dont know much about cams, except that they produce power.

[ADRENLN]

ok guys i know that cams are producing good power gains to the wheels on the 99 and up gt. the average power is about 25 hp, correct?

anyway my question is how do cams effect emissions? are there some cams that do not effect emissions? i want to build my car so that i will have abosolutly no emissions problems, even if it will cost me a couple of hp.

i thought that maybe that the stage of the cams, or the mildness of them is what effects the emissions, can somone explain please.

 

[johnnyvista]

yes. your cams affect the emissions of your vehicle. there are other guys that can better explain what happens with lift and duration and how it changes hp and emissions.

i went with a compcams stage1 cam and the rep from comp promised me that the stage1 will pass the emissions laws here in CA and should make about 20 extra HP at the wheels. i can't confirm the HP increase because i did a bunch of other mods at the same time.

 

[bdcardinal]

when the duration increases the valves are open longer and generally there is valve overlap. valve overlap is that period in time when the exhaust valve is closing while the intake cam is opening, so there is some air/fuel that goes straight out the exhaust and not getting burnt in the combustion chamber. this increases the HC output on the gas analyzer.

 

[Grady96GT]

Nice..bdcardinal

 

[bdcardinal]

that overlap also contributes to the nice idle you get with cams. the mroe overlap the more grumbily idle. but the more overlap the higher the rpm range moves to.

 

[stallion98gt]

bdcardinal is our expert smog

j/k

 

[bdcardinal]

i accept checks, money orders and major credit cards. i also accept "special payoffs" of you are female haha just kidding. glad i can be here to help everyone out.

 

[bdcardinal]

o something i forgot to add is that you can use any cam you want because there is on way to do a visual. the problem is that the tailpipe readings will be higher so you will have to get a smog tune that will try to lower the numbers a bit.

 

[ADRENLN]

bd are you saying that it would be difficult to pass emissions with any kind of cam?

 

[bdcardinal]

no, just the higher stage cams. like usually a stage 1 cam, with a little more lift and duration but not as much overlap will be fine. but when you start to use like stage 2 or 3 or blower type cams with lots od overlap is when you get issues with the higher HC outputs.

 

[stallion98gt]

bdcardinal: i'm in cali and plan on dropping a forged engine with stage 2 heads and stage 1 cams. engine might be a stroker too, am I in good shape for smog ? thanks

 

[ADRENLN]

stallion, that was my plan also, stage 2 heads, build engine and some cams.

however i think it is going to be two risky for emissions, i will just do the built engine stage two heads, and a blower instead.

i would skip the cams if i were u.

p.s. blowers will no effect emissinos will it?

 

[bdcardinal]

well you will pass visual because they cant take apart the motor to verify internal components. do you plan on supercharging, if so what blower are you gonna use? i think the main issue will be the tailpipe emissions. also being in LA i believe you have to smog on a dyno. if you give me a list ill ask the guy i go to with questions(smog referee) and see what he says.

 

[stallion98gt]

yes I plan on supercharging, most likley a KB which has a CARB #. I might have to skip on the cams then ? was thinking of stage 1 blower cams...
if i switch to stock hpipe before the smog will it attenuate the #s a little bit ?

 

[bdcardinal]

i was wondering that about the stock h. i just went to a dyno with my buddy and he has a 04 mystichrome with a KB, he put down 531hp 492tq on 91, but his A/F ratio was around 11.4:1. i think that would be the major problem because its a little rich. something you can do maybe is get a seperate smog tune when you go to the dyno.

on a side note, who do you plan on going to for the install? my buddy went to Earls Performance for the install on his cobra, awesome shop and the owner is really cool.

 

[stallion98gt]

i was wondering that about the stock h. i just went to a dyno with my buddy and he has a 04 mystichrome with a KB, he put down 531hp 492tq on 91, but his A/F ratio was around 11.4:1. i think that would be the major problem because its a little rich. something you can do maybe is get a seperate smog tune when you go to the dyno.

on a side note, who do you plan on going to for the install? my buddy went to Earls Performance for the install on his cobra, awesome shop and the owner is really cool.

dunno yet, was thinking of Chicane. I always had good experiences with Joe.

 

[StangLou]

I posted a thread similar to this talk many months ago. I was curious if a tune on an NA car with say a 13.5-14+ a/f would put out a "cleaner" smog reading than a car with around a 11.5-12.5. Only a few people commented and most were just like hey this is a valid question, any answers.
I dont see why there would be a problem passing emissions with a car as long as your a/f tune is around 13+ on an NA car. Anything thats s/c I would be scared to have anything above a 12.0-12.5. After my tb/plenum combo my a/f dropped from a 14.5 to an 11.3/11.5. 2 burns later I was sitting at 13.5, but I think there is still more room to improve my a/f. I am going to see how I do emissions wise this year with the L/T's before I decide if Im going to add a cam to the '03. Id love to due to the power gains and sound, but I have to pass emissions since its my daily driver. Sorry, not trying to hijack the thread, Im just really interested in this conversation

 

[ADRENLN]

stanglou, whats up. your saying that the t/b plenum made u run a little rich?

ok so how do i pass emissions with a supercharger, if the air fuel has to be so high to pass?

i need the blower that was going to be my final huge power mod, that is what all of this was leading up to. i cant do without it my car will be to slow why! why!

 

[bdcardinal]

when you get it dyno tuned jsut tell them to make a seperate program for economy/smog. they should be able to make a safe tune based on your states smog check system that will allow you to pass.

 

[ADRENLN]

thats cool, what about the blown cobras, saleens, and roushs? how do they pass emissions specifically the roush 3. it was a gt once. whatever they do to them i want to do to mine to make sure it passes.

is it that they are set at a lower psi, or does psi not play a role in emissions?

if i got a flip chip, what do you do just flip a switch or somthing before smog test? that wouldnt damage the blower would it?