I originally posted this in F-I forum and got no replies....I want to put some low compression CP pistons (9:0 c/r) in my GSR.... but i want to be able to take my turbo kit off and pass smog just in case my smog hookup goes away..... anyone running low compression and passing CA smog?

so basically i want to know if a stock GSR with lower compression will pass CA smog.....

 

talked to a smog tech... it will pass...

 

Your emissions numbers WILL be different than a stock GSR. Compression is a very important number during combustion, and plays a large role in the combustion characteristics. Your stock compression and ECU/fuel/air/timing/etc settings were all meticulously set by engineers, if you change it, those will change possibly altering your emissions.

You may or may not pass. I'm sure the "tech" was just assuming it will read similar to a car that came stock with 9.0:1 compression.

 

my answer is no, you will not.

 

i told him it would be lower compression from stock GSR.... from 10:1... he said it would pass.... iono.. i will just take my chance i guess...

 

if it only a couple tenths of a point in compression you'll be fine otherwise you have to change your timing in order to not produce too much NOx( too much timing) or toomuch hydrocarbons (not enough timing). If you notice you have one too many Nox emissions then you know to reduce timing and vice versa..otherwise no problem to pass. I made a post on how I passed with my car without CAT and I passed with flying colors. I have a few tips on how to do it to

efit: without a cat


Modified by adseguy at 12:00 PM 11/12/2005

 

my ls-vtec passed smog as a LS...the tech didnt know the difference so I passed visual...in case people start flaming. I passed on 2 differenet occasion, once with b16 pistons another with itr pistons.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ricebucket &raquo;</TD></TR><TR><TD CLASS="quote">my ls-vtec passed smog as a LS...the tech didnt know the difference so I passed visual...in case people start flaming. I passed on 2 differenet occasion, once with b16 pistons another with itr pistons.</TD></TR></TABLE>

ok but that does not relate you had HIGHER compression, he dropped a whole point on his compression

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy &raquo;</TD></TR><TR><TD CLASS="quote">if it only a couple tenths of a point in compression you'll be fine otherwise you have to change your timing in order to not produce too much NOx( too much timing) or toomuch hydrocarbons (not enough timing). If you notice you have one too many Nox emissions then you know to reduce timing and vice versa..otherwise no problem to pass. I made a post on how I passed with my car with CAT and I passed with flying colors. I have a few tips on how to do it to </TD></TR></TABLE> im all ears! bring those tips..... remember im in CA.. i think the most strict smog laws in the US

 

https://honda-tech.com/zerothread?id=1305346

without CAT by the way....I wrote with cat on accident

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy &raquo;</TD></TR><TR><TD CLASS="quote">https://honda-tech.com/zerothread?id=1305346

without CAT by the way....I wrote with cat on accident</TD></TR></TABLE>


thats fine and dandy but you are in IL and we are in CA, CA is the most strict state when it comes to emissions

 

Unless you are just changing pistons or have a Greddy kit, In CA you won't pass the underhood inspection because it needs to be CARB approved. All my tips though will help on your low compression GSR especially the timing part, because that WILL be off. GL either way

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy &raquo;</TD></TR><TR><TD CLASS="quote">Unless you are just changing pistons or have a Greddy kit, In CA you won't pass the underhood inspection because it needs to be CARB approved. All my tips though will help on your low compression GSR especially the timing part, because that WILL be off. GL either way</TD></TR></TABLE>


lol i know plenty about california smog, again, he wont pass, not without significant adjustments

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy &raquo;</TD></TR><TR><TD CLASS="quote">Unless you are just changing pistons or have a Greddy kit, In CA you won't pass the underhood inspection because it needs to be CARB approved. All my tips though will help on your low compression GSR especially the timing part, because that WILL be off. GL either way</TD></TR></TABLE> yea mna... thanx ill try them...

 

resurrecting this thread from the dead to get more opinions. i will be doing the same.

 

Talk to the OP about his results. But legally, NO this will not pass. No internal engine modifications were ever CARB approved.
Will it pass the sniffer? Probably.

 

I wanna know the chances of it passing the sniffer.

 

if other people on ht could pass smog with a higher comp. piston like itr or p30 (b16) then i think you should be able to pass with lower comp. isn't 9-1 ls comp.?

 

As long as your o2 sensor(s) is not disabled or fouled, and your tune is not too rich or lean, it should pass the sniffer. All of the other emissions crap has to be hooked up also.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hmongyaj87 &raquo;</TD></TR><TR><TD CLASS="quote">if other people on ht could pass smog with a higher comp. piston like itr or p30 (b16) then i think you should be able to pass with lower comp. isn't 9-1 ls comp.? </TD></TR></TABLE>

yea but the air/fuel is tuned to that stock compression. the gsr ecu is designed to run 10:1 compression pistons.

 

Compressing the mixture does not change the ratio of fuel:air. Your o2 should put you at stoch when crusing anyway. I think timing would be the issue here (if there is an issue).

 

ummmm they have no way of knowing what is inside his engine and if your car passes the visual and you tune it to pass the sniffer and assuming you have a integra gsr for that gsr motor than you should be fine
unless you look sketchy or are a dick a lot of smog techs don't even look at visual or timing
but if he checks you timing and its been tinkered then he will fail you

 

well to pass CA smog that i know of is to get your motor cold and you will pass... thats how i passed