Emissions question - add timing to idle?
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TECH Veteran
Joined: Aug 2002
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From: Hartsdale, NY
Emissions question - add timing to idle? Does adding timing to the idle using LS1 Edit help reduce emissions? How much is enough?
I will also raise the idle RPM by 10% which should help...
I will also raise the idle RPM by 10% which should help...
Re: Emissions question - add timing to idle? Retard timing to reduce CO and HC emissions. Try going -5º from 400-2400rpm. The engine should have a pretty smooth idle. Raising the idle is going to help too.
Richard
Richard
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
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From: Hartsdale, NY
Re: Emissions question - add timing to idle? OK Thanks... I'm trying to reduce hydro carbons from 73 to 60PPM on a H/C car with LTs...
What if you removed timing above 2400rpm; would that also reduce HC emissions?
I'm also planning to dump several cans of carb cleaner and dry gas before my next test...this helps too; right?
What if you removed timing above 2400rpm; would that also reduce HC emissions?
I'm also planning to dump several cans of carb cleaner and dry gas before my next test...this helps too; right?
Re: Emissions question - add timing to idle? Only reduce the timing for the parameters of the test. Here in Kalifornia they test the cars under cruise (15 & 25mph). Try to get the engine as warm as possible.......perhaps install a 195º thermostat.
How do they test the cars in NY? I'm curious as to what the test conditions and standards are.
You can blend 10% alcohol with 2-3% MEK (or Acetone) and dilute the gas somewhat.
Richard
How do they test the cars in NY? I'm curious as to what the test conditions and standards are.
You can blend 10% alcohol with 2-3% MEK (or Acetone) and dilute the gas somewhat.
Richard
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
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From: Hartsdale, NY
Re: Emissions question - add timing to idle? Richard:
My test in NY was conducted by a registered gas station.
I assume that it was a sniffer test that tested the engine above idle but without a load....I'm not sure on this since my wife took the car for the test, however...
...In any event, if I take timing out at all RPMs, I assume I would be covered under all NY parameters of the test; right?...
Question: Is the injector cleaner that you buy mostly alcohal; if no, is it better to use injector cleaner as a gas additive for the emissions test or just straight dry gas which I assume is straight alchoal?
Why 10% alcohal, 90% gasoline; is this the level at which hydrocarbons are reduced the most?
Thanks...
My test in NY was conducted by a registered gas station.
I assume that it was a sniffer test that tested the engine above idle but without a load....I'm not sure on this since my wife took the car for the test, however...
...In any event, if I take timing out at all RPMs, I assume I would be covered under all NY parameters of the test; right?...
Question: Is the injector cleaner that you buy mostly alcohal; if no, is it better to use injector cleaner as a gas additive for the emissions test or just straight dry gas which I assume is straight alchoal?
Why 10% alcohal, 90% gasoline; is this the level at which hydrocarbons are reduced the most?
Thanks...
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Verdad Gallardo Re: Emissions question - add timing to idle? Just remember that if your going to mix alcohol with your gas, you MUST use a small amount of MEK or Acetone to allow the two to mix. Otherwise, the alcohol would not mix properly with the gas. Mixing too much alcohol can cause other problems ranging from driveability issues to injector problems. Gasoline contains some lubricating properties and alcohol does not. Increased ring and cylinder wall wear, valve and guide wear and injector wear can occur. Blending fuels can be dangerous. Best to stay within safe limits especially for a smog test.
Try to get the CATS as hot as possible just before the test. Highway driving will usually accomplish this.
Let us know how you do.
Richard
Try to get the CATS as hot as possible just before the test. Highway driving will usually accomplish this.
Let us know how you do.
Richard
Re: Emissions question - add timing to idle? You can get methanol at any of the big companies that sell fuel, or buy it at a drag race track for about $2 a gallon. I bought several gallons from a place called "Keller-Strauss." The alcohol they sell at Home Depo is not methanol, but ethanol. However, for help passing emissions, the ethanol should work fine. I would add about a gallon of ethyl alcohol to 4 or 5 gallons of gasoline, but as soon as the test is done top off the rest of the tank with gasoline for reasons mentioned above by Richard.
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From: La Porte, TX
How about welding 2 cats in line of each other in the y-pipe so that you actually had 4 cats? Would that help at all...I know probably a stupid question, but if you could simply bolt in a modified y-pipe that would be great. Also would running the test with the cut out open help any. This is assuming you know the person running the test and they are willing to look past the fact that the cutout is open.
Cats only knock down HC if there is an air
surplus. The AIR pump on these cars shuts
down after the cats light off. Maybe that's
another thing to try, could you set the AIR
to run full time?
Ethanol is one oxygenated fuel. These are
supposed to cut emissions by pushing the
mixture slightly lean. But going either
direction from stoich raises HC (as does
any injector imbalance within a bank since
then some can be off, high or low, from
proper).
Denatured alcohol (ethanol plus just
enough methanol to make you go blind)
is widely available. Question is, does the
car respond better or worse (emissions-
wise) to oxygenated fuel. Only your buddy
Mr. Sniffer will tell you that.
