SIK IN DA HED

It was time to re-register my car and I had to get the smog done. Unfortunately, I was stuck having to take my car to a smog test only center. I took off the turbo and tested my car...
**Smog pre-test done in August 2004**
Modifications: Comptech ice box, DC header, stock catalytic converter, old o2 sensor, and 2.5 Tanabe racing medallion exhaust. Ignition timing retarded -2 degrees. (158,000+ miles on the LS)

HC(PPM) MAX AVE MEAS
M1: 15 MPH 90 21 137 -FAILED
M2: 25MPH 56 13 67 -FAILED

CO(%) MAX AVE MEAS
M1: 15 MPH 0.54 0.06 0.49 -FAILED
M2: 25 MPH 0.53 0.05 0.65 -FAILED

NO (PPM) MAX AVE MEAS
M1: 15 MPH 711 150 1118 -FAILED
M2: 25 MPH 754 136 95 -FAILED

After procrastinating for 6 months, I finally installed the brand new o2 sensor...

**Smog pre-test done in January 2005**
Modifications: Comptech ice box, DC header, stock catalytic converter, new o2 sensor, and 2.5 Tanabe racing medallion exhaust. Ignition timing retarded by -2 degrees. (165,000+ miles on the LS)

HC(PPM) MAX AVE MEAS
M1: 15 MPH 90 21 65 -PASSED
M2: 25MPH 56 13 31 -PASSED

CO(%) MAX AVE MEAS
M1: 15 MPH 0.54 0.06 0.23 -PASSED
M2: 25 MPH 0.53 0.05 0.06 -PASSED

NO (PPM) MAX AVE MEAS
M1: 15 MPH 711 150 713 -FAILED (by only 2!)
M2: 25 MPH 754 136 301 -PASSED

What a difference the o2 sensor made! However, it still sucked to fail. I only missed it by 2!!

I drove my car hard on the freeway for an hour before the smog test. Unfortunately, when I got to the shop, I had to wait an hour before I was able to take the smog test. Maybe I should have drove it around before I took the test. I was running on 89 octane (unleaded +).

Any suggestions on how I can bring the NO down? Would driving it before the test have made a noticable difference? Should I use super unleaded gas next time? Should I retard my timing more? Put it back to stock timing? Does weather play a factor? I'm going to re-test it this weekend. Any helpful advice would be appreciated

hondaguyef

Try using 87 octane on your next test. The octane rating is the fuels resistance to detonatoin. The higher the number the higher resistance therefore, 87 will burn more completely than 89 will in an application (such as yours) when the high octane gas isn't needed. Leave the timing where it is and raise the idle to the highest allowable limit(1K in CA now?). Good luck

Phil


Modified by hondaguyef at 1:20 PM 2/1/2005

dornon13

huh? im confused

Sonny

The high NOx is caused by excessive chamber heat. You do NOT want less octane for this. This is the exact problem I had when trying to get my car ref'd. One of the guys testing it casually mentioned that some 100 octane unleaded would probably do it.

I ended up raising the fuel pressure a bit and dialing a bit if overlap into the cams.

Sonny

SIK IN DA HED

so some good ol' octane booster should do the trick, huh? i was thinking about dumping some fuel system cleaner in the tank to get rid of some carbon deposits, too.

_gurusan_

Give it a sea foam treatment.

Can work wonders.

SIK IN DA HED

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by _gurusan_ &raquo;</TD></TR><TR><TD CLASS="quote">Give it a sea foam treatment.

Can work wonders.</TD></TR></TABLE>

i havent tried that yet. what exactly is sea foam and how is it used?