18A5SB

What was the outside temperature on the day when the temp was measured? Was the temp measured after long/ish drive or immediately after a long stop and go crawl along drive in the middle of summer heat? There is not much air flowing under the hood in such traffic. Manufacturers design and test cars for reliability in all possible extreme conditions the ridges on the ECU is likely to account for extreme hot conditions. Personally I'd be rather safe than sorry with a heat damaged ECU costing buko bucks to replace but spend the $35 for the cover on a nice bottle of wine instead. But that's me - I tend to calculate cost/benefit or cost/utility ratio for most of my discretionary spend.

MRA5SB

To each his own, i have had it on for 18+ months with no issue in Houston weather.

Bobby Kinstle

You can't use an IR gun to measure the temperature of a bare metal surface. Metals have such low emissivity that you will end up measuring the reflection of something else instead. A better way would be to attach a surface thermocouple and then record it while you are driving around and correlate for external ambient temp.

Nikon1

I’m sure when the Audi engineers are in design phase they design for the worst case — which COULD mean that for 99% of the cars, that system is over designed. In this particular situation, in speaking of the ECU & the after-market plastic cover, if you are constantly driving in Death Valley or Sahara Desert conditions, maybe you should give the plastic cover a pass. If you’re driving doesn’t include heat and weather condition that are not that extreme and you want to dress up the engine bay a little, then go for it.

Ive had my cover on for quite awhile and have not seen any issues. But, as always, YMMV.

— John

synergize

I've had mine ECU cover on for about 1 year and 4 months and 4000 miles of driving in a warm/hot climate (temps 90 to 108). After many spirited drives in temps nearing 100, the ECU is always to coolest part under the hood. I use the best thermometer I have, my "right hand" and it is always just warm compared to the engine cover and air-box that are usually way to hot to touch. The way the cover is designed with the raised area on top adds rigidity and ample airflow. The engine in the B9 S5 gives off an enormous amount of heat, sometimes I wonder why the ECU cover stays so cool.

Bobby Kinstle

If the cover acts as a duct it could possibly increase airflow velocity over the surface of the ECU which increases the cooling effect. But I wouldn't guess on something like that.