Its very easy. Have a good factory cat converter on and simply change the timing to 12-13 degrees and the a/f to 15.2:1 in the cells that being used during light cruise. Adjust the v/e table so the desired a/f can be achieved. Be sure the engine and cat converter are hot. Request that the car not be shut off while they get ready to test it. Keeping it hot is very important. Otto J's advise worked with no problems at all. Then switch back to your real program:smile:
Passing emissions with FAST
- Thread starter bison
- Start date
I beg to disagree with that set up. A extra lean mixture and retarded
timing that you post will raise nox due to excessive heat in the
combustion chamber.The lean mixture also creates another nox problem the catalytic converter needs co to make its state of change to the ehaust
gases. Many technitions make the mistake of condeming the converter and replacing it to no avail because the co was too low.Most people who run a
fast have deleted the egr the egr lowers combustion chamber temps, So
i would not test the car hot but just warm enough for good co & hc.
Also most people who run a fast have a very good ignition system & the
mechanical integrity of the engine is good which enables the engine to burn
a richer mixture with out producing too much hc.So many back yard mechanics always want to lean the car out thinking this is all it takes to
make it pass when the car goes too lean this will also raise hydrocarbons.
timing that you post will raise nox due to excessive heat in the
combustion chamber.The lean mixture also creates another nox problem the catalytic converter needs co to make its state of change to the ehaust
gases. Many technitions make the mistake of condeming the converter and replacing it to no avail because the co was too low.Most people who run a
fast have deleted the egr the egr lowers combustion chamber temps, So
i would not test the car hot but just warm enough for good co & hc.
Also most people who run a fast have a very good ignition system & the
mechanical integrity of the engine is good which enables the engine to burn
a richer mixture with out producing too much hc.So many back yard mechanics always want to lean the car out thinking this is all it takes to
make it pass when the car goes too lean this will also raise hydrocarbons.
I beg to disagree with that set up. A extra lean mixture and retarded
timing that you post will raise nox due to excessive heat in the
combustion chamber.The lean mixture also creates another nox problem the catalytic converter needs co to make its state of change to the ehaust
gases. Many technitions make the mistake of condeming the converter and replacing it to no avail because the co was too low.Most people who run a
fast have deleted the egr the egr lowers combustion chamber temps, So
i would not test the car hot but just warm enough for good co & hc.
Also most people who run a fast have a very good ignition system & the
mechanical integrity of the engine is good which enables the engine to burn
a richer mixture with out producing too much hc.So many back yard mechanics always want to lean the car out thinking this is all it takes to
make it pass when the car goes too lean this will also raise hydrocarbons.
Timing is too retarded for bmep to get high enough to get NOX emissions up. Reducing timing limits heat in the combustion chamber (unlike your statement that it increases it) and throws it in the exhaust which increases the catalyst temp rapidly. No EGR. Water temp around 170. Cold plugs. AC CR42TS. I dont have the test in front of me but 1300 was the approx allowable. Actual was around 380. If the timing was left alone it could have had potential problems with NOX. Testing the car cold will cause a CO failure. CO is increased when its too rich or the cat is not lit off. A cat that is not lit off will not work effectively burning HC or reducing other emissions either. Based on my past experiences i knew i could go leaner than 14.7:1 and get a lower CO number every time. Ive had failures at 14.7:1 and 128 blm. I used to accomplish the same thing as i did with the FAST with narrow band cars by adding methanol to the tank to cause a leaning effect. Once the blms climbed well over 128 i knew the correction was at its limit and i either added more methanol or reduced fp a little. It lowered CO every time. All my previous failures were always CO related. You will not have a raise in HC unless you get a lean mis-fire from a lean mixture. All this potential doesnt mean much anyway. CO, HC, and NOx were way under the limits on that tune. The test was only about 20 seconds long. The minimum. The guys in the shop were very suprised. Cat was falling apart inside and probably didnt work as well as it could have. It even had a little lead coating on it from the residual leaded gas i had in my tank. Not bad for a 23 year old GM cat converter imo. Most guys who run FAST have stock ignition systems which are very strong themselves. The cam profile and timing has more to do with the HC than the type of ignition system. Overlap = increased HC and CO every time. Leaning and retarding timing overcomes these issues. You have to remember were dealing with a calibration thats way off from the factory spec. Things that would hurt a nearly stock factory car new or old may actually help an engine with a bigger cam and 20+year old catalyst. It is very true that its easier for an ignition system to fire a richer mixture. Problem is it wont burn it completely if its too rich. Ive noticed a lot of CO failures on TR's due to cracked manifolds. Any ambient air that goes over the O2 sensor will make it add fuel regardless of the actual condition in the combustion chamber
Beg to differ all you want,But ive never had a car fail using this procedure even with no cat and no egr,Even on a few different stage cars running large solid roller cams.And the NOX usually ends up barey reading.I beg to disagree with that set up. A extra lean mixture and retarded
timing that you post will raise nox due to excessive heat in the
combustion chamber.The lean mixture also creates another nox problem the catalytic converter needs co to make its state of change to the ehaust
gases. Many technitions make the mistake of condeming the converter and replacing it to no avail because the co was too low.Most people who run a
fast have deleted the egr the egr lowers combustion chamber temps, So
i would not test the car hot but just warm enough for good co & hc.
Also most people who run a fast have a very good ignition system & the
mechanical integrity of the engine is good which enables the engine to burn
a richer mixture with out producing too much hc.So many back yard mechanics always want to lean the car out thinking this is all it takes to
make it pass when the car goes too lean this will also raise hydrocarbons.
I would NOT drive the car around with these settings but they work for the CT wheel dyno test.
lol
A race program has nothing to do with it.
You tune down low is the same for a race or street program.
MOST race program changes will be may at boost levels exceding 15# on my programs.
He may have passed on his normal program as we set it up for great mileage and a nice lean a/f.
But without a working EGR i make those changes for NOX.
I do what i know works so you dont have to go back for a retest.
LOL! That test result says enough.
turbobitt
Well-Known Member
- Joined
- Feb 14, 2002
Emmisions
This was my point, A race program has nothing to do with it. My cells down low are optimized for mileage and drivability. Didn't think there was a need for anything special. Oh , no EGR on my stage II also.
This was my point, A race program has nothing to do with it. My cells down low are optimized for mileage and drivability. Didn't think there was a need for anything special. Oh , no EGR on my stage II also.
turbobitt
Well-Known Member
- Joined
- Feb 14, 2002
What's this!!
Who's that bare-chested ugly kid with the count dracula haircut ?? :tongue:
Shows how smart you are
This pic says it all LOL
Who's that bare-chested ugly kid with the count dracula haircut ?? :tongue:
No. Why does that matter? Whats the IQ requirement? I may not have the knowledge for a hard pressed job like that. Ive had my car and many others pass with no problems
. Its a state run program that wastes taxpayers $ imo. It would be about $10 more per registration if the state didnt observe the program. The tests cost the owner of the vehicle $20. Where does the extra $10 go? If and when i have a dyno it will be for high performance tuning not emissions testing :tongue: .Shows how smart you are
This pic says it all LOL
whats my IQ based on the pic? I hope a least 80
Never seen him before. Looks like some wise ass though.
My test result is plenty of validation. Good thing my NOx was low. Smoking causes lung problems too. It isnt regulated to well though is it? Do you have emissions control on your TSO car ? We need to get this moved to the political forum, lol!
? We need to get this moved to the political forum, lol!