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Discussion Starter · #1 ·
Can I get a catless uppipe here in California and still be ok with emissions?

or let me rephrase it.. can i GET AWAY with it hehe.. (like go through smog and be ok)

also, what about the downpipe? can I maybe remove 1 cat and be ok for emissions / visual inspection / sound?

and finally.. what do you guys think about HKS's Hi-Power exhaust? what kind of exhaust is it (cat-back.. turbo back?)

AND finally.. do you guys know where I can get some hp/torque graphs for different exhausts for the wrx / sti.

Thanks guys.. I really appreciate it.
 

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I don't know about getting away with it, but the smog check is every four years in Cali...so I kept my stocker just in case and worry about my smog check in 2006;)

I think there is a sticky in this forum with some tests from turbo mag that should have dyno charts.

Sorry, don't know anything about the HKS exhaust. I'm running a Turbo XS stealth back and a prodrive muffler. Love the sound and performance.
 

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Four years after first registration for NEW cars.
After the first 4 year period it is every other year.

I don't know about the HKS unit.

You should be fine with passing the sniffer test if you only remove the uppipe cat.
They usually aren't looking there for a cat and it's hard to see anyway.
The downpipe cat removes the most emissions so when it is time for smog that cat MUST go back on.
You would probably pass the sniffer with just the DP cat.
Visually a midpipe without a cat is going to be obvious.
I say go catless and throw the down and midpipes back on for smog. I know that sounds like a PITA but it's worth it.

I am running a Autospeed Flex Up, Bosal Down, Custom Mid, and a Prodrive/Scorpion axel back. That setup was about 1000 total.

Catless is worth it. I had the up and down pipes on for a while but that last cat was still restricting things.
My butt dyno can tell the difference between almost and completely catless (sorry no dyno graphs).

Sound should be fine, the muffler you choose will be the deciding factor on volume.
I like things somewhat quiet, my Prodrive/Scorpion is perfect, not too loud but definitely noticable.
 

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See the SPD Tuning site. They're located in CA also, and they have *very* specific recommendations about the cat setup, and how restrictive -- or not -- the cats actually are. Also, compare the setup with the non-US versions and compare their power output to your stock output; a car making more power using the same cat setup implies the cats aren't the real bottleneck.

Depending on your ultimate power goals, you may end up committing one or two less federal offences than originally anticipated, and it's a very interesting site anyway. Have fun.
 

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quick answer, replacing up is no problem to pass ca emission.

replacing dp only, and keeping the up and midpipe cat, then u might get away w/that as well

replacing up and dp cat, then u'll be very lucky to pass
 

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Messing with anything before the last cat is grounds for a failed smog test.

With that said...if you gut the OEM uppipe or even get a part that is similar in look (STI) you should be able to get away with it. I would keep at least two of the cats just for the sake of not relying on luck to pass the smog test. All cars are given a certain range in which they are allowed to perform. I am guessing that removing two cats might put you out of that range.
 

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I have been talking with a friend who is a SAE certified mechanic, and he says that there is a sticker inside the engine compartment that states how many cats the car has. The tech will then have to check to make sure they are all in place. That means look underneath the car. You might get lucky, and you might not. That is why I went with the JDM STI uppipe. It looks like a cat from the outside, but there is no cat on the inside.

That is why I have also kept every single piece of equipment I have taken off the car. Just in case. I will be replacing the entire stock turboback exhaust when it is time for smog. That is also another reason I went with the UTEC instead of the EcuTek reflash. With the UTEC, you can just unhook it and go. With the EcuTek, you will have to be reflashed again in order to pass smog.

I have gone through hell before trying to get a VW bug I used to own, smoged every year, since I had a high performance motor in it, with dual carbs, headers and such. So every other year I would have to swap to my smog motor and get it smogged. Pretty much a hassle. I don't want to have to go through with that again.

You people out there that live in areas with no smog laws. I envy you.
 

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California smog regulations...

California has 2 different requirements for smog certification. They are as follows:

1) Visual inspection of the vehicle's pollution control equipment
2) Vehicle emissions test at the exhaust tip at idle and at 3500rpm (I might be mistaken about the rpm - it could be 2800 or 3000 or so)

Removing any of the factory cats or any other factory-installed pollution control systems will result in the failure of the visual inspection. The exhaust emissions test is run automatically and the data is fed directly into the computer. This data is automatically sent to the DMV, thus if you don't pass, the DMV will know about it (no paying off the attendant to not submit the form :) ).

For the visual inspection, there is a tag (usually located either on the hood or somewhere easily visible in the engine bay) that describes in detail the pollution control systems of the vehicle. The smog inspectors know where these are and how to find them, and that's how they do the visual inspection (so you can't lie to them :) ). And yes, it's a violation to remove the smog system diagram as well.

For vehicles manufactured after 1997, they are required to submit a smog certification 4 years from the date of purchase, then every other year after that point.

