Sound absorber. This part number supersedes to 99355623905 Genuine Porsche part 99355623902

Engine bay insulation mat
This OE match engine bay insulation mat is a direct replacement for the original Porsche soundproofing panel fitted to 993-generation 911 models. Installed on the underside of the engine lid or within the engine compartment, it helps absorb engine noise, damp vibration, and provide thermal insulation from the air-cooled engine.  
Fits:
Porsche 993 1995 - 1998
Diagram ref no 13
These insulating mats are produced to the highest quality standards and hardly distinguishable from the original, partly no longer available insulating mats. 
This insulation mat absorbs engine noise and vibration generated within the engine compartment, helping reduce sound transmission into the cabin. It also provides thermal insulation, reducing radiant heat transfer and improving driving comfort.
Advantages:
• Self-adhesive back
• Temperature resistant from -40 ° C to + 150 ° C
• Meets the automotive standards for fire behavior according to FMVSS302, DIN 75200
• Precise design (structure, thickness and shape) according to the original insulation mats
• True to original material
• noticeably less noise and radiant heat from the engine compartment
Original engine bay insulation mats commonly deteriorate over time due to heat, oil vapour, and age. As the foam breaks down, it can crumble into the engine bay, reduce sound insulation effectiveness, and negatively affect engine bay appearance. Replacing the insulation mat restores acoustic performance, improves thermal protection, and refreshes the engine compartment.
When to replace
•  Original insulation foam is crumbling or deteriorating
•  Increased engine noise inside cabin
•  Visible sagging or peeling insulation
•   During engine bay restoration or repainting
•   Heat or oil contamination damage

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

99355628100

The product you are viewing cross references to these numbers

Sound absorber rear window lower. 
Fits:
Porsche 993  - 1994 to 1998
Targa models only

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

99355624500

The product you are viewing cross references to these numbers

Rear Sound Absorber.
Restore the acoustic performance of your Porsche with this genuine OEM sound absorber panel from Porsche. Designed for the body/trim of the 993 this part improves road-noise insulation, reduces rear-end rattles and helps maintain the quiet, refined cabin Porsche intended.
Fits:

• Porsche 993 (911) C2 1994-97
• Porsche 993 (911) C4 1994-97
• Porsche 993 (911) RS 1994-97
• Porsche 993 (911) C2S 1994-97
• Porsche 993 (911) C4S 1994-97
• Porsche 993 (911) TURBO 1994-96
• Porsche 993 (911) GT2 1994-97
• Porsche 993 (911) TURBO S 1994-97

Diagram Ref No 5
What This Product Does:

• A sound absorber in this context is a piece of material (panel, mat, liner) mounted inside the body structure (often rear wheel-house, rear body panel, underside or inner arch) that reduces transmission of road noise, exhaust noise, underbody noise, and helps improve cabin quieter ambience.
• It also helps with vibration damping and may assist in reducing resonance or panel noise from wheel wells or rear structures.
  
• So although it may be called “Rear Sound Absorber”, the role is acoustic & NVH (Noise-Vibration-Harshness) control rather than structural or driving component.

Symptoms & Signs You Might Need Replacement:

• Increased cabin noise, especially from the rear wheel well, rear body area, or under-carriage.
  
• Rattling or buzzing noises in the rear portion of the vehicle (especially with ageing inner liners or insulation panels) — the material may have detached or degraded.
  
• Visible damage or missing panel: The insulation mat or absorber might be missing, torn, sagging, wet (water ingress) or corroded substantively.
  
• Age and wear: Over time, especially on older 993 vehicles, insulation mats can break down, delaminate, or allow noise ingress compared to new.
  

Why Replacement Matters:

• Improves cabin comfort: For premium vehicles like Porsche 911, maintaining a quiet interior is part of the driving experience. A degraded sound absorber reduces this comfort.
  
• Maintains NVH integrity: A whisking of rear-end noise, tyre/road noise or exhaust resonance can intrude into the cabin if the absorber is missing or ineffective. Replacing helps maintain factory spec.
  
• Prevents hidden issues: Sometimes, missing or degraded insulation allows moisture, road debris or dirt to encroach into body cavities, potentially causing rust or other unseen damage.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

99355621

The product you are viewing cross references to these numbers