Biggest Smog Cam for LS1~
 

This is related to bringing my LS C3 Corvette back online, however, because it is a very specific cam question, I will ask it in dedicated thread.

QUESTION
What IS the largest I can go before I can't pass the sniffer?

ASSUMPTION
Declared as 2001 F Body
346ci and 11:1~ comp if it matters

TARGET
Street performance and passing sniffer.

HISTORY
Mine was advertised as 224/224 114 LSAm .566 lift. My understanding is that this was a common "smog" cam, the biggest you could go before busting the sniffer. I have stock manifolds and OE cats. Despite the cam, heads, LS6 intake, and larger TB I always passed the sniffer by a fair margin. Depending on how things go, I plan to get custom headers including hi-flow cats.

I'd say you are the limit with an off the shelf cam. The Comp cam I put in the 347 in the Cobra is 212/218 @ .050 on a 114 LSA with a .544 lift and with a brand new 4 cat X-pipe I just passed. I think your only option for more performance from the cam is to get a custom grind.

"Big" is relative, you can have a ton of lift with relatively small duration that will make better better power in a street car. Less overlap, more vacuum, no overlap, tons of vacuum.

If you didnt want to spend the money on a custom grind from FTI. I would pick something in the .6XX lift range with around 220 duration depending on the rocker arm ratio. That wiuld make for an extremely snappy street car and power would come on insanely fast. It wont spin to 7500, but it will get to 6500 in a flash

Cool. I'll take it up with Troy. Something that puts around nice, passes smog, and jumps to 6k~ for peak power of around 430whp when all is said and done is about where I want to be. In a 3,000lbs car with everything else set up good n' proper is going to be plenty fast to be fun, more than I could really use other than romps onto the freeway, the occasional open road, etc.. At some point it becomes pretty pointless in a streetcar. Nothing wrong with that, just I'm not interested in having a mountain of power I won't ever really use.

The cost of a custom grind is around ~$75 more than a shelf cam, the difference is, even if the specs are the same, the lobe designs are proprietary to each grinder and they make a significant difference in ramp rates and what not. Justin and I use FTI and the cam i'm running now was spec'ed using help from FTI. He'll probably cut you a deal on a cam package if you're buying lifters from him anyhow.

I was just going to ask, how much for a custom cam anyhow? $75 over off the shelf is trivial if it makes much of a difference in performance behavior. I don't want a cam that is only really performing around peak RPM, but my understanding is that is more of an overlap issue than anything. I want a smooth "street performance" cam that works well cruising or WOT and passes smog. Given those requirements if a custom grind can improve over an off the shelf and it's <$100 difference great, if it is $100 for nothing noticeable really, then forget it. I have literally no idea.

The difference is mostly, in what i've seen for most custom grinds, not just FTI is massively different torque, and torque curves. HP is also higher but the torque is what is noticeably different, at least for me.

http://www.flowtechinduction.com/fti...ller-camshaft/
Just the cam
Or Choose whatever kit you want for whatever long block you choose.
http://www.flowtechinduction.com/fti...shaft-package/
Add in some Morel Lifters and you have a bad ass valvetrain, where the money really needs to be spent anyhow, that will fuckin move. Just tell Ed your intentions, weight, etc and he'll make it happen.

OTOH, if a custom grind more or less dictates a tune, I'm not ready for that. I'd want to get my exhaust done, and that's gon' be a couple g. Mmm.

Necessary? No. Beneficial? Absolutely.

I suppose the difference between a custom smoggable street cam and an off the shelf smoggable street cam is not going to be so large as to be dangerous around lean-out conditions where shit melts. The computer can adjust trim based on O2 to some degree. But it already doesn't warm start idle for shit, don't need that to take a dump any further. I'll look into it further once I know the condition of the block and heads.

Then you could bump the fuel pressure up as a bandaid if needed, but i'd say the half assing it ship has sailed. Either go with a straight up stock replacement, and hock it. Or do it all the way and keep it.

It's tuned for, and ran fine on the cam I had other than crappy warm start idle, a common H&C problem from the olden times on the LS1. A stock cam wouldn't run very well, but one with specs close to what I had *should*. . .

But the cam that came out of it had no common manufacturer markings or numbers we could look up. A little bit of a mystery. It will have to be analyzed to confirm what the hell it actually was.

Then I'd say anything in an advertised range, regardless of lobe design will run just fine. However I would not run it for long without a tune. Figure even if you do have it tuned without having the exhaust done, its such a minute change that the computer should accommodate for it. Not ideal, but its better than nothing. If there was any time to have Jamie do the job, it would be now, whole hell of alot of time would be saved since everything is already out. I don't believe he has the ability to do side work at DT any more but I'm sure it could be done here at the shop. Do you have his contact info?

You mean bench tune? The ECU is just in the back by the battery, I can get that any time. I may not be following you here.

What I'm saying is, if you have a cam that is now 224 now and go above or below 4-5* the ECU should accommodate enough for changes. We're not talking drastic changes, but it should be tuned. For the $300-400 it costs, it's a safe thing to do.

While the engine is out, and the manifolds, blah blah. Now would be time for Jamie to work his pipe magic and do the exhaust.

Oh, do the exhaust while the engine is out. Well. the block is at the shop. Sorry to be dense here but I figr'd he'd want the car with the engine in it to see the clearances with suspension, etc. I remember investigating this years ago and the reason custom is basically just required is that, AIR, is that the exits from #1/2 are very narrow to the control arms.

Well yes, he needs it in the car, but, his major bitch with vettes, and lsx cars in general is the amount of time it takes to remove everything like the coil packs, manifolds, etc

So the engine should be in and mounted but that's it. Would make the whole process alot quicker, which I'm sure means cheaper, but I can't say for certain. Do you have his number?

PM or text with his info. I'd just take the car to him complete and pay for the work to be done, including mod of the cross member as mind is a little Mad Max at present.