California is not getting any easier with smog regulations, and in fact it's currently up for debate as to whether or not it's going to get worse. How much worse you ask? How about random mobile smog checks. How about emissions tests not for 2 RPM levels, but across the entire range - from idle to redline. How about mobile dynometers for both 2WD and 4WD vehicles that will test your vehicles emissions under load across the whole range of revolutions. If you think I'm kidding about this stuff, head over to the California Air Resources Board (http://www.arb.ca.gov/) and read the fun and games for yourself. These things all fall under the new "Smog 2" legislation, along with the new taxes and such that will be imposed on SUVs and minivans (I think that goes into effect in 2009).

So how do you get around this? First, make sure you keep your ENTIRE factory exhaust system. You'll need it if you want to pass. Just bolt it back in before you go down to the smog center. If you have a user-tunable ECU, have your tuning house create a "smog" or "stock" map for you (or create one yourself). I would highly recommend verifying that with this map it does indeed pass smog before going for your actual inspect. If you fail even once, you can end up with all sorts of problems. They log your VIN number, amongst other things, and I have heard (not verified) that they can even request an in-depth inspection to be performed by authorized DMV officials to ensure your vehicle conforms to California smog laws. So yes, it's a pain in the ass to keep your old exhaust system and such and create a "smog" map for your ECU just so it can be bolted back in every other year. But that's what you have to do these days.

Sorry for making this such a long post, but I figured I'd get all this in here while I could.

-Todd
 

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Discussion Starter · #9 ·
Cool thanks for the info... So now the final question: would you recommend I get catless and just bolt on my stock stuff every other year? I think thats what Im going for..

Here in San Jose Ca, they have a lot of ******* cops who stop people for the sound of their exhaust (it being too loud and what not).. I do have 2 very close cop friends that can probably just write-off the fix-it tickets..

Man, you non-cali drivers have NO idea. hehe
 

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hazeion said:
Cool thanks for the info... So now the final question: would you recommend I get catless and just bolt on my stock stuff every other year? I think thats what Im going for..

Here in San Jose Ca, they have a lot of ******* cops who stop people for the sound of their exhaust (it being too loud and what not).. I do have 2 very close cop friends that can probably just write-off the fix-it tickets..

Man, you non-cali drivers have NO idea. hehe
Anytime. :D I'm just over in Saratoga, so I know exactly what you're talking about. I absolutely recommend you just bolt on the stock stuff when you need a smog check. It's little more than a few hours work and it'll save you a ton of headaches . I've got an 04 Sedan and I'm going with a full stainless, no cats exhaust system (Godspeed up/down pipes, Blitz Nur Spec Touring exhaust). When it comes time to smog it in 2007, I'll just bolt the stock components back in the car.

BTW, be careful having you friends sign off too many tickets for you. They can get in some serious trouble for doing that (if it can be proved they knew the car had not in fact been "fixed").

-T
 

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With just a Catless Uppipe and a Stock Downpipe you WILL pass the sniffer. (I already went through that, buying a used wrx requires smogging it) Had to replace my HKS DP with the stock one to smog. But now I am completely catless with the full HKS "Turbo-back" (HKS DP + HKS Hi-Power cat-back exhaust). When it comes time to smog, i'm willing to spend the time to throw back on the stock downpipe because the performance with no cats is a GREAT improvement over stock.

Overall set-up, the HKS exhaust is hella loud when you get on it, but luckly my silencer is in the mail.
 

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depending on the final power output you want, you can go the route i did....just gut out all the cat's.....i went out and bought a used up, dp, and midpipe....makes gutting easier, you can take your time to do it right

btw, this makes my system completely stealthy

i still haven't gutted the d/p, and not sure that i will. i'm happy w/the power gain from the up and midpipe....i figured after an ecu reflash, i'd be happy

one more thing....i haven't thrown any cel's just w/the gutted up and midpipe, yet another advantage
 

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Now that I think about it there is that catalyst chart Hmmm, not good.
I will still try to get lucky, there is no way I'm gonna replace the uppipe every other year.
It looks like I will be bolting on the entire stock turbo back. That's what I expected anyhow.

I am going to have to rethink my engine management choice now though, I had gone catless in preparation for an ECUtek reflash.
So the car makes more emissions just as a result of the reflash huh? I didn't think that was the case. What kind of paramaters did you have to change on your Utec to make a "smog check" map?
 

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PKer said:
So the car makes more emissions just as a result of the reflash huh? I didn't think that was the case. What kind of paramaters did you have to change on your Utec to make a "smog check" map?
Yep. The basic reflash changes things like the A/F ratio and ups the boost. More stuff burning in the cylinder = more stuff coming out the exhaust pipe.

I don't have my UTEC installed yet, so I'm not sure what a smog map is going to look like. When I get all my maps done, I'll probably go ahead and post them, unless it's some sort of I.P. or copyright violation (I don't think so, but who knows these days). Chances are the smog map will run lean with very little boost. Gotta be careful though, as too lean will burn holes in your cylinders and pistons. :) It's also possible that you could simply disconnect the UTEC and run with the unmodified stock computer. Again, I don't have any definite answers since my parts aren't in yet.

-T
 
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