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2G Need suggestions on passing emissions

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DoseThemAll

Probationary Member
23
5
Dec 21, 2020
Denver, Colorado
As the title says, I have a BOV and though I love the sound, I have to pass emissions and the sound would lead to an auto fail.

The car came from an area with no emissions so it also has the emissions system in place but all the tubing has been pulled and the manifold has been plugged, auto fail. The icing on the cake is the O2 housing w/ external dump which is also another auto fail as well as being ridiculously loud. Oh, I almost forget, I guess the sprinkles on top would be the 3 inch exhaust which I can't tell but might not have a high flow cat in there (I don't know how to tell 😅) if it doesn't, auto fail.

I've read allot on the forums, people talking about passing without emission systems, no cat, e85 blah blah blah but I don't even know where to start.

They never pop the hood so I'm not too concerned in the emission system if I can get away without it.

My plan is to run the car by these remote testing boxes on the side of the roads and I can check the results online. If I get two passing scores I can skip the dyno and just do the gas cap pressure test and the idle smog. But I'll have to replace the bov and remove the o2 dump because I can drive the car and not have it go stu-stu-stu-stu but I don't want to gamble with them. I'm sure if I fail once, it'll draw more attention to the setup.

I guess the first step would be to replace the O2 dump and figure out how to silence the BOV for the test. How can I go about doing the latter?




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First things first, there should be a hose connecting the bov to the intake pipe. This will fix the sound problem. I see that you're running speed density so it’s probably not causing any other issues being atmosphere dumped.

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First things first, there should be a hose connecting the bov to the intake pipe. This will fix the sound problem. I see that you're running speed density so it’s probably not causing any other issues being atmosphere dumped.
Is it really that simple? Think I'd need a retune for the test with that change?
 
The o2 dump and bov won't make any noise unless they're really getting on it. You said all they're doing is idle right?
When I get there, I typically hop out the car and leave it running for them, they only move the car through the building. So ya, maybe I'm over thinking it but then again that dump is almost always pumping out noise since the boost is only at to 15psi, very easy to do, especially in first. I ordered an recirculation version last night on ebay. I'm now also wondering how detrimental the changes will to the tune.
 
I ordered an recirculation version last night on ebay.
That IS the recirculated version.
I'm now also wondering how detrimental the changes will to the tune.
None. Because your tune doesn't care about the BOV at all. Assuming that your tune is actually running speed density and not just ignoring the sensors that have been installed. If you're using the MAF at all then it might get complicated.

These crappy Greddy clones have an adjustment on top. You can set it to full hard for the test to make it much harder to open. And if you're leaving it unfiltered it should be set pretty far toward hard anyway. The ringing that it makes when cruising is it pulling unfiltered air into the engine, which is no bueno.
 
That IS the recirculated version.
Oh, I was referring to the O2 housing w/ external dump 😀
None. Because your tune doesn't care about the BOV at all. Assuming that your tune is actually running speed density and not just ignoring the sensors that have been installed. If you're using the MAF at all then it might get complicated.
That's good to know. And I'm not sure how elaborate the tune is tbh. I know it was worked on by a business out where she came from.
These crappy Greddy clones have an adjustment on top. You can set it to full hard for the test to make it much harder to open. And if you're leaving it unfiltered it should be set pretty far toward hard anyway. The ringing that it makes when cruising is it pulling unfiltered air into the engine, which is no bueno.
Ya you're right, I did notice the knob on it yesterday and thought the same. One clarification I'd like you to make is with the unfiltered air part. I thought the BOV was "blowing out" pressure, not taking it in?
 
When I get there, I typically hop out the car and leave it running for them, they only move the car through the building. So ya, maybe I'm over thinking it but then again that dump is almost always pumping out noise since the boost is only at to 15psi, very easy to do, especially in first. I ordered an recirculation version last night on ebay. I'm now also wondering how detrimental the changes will to the tune.
Your car will NOT be idle tested. It will be put on the rollers and load tested through various speeds. All cars older than 8 years (iirc) have to go on the rollers now. And a heads up, emissions standards were lowered for 2022, it's harder than ever to pass.
 
Your car will NOT be idle tested. It will be put on the rollers and load tested through various speeds. All cars older than 8 years (iirc) have to go on the rollers now. And a heads up, emissions standards were lowered for 2022, it's harder than ever to pass.
"My plan is to run the car by these remote testing boxes on the side of the roads and I can check the results online. If I get two passing scores I can skip the dyno and just do the gas cap pressure test and the idle smog. But I'll have to replace the bov and remove the o2 dump because I can drive the car and not have it go stu-stu-stu-stu but I don't want to gamble with them. I'm sure if I fail once, it'll draw more attention to the setup."

