LSXnorcal

I am taking off my longtubes and going back to a stock exhaust and cats for stupid CA smog purposes. My friend is a mechanic and works with a tuner in town, that have his buddies passing the sniffer with both a G5X3(114lSA) and also an MS3 believe it or not, with stock cats. I currently have a 224 cam, but wonder if I could go bigger to recapture some of the hp I'm going to lose when I take off the longtubes. Most say the 224 cam on a 114 LSA, or -3 to -4 degree overlap, is about the biggest to safely pass. Now my question is, is this criteria(-3 to -4 overlap) based on a car with longtubes and high flow cats? Because it seems that cams with much more overlap are passing, with stock cats.

BruceBufferTA

iTrader: (1)

TSP 224R on a 116lsa

Sales2@Texas-speed

iTrader: (5)

^^We have had many of our CA customers report back the 224R 114LSA (-4º overlap) passed the sniffer test over there!

LSXnorcal

Thanks for the responses guys, but thats not really my question. I already have a 224 cam on a 114 and have passed the sniffer twice with longtubes and high flow cats. My question is...was the idea that a cam should pass smog in the -3 to -4 degree overlap range, based on cars with longtubes and high flow cats? Based on my findings in my post up top, I have to believe this might be the case. Otherwise, I don't know why guys are passing with G5X3's and MS3's with stock cats. If indeed the -3 to -4 degree criteria was developed with longtubes and cats, and much bigger cams will indeed pass on a car with stock cats...then I'd like to go much bigger than a 224 on a 114.

Sales2@Texas-speed

iTrader: (5)

Good question! I've never heard of anybody passing the CA sniffer tests, legitimately anyway, with those large camshafts even on stock manifolds and cats. Maybe some more CA residents can chime in to help! We're blessed out here in West Texas not to have to deal with any of that headache

LSXnorcal

I'm very jealous you guys don't have to deal with any of this CARB junk! Maybe I should post this in the CA regional section as well..

FRiCK

iTrader: (7)

I thought *8 of overlap was the max for passing emissions. Although I've personally seen a 04 Z06 with kooks and cats with a comp 228 on a 111 pass with ease.

Ide say go with a 228-230 cam and play with the LSA to get the overlap down. I'm a newb when it comes to cams tho, don't take my advice at all lol, seriously..... My cam specs in sig...

Sales2@Texas-speed

iTrader: (5)

https://ls1tech.com/forums/western-m...performed.html

That thread has some great info (Post#4 to be exact)!

Sales2@Texas-speed

iTrader: (5)

It is most often agreed on that approximately -4º of overlap is the limit.

LSXnorcal

I agree, as my car with a 224(114lsa) passed with the max level for HC's. The question is whether or not stock cats help out enough to revise the max suggested amount of overlap for passing a sniffer test. And how are guys with much more overlap passing smog, when my 224 cam passes just barely with the max level? Are they using additives in their tank, etc.? Is there some sort of trickerie involved?

My car is due for smog in 2 months and I'm going back to stock manifolds and cats, so this should be a good test to see how much of a difference a stock exhaust/cats makes.

FRiCK

iTrader: (7)

Again I'm no expert, but in the link provided above it appears he added alcohol to his fuel for the smog. Maybe in efforts to cool the combustion down and cut down the HC's????

SNLPerformance

iTrader: (15)

I thought you could get away with anything that is negative overlap @.050", but again I don't live there. IMO the bigger cam make not really make anymore power as, it'll have more overlap and a later IVC bleeding off lowend and the top end will be choked as it'll be a less efficient burn because of the more restrictive exhaust. If anything, I would change the cam to a wider lsa and more exhaust bias. my2cents, Chris

GTOworshiper9

iTrader: (5)

Biggest I've seen pass was 228/230 on a 114 with just under .600 lift on both sides with LTs and high-flow cats

LSXnorcal

That makes sense..going too much bigger might be a case of diminishing returns. I might be best off with something like the cheaTR cam. I wonder if some of the bigger cams are being tested in an area that does not do the smog "enhanced" protocol, or if they are just using alcohol or another means to pass?

99 Blue Bird

iTrader: (3)

OP what year is your car?

LSXnorcal

It's a 98 why?

ebk06

iTrader: (5)

So is a 228r 112 fine for passing a sniffer test?

LSXnorcal

Based on the -3 to -4 degree overlap rule, it shouldn't pass. Your cam has +4 degrees overlap. Maybe with some smog tricks though?? Thats basically the question in this thread. Since guys with much more overlap than -3 to -4 are passing, how are they doing it? How much will a stock exhaust/cats clean up the sniffer reading?

ebk06

iTrader: (5)

Well i guess im screwed. Although Ill have magnaflow cats (not high flow) not sure if that will help at all? So yea any tips or tricks on passing would be helpful.

LSXnorcal

Do they even have smog in Texas where you're at? If they do, isn't it just to check for check engine lights, etc.?