tinman12

Looking to add a set of headers and x pipe as my first mod to LS3. Been searching for the pros vs cons of no cats on the X pipe. Really not much straight foward info so just asking the question hoping some have done both or maybe some of the tuners can comment on HP gains if any. I am not in state that requires exhaust testing.

Will adding a CAI really add any true HP gains? My plans is 1 7/8 headers, no cats, x pipe and using one of the forum vendors to mail order a ECM / PCM tune for now. I think most of this is pretty standard and should be you very close to what a tuner could get you. I plan a supercharger and cam around spring and will then get a full tune and dyno.

car is a 2011 GS A6 NPP exhaust

Thanks

deadsexyii

I did extensive research before buying headers. The general consensus I could determine is that if you're going FI then go 1 7/8. I you're staying N/A then go 1 3/4. In terms of which brand/make, I couldn't find any brand that had a huge advantage over another. I chose Kooks, but AR, LG all make quality products. Honestly I really wanted PFADT but they went out of business before I ordered. I put the K&N "CAI" on it and it's the worst 250 I've ever spent. I wouldn't waste the $. Put that $ towards porting the TB.

psp6158

"Most" guys that have gone without cats have complained of a gas smell in their car and of course it may be illegal in your state not to have them. From the consensus I got, I went with hi flow cats as the performance gained was not worth the possibilities of fuel smell and we have emissions testing in Pa.

mysloride

Tinman,

I just bought the Kooks 1-3/4 headers with the Hi-Flow Catted X pipe with the Halltech CIA and will get it installed and dyno tuned in the next couple of weeks.

Gearheads is doing the installation and tune. They are going to do a before and after install dyno pull so that I can tell what my $$$ really bought me.

I will keep you posted on the results

77vette05

I would go 1 7/8 if your definitely going with the supercharger/cam. Do not get a CAI kit if your going supercharged. You will no longer need it. If you decide with not getting a s/c get a vararam. It is the only true cai for the vette. It is also ram air too. No other cai comes close to the performance of vararam. You will gain 5 mph in the 1/4 mile with the vararam. There will be no water issues with it unless you submerge the front end of the car in two feet of water. I gained no power removing my cats. I only did because my supercharger and alky were melting my cats. I would run no cats. It has to be tuned properly. I barely have any gas smell sitting at an idle. A good tuner can pull this off.

tinman12

thanks everyone. I read so much about the Cats vs No Cats and glad you guys that have tired by chimed in. I plan the headers and cam around the first of the year. Hopefully, will find a decent cam that has a nice loop, adds power and does not surge with the stock convertor in the A6.

MySloRide- That would be awesome if you could keep me posted on the results. would love to know what that combo will bring over stock. You should be happy with the numbers once tuned.

05Z51C6

I have 1 7/8 with off-road X setup on my LS2. Gas smell is not too bad in my opinion, but maybe I have become accustomed to it since my days of LS1 F-bodies with no cat setups. What brand headers you going with?

tinman12

looking at the Texas Speed brand 1 7/8 with x pipe, just due to cost. Not sure if the Kooks, ARH or other brands are work the extra cost.

And same here, I never ran cats on my LS-1 motor and was not bothered by the smell.

05Z51C6

I have the Texas Speed headers/X right now. Kooks, ARH, and LG are what I see most common on here and are all nice in their own right. I decided to get the TSP headers and a Fast 102 at the same time. I got both items for about the same price as the Kooks by itself.

tinman12

exactly my thoughts as well, with TSP headers and a cam, me doing the labor I can have about the same amount of money into the other brand headers themselves.

tinman12

add a tune to the above and hopefully gain 60+ RWHP.

05Z51C6

what cam/specs are you looking at?

tinman12

That i am not sure,, I have a 2011 GS A6 and would like to see how the power felt with headers, cam and tune. I would like to have a cam that could perform well in the future if i add a supercharger. I dont want to add a stall convertor and would like to keep the surging to a minimal if possible. Love to have some lope at idle but not something the GF will think is falling apart if she drives it.

tinman12

I have heard some of the nasty loop cams on youtube and love them but really want to have cam that pulled hard, noticeable loop at idle if possible. This is just a weekend car, date car not a daily drive. I want to keep it aggressive but not something thats to crazy where you got have worry about it being easy to drive.

ls1121

CAI is a plus as long as it is really a cai and not just a filter change.

tennblkc6

you need to speak with someone specs custom cams. they will be able to get you a custom cam and the supporting parts specifically for your needs.
good luck!

berk4422

I went with a kooks headers and a catted X-Pipe. I don't race for money and I'm not chasing any numbers. All I want is a dead nuts reliable build. If cats help the environment and reduce the pollutants, its worth sacrificing a couple extra HP... Let your conscience be the guide.

saplumr

Years ago when I first my blower and everything else I went with the offroad. Sound was frightening to some people but I loved it. What I hated right off the get go was the horrific clothing and skin penetrating odor! I put up with it for a few years but got rid of the offroad and went to high flow cats. No power to be gained but the sound volume difference between the two is not even close.

berk4422

You aint gettin any without Cats.

tinman12

Berk4422- too funny, that alone is enough to convince me to run the Cats.

Everyone, thanks for the comments.