bad2000ss

iTrader: (6)

I plan on a camshaft install in the near future and unfortunately I must abide by california emissions. What about a camstaft basically makes it not pass? Too low a lobe separation, too high a duration, too high a lift? I would like to design this cam with the intension of using nitrous so it will probably have a lobe separation over 114. The motor will also be dyno tuned after the install. Would an MTI X1 not pass emissions if anyone has any experience with that particular cam? Thanks very much in advance.

jrp

iTrader: (16)

lots of duration and a low lsa. my cam wont pass in cali. if you dont want to cam swap a TR224 114 has passed smog here clean by several memebers. the 112 with a good tune should pass also.

the X1 wont pass, im pretty sure of that unless you can pull some kinda tuning miracle out of your ***. the C1-C1 will pass with a decent tune.

basically you want to stay in the 224 range 114 for guaranteed passing. the 112 should pass on tune. anything else prepare to swap out come smog time.

i myself might swap in a 224 on the 112 when it comes time for me to go up for emmissions. then just leave it in.

bad2000ss

iTrader: (6)

Could the high duration of the cam be compensated by an increased lobe separation?

jrp

iTrader: (16)

i believe so, dont quote me on it though. i've seen some MMS grinds with high duration and like a 113-115 lsa and im pretty sure they passed smog.

honestly, if i were you i'd just get a 224 114 or similar and call it a day. on stock heads with bolts they make great power and with heads even more power.

its prove to pass emissions and make the power, cant ask for anything more.

Crazyquik

Overlap is what makes a cam fail, as this introduces more volatile organic compounds and NOx to the exhaust.

Shorter duration or higher LSAs both decrease overlap.

Revelation222

What about a cam that has a larger intake duration than exaust duration such as a 228/224 114lsa or a 224/220 114lsa? Since the exaust duration is low does that mean it can still pass smog?

robertbartsch

I just failed NY state inspection; a sniffer test.

My car has a cam similar to the C1; 220/220, 564/564, 112 LSA. Car also has ported heads and a CR of 11.2 to 1 and LT headers with cats.

My hydrocarbons are 73 and the limit is 60!

I will tune the car with LS1Edit and hope it passes....


a bunch of dry gas in the tank helps...see the tuning section of this forum for more advice on passing emissions...

KF2KZ

Ouch...failed the NY test on a 220?!? I have the TR220 ground on a 113, 10.8 CR, LT w/cats, tuned, and I notice it far more smellier than the stocker was. So the above post does not give me comfort....

Cal

iTrader: (1)

As was said above, valve overlap between the intake and exhaust causes big cams to fail smog. And that overlap is a result of intake duration, exhaust duration, and lobe separation angle. Keep in mind though that LSA is measured in camshaft angle, while duration is measured crankshaft angle. This means increasing the LSA 2 degrees would be more effective than decreasing the duration 2 degrees. The disadvantage of the wider LSAs is the engine will have to spin at a higher rpm to reach peak power. Since increasing duration also requires the engine to spin higher to peak, most big cams must use the smaller LSAs or they would not be useable.

To make a long story short, just put in no bigger than a 224 114 as was stated above.

Pro Stock John

iTrader: (34)

I think robert's car should pass with a basic tune.

224//112 cams pass all the time.

My old 222/224/113 passed in WI.

J-Rod

Read the long camshaft thread...

93Pony is grinding cams for guys in Northern California and they are passing emissions. Overlap is what makes a car fail emissions. You need negative overlap to pass emissions. But overlap is also what makes power. So its a matter of finding the maximum ammount of overlap while not creating too much fugitive emissions...