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SacramentoE-85

CA Smog Test Results

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We had our 2003 Chevy Tahoe FFV 5.3L V8 smogged 2 years ago when we came to CA, and now did our biennial smog:

 

2007:  Hydrocarbon (HC) 13 PPM @ Idle (569 RPM)

2009:                            6 PPM @ Idle (562 RPM)

 

2007:  Hydrocarbon (HC) 14 PPM @ 2500 RPM (ours 2354 RPM)

2009:                            0 PPM @ 2500 RPM (ours 2425 RPM)

 

2007:  Carbon Monoxide (CO) 0.01% @ Idle

2009:                                  0.00% @ Idle

 

2007:  Carbon Monoxide (CO) 0.01% @ 2500 RPM

2009:                                  0.00% @ 2500 RPM

 

2007:  Carbon Dioxide (CO2) 14.5%

2009:                                  14.5%  (14.5% for both years both Idle & 2500 RPM)

 

2007:  Oxygen (O2) 0.2% @ Idle

2009:                    0.3% @ Idle

 

2007:  Oxygen (O2) 0.1% @ 2500 RPM

2009:                    0.2% @ 2500 RPM

 

 

So, what cause the dramatic drop in Hydrocarbons and Carbon Monoxide?

 

A:  2 years ago we smogged on gasoline E6 (no E85 available) and now we smogged on E85.

 

I believe there is more oxygen O2 recorded this time because of the higher octane in E85, correct?

 

For comparison sake, the average emissions for passing vehicles this year is 26 PPM HC @ Idle and 11 HC @ 2500 RPM (notice ours had 0 HC @ 2500 RPM).  Average is 0.00 CO @ Idle and 0.10 @ 2500 RPM (notice ours still @ 0.00 @2500 RPM).

 

Q:  Did we make any modifications, even just new spark plugs or air filter since 2 years ago?

A:  No modifications whatsoever, same plugs, filter, etc.  Oil is at 3,000 miles (will change in a while).

 

Q:  How many miles traveled in 2 years?

A:  23,000 mi.

 

So with literally no changes, we decreased our HC over half @ Idle by using E85.  We eliminated completely our HC @ 2500 RPM by using E85.

 

Also we completely eliminated our CO @ both Idle and @ 2500 RPM by using E85.

 

Anyone else care to share their smog test experiences?

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Thanks DW--I think it is an amazing testament to E85 fuel that at 2500 RPM there are no HC's nor CO.  I hope that some others that are getting smog tests done will share their results as well to confirm this as for now I am just one anecdote.

 

Do you know why they test O2?  I know that O3 is a smog contributor, but they don't test that for some reason.  I figure the O2 is increased due to higher octane (but that's just more O2 for you and me to breathe right?). 

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Interesting test numbers.  Seem to go slightly against conventional wisdom - though E85 has a tendency to do that!

 

Generally, you would have either more HC's (unburned fuel) or more CO, NOx, CO2, etc (products from burning the fuel).  Basically for a given amount of fuel it is either burned or unburned...not much other way for it to get out!  The only way to get 0 HC is with a well functioning catalytic converter.  This is simply a limitation of the piston engine efficiency, not so much fuel, tune, etc.  Though I would wonder if cleaner burning E85 meant the cat was clean and fully able to light off any unburned fuel.

 

I think they look at oxygen for a couple of reasons.  One way to get "better" emissions would be to pump more air into the exhaust - effectively diluting the exhaust gasses.  This would also show up as a high O2 content.  If it falls to 0 O2, that would be a sign of too rich a mixture - which may indicate other problems.  So looking at O2 is part diagnostic tool, part "cheating" monitor.  O2 would have no direct relation to octane.

 

Also curious, they don't measure / give number for NOx?  Higher NOx is generally a trade off for lower HC's.  You need a high temperature for more complete combustion, but the high temp generates more NOx.  Lower the temp, lower the NOx, but it leaves more fuel unburned.

 

Either way, good report showing the difference running E85.

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Your results are consistent with what I have seen several times here in Colorado.

My WRX passes our IM240 dyno test with flying colors on E85. We have a lot of performance enthusiasts that fail first test on gasoline, and add 3 gallons of E85 and nail the test the second time through.

 

These are my July 2008 emissions test numbers on my WRX running 100% E85 on the IM240 test.

 

 

 

Here are my readings vs the limits for my car

............ reading .... limit ...

HC GPM        0.3335    1.20000

CO GPM        3.9638    20.00000

CO2 GPM      414.3504      -- NA ---

NOx GPM        1.9216    3.00000

 

Larry

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Corey, thank you for the thoughts.

 

No, I was wondering also why they don't test NOx--they don't.

 

I wonder also about this new "Nitrogen-enriched" Shell gasoline they've rolled out this year.  Would increased nitrogen in gasoline lead to more NOx?

 

No kidding--I was very surprised to have both 0 PPM HC and 0.00% CO @ 2500 RPM.  But this is a state licensed smog test center that does many smogs per day, so I think the odds of an error are very low.

