previously (2).



Peel the backing from the pre-cut square of covering film and install it over the previously used hole (1). The paper on the front of the film may also be removed..


Pull the trigger until the cartridge is empty.

Remove the tube from the storage compartment cover and wipe away any foam which may have spilled onto the outside of the cover.

Repeat steps 4-22 for the opposite side of the storage lid using the 2nd foam cartridge as well as a new mixing nozzle and extension tube.

Allow the foam to cure for 24 hours.

Rear Axle Carrier Mounting – (Does NOT apply to the 335i equipped with a manual transmission)

Replace the rear 2, rear-axle carrier bushings per repair instruction RA 33 33 101.

While the rear axle carrier is lowered, install a damping disk to the top of each of the 4 sub-frame bushings. Ensure that the damping disk is rotated until it's fully seated on top of the respective bushing.

After raising the rear axle carrier, install the new Stop plates to the bottom of the rear two sub-frame bushings.

PARTS INFORMATION
Part Number
Description
Quantity

83 19 0 445 721
Structural Foam
1

51 32 8 146 401
Covering film
1

33 31 6 768 645
Rear axle carrier bushings (not for 335i
2

manual transmission)

33 30 6 776 886
Damping disc for rear axle carrier bearings
4

(not for 335i manual transmission)

33 30 6 778 481
Stop plate for rear axle carrier bearings (not
2

for 335i manual transmission)

The recommended applicator for the structural foam is the MIXPAC® pneumatic applicator; model number DP 400-85-01. This applicator may be obtained from Conveniently Packaged Adhesives (CPA) by calling (401) 946-5508, faxing an order to (401)-946-5508, or emailing info@forcpa.com. For additional information on this product or how to order it, please visit the CPA website at:http://www.forcpa.com/

WARRANTY INFORMATION
Covered under the terms of the BMW New Vehicle Limited Warranty.

Defect Code
01 16 87 39 00

Main Work*

Labor Operation:
36 12 090
Repositioning tires on rims for front or rear wheels

Labor Allowance:
Refer to KSD
(includes balancing)


Labor Operation:
41 99 000
Work time for the structural foam portion of this

Labor Allowance:
9 FRU
Service Information


Labor Operation:
33 33 101
Replacing two rubber mounts for rear axle carrier

Labor Allowance:
Refer to KSD

*Main Work:
Use this labor operation number when this is the only repair being performed, or if this is the main repair when performed along with other repairs at the same time. If this is not the main repair, refer to KSD for the associated (+) labor operation code.

[p1zaul]

yes thats what i read about, sounds like i guess it doesnt work. maybe new tires.

[p1zaul]

I recently got new wheels with the same tires put on and this has gone away. from this I'm thinking it's actually the wheels causing this issue. I had style 189