Solar Shield Bubble Pack Insulation

By: Keith Jurena     Email: kjurena@yahoo.com     (November-01)

Make & model of car the product was used on: 1998 A4 2.8 QM

Air intake duct insulation, improvised but sharp!

Comments: I had a frustrating problem here in the Texas heat that no dealer was able to fix. I had a stumbling shudder at low RPM in town traffic. It always happened under light load and 
low RPM, like taking off from a light during hot driving conditions.

Choy Ngee Hoe's FAQ suggestion of using white cloth to insulate the intake is right on line but using this product is a much more effective method. I have most of it left along with the aluminum foil tape I used to install and might be releasing some cheap (read under $5.00)
DIY kits.

The problem started at the 30k service. My almost proven hypothesis is the 30 k service did two things to upset the balance, first of which was the intake screen recall. This changed the screen in front of the intake air absolute pressure sensor immediately after the air filter box from a plastic unit to stainless steel. The plastic unit disrupted the airflow and induced enough turbulence to mix the skin flow heated layer so by the time it reached the hot wire
sensor, the flow was uniform in temperature. The stainless screen being of much finer mesh did not do this and the location of the  hot wire sensor on the outside edge of the intake tract shows the mass flow of hotter air, causing a lean condition. The new spark plugs with lower gap are challenged to ignite such a charge, the second contributing factor. Mileage on the new plugs has reduced the tendency but its still there.

My solution is a perfect blend of a readily available material and ease of installation. It looks "cool" but proof is it is much cooler than non-insulated. My problem is gone and hot weather drivability/performance is much better

 

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