Atilla the Fun

I'm not really sure what's the best way to present this, but this thread is for me to give you
accurate, useful information on the relationship between cam specs and emissions.
For this thread I'll assume that you need to pass a tailpipe sniffer test to get your registration
renewed. I'll also assume you're using either a SBC or an LSx. Because a BBC can't be
legal no matter what cam you try.
California being the strictest test on earth, I'll present what you can be sure will pass in Cali.
If you follow these rules and don't pass, then the cause is something other than the cam.
I'm not gonna be conservative, either. I know you want to push your luck just as far as is even
imaginable. And what's clean enough for Cali. IS clean enough for any other sniffer test on
the planet.
So, if you have a 305 with 1.5:1 rockers, you can get away with 2 degrees of overlap at 0.050"
if you got 1.6:1 rockers for your 305, you can get away with exactly zero overlap a 0.050"
More cubes allows slightly more overlap. But, newer standards require less overlap. So if you
did an LSx swap, and it's being smogged as a '98 Z28, then you'd seem to be in a similar boat
to the 305 guys. But your LSx computer is far more advanced, allowing a wee bit of cheating.
For the LSx guys, a TR220-112 is Cali.-clean. Barely. So is a TR224-114. Barely. Both are
Barelys in 346-inch versions. In a LS2, LS3 or LQ block with a 4" stroke, these are baby cams
that'll easily pass the sniffer test.
I need to type more on this. If you want to post a combo that passed, I can't stop you. If you
have a question, that's good by me.

Orr89RocZ

iTrader: (20)

You say in the other post when I raised this question that duration is no guide at all to whats clean and whats not clean, but you need duration to calculate overlap. So it is important to know, just not by itself.

Here are two of the best motors i've seen yet from california on these boards claim to pass emissions just fine and make incredible power numbers.
One is a 369" sbc that made 535hp on the engine dyno, holding power all the way up to 6800 rpm. It uses a 280/280 233/233 113 lsa cam on a 110 icl. .594" lift and 7 deg overlap at .050.

Another is a 360inch sbc superram motor with xfi 280 cam. 280/286 230/236 .57x/.56x lift if i recall, on a 113 lsa. 7 deg overlap as well.

It may be possible to go as high as that on a 355-370" motor. There is a 406 that also makes 400whp with the 280xfi cam and passing out there.

Just some more information to support emissions cams. I guess good quality cats that are close to the collector for best heat also helps

Burnout91

I don't think the 369" motor has passed smog, nor the XFI280 superram motor; the 369" motor is not yet installed (I believe), the superram XFI280 has yet to be tested (I believe). Anyway, my real point is that with the good tuning we get from Kevin91Z, (and putting together a well thought-out combo) I have no doubts that they will pass smog. The 406" / XFI280 passed. My 350 / modded TPI / XFI268 (320rwhp / 377 rwtq) passed so cleanly that I have no doubts that my HSR (with the BO91 EGR mod) / XFI280 will also pass.

Orr89RocZ

iTrader: (20)

Thats why I said Claim. I didnt think they were tested yet but the previous builds passed, and these ones should do it.
Forgot about your motor. Another potential to pass even tho HSR has no CARB/EO number, but could still pass sniffer. Another 380+whp build.

Burnout91

I have yet to have a smog tech ask me for any CARB EO numbers. A lot of them don't really know what these motors (that are pobably older than the smog tech, lol) are supposed to look like. If everything is present and hooked up and it blows clean, most people don't have any problems passing. I apologize for going off topic.

Bill

one92rs

iTrader: (5)

houston smog stuff is easy to pass. with the pcm and the tune ability of it a lot can be done with it. so many things can be turned off and on and to make the engine run as lean as you want it to pass smog. not sure about cali but im sure that it can be tuned to pass there also.

Atilla the Fun

7 degree cams are awfully hard for the average enthusiast to get through the test. I'm not putting any 7 degree overlap cams on my list without some proof.
This Kevin91Z or whomever, and a few other top tuners can work wonders. But if they're not in your city, forget it. Mail order tunes can't accurately compensate for elevation.
And even for those who can get such a tune, it's so expensive that you're cheaper to use a safe cam and buy nitrous.
4 degrees is known safe for smogging a 350. Back that off to 2 degrees with 1.6:1 rockers.
If you are playing the LS game, there's something else you need to understand. A TR220-112 cam with LS 1.7:1 rockers has the same overlap at the valves as if you could switch to 1.5:1 rockers and 224 degree lobes.
You must not forget to correct for rocker ratio.
a 7 degree SBC cam equals a 3 degree LS cam. Because of the rockers.

one92rs

iTrader: (5)

so a cam that is 226-228-581-588-114+4. what is the overlap for that cam.

Atilla the Fun

real is plus 3 at 50, after correcting to 1.7 rockers. should make my safe list in a 364+ cube, borderline in a 346.

one92rs

iTrader: (5)

that cam was in a stock 5.3 engine with minimal headwork. longtubes-freeflow cats-ported throttle body-freeflow exhaust-and a 175 shot of nos. with about 20 hours tuning to run 32* timing on and off. passed inspection easily here in houston. in this i ran a 12.79@107. this was with a built 4l80 instead of a 60 and a vig 3000 verter. on nitrous it put down 425hp and 448tq to the wheels.

Orr89RocZ

iTrader: (20)

Houston doesnt do a sniffer test do they? I dont recall having that test on my car? I thought it was a plug and check for codes/readys.

My car passed fine since all codes were turned off. I deleted rear o2's and EGR

one92rs

iTrader: (5)

i bet it would have passed sniffer to. i could have made it run as lean as possible. i had way more not deleted. but didnt allow it to test so it would not throw a code. what are rear 02 sensors?????? lol. cut off the ends inside the exhaust and turned them off. also ran a pipe inside the cat housings for a while. with a gm hp tuners is your best friend.

Atilla the Fun

Lean isn't always clean. I don't care if it passed in Houston. If you would read the post that started this thread, you'd see we're only concerned with what WILL pass in Cali, first try, every try, for any and all enthusiasts. Every other cam sucks and should be melted down. If your clean cam doesn't make enough power to suit you, get MAST heads. Still not enough? Add boost. Still not enough, add spray. You can get 2000 HP emissions legally, and still have daily driveability.