Re: [DML] Delorean exhaust (Emissions Testing)

["endotex23" <endotex23@xxxxxxxxx>]

> For example: only 5 urban North Carolina counties did tailpipe
> emission tests. Now the remainder of the state is going OBD II
> (nothing built before 1996 will be tested). Have no idea if 5 
original counties will be dropping tailpipe test in lieu of OBD II 
too (Louie? Jason? Jeff? Anybody know?)
> 

States have varying degrees of emmisions testing but they're driven 
by the federal government (EPA). If a state is considered to be a 
high emmisions area of the country the Feds will put enormous 
pressure on a state to comply by witholding millions of dollars in 
funds.

Northa Carolina has very lax standards compared to most states: 
http://www.ncdot.org/dmv/vehicle_services/emissioninspection/requireme
nts.html

The California Bureau of Automotive Repair (BAR) and the US EPA set 
the standard for most state emission testing. NC emission testing 
appears to be little more than the old two speed idle test (TSI) 
reminiscent of the BAR 90 protocol. This refers to the specification 
the analyser must meet (4 gas) as well as the test protocol. The 
current spec for most states in the BAR 97. This means the analyzer 
must include not only a 5 gas bench but also be self calibrating, 
monitoring, and able to communicate electronically directly to the 
state agency responsible for emissions. It removes most of the 
emission tech's ability to conduct a fraudulent test and insures the 
analyzer is always caibrated and operating properly. It also 
automates non-tail pipe emission testing. There is more to emission 
testing than what comes out of the engine. For example the 
evaporative emission system must be tested.

The BAR 97 also requires a dyno and either an accelerated load test 
(ASM) or an IS-240 test. The ASM is more common and involves testing 
at 15 and 25 mpg. Basically the difference between BAR 90 and BAR 97 
is the extra measurement of NOx and the use of ASM rather than TSI 
testing.

As far as testing protocols go calling one an "OBDII" test is a 
misnomer. OBDI and II refer to engine management and emission control 
with OBDII being a standardized design required on all 1996 and newer 
vehicles. A standardized diagnostic connector, codes, and dual O2 
sensors are some of the charateristics of an OBDII system. OBD is  
far more than emission control. It's complete engine management and 
diagnostics. This is what makes a modern car so much easier to 
diagnose problems on than older vehicles in addition to making them  
run better and cleaner. An OBDII "test" only verifies the system has 
not set any codes and will never replace tailpipe testing because 
there are many cases where OBD will test correctly but emissions 
could still be high. 

North Carolina is lucky to have avoided the EPA's attention thus far 
but that'll change in the future. I'm assuming the state's pollution 
falls outside the limits required or it has simply choosen to pass on 
federal assistance. Either way the ability to operate many vehicles 
without emmisions testing may be a convienence to it's citizens but 
hardly fullfills the moral obligation to protect the environment. 

An older vehicle is more difficult to maintain and diagnose compared 
to one OBDII equipped, not as fuel efficent, and far dirtier. 
Contrary to popular believe modern emission controls rob very little 
power from a vehicle. Other than shifting the Lambda slightly rich 
for a best power mixture and removal of the catalyst (because of 
shifting rich, not because it's restrictive) there isn't much that 
can be done to improve power on a vehicle other than installing 
aftermarket products and retuning. Even then (in most states) the 
vehicle's emissions must be brought back to the limits for it's model 
year. For most vehicles that means using a Lambda of 1 and a 
catalyst. Use of a Lambda other than 1 requires removal of the 
catalyst and only increases power a very modest amount while greatly 
increasing emissions. In the Delorean's case removal of only the 
catalyst alone gains you almost nothing unless it's been damaged.

Mr. Robinson, you may have the luxury of running emission control 
free but you're shirking a responsibility by not knowing the 
emission levels of your vehicles. Without the use of an analzyer 
you're simple guessing. Not to mention it's likely costing you in 
the areas of drivability and fuel economy. As to why your posts seem 
to generate controversy perhaps you're asking the wrong people. From 
your posts I get the impression you're from the "old school" of do-it-
yourself mechanics and somewhat unknowledgable in many areas. 

With all due respect you may wish to further educate yourself in 
basic automotive and combustion theory or even procure an analyzer. 
There are many good BAR 90 machines available for a fraction of their 
original cost and they can be an invaluable tool for tuning and 
maintenance. Fwiw, in testing Deloreans (and other K- Jet equipped 
cars) I've found that when adjusted properly they can be very clean 
vehicles compared to other cars of their vintage.

Greg








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