I believe you can also get elevated HC
from burning oil (hard to crack and burn
so out the tailpipe it goes, in chunks). For
this, go in with a fresh oil change and make
it a heavier weight (less uptake past the
rings / seals). Also, if you've never had a
top-end clean done and your car is a PCV
oil slurper, now might be a good time to
get the intake walls scrubbed of their oil
load (maybe the PCV valve & hoses cleaned
out too, just so there's nothing in the
short term to draw in).
surplus. The AIR pump on these cars shuts
down after the cats light off. Maybe that's
another thing to try, could you set the AIR
to run full time?
Ethanol is one oxygenated fuel. These are
supposed to cut emissions by pushing the
mixture slightly lean. But going either
direction from stoich raises HC (as does
any injector imbalance within a bank since
then some can be off, high or low, from
proper).
Denatured alcohol (ethanol plus just
enough methanol to make you go blind)
is widely available. Question is, does the
car respond better or worse (emissions-
wise) to oxygenated fuel. Only your buddy
Mr. Sniffer will tell you that.
I believe you can also get elevated HC
from burning oil (hard to crack and burn
so out the tailpipe it goes, in chunks). For
this, go in with a fresh oil change and make
it a heavier weight (less uptake past the
rings / seals). Also, if you've never had a
top-end clean done and your car is a PCV
oil slurper, now might be a good time to
get the intake walls scrubbed of their oil
load (maybe the PCV valve & hoses cleaned
out too, just so there's nothing in the
short term to draw in).
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
The heads were changed recently so there is no significant amount of carbon build up. I also confirmed this by removing the plugs after the test....The oil and filter were changed 100 miles belfore the emissions test...
My L-trims are high - 10.5 - 11; I added carb cleaner before the test so this may have made it worse, however...
I also installed an LS6 valley cover and catch can before the test; the car does not suck in any oil via the pvc.
I suspect the the following probable casues:
1. LT headers place the cats waaaaay back so they may not be getting hot enough...
2. The heads are milled .055 and produce CR of 11.2-1.
Question: Will my L-trims be impacted by the addition of alcohal in the fuel system?
My L-trims are high - 10.5 - 11; I added carb cleaner before the test so this may have made it worse, however...
I also installed an LS6 valley cover and catch can before the test; the car does not suck in any oil via the pvc.
I suspect the the following probable casues:
1. LT headers place the cats waaaaay back so they may not be getting hot enough...
2. The heads are milled .055 and produce CR of 11.2-1.
Question: Will my L-trims be impacted by the addition of alcohal in the fuel system?
Alcohol has a different ideal AFR. The methanol cars run
something like 6 or 7:1? So running at the normal 14.7:1
will be well leaner than methanol would want. Ethanol
is a lot more mellow but still will effectively lean out the
mixture and likely elevate your LTFTs some more as the
car tries to pull it back into line.
Here's another thing - when you have gross high LTFTs
you are depending on the closed loop to make mixture
right. But, the loop only makes it right -on average-. The
mixture (seen as the O2 voltage) is bouncing all over in
real time. I bet with headers and maybe cooler O2s,
your loop does not swing tight about center but has wider
excursions (I've looked at older EFI cars and an old O2
will swing like 0.2 - 0.7V, slow, install new sensor and it
swings only 0.3 - 0.6V and faster). So I believe (and you
may, or may not) that an older, colder O2 sensor will have
you traveling further and for longer into bad emissions
territory.
something like 6 or 7:1? So running at the normal 14.7:1
will be well leaner than methanol would want. Ethanol
is a lot more mellow but still will effectively lean out the
mixture and likely elevate your LTFTs some more as the
car tries to pull it back into line.
Here's another thing - when you have gross high LTFTs
you are depending on the closed loop to make mixture
right. But, the loop only makes it right -on average-. The
mixture (seen as the O2 voltage) is bouncing all over in
real time. I bet with headers and maybe cooler O2s,
your loop does not swing tight about center but has wider
excursions (I've looked at older EFI cars and an old O2
will swing like 0.2 - 0.7V, slow, install new sensor and it
swings only 0.3 - 0.6V and faster). So I believe (and you
may, or may not) that an older, colder O2 sensor will have
you traveling further and for longer into bad emissions
territory.
Originally Posted by robertbartsch
My L-trims are high - 10.5 - 11; I added carb cleaner before the test so this may have made it worse, however...
Question: Will my L-trims be impacted by the addition of alcohal in the fuel system?
Good luck,
Richard
Thread Starter
TECH Veteran
Joined: Aug 2002
Posts: 4,055
Likes: 1
From: Hartsdale, NY
OK - so I added 4 oz of acetone to a 3/4 tank of corn gas this weekend and drove 100 or so miles.
I don;t have any scientific data, but the car ran smooth - better than it did with just corn-gas. The idle was also smoother. The exhaust gas smell was definately cleaner and was the most notible....
No troubles so far...
I don;t have any scientific data, but the car ran smooth - better than it did with just corn-gas. The idle was also smoother. The exhaust gas smell was definately cleaner and was the most notible....
No troubles so far...
