Cams, heads and emissions testing.
Thread Starter
TECH Fanatic
iTrader: (2)
Joined: Dec 2001
Posts: 1,648
Likes: 3
From: Wilmington, MA
Cams, heads and emissions testing. Hey guys,
Is there a cut-off for cams where they will no longer pass emissions?
We have dyno testing here in MA, if that helps. I am planning on going with LTs with cats. Will retain stock EGR and AIR. Stock heads for this year, but with a cam. Been looking at the 220/220 - 222/222, 112 and 114 lsa ranges. Lift - .550-.570.
Does it HAVE to be a 114lsa to pass? Or will any cams in that range (pretty much T1/B1 and hammer cams seem to be the ones I've been looking at). I'd rather NOT go with the 114lsa because the car is a daily driver (14k a year) and moving the power band up a lot does not sound appealing to me.
So, is there any magic 'line' that you cannot pass? Is it JUST the lsa, or just the i/e durations? Lift? And finally, will ported heads change my emissions at all (by themselves)? Have any of you passed emissions with cams in this range? I don't want to be borderline either. Like I said, it's a daily driver. However, it does see the strip once a week or so.
Oh, and on a kinda off-topic question, those with T1/B1 and hammer (C1?) cams, what are your shift points? Just wondering the power ranges.
Dope
Is there a cut-off for cams where they will no longer pass emissions?
We have dyno testing here in MA, if that helps. I am planning on going with LTs with cats. Will retain stock EGR and AIR. Stock heads for this year, but with a cam. Been looking at the 220/220 - 222/222, 112 and 114 lsa ranges. Lift - .550-.570.
Does it HAVE to be a 114lsa to pass? Or will any cams in that range (pretty much T1/B1 and hammer cams seem to be the ones I've been looking at). I'd rather NOT go with the 114lsa because the car is a daily driver (14k a year) and moving the power band up a lot does not sound appealing to me.
So, is there any magic 'line' that you cannot pass? Is it JUST the lsa, or just the i/e durations? Lift? And finally, will ported heads change my emissions at all (by themselves)? Have any of you passed emissions with cams in this range? I don't want to be borderline either. Like I said, it's a daily driver. However, it does see the strip once a week or so.
Oh, and on a kinda off-topic question, those with T1/B1 and hammer (C1?) cams, what are your shift points? Just wondering the power ranges.
Dope
Joined: Nov 2001
Posts: 34,651
Likes: 2,577
From: Schiller Park, ILL Member: #317
Re: Cams, heads and emissions testing. I have a B1 but it’s not in the car yet. I was told by my installer-to-be (site sponsor Speed Inc.) that cams with 114 LSA and less than 224 duration should pass the I/M240 test (which is the dyno emissions test you are referring to). Anything on a 112 will most likely not pass I/M240, according to him.
With stock heads, you could shift as high as 6400 rpm with this B1 and still be at or very near peak power from all the dyno graphs I’ve seen. Much above 6400 and the stock heads won’t breath too well, but with ported heads you could probably shift at 6600 with this cam, maybe even more. I had MTI set my shift points up, but I think they’re a little low (about 6200) and I might have them raised a little more to about 6300/6400. Remember though, the higher you spin the motor, the more stress you’re putting on the valve train AND bottom end.
Hope this helps...
With stock heads, you could shift as high as 6400 rpm with this B1 and still be at or very near peak power from all the dyno graphs I’ve seen. Much above 6400 and the stock heads won’t breath too well, but with ported heads you could probably shift at 6600 with this cam, maybe even more. I had MTI set my shift points up, but I think they’re a little low (about 6200) and I might have them raised a little more to about 6300/6400. Remember though, the higher you spin the motor, the more stress you’re putting on the valve train AND bottom end.
Hope this helps...
Re: Cams, heads and emissions testing. Based on emission results posted by members, there is no magic line. You improve your odds of passing by using a 114 LSA and staying 220 and below. That doesn't mean that a 224/224 112 won't pass, but the odds are lower, nor is there a guarantee that a 220/220 114 will pass. If look at Lingenfelter who generally makes smog legal stuff, I think you'll find that he uses a 218/218 114 and that MMS frequently recommends their 218 cam to California customers.
Bottom line is I would suggest a 220/220 114 .56X Comp. You'll be fairly emissions safe and you're not leaving that much on the table compared to a 222/222 112 cam. you can make up any loss of low end power with slightly more stall or by getting some 3.73s.
Bottom line is I would suggest a 220/220 114 .56X Comp. You'll be fairly emissions safe and you're not leaving that much on the table compared to a 222/222 112 cam. you can make up any loss of low end power with slightly more stall or by getting some 3.73s.
Thread Starter
TECH Fanatic
iTrader: (2)
Joined: Dec 2001
Posts: 1,648
Likes: 3
From: Wilmington, MA
Re: Cams, heads and emissions testing. Hmm.
