nkadisha

Hey guys,

Thinking of picking up headers for my LS6. Currently stock. My question is, where are the cats for this engine located? Are there cats in the headers or only headers back? Has anyone tried a headers + tune on a stock x-pipe and catback? Dyno?

Car is a track focused car, but driven on the street time to time - looking for around 400whp without a cam or free flowing (loud) exhaust. Is this possible with just headers and an intake (previous owner installed a K&N)?

Input is greatly appreciated - new to these cars as I'm coming from BMWs. Thank you guys.


Nathan

nkadisha

Also - do I need an aftermarket x-pipe to run LG headers? Or can I just find a set of headers and run them to my stock mid section?

2003Evo

I am making close to 400 with american racing 1 7/8, offroad xpipe (no cats), vararaam intake to the Ti oem exhaust

grantv

Earlier years had 4 cats (I think up to 2001?); 2 "pup" cats right after the manifolds and 2 under the car at the start of the tunnel. Later models improved the cat design and had 2 only down in the tunnel, same place.
How much power you end up with will depend somewhat on the year of your car also, as later cars came with 405HP, earlier 385HP.
Lots of people run headers into the stock H-pipe (stock is H, after market are mostly X). You will need some piping depending on whose headers you get (Texas Speed for example provide pieces to hook up to your factory pipes). Cats or not cats makes pretty much the same power, your state (geographically) and state of mind (environmental concern) will dictate what you do there.
I think stock motors turn 350RWHP or so, adding headers and a tune gets you pretty darn close to 400.
Stock Ti's don't lose you much if any power.
Also from BMW's but basically stock 3 series (cat back only mods), the mod bug hit once I had serious power again = Z06.

bumble-z

2003 Z 06 (stock motor)
LