b17a smog

Has anybody pass smog (Nox reading) with CTR pistons in their b17a? I got hit with a “test only” test. My smog is due very soon. I want to make sure that it will pass. I was going to get a pretest but not sure if I need to. My smog setup will be

CTR pistons
2 layer headgasket (have a thicker .54 cometic if needed)
stock header, stock ecu, stock air box, stock cat
7’s spark plugs
will set timing to 14
will overlap sk2 stage 1 cams +1 -1

I will toss in some cheveron techron this week to clean up carbon buildup. I will probably throw in some HEET before the smog test as well. I have a stock fpr but it was “crushed” to increase fuel pressure. Any ideas if I will have problems with NOx just because of the CTR pistons? Any advise will be appericated.


Traditionally the 17’s have really high nox… but I don’t know about your specs and the effect on smog… keep us posted on the out come please


I will post my results after I get the car smogged. Hopefully this might help us get a better idea if ctr pistons in a stock b17a will be able to pass smog without any major work.


oooou yes keep us updated. i was planning on putting ctr pistons in my engine when i rebuild it (hopefully not in the near future).

i think you should use seafoam also to really clean up all the gunk in there.

I passed smog with the CTR pistons. Turn your idle up to about 900-1000. Also if you can, make sure it is not to lean at idle. With the aftermarket cams it has a bit more duration at idle.


what’s your setup besides the CTR pistons? What was your Nox reading?

Thanks for the info!

i don’t think adjusting your idle will work here in CA, i think they readjust your idle to stock. damn hippies!

that is true your idle here will have to be at 750 +/-50. its a slim door of oppurtunity for those with aftermarket cams and stuff.

The idle in Washington can be up to 1100. I’m glad I don’t live in Cali. Here is my setup.

CTR pistons
skunk2 stage 2 cams
mugen thin head gasket
skunk2 computer program
typr r intake
dc header
greddy sp exhaust
fuel pressure set to 40psi
fields vtec controller set -15% at idle
timing at 12 btc

also readings were

idle HC 40
idle CO% was 0
idle CO+O2% 14.3
idle O2% 1.7

cruise HC 79
cruise CO% 0.04
cruise CO+O2% 14.34
cruise O2% 1.64

hope this helps you out



No NOX… NO=Nox

oh as i keep saying, damn hippies! :tsk:

There is no NOX reading on the report that they gave me. The test must be different in Cali.

yeah, it started late last year. we have a NOX reading now and all cars except 4wd have to go on the dyno.


what so funny schu?

Hippies :shy:

oh, lol.
i actually work with a lot of them here at whole foods market, go figure.