I am also exempt from OBDII since I'm a 95', it's required for 96' and up in my state.

But you're right about the standards. I did wonder that when reading what people have passed with, wondering if they'd pass with current standards.
 
"My plan is to run the car by these remote testing boxes on the side of the roads and I can check the results online
You'll have better luck passing on the dyno. The rapidscreens are REALLY hard to pass. You HAVE to be accelerating (they log it) and be cleaner than the dyno limits, which are already really strict.

 
You'll have better luck passing on the dyno. The rapidscreens are REALLY hard to pass. You HAVE to be accelerating (they log it) and be cleaner than the dyno limits, which are already really strict.

It's simply a starting point. If the online records read a fail, I have no issue reinstalling the emissions, besides the hassles of figuring it out. I'll keep that in mind about the dyno tho, which shouldn't be a issue anymore if I can route the BOV into the intake and replace the O2 housing with a recirculating version.
 
You'll have better luck passing on the dyno. The rapidscreens are REALLY hard to pass. You HAVE to be accelerating (they log it) and be cleaner than the dyno limits, which are already really strict.

You got me thinking again and after a bit more research I think I had it mixed up. I've been doing emissions on my vehicles for ten years here and only once had to do the dyno. I always assumed it had to do with the rapid screens but after looking it up some more I see now they were using the OBDII to do the test instead of the dyno, meaning this car, being a 95' will end up on the dyno.
Then I also mentioned they never popped the hood and now I'm seeing this for my state.
"In addition, vehicle model years 1975 through 1995 are given the following equipment checks, to ensure all required equipmwnt is installed, intact, and in apparent working order:

* catalytic converter
* air injection system
* O2 sensor system
* "check engine" light"

There's no check engine light, there are O2 sensors on engine and exhaust but I'm not sure about the other two.

Ughh 😦
 
As the title says, I have a BOV and though I love the sound, I have to pass emissions and the sound would lead to an auto fail.

The car came from an area with no emissions so it also has the emissions system in place but all the tubing has been pulled and the manifold has been plugged, auto fail. The icing on the cake is the O2 housing w/ external dump which is also another auto fail as well as being ridiculously loud. Oh, I almost forget, I guess the sprinkles on top would be the 3 inch exhaust which I can't tell but might not have a high flow cat in there (I don't know how to tell 😅) if it doesn't, auto fail.

I've read allot on the forums, people talking about passing without emission systems, no cat, e85 blah blah blah but I don't even know where to start.

They never pop the hood so I'm not too concerned in the emission system if I can get away without it.

My plan is to run the car by these remote testing boxes on the side of the roads and I can check the results online. If I get two passing scores I can skip the dyno and just do the gas cap pressure test and the idle smog. But I'll have to replace the bov and remove the o2 dump because I can drive the car and not have it go stu-stu-stu-stu but I don't want to gamble with them. I'm sure if I fail once, it'll draw more attention to the setup.

I guess the first step would be to replace the O2 dump and figure out how to silence the BOV for the test. How can I go about doing the latter?





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Looks like there are some discrepancies in your understanding of the emissions test...

They will do a visual test and since your car is modified they will be looking extra hard to ensure all vacuum lines are hooked up, mainly to the charcoal canister. They will also look to see that the EGR is present and hooked up. They look for mine but since I have a Cyclone intake, it doesn't exist. They give up and move along.

They fail for a blow off valve due to noise ? @ErikTande can you confirm or deny this ?


I would also suggest to turn your boost all the way down to WG pressure just in case the technician gets a little throttle happy on the dyno...

I failed and had to get "creative" to meet thresholds....
 
Looks like there are some discrepancies in your understanding of the emissions test..
💯
They will do a visual test and since your car is modified they will be looking extra hard to ensure all vacuum lines are hooked up, mainly to the charcoal canister. They will also look to see that the EGR is present and hooked up. They look for mine but since I have a Cyclone intake, it doesn't exist. They give up and move along.
Yea, I figured that would be the case 🥲
They fail for a blow off valve due to noise ? @ErikTande can you confirm or deny this ?
It was my understanding that the sound is indicative of vent to atmosphere setup. Given, it was through a Google search that I came to that conclusion.
 
They fail for a blow off valve due to noise ? @ErikTande can you confirm or deny this ?
I don't know if that's supposed to be a fail or not. I doubt it. The last car I tested was my 1997 talon, and you can hear that BOV and it passed just fine. They never did any visual inspection either. But maybe that's just '95 and older.
 
