2000SSNB

iTrader: (4)

Hello,

I just barely passed NY State inspection in Tarrytown, NY.
The HC was 0.57 out of a 0.60 limit. The other two had much more margin. What impacts HC the most? What are some of the tricks to lower this? I have a MAFT but did not have it installed during the inspetion. I have an SLP85 MAF, mild cam (212/218 .522,.528, 115 LSA) stage 1 ported heads, JBAs and Random Flow high-flow cats as well as a lid etc...
It also has Ed Wright programming. The fans kick in at 195 deg C.

Thanks,

Gert

wrencher

iTrader: (2)

What was the scale fomat was it PPM (parts per million) or GPM (grams per mile)??
I'm guessin that is GPM & they dyno'd it? Is NY going to fazing out dyno testing OBD-II cars soon?
There are alot of factors that can affect the HC readings on a dyno test for GPM.
If your car is just gonna squeek by , dont go on a high ambeint temp day, it will increase readings.
How it is driven on dyno & how long it sat before dyno test have a big impact. If your car is a M-6 can increase your readings due to the "inspector's" inexperince with your car.Then the most important thing the catalytic converters. Hi-flows are always a problem they work but barly. You would be better off running off roads , then come emissions time install the hi-flows & remove after the test. This will keep the cats in new condition & they will work much better.I have seen hi-flow's degrade with time on almost everything there put on. That's why I recommend removing them & having them for one use only.

SScam68

iTrader: (20)

Someone correct me if I am wrong.

Running richer increases HC's.
Running leaner increases NOX gases.

EGR controls NOX gases while CATS control HC's.

In all honesty its a matter of tuning and having the ability to see how the changes you have done affected the emissions output.

Hopefully someone with some experience on this can give adive on what timing & fuel trims to run during testing.

jimmyblue

iTrader: (11)

I have seen it that rich makes CO.

Both rich and lean make HC (especially lean misfire).

An injector imbalance or gross bank-bank imbalance can make it so you have some cylinders
rich and some cylinders lean, giving you the
worst of both worlds.

Lean, hot, high pressure makes NOx
which is what EGR is meant to kill (its primary
reason for existence). Big cam overlap will let
raw HC blow through from intake to exhaust if
the scavenging pulse of headers or even regular
exhaust is strong enough at low RPM. Blowby-laden
oil will elevate HCs. So will exhaust valve stem
seals that let oil into the exhaust port.

Timing should be well short of knock and mixture
should be as near to stoich as you can stand. You
want no misfires at all because misfire dumps a
wad of uncracked gasoline right down the chute.
Too much advance makes more HCs.

If you have HC and CO you are definitely too rich.
If you HC and NOx you are definitely too lean

Change your oil before any big date....

wrencher

iTrader: (2)

The tuning for any car is specific to that car & it's modifications. I'd never heard of a one tune fix 'em all.
Assuming the car is tuned & running correctly, to get any vehicle down to a .60 GPM HC spec the catalyist is playing a large role in obtaining those type of emissions.



Without a cat running the best it could would produce 3 times the #'s.
I deal with this all the time here in hellinois & have to get many vehicles to pass emissions & the problems are usually all the same. If your car runs like $hit are you gonna take it to try to pass emissions??
Most people are smart enough, so why do they fail if they run fine?

2000SSNB

iTrader: (4)

Thanks for the feedback. I have to go back and check,
but I recall that all three readings were high. The HC
reading was closest to the (new) limit. Last year the
HC limit was 0.80, this year it was lowered to 0.60.
The CO reading was also higher than last year but had
more than 50% margin, the NOx had even more margin but was
higher than last year (last year I did not have the cam and Ed Wright programming).

Gert

2000SSNB

iTrader: (4)

Here are the actual numbers - the emission test is done
on a dyno doing a programmed road-course. The guy who does this testing has worked for many years at this station and
I have used it for equally many years.

HC CO NOx

year 2002 .25 2.03 0.07
year 2003 .57 3.43 0.41

year 2003
limits .60 10.0 1.20

The main differences between 2002 and 2003 are the
cam (see top post) and Ed Wright programming. It was aroun
80 degress F that day and the car was warmed up already -
it sat about 20 minutes in the lot before testing.

Are there any neat ways to gauge emissions before going
to the inspetion 0 I do have EFILive etc. and a MAFT.

Gert

jimmyblue

iTrader: (11)

With HC, CO and NOx all out-of-bed I guess the
finger points to the RT cats being sloppy little
housekeepers. And/or too cold to work well.

If you are on good terms with the inspections
dude, maybe you could get some pulls with the
MAFT in at 2 clicks lean and 2 clicks rich, and
see whether either of these is an (emissions)
improvement. Then you'll have an idea whether
tuning can help you or if the cam is just too
cool for school.

highgear

I don't think the small cam would be a problem.
The JBA headers keep the Cats in the stock location; right?
I would suspect the MAF. I would put the stock MAF back on and do a re-test to see what happens.
What did the Ed Wright tuning consist of?

2000SSNB

iTrader: (4)

Yes, the JBAs leave the cats in the stock location.
The cam does have 3 degrees of advance ground in.
The Ed Wright programming is supposed to be optimized
for the mods I have. I suppose I need to check the
fuel and spark tables Ed's program generates, with EFILIve and check ltrims etc. I am pretty sure that his programming tends to the "rich" side. I can also look at the A/F ratio
the program calls for under different conditions,

Gert