 

Also--the vehicle was driven a very short distance to the smog test center.  Then it sat parked for a short while, maybe 15 minutes.  I think they run it for 15 minutes during the test.  I don't think the engine temperature was very high compared to an engine run for a long time.  Also, the coolant temperature stays in a comfortably low range (not sure on the measure--will check it and post again soon).

 

This may be one odd amazing machine that beats conventional wisdom.  Or, maybe we will find others post similar results eventually.

 

Hey all--if this topic doesn't update for a long time, go ahead and still add to the comments once you have a smog test (good to keep this all in one thread if possible).

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Larry, thank you for your results.  What does GPM measure (grams per million?)?

 

It is interesting that Colorado measures NOx while California does not.

 

Your results are consistent with what I have seen several times here in Colorado.

My WRX passes our IM240 dyno test with flying colors on E85. We have a lot of performance enthusiasts that fail first test on gasoline, and add 3 gallons of E85 and nail the test the second time through.

 

These are my July 2008 emissions test numbers on my WRX running 100% E85 on the IM240 test.

 

Larry

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Larry, thank you for your results.  What does GPM measure (grams per million?)?

 

It is interesting that Colorado measures NOx while California does not.

 

It stands for grams per mile.

Yes we just recently tightened up our emission standards as well. These are the standard changes for cars like my WRX (2002 LEV)

 

HC limit stayed the same at 1.20 gpm

CO limit dropped from 20.0 to 15.0  gpm

NOx limit was cut in half from 3.00 to 1.50  gpm

 

Our test is called the IM240 test and is done on a chassis dyno under a simulated road driving cycle that lasts 240 seconds.

They also have a fast pass cycle that if the car is way below the limit standards they save time by kicking you off the dyno early if you obviously will pass easily.

 

We use the dyno test because of our high altitude and winter emissions problems, a simple sniffer test is essentially useless as a car can be custom tuned to be nearly emissions free at set point rpms but under real world load will pollute like crazy.

 

We also have a system called rapid screen that does drive by screening on highway merge ramps and if your car gets 3 clean readings on the rapid screen within 10 months of your emissions renewal date, they mail you a free pass that says no emissions test required just pay the registration costs for your new emissions sticker.

 

That way they are only actually testing cars that need it as they have not been screened successfully or are new to the area. You can fail the drive by but still pass the IM240 test as the rapid screen uses lower passing thresholds than the real IM240 test.

 

Larry

 

 

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...I wonder also about this new "Nitrogen-enriched" Shell gasoline they've rolled out this year.  Would increased nitrogen in gasoline lead to more NOx? ...

 

Many 'nitrogen containing' compounds are used as gasoline detergents. ie quaternary ammonium compounds, polyether amines, etc.  I've read two stories on this - 1 Shell has developed a new detergent using a nitrogen group to provide high temperature stabilization to the molecule or - 2 Shell simply adds more of an existing nitrogen containing detergent to create a "Top Tier" gasoline.

 

Though, IMHO, it is a bit of a catch-22.  The people likely to have some deposits in the engine are the little old ladies who only use the car for trips across town and on Sunday and never crack the gas pedal over about 10%.  But most of their loss in mileage is due to stop/go traffic, multiple short trips with cold engine, etc.  Cleaning out deposits isn't likely to have much of an effect.  Where the better mileage would show up is when people make long highway/interstate trips at moderate speeds, engine fully up to operating temp for a long time, etc.  But those type of conditions minimize deposits in the first place!

 

Either way, throw in a bit of marketing hype to convince people how dirty their engines are, then suggest "Shell Nitrogen Enriched" gasoline to clean it is a pretty good marketing scam....uh scheme.  "Nitrogen Enriched" sound much better than "double the concentration of quaternary ammonium salts!" or "Now more polyether amines than ever before!"

 

As for emissions, the air is 78% (780,000 ppm) nitrogen, most detergents are added in the tens to low hundreds of ppm.  So even if Shell gives a 'super dose' of nitrogen at 500ppm, you'd still only raise the total nitrogen to 780,500ppm - about a 0.06% boost.  Assume that was carried straight through to emissions, that would make a 10ppm NOx reading jump to 10.006 - which is below insignificant.

 

 

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...I wonder also about this new "Nitrogen-enriched" Shell gasoline they've rolled out this year.  Would increased nitrogen in gasoline lead to more NOx? ...

 

Either way, throw in a bit of marketing hype to convince people how dirty their engines are, then suggest "Shell Nitrogen Enriched" gasoline to clean it is a pretty good marketing scam....uh scheme.  "Nitrogen Enriched" sound much better than "double the concentration of quaternary ammonium salts!" or "Now more polyether amines than ever before!"

 

 

 

 

::) ::) ::) ::) ::) Would a company in part owned by an Arabian Oil Company dare do such a thing?  :o :o :o :o

 

;D ;D ;D ;D ;D ;D ;D ;D

 

 

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