- Joined
- 5 December 2013
- Messages
- 3
Let me start off by saying that CARB, (California Air Resources Board) is on a rampage against us. No one is concerned until it happens to them. I don’t know what we can do to make smog testing our cars fair and honest. CARB is certainly not playing fair.
My story starts with failing my smog test, not because my basically stock 1991 NSX is running poorly, it is running fantastic, but because CARB keeps lowering the allowable PPM threshold numbers. Yes, I got my cats hot before each test.
Back in 1999 the max CARB threshold numbers were:
Lo speed 15mph HC 138 CO .73 NOx 1982
Hi speed 25mph HC 88 CO .61 NOx 1782
Current max numbers at time of test (Nov of 2013)
Lo speed 15mph HC 80 CO .52 NOx 549
Hi speed 25mph HC 62 CO .61 NOx 507
You can see how the numbers have dropped, especially the NOx numbers and the gross polluter level is below what was a passing level 12 years ago.
Forum user mrbythatmuch created a good thread http://www.nsxprime.com/forum/showthread.php/150753-91-NSX-Manual-Smog-Limits-Changed that shows how the 1991 manual transmission NSX has lower threshold numbers than an 1991 auto or a 1992. Excuse me, how does that make sense. Oh, I forgot we are talking about the government.
In my case I failed on the low speed NOx test, all other tests passed easily including high speed NOx test. My car would have passed if it was an auto or a 1992. Do a study on why a car fails a NOx test and you will see that it will include the EGR system, which lowers combustion chamber temps and lowers NOx. But wait, My car failed low speed but passed high speed. So it sounds that the EGR is working. I went ahead and had Jerry @ Greenlight run some magic formula thru the EGR and intake to clean things up. The result was no improvement in the next smog test. So the next thing I did was replace the spark plugs and the O2 sensors. I went and retested and failed again with no improvement. Feeling discouraged and not wanting to go thru the expense of replacing the catalytic converters I started to analyze. Also, the smog tech stated that he thought the cats were doing their job by looking at the numbers. I started looking up zip codes in San Diego county that have different smog requirements http://smogcheck.ca.gov/pubwebquery/Ziparea/ZipLookup.aspx. I live in an ENHANCED area which most people do. I have friends in the BASIC area which is a static test and not a dyno test. I needed someone in the CHANGE OF OWNERSHIP area so I would never have to smog the NSX again.
During the second test I observed the smog tech running the 15 mph test in 2[SUP]nd[/SUP] gear. I later asked him why. He stated that CARB requires him to use 2[SUP]nd[/SUP] gear. That is insane, that is only 1500 rpm. This engine is not designed to operate at that level. I asked if he could do it in 1[SUP]st[/SUP] gear. He stated that CARB audits his results and data weekly and the fines are huge, so no. He was definitely nervous of BIG BROTHER watching him. This made me start to think, I need to find a smog test place that would allow me to test in 1[SUP]st[/SUP] gear, highly recommended concept. I wanted to see if I played around with placing a vacuum on the EGR valve how it functioned and saw that the car won’t run with the EGR open at low rpms. This made me start to think, at what rpm will the car open the EGR enough to pass. I knew that the 25mph test was at 2500 rpm and the NOx levels were at 415, a passing number. So I needed the engine rpm to be above 1500 and somewhere below 2500. How do I get the rpms up during a test, then it hit me. The NSX has smaller tires on the front than the rear. So I installed my old set of fronts on the rear of my car, pumped up the tire pressure to 40 psi which lowers rolling resistance. I also manually cleaned the EGR ports that go into the intake manifold by removing the rectangular plastic Honda piece in the top middle of the engine and removed the plate under it exposing the EGR ports and tried to clean up gunk in the ports, there was some and headed to the smog place. I should add that when driving the car with front tires on the rear you have to turn off the traction control, otherwise the TCS system keeps activating. Guess what, it passed with a low speed NOx level of 411 ppm, rpm was 1660. I increased the rpm by 10% which lowered the NOx level by 300ppm.
So my take away from this is the state of California is trying their best to get older cars off the road by imposing stricter and stricter requirements while creating a testing environment that makes it increasing more difficult to pass. Also, save your old 91 rims, they are a life saver. Cars with a 6 speed or different gearing may have an rpm range that will help them thru this stupid exercise.