Just a heads up, the HC and NOx limits are less than HALF of what they were just 10 years ago. It's going to get very difficult to pass a DSM.

In 2013 the limits were:

HC: 2.0
CO: 20.0
NOx: 3.5

In 2021 limits were:

HC: 1.2
CO: 15.0
NOx: 2.0

This year (2022) limits are:

HC: 0.8
CO: 15.0
NOx: 1.5
 
Oh, I was referring to the O2 housing w/ external dump 😀
Oops! I completely missed the discussion about the wastegate. Ignore me...
That's good to know. And I'm not sure how elaborate the tune is tbh. I know it was worked on by a business out where she came from.
Idk if this is what you were asking or not, but the tune ALSO doesn't care about recirculated vs. dump wastegate either. If you run electronic boost control you'll have to adjust the PID constants but if you're just running a simple manual boost controller then you don't need to make any changes at all. Ah, the simplicity of older cars.
Ya you're right, I did notice the knob on it yesterday and thought the same. One clarification I'd like you to make is with the unfiltered air part. I thought the BOV was "blowing out" pressure, not taking it in?
The valve gets pulled open by low manifold pressure. Normally yes, it opens to vent pressure out, but there is a singular situation where it can pull air in. If your spring is weak (or adjusted to the "soft" setting) it absolutely can get pulled open when the pressure in the charge pipe is lower than atmospheric, drawing unfiltered air in. It's not a lot, certainly, but it happens. Back when I had a 1g BOV it was REALLY noticeable and when I switched to speed density and ran my knockoff Greddy (I have the same one as you) to atmosphere I could hear the ringing on in-gear deceleration. Just slowly adjust the BOV toward "hard" until you don't get any ringing at any point when decelerating in gear from high revs to idle, then you're good to go. Or you could stick a breather filter on the BOV. That's what I did on my van because the BOV is on the bottom of the car and gets hit by all kind of debris.
 
Just a heads up, the HC and NOx limits are less than HALF of what they were just 10 years ago. It's going to get very difficult to pass a DSM.

In 2013 the limits were:

HC: 2.0
CO: 20.0
NOx: 3.5

In 2021 limits were:

HC: 1.2
CO: 15.0
NOx: 2.0

This year (2022) limits are:

HC: 0.8
CO: 15.0
NOx: 1.5
Ughhh 🥲 This will definitely be a challenge but I've been toying around with the idea of buying a GSX for ever so I gotta figure this out.

Since I get to skip OBDII testing for being a 95', I don't necessarily have to put back the entire emissions system. (I found a picture of when people pull it out and it's allot!) So, what do you think I HAVE to have in there to pass?

I saw your profile mentions Bandimere Speedway, are you still in Colorado? In a emissions County? I ask to see how your testing with your 90' GSX?
 
Ughhh 🥲 This will definitely be a challenge but I've been toying around with the idea of buying a GSX for ever so I gotta figure this out.

Since I get to skip OBDII testing for being a 95', I don't necessarily have to put back the entire emissions system. (I found a picture of when people pull it out and it's allot!) So, what do you think I HAVE to have in there to pass?


I saw your profile mentions Bandimere Speedway, are you still in Colorado? In a emissions County? I ask to see how your testing with your 90' GSX?
I'm not. The last time I passed emissions in the 90GSX was in 2016. I've been driving with expired tags ever since. Not ideal though.

I'm considering adding a secondary air injection pump to the exhaust to pump clean air into it (lots of cars have these from factory).






My other thought was add a subaru style muffler so only HALF the exhaust gets measured, like this:

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I'm not. The last time I passed emissions in the 90GSX was in 2016. I've been driving with expired tags ever since. Not ideal though.
😄
I'm considering adding a secondary air injection pump to the exhaust to pump clean air into it (lots of cars have these from factory). My other thought was add a subaru style muffler so only HALF the exhaust gets measured, like this:

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That's pretty slick tbh 😎

I'm determined to figure this out so I'll keep this post updated.
 
Hey guys,
Lets ignore the technicalities of the carb compliance by EFN for the sake of answering my question.

So I'm looking at catalytic converters for my car and stock size it 2.5". If I were to up the size to 3", a cat that would typically go onto a truck, do you think that might effect the efficiency of the cat or should I be fine? I ask because I'd hate to spend 400 bucks on a cat that didn't work only to have to go buy a 2.5' that I'd probably take off the car right after I pass emissions.
 
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