Right now, I am running a basically stock 350 rebuild (mid seventies) with a weiand action+ intake, carter afb carb, shorty headers, and no emissions except for a cat. When tuned right, it passes emissions easily. I'd like to upgrade to vortec heads (which, all else remaining equal) should improve both my performance and my emissions. Of course, however, I want to get a new cam to complement the heads. That could potentially give me some emissions problems. Does anybody know what kind of cam I could get away with and still be able to pass the dyno smog test? or is it a lost cause? I think that I could get a better cam than stock and still pass with the vortec heads, but don't know enough about cams to be able to pick a promising one. Any input would be great.

Mike

 

Mine passes the dyno emissions test here w/ total ease. I run a CompCams Xtream Energy 262 cam (218/224 @ .050). The only emissions device anywhere on the car was the Catco 3" cat. Passed the test w/ numbers so low it wasn't even close. I think w/ a good cat you'll pass w/ any of the typical street cams...

I should also add that without the air hookup to the cat, and running a little rich, I killed the Catco cat in one year and it wouldn't pass this year. Had to replace the cat (replaced w/ same catco 3" cat) and it again passed w/ flying colors. I have decided to remove the good cat to keep it fresh, and am now running a gutted cat until it's test time again...

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Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

 

Hey, it took me a little while before I realized that you are in Atlanta too! I like the buildups that all the magazines have been doing since HOT ROD's junkyard jewel with the vortec heads and want to do something similar to that. I don't recall what cam they used and my copy of the article is back in Conyers. That's definately encouraging news though. I checked out your site and see you have the Hooker exhaust. That's yet another mod I've been wanting to do. I just have a hard time making myself part with the cash. I guess there's no better reason though. Later

Oh yeah, how did you get 10:1 compression? What pistons are you using/heads milled/headgasket, etc?

[This message has been edited by MikeS (edited April 18, 2001).]

 

Heh, I didn't realize you were in Ga either. I'd say the emissions test results from my engine are darn relevant then, lol. Mine was tested here in Gwinnett, I think all of the counties surrounding Atl here have the same test limits. So you're fine w/ a Vortec headed 350. I'm not kidding, with the fresh cat on the car I DESTROYED the allowable levels, nothing to worry about there. Just be in decent tune w/ the cat and no problems. But again I killed the cat in one years time...

I'm figuring 10:1 compression because this motor was rated at 8.5:1 compression w/ 76cc heads, and I swapped the 64 cc Vortecs on. (motor was originally the 265 hp crate 350 available from Autocenter www.goautocenter.com) According to a little calculator I found on the Net (that I can't find now) the change from 76cc to 64cc should put me up around 10:1. I could be completely off and be lower though...

I believe most of the magazine buildups w/ the Vortecs have been using the CompCams 268 cam (224/230 @.050, lift of .477/.480 I believe). That is the next cam up from mine, but it's lift puts it right at the max lift you can safely run w/ the stock Vortec heads and springs. I wanted to stay slightly on the safe side so I went w/ the 262.

Good luck with your car, I hear you about the cash thing though. I'm trying to save up and get my Z painted (needs it pretty badly) but the money keeps disappearing on me. One of these days...

------------------
Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray


[This message has been edited by Ray87Z (edited April 18, 2001).]

 

Man, I wish they did that here in NC. They do both the sniffer test and the visual inspection. You could have the cleanest running car in town, but if it doesn't have carb can, or smog pump, you fail. Really ticks me off. Why do they care what equipment we've got on it as long as it passes the sniffer test? That means anyone who doesn't want smog equipment has to have a buddy with an inspection station. Arghhhh.... Just venting...

-Joel Likness

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- 84 Z28 In Progress (Road Racer)
- 85 S10 350/350 (Drag Racer)
- 85 Nissan 200SX Yes, it's Japanese (Circle Track Car)
- 91 Lumina 3.1 Euro (Daily Driver)
Carolina F-Body Club
NC Third Gen Association

 

Does your test in GA check for NOX? The Vortec heads don't have the exhaust cross-overs, meaning the EGR won't work unless you plumb a line from the exhaust manifold/header to the intake.

------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam and intake, World 305 heads, Hooker headers & y-pipe, 3" Catco cat).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" Hedders, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere w/open diff & slipping tranny. Daily driver while Camaro was being put together.

 

Yeah they check for NOX. The allowable levels (officially for a 87 305 TPI, I never mentioned I had a non original engine) was somewhere around 1500 for NOX. I can't remember exactly. I was under that limit even when the cat was clogged (was around 1000). W/ the new cat NOX levels were barely even there, lol. I scored under 100, 82 I think it was...

Allowables were like this:
152 ppm for HC,
1.00 (a percentage?) for CO,
& around 1500 for NOX.

It blew w/ the clogged cat originally:
256 for HC
freakin 3.95 for CO,
1050ish for NOX.

Tuned up, jetted leaner, still with dead cat it scored:
115 for HC (passing now)
1.95 for CO (still failing)
around 1000 still for NOX.

W/ the new Catco Cat it scored well below levels on all tests. I can't remember the exact numbers since it's been a couple weeks now, it was around:
45ish for HC,
.38 for CO,
and 82 or something around there for NOX.

The final numbers w/ the Catco cat are very close to what it ran last year when the old Catco cat was new. With that fresh cat it destroys the numbers... Like I said I've since taken it off and will swap it back on only at test time so I don't have to worry about screwing it up again. I blame the lack of a air pump hooked up to the cat and the fact that I was running a little rich for killing the cat...

The cat was a "3 way" cat, which I assume means it is supposed to tackle all 3 of the main pollutants. At least thats how I understand it.

------------------
Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray


[This message has been edited by Ray87Z (edited April 18, 2001).]

 

I had a few problems passing the two tests i've had since I put the engine in, but after it was diagnosed as a faulty vac. advance canister, I passes easily. Didn't even register on CO%, which is what I had problems passing on. I asked about the compression because I thought that the vortecs were designed either for a dished or flat top piston and 10:1 sounded high. Just wondering. I'm tempted to go with the 268 cam, but don't want to push my luck. I would be ok with prepping the heads for the extra lift, but still don't want to push it with emissions and all.

five7kid,
Thanks for the alert about the EGR. I've seen a few pictures of setups for either the vette heads or vortecs (don't remember which ones) that had the tube from the #8 exhaust tube to a passage that I believe is on all aftermarket intake manifolds. I wasn't too concerned with NOx anyways though, because I have been passing it ok with the EGR blocked off on my action+.

I can't remember what my allowables are, but the orig. engine was an '84 carb'd 2.8L. I'm guessing it is allowed to run at least as dirty as your 87 TPI. And I think you're right about the 3 way referring to the 3 gasses it's supposed to reduce.

RoadRacin85Z, I kind of like the way the tests go here in Atl. Well, none was nice, and just an idle test was almost as nice. But as long as you can pass the sniffer, the only visual check is if you have a cat or not. Oh yeah, a pressure check on the gas cap too.

Thanks for the input everybody. I like how this thread is going. Its really got me feeling a lot more confident to deviate from 'status quo'.

 

Hey, I just found my emissions record for this year. If anybody cares to look, these are the allowables for an 84 2.8 in a manual car and the actual amounts my car blew. Scratch that, those allowables are not for an 84 2.8 V6. They messed around and got it tested as a 1984 Chevy Camaro with a 5.7L V8 (and we all know how many of those came out of the factory).

allowables:
HC-ppm 137
CO-% .87
NO-ppm 956
CO+CO2% 6.0 min

actual:
HC-ppm 20
CO-% 0.00
NO-ppm 683
CO+CO2%-13.9

[This message has been edited by MikeS (edited April 19, 2001).]

 

Hmm, wonder why the allowables for a 84 5.7 would be lower than my 87 305 TPI. You sure those aren't still the allowables for the v6?

Anyway, you should still be able to pass those standards anyway w/ a set of Vortecs and a decent cam.

------------------
Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

[This message has been edited by Ray87Z (edited April 20, 2001).]