My story starts with failing my smog test, not because my basically stock 1991 NSX is running poorly, it is running fantastic, but because CARB keeps lowering the allowable PPM threshold numbers. Yes, I got my cats hot before each test.
Back in 1999 the max CARB threshold numbers were:
Lo speed 15mph HC 138 CO .73 NOx 1982
Hi speed 25mph HC 88 CO .61 NOx 1782
Current max numbers at time of test (Nov of 2013)
Lo speed 15mph HC 80 CO .52 NOx 549
Hi speed 25mph HC 62 CO .61 NOx 507
You can see how the numbers have dropped, especially the NOx numbers and the gross polluter level is below what was a passing level 12 years ago.
Forum user mrbythatmuch created a good thread http://www.nsxprime.com/forum/showthread.php/150753-91-NSX-Manual-Smog-Limits-Changed that shows how the 1991 manual transmission NSX has lower threshold numbers than an 1991 auto or a 1992. Excuse me, how does that make sense. Oh, I forgot we are talking about the government.
In my case I failed on the low speed NOx test, all other tests passed easily including high speed NOx test. My car would have passed if it was an auto or a 1992. Do a study on why a car fails a NOx test and you will see that it will include the EGR system, which lowers combustion chamber temps and lowers NOx. But wait, My car failed low speed but passed high speed. So it sounds that the EGR is working. I went ahead and had Jerry @ Greenlight run some magic formula thru the EGR and intake to clean things up. The result was no improvement in the next smog test. So the next thing I did was replace the spark plugs and the O2 sensors. I went and retested and failed again with no improvement. Feeling discouraged and not wanting to go thru the expense of replacing the catalytic converters I started to analyze. Also, the smog tech stated that he thought the cats were doing their job by looking at the numbers. I started looking up zip codes in San Diego county that have different smog requirements http://smogcheck.ca.gov/pubwebquery/Ziparea/ZipLookup.aspx. I live in an ENHANCED area which most people do. I have friends in the BASIC area which is a static test and not a dyno test. I needed someone in the CHANGE OF OWNERSHIP area so I would never have to smog the NSX again.
During the second test I observed the smog tech running the 15 mph test in 2[SUP]nd[/SUP] gear. I later asked him why. He stated that CARB requires him to use 2[SUP]nd[/SUP] gear. That is insane, that is only 1500 rpm. This engine is not designed to operate at that level. I asked if he could do it in 1[SUP]st[/SUP] gear. He stated that CARB audits his results and data weekly and the fines are huge, so no. He was definitely nervous of BIG BROTHER watching him. This made me start to think, I need to find a smog test place that would allow me to test in 1[SUP]st[/SUP] gear, highly recommended concept. I wanted to see if I played around with placing a vacuum on the EGR valve how it functioned and saw that the car won’t run with the EGR open at low rpms. This made me start to think, at what rpm will the car open the EGR enough to pass. I knew that the 25mph test was at 2500 rpm and the NOx levels were at 415, a passing number. So I needed the engine rpm to be above 1500 and somewhere below 2500. How do I get the rpms up during a test, then it hit me. The NSX has smaller tires on the front than the rear. So I installed my old set of fronts on the rear of my car, pumped up the tire pressure to 40 psi which lowers rolling resistance. I also manually cleaned the EGR ports that go into the intake manifold by removing the rectangular plastic Honda piece in the top middle of the engine and removed the plate under it exposing the EGR ports and tried to clean up gunk in the ports, there was some and headed to the smog place. I should add that when driving the car with front tires on the rear you have to turn off the traction control, otherwise the TCS system keeps activating. Guess what, it passed with a low speed NOx level of 411 ppm, rpm was 1660. I increased the rpm by 10% which lowered the NOx level by 300ppm.
So my take away from this is the state of California is trying their best to get older cars off the road by imposing stricter and stricter requirements while creating a testing environment that makes it increasing more difficult to pass. Also, save your old 91 rims, they are a life saver. Cars with a 6 speed or different gearing may have an rpm range that will help them thru this stupid exercise.
