Name:
GMNA GM269M PDF
Published Date:
08/01/2012
Status:
[ Not for New Design ]
Publisher:
General Motors North America
This specification describes the requirements for an engine compartment sound absorber (ECSA) used for noise control in the engine compartment.
Construction.
Type A – Fiberglass ECSA. The fiberglass construction shall consist of the following:
A. Fiberglass insulation core (per GM2215M):
1. Surface Density
(a) Nominal: 615 g/m2 ± 10%
(b) Range: 410 TO 820 g/m2
(c) Design value: As specified on engineering drawing
2. Color – Black (or Dark Gray, as approved)
3. Thickness – As thick as possible within packaging constraints. See part drawing for specific geometry.
B. Facings (As required for appearance or dust irritant control):
1. Material - Nonwoven polyester or polyester/ rayon blend (per GM2767M)
2. Color - Black (or Dark Gray, as approved)
3. Surface Density
(a) Engine side: 36 to 68 g/m2 as specified on engineering drawing
(b) Hood side: 20 g/m2
C. Edge Treatments (As required for dust irritant control):
1. Pinched Edges - As specified on engineering drawing
2. Waterjet Trimming - If specified on engineering drawing
Type B – Polyester Sheet ECSA. This construction shall consist of 100% polyester fibers in a thin stampable sheet configuration having the following properties:
A. Color: Black (or Dark Gray, as approved)
B. Surface Density (Per ASTM D3776):
1. Nominal – 370 gm/m2 ± 10%
2. Range – 320 to 420 gm/m2
3. Design value – As specified on drawing
C. Thickness = 0.7 to 1.4 mm
D. Tensile Strength = 70 N minimum (machine and across machine direction) when tested per ASTM D5034 grab method, 305 mm/minute jaw speed.
E. Tear Strength = 125 N minimum (machine and across machine direction) when tested per ASTM D1117, Trapezoid method.
F. Wear Resistance = 300 cycles minimum when tested per SAE J1530.
Type C – Shoddy ECSA. This construction consists of synthetic resin bonded textile fiber fleece, compression molded core with an upper and lower facing (per GM Opel TM 237400) having the following general properties:
A. Surface Density:
1. Nominal – 1250 g/m2 ± 10%
2. Range – 1150 to 1350 g/m2
3. Design value – As specified on drawing
B. Facings (As required for appearance or dust irritant control):
1. Engine Side - Nonwoven polyamide 66, polyester or cellulose at 75 g/m2 (minimum).
2. Hood Side - Same as above or optionally crepe paper at 100 g/m2 (minimum).
C. Color: Black on appearance side
D. Edge Treatments: Trim edges heat sealed
E. Thickness: As thick as possible within packaging constraints. See part drawing for specific geometry.
Type D – Polyester Insulator ECSA. This construction consists of a blend of several types of 100% thermoplastic polyester fibers having melt point differences which permit compression molding into parts with the following properties:
A. Surface Density:
1. Nominal – 1000 g/m2 ± 10%
2. Range – 800 to 1200 g/m2
3. Design value – As specified on drawing
B. Color: Black (or Dark Gray, as approved)
C. Thickness: As thick as possible within packaging constraints. See part drawing for specific geometry.
Type E – Blended Synthetic Fiber Insulator ECSA. This construction shall consist of a homogeneous mixture of synthetic fibers entangled or needled together into a random orientation. A sufficient percentage of thermoplastic fiber or thermo set resin is included in the blend to enable molding by a thermoforming process. A decorative facing may be required per the part drawing.
A. Surface Density:
Nominal – 1000 g/m2 ± 10%
Range – 800 to 1200 g/m2
Design value – As specified on the part drawing
B. Color: Black (or Dark Gray, as approved)
C. Thickness: As thick as possible within packaging constraints. See part drawing for specific geometry.
Type F – Polyurethane Foam for ECSA. This construction shall consist of a polyurethane foam laminated on one or both surfaces with either an aluminum foil, scrim facing or both.
A. Polyurethane Foam Tested per ASTM D3574
1. Density
B. Facings:
1. Material - Nonwoven polyester or polyester/ rayon blend (per GM2767M)
2. Color - Black (or Dark Gray, as approved)
C. Aluminum Foil:
1. Foil thickness to be called out on part drawing.
Drawing Callout. To properly use this specification, the specification number must be followed by a type. Example: GM269M Type A for fiberglass hoodliner.
| Edition : | 4 |
| File Size : | 1 file , 170 KB |
| Number of Pages : | 4 |
| Published : | 08/01/2012 |
