Emissions Testing Note
(for those cars subject to the dynamometer procedure)

I just experienced the pleasure of the new Texas annual inspection. The basic safety inspection was a breeze as always, but the emissions test was a problem.

The computer is loaded with all the various cars, engines, etc., and tells the technician how to run the test. The dynamometer test is done at 15 and 25 mph. The parameters for my 1986 951 (121K miles) indicated second gear for the 15 mph test and third for the 25 mph test. I failed both tests due to high hydrocarbon levels by a healthy margin at 15 mph but was closer at 25 mph.

I asked the technician about the gears suggested as the RPMs which tie to these speeds are at levels well below how the car is to be driven. We reran the tests at 15 mph in first gear and at 25 mph in second gear being careful not to exceed 2500 RPM as specified by the test.

In the appropriate gears and at realistic RPMs, I passed both tests by a considerable margin.

I hope this helps someone else to save an unneeded repair!

Russ Herman
Office: 936-321-7703
Mobile: 713-254-3961