I finally got around to checking the EPA recommended limits for the
dynamometer emission tests that are being implemented in several
states. EPA does not set the limits the states do, however EPA has
recommended limits and they will accept these from states without
questions so most states use these. Be aware that there are several
different EPA tests. The limits I'm supplying are for a test with a
steady 15 mph and a steady 25 mph cruise test where HC is in ppm, CO is
percent, and NO is in percent. These limits are for MGBs only (the
limits are based on model year and vehicle weight so Midget numbers are
slightly different
Also EPA recommends a phased in (more emissions are allowed in the first
year of the program) system. I'll give the first year limits and the
final years limits.
FIRST YEAR MGB LIMITS
HC HC CO CO NO NO
Year 15mph 25mph 15mph 25mph 15mph 25mph
1980 193 189 1.84 2.39 3416 3181
77-79 503 495 2.58 3.56 3416 3181
75-76 554 544 2.83 3.91 4685 4620
73-74 800 786 5.78 8.25 4685 4620
68-72 800 786 5.78 8.25 4990 4772
FINAL YEAR (AFTER RAMP-UP) MGB
HC HC CO CO NO NO
Year 15mph 25mph 15mph 25mph 15mph 25mph
1980 96 93 1.10 1.21 2142 1976
77-79 247 241 1.96 2.58 2142 1976
75-76 271 269 2.15 2.84 3771 3512
73-74 505 496 3.65 5.21 3771 3512
68-72 505 496 3.65 5.21 4676 3881
I've lost Pat's results so I can't compare his limits to the EPA
guidelines. I didn't find the idle limits. If these turn up I'll pass
them on. If there's interest I'll calculate the numbers for Midgets.
The NO numbers are suppose to be percents but the table didn't have any
decimal points so I'm not sure of the exact limits. Also I believe I
followed EPA instructions correctly but no guarantees. Measures of
CO+CO2 are used to determine if the exhaust system is leaking air into
the exhaust stream (or the probe is no inserted far enough into the
exhaust pipe). I did not calcualte these limits.
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