schpenxel

Looks like I'm pulling the torque tube again soon, SO, I think I'm going to just gut the stock cats when I have them off. I'll get some headers from TSP when they're back in stock.

Note to self: If you find that your torque tube input shaft is worn at the tip due to a pilot bearing locking up, don't reinstall it. I have a shuddering issue now that I think is from that.. I thought it was just the clutch needing to be broken in but I'm not so sure now. It has 700 miles on it and hadn't changed at all.

schpenxel

haha.. here's my dog.. english bulldog. Total fatass (girlfriend put the collar on her..I swear)

Streetk14

It's not a black and white situation. Like I've said, I don't recommend anyone run stock LS2 or LS3 cats with FI. Like I've also mentioned, 700 whp or so is the point where typical high-flow cats just aren't likely to survive too long. I'm not too shocked yours had issues.

There are high-flow cats that will hold up to big power for extended periods, but they aren't cheap. If you've ever had to buy a high quality OEM cat, you'd know they are expensive. Usually $500+ a pop. Companies like HJS Motorsport or GESI are used on cars like the AMS Alpha GTRs (http://www.amsperformance.com/cart/a...d-midpipe.html) and are meant to handle big power. The catch is they are expensive @ $450-$800 a piece. The typical $100 high-flows that come with most header systems aren't quite the same.

I destroyed a set of LG metal matrix cats @ 10 psi, but couldn't kill a set of earlier production ZR1 cats at 12 psi on the same car. I have no reservations about recommending something like the factory ZR1 cats (especially the 2012+ version) on an FI build making ~600 whp. At that level, you aren't far from what GM intended the cats to put up with. I don't believe Schpenxel is looking to make much more than that, but I could be wrong.

Streetk14

Looks pretty mean with that collar

realcanuk

I am not doubting any of this. I just don't think many of us want to spend 1000 bucks on cats unless we really have to.

schpenxel

You are correct.. I will be happy with 600rwhp. Or at least, content.. I'm trying to play it reasonably safe on the stock bottom end until I win the lottery I went ahead and order an alky control kit from Brett, so that should help with the safety side of things at least. Perhaps not so much on the cats longevity side, though.

I may get bored at some point and throw in some decent pistons/rods and turn it up a bit. I just know I'm horrible about going overboard once I have something apart.. so I'm trying to leave it where it's at for a while

Then there's the stock '05 rear end that should explode at the first sign of wheel hop

I'll take a look at the ZR1 cats.. although I'll probably just gut the stock ones at this point. I wish TSP had their headers in stock, but they're a month out, so it is what it is for the time being

m_LeDez

I ran the Kooks off-road pipe for awhile, but just couldn't deal with the odor so figured I'd try this option instead.
Kooks told me, "Unlike the original cats their new "Green" cats are rated for up to 12 lbs. boost"....guess were going to find out.

GeneSch

Is there any negative power or drive ability issues with removing the cat material from the stock pipe and leaving the chamber in the pipe or the bubble in the pipe? Will this cause any issues with flow or turbulation in the exhaust that may cause issues?

SPIN20

If you are looking to unload that off road pipe let me know!

Streetk14

That is probably true. I might be crazy enough to do it, but haven't had the need yet. I nabbed my lightly used ZR1 parts for cheap though.

I'd say gut the stock cats and see how you like it. They aren't worth anything, so nothing to lose there. If the smell doesn't bother you at all for daily driving, then just go catless when you buy headers. I don't like headers that use a ton of slip-fit connections though. Been down that road before with a set of LGs.

If you decide you like having an OEM style cat on the car better, then keep an eye out for a set of Z06/ZR1 manifolds and cats. While not the same part number (cats only), the Z06 parts look identical and are much more common. I know guys running the Z06 cats on high 600 whp cars here in CA, and they've been holding up too. Can't tell you what's different between the two, just that the ZR1 cats retail for more $$$ and have a different part number. All can be had for cheap used though.

schpenxel

I was just checking out the Z06 style cats and noticed that the connection to the header was different than mine.. so I would need the manifold too (which you stated and I originally missed)

I bet some of the Corvette speed shops have these just about laying around due to all the header installs that they probably do. That might be a better bet than something like eBay

I guess the slip fit ones tend to leak?