Has anyone passed with the hammer cam?
Are there any tricks to use for the emissions testing? I've heard of hot-wiring the AIR pump, but I think that would only help at idle - at 3000rpm or whatever they make you do on the dyno, I think the cats would overheat.
Good info guys, appreciate the help.
Dope
Has anyone passed with the hammer cam?
Are there any tricks to use for the emissions testing? I've heard of hot-wiring the AIR pump, but I think that would only help at idle - at 3000rpm or whatever they make you do on the dyno, I think the cats would overheat.
Good info guys, appreciate the help.
Dope
TECH Senior Member
Joined: Nov 2001
Posts: 10,341
Likes: 1
Re: Cams, heads and emissions testing. I have an ARE heads and cam setup with 221/221 558 lift and 114LSA cam. I passed easily and the car ran VERY clean. Cleaner than stock. I had dual 3 inch CnL cats on the car.
Cheers,
Chris
Cheers,
Chris
Trending Topics
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: Cams, heads and emissions testing. Dope, air pump wont be needed at anything above idle anyway, so hot wiring could still be the ticket for passing. NOX is what most cars have trouble passing, and if your compression is stock and you have a cam, yours should be fine. CO is never a problem with a cam, because they dont run rich at idle, the fumes are missfires HC, you can fix this somewhat with raising idle speed(just dont set ses light)
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Teching In
Joined: Nov 2001
Posts: 20
Likes: 0
From: HOUSTON
Re: Cams, heads and emissions testing. I've got the hammer cam with stage two MTI heads with FLP's & cats, passed emissions with flying colors. also don't have EGR or air pump assembly. The trick with an A4 car is to test with the car in drive for the low load portion of the test. The car was inthe 600 to 650 range in park, but stick it in drive & it went down to 11!!!!!! Allowable limit here is 220. In the high load portion of the test(between 2300-2800 rpm) the car put out 1 hydrocarbon. Hope this helps. <img src="gr_stretch.gif" border="0">
TECH Enthusiast
Joined: Nov 2001
Posts: 652
Likes: 0
From: Newport Coast, Ca
Re: Cams, heads and emissions testing. [quote]Originally posted by Memphis Raines:
<strong>I've got the hammer cam with stage two MTI heads with FLP's & cats, passed emissions with flying colors. also don't have EGR or air pump assembly. The trick with an A4 car is to test with the car in drive for the low load portion of the test. The car was inthe 600 to 650 range in park, but stick it in drive & it went down to 11!!!!!! Allowable limit here is 220. In the high load portion of the test(between 2300-2800 rpm) the car put out 1 hydrocarbon. Hope this helps. <img src="gr_stretch.gif" border="0"> </strong><hr></blockquote>
Are u saying that Houston Allows you guys 220 hydrocarbons?
<strong>I've got the hammer cam with stage two MTI heads with FLP's & cats, passed emissions with flying colors. also don't have EGR or air pump assembly. The trick with an A4 car is to test with the car in drive for the low load portion of the test. The car was inthe 600 to 650 range in park, but stick it in drive & it went down to 11!!!!!! Allowable limit here is 220. In the high load portion of the test(between 2300-2800 rpm) the car put out 1 hydrocarbon. Hope this helps. <img src="gr_stretch.gif" border="0"> </strong><hr></blockquote>
Are u saying that Houston Allows you guys 220 hydrocarbons?
TECH Apprentice
Joined: Jan 2002
Posts: 356
Likes: 0
From: Texas
Re: Cams, heads and emissions testing. My MTI Stage II heads/B1 cam/LS6 intake set up passed the IM240 test in Maricopa County, Arizona very clean. Actually, it passed so clean that I truely believe the "Hammer, or C1" cam and the T1 cam could both pass the test as long as the programming is good. My idle was raised to 900rpm on it and the idle test was actually a tad higher than my stock emissions, but the drive portion was lower than stock. I will try to dig up my actual test results and post them.
The exhaust side of the set up consisted of MAC headers with the 3" collector mod, customer 3" y-pipe with CarSound 3" in/out high flow cats. I had just installed new O2s, as the shop that did my 3" y-pipe must have damaged the O2s when they did the work. The car was running rich on return to me.
Todd
The exhaust side of the set up consisted of MAC headers with the 3" collector mod, customer 3" y-pipe with CarSound 3" in/out high flow cats. I had just installed new O2s, as the shop that did my 3" y-pipe must have damaged the O2s when they did the work. The car was running rich on return to me.
Todd
Teching In
Joined: Nov 2001
Posts: 20
Likes: 0
From: HOUSTON
Re: Cams, heads and emissions testing. Here in Houston the allowable limit is 220. I don't know if that is ppm or just some number that they throw out there. I'll look at my paperwork when I get home, maybe it's got some info concerning the #. <img src="gr_stretch.gif" border="0">
