Biggest cam to meet ULEV Emissions on an LS1

[Vettezuki]

My swap is considered a 2001 F-Body. I run a 224/224 114LSA .566 lift cam and with my stock manifolds and cats pass emissions with flying colors. My heads supposedly flow 305cfm. I'm wondering how big I could go before running into trouble. Also, on a higher compression NA motor, what's the theory for in/out duration?

I don't want a HUGE cam that lopes hard (which wouldn't pass anyway), but I could certainly tolerate something slightly more aggressive. I guess the best question is what are the gnarliest street legal cams in 01 F-Bodys.

[SeanPlunk]

My swap is considered a 2001 F-Body. I run a 224/224 114LSA .566 lift cam and with my stock manifolds and cats pass emissions with flying colors. My heads supposedly flow 305cfm. I'm wondering how big I could go before running into trouble. Also, on a higher compression NA motor, what's the theory for in/out duration?

I don't want a HUGE cam that lopes hard (which wouldn't pass anyway), but I could certainly tolerate something slightly more aggressive. I guess the best question is what are the gnarliest street legal cams in 01 F-Bodys.

I think that's about as big as you can go. I know a 112 LSA cam won't pass here. Not sure about everything else though.

[BRUTAL64]

My swap is considered a 2001 F-Body. I run a 224/224 114LSA .566 lift cam and with my stock manifolds and cats pass emissions with flying colors. My heads supposedly flow 305cfm. I'm wondering how big I could go before running into trouble. Also, on a higher compression NA motor, what's the theory for in/out duration?

I don't want a HUGE cam that lopes hard (which wouldn't pass anyway), but I could certainly tolerate something slightly more aggressive. I guess the best question is what are the gnarliest street legal cams in 01 F-Bodys.


That is a tough one. it takes about ten degress more duration to get a drop in compression. Closing up the LSA will also bleed off some compression, but pass smog-- that is a tough one.:huh:

Just for info--- My cam has 254 degrees at .050 ---flat tappet solid lifter.

[94cobra69ss396]

I think that's about as big as you can go. I know a 112 LSA cam won't pass here. Not sure about everything else though.

I'm running a 110 LSA cam in the Cobra and it passes with ease.

[Vettezuki]

I'm running a 110 LSA cam in the Cobra and it passes with ease.

Your passing as a 94 Cobra though right? I'm passing as a 2001 ULEV (might be SULEV). Do you have your smog cert? What are your numbers, I'll post mine later.

[SeanPlunk]

I'm running a 110 LSA cam in the Cobra and it passes with ease.

Seriously? I remember on LS1 back when I had a Camaro that basically a 114 was the most you could pass in California :huh:

[SeanPlunk]

Here is a thread about it on tech. (http://www.ls1tech.com/forums/generation-iii-internal-engine/187437-112-lsa-cam-cali.html)

Here is a quote:
"A 112 LSA is almost guaranteed not to pass the sniffer in California; haven't seen one person do it even with tuning, a 224/224 114 Cam is biggest cam I've ever seen pass the sinffer here in Cali."

Some guys do claim on the 2nd page to have passed with a 112 though.

[94cobra69ss396]

Your passing as a 94 Cobra though right? I'm passing as a 2001 ULEV (might be SULEV). Do you have your smog cert? What are your numbers, I'll post mine later.

Yes the Cobra passed as a 94 Cobra so I'm sure my limits are higher than yours. I don't have my smog cert but if you have yours post it and I'll have Throttle Crazy take a look at it. He'll be able to tell you how close you are with your cam.

Here are the specs on the cam I have in the Cobra.

Product Line: Crane CompuCam Camshafts
Part Number: CRN-444231
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 2,400-6,000
Duration at 050 inch Lift: 220 int./220 exh.
Valve Lift with Factory Rocker Arm Ratio: 0.498 int./0.498 exh. lift
Lobe Separation (degrees): 110
Computer Controlled Compatible: Yes
Grind Number: 2040
CARB EO Number: D-225-46

[Vettezuki]

Well you can see here I'm well above the average with my setup, but still quite a bit of headroom it seems.

Hydro Carbons
MPH Max Ave Meas
15 52 4 33
25 36 4 25

CO%
MPH Max Ave Meas
15 .49 .01 .31
25 .46 .01 .28

NOX
MPH Max Ave Meas
15 424 16 112
25 711 18 114

[BRUTAL64]

Here is a thread about it on tech. (http://www.ls1tech.com/forums/generation-iii-internal-engine/187437-112-lsa-cam-cali.html)

Here is a quote:
"A 112 LSA is almost guaranteed not to pass the sniffer in California; haven't seen one person do it even with tuning, a 224/224 114 Cam is biggest cam I've ever seen pass the sinffer here in Cali."

Some guys do claim on the 2nd page to have passed with a 112 though.


We had some serious LS1 guys working here a few years ago. They told me the same thing- 224/224 114 Cam is biggest cam to pass Calif. smog. Then one got fired and the other quit.:drink:

[enkeivette]

Lars Grimsrud claims that ANY car can be tuned to pass smog. I'm sure that is with the exception of cars burning oil and/ or coolant. But any... car that's running right? Bold claim, but I'd never be one to object to something that he said.

[Vettezuki]

Lars Grimsrud claims that ANY car can be tuned to pass smog. . . .


Yeah, that doesn't make any sense to me at all.

[big2bird]

The main trick is to lean it up and retard the timing.:D

[geeeezer]

A too lean mix will blow the HC reading off the scale and ultimately kill the catalytic converter .

G

[Vettezuki]

A too lean mix will blow the HC reading off the scale and ultimately kill the catalytic converter .

G

I thought it was the other way. Lean means hotter, more NOX less HC. Rich means cooler, less NOX more HC. In other words you can't really go too far either way before getting bounced by the sniffer I suspect.

[geeeezer]

You are quite right about the nox , but a lean mix will result in a lean misfire and swing the hc reading up and drop the co's . Enrichening the circuit will bring them down but also will cause a co rise . In the end it is a balancing act and varies from engine to engine . The egr sys is utilized to drop egt and lower nox .

G

[Vettezuki]

Thanks for the xtra info. I know lean misfires can fry O2 sensors very quickly. My LS engine is setup as a 2001 Camaro, which I believe is the first year there were no EGR.