Also.. at least gutting the stock ones will give me an idea how bad the gas smell is or isn't.. if it's just all out intolerable then I'll have to see if I can make sense of the cost for some of the other options.

Will the car be a bit louder without cats or about the same?

mfoti

So what about a car that is NEVER raced? The base Eforce on an LS2 puts out less than 500 rwhp. Would i cook high flow cats with a random zero to 90 run with a setup producing such little power?

Streetk14

Yeah, that's why I suggested gutting your LS2 cats for now. See how you like not having them. Then you can really decide what you'll be happy with in the long run. If you go with headers, I'd spring for a quality brand like ARH, but again that's just my personal opinion after dealing with a few different brands.

Feel free to PM me if you have any questions about what factory C6 exhaust parts work together, the differences, etc. Don't really want to clog up this thread with all that. But you would basically need a whole 3" Z06 or ZR1 system to make it all work. Manifolds, cats, mid/X-pipe, and mufflers. All can be had for cheap, and I'd agree that a shop that does a lot of C6 header installs would probably be a good place to look. I see them on the forum all the time too.

Oh, and to answer your other questions: I just haven't had great luck with aftermarket slip-joints. Not only do they usually leak, but they can be damn near impossible to take apart after a few thousand miles. That's probably what I hate about them the most. I was so fed up with dealing with my LGs that I ripped them off for those ZR1 parts. Eventually went back to headers on that car when Pfadt released their headers. The V-band flanges and 1-piece X-pipe were very nice features. No leaks and easy disassembly if needed.

And with all else being equal, cats quiet the exhaust down and seem to mellow the tone out a little. When I gutted the cats with my LG/B&B Fusion setup, it got significantly louder, and the drone more noticeable. So yeah, definitely louder without the cats.

Streetk14

Probably not an issue the way you use the car, but it's still something to keep in mind as a possible failure point. I can't comment much on the factory LS2/3 cats, as that's the first thing to go on any build I do.

saplumr

I originally had the offroad when my blower was installed. I put up with the stench far to long. I'll replace my cats periodically before I ever do that again!

schpenxel

I'm curious about the tuning everyone is using too. Open loop or closed loop?

realcanuk

Mine is maf only, closed loop and the smell can be greatly reduced with tuning. To the point where I don't feel its a problem, but then again, that is a matter of preference.

schpenxel

That's what I was thinking.. I know some run open loop, which seems like it would be just asking for gas smells unless you ran it lean all the time. I'm running MAF only / closed loop right now too and it's working well. Still dialing in injector data but I'm close

I guess on the other side of the proverbial coin, when in closed loop it's constantly going a little rich then a little lean.. so I guess it's possible that small amount of rich'ness may be enough to cause some smells. I still think that would be better than running rich all the time though.

I just need to gut my cats and be done with it I think.. I'll figure out the rest from there

realcanuk

Dialing in injector data ? Lost me. Just use good data for those injectors, and never touch it again. Unless you have injectors and no data for them.

schpenxel

eh, it's some knock off 60#'rs. I've tried every set of data that is out there for them and it's just not right. A friend of mine has developed a system that takes fuel trims / maf curve / inj data and spits out a new maf curve / inj data that takes into account the errors seen in whatever log you take of the previous tune.

It's taking some time, but I think I will have very accurate data when it's all said and done. I'll post it up after I get it completed.

I was having all kinds of problems where at one Injector PW or MAP it'd be rich, then another it'd be lean, both at the same spot on the MAF curve.. so my choices were either to switch to SD and just make it work out right on average or try to actually fix the injector data to match reality so that I could run MAF only and it be right everywhere.. Or I guess I could have just let the fuel trims deal with it, but I'd rather it be as right as possible to begin with.

Or I could have bought a set of ID's and been done with it, but where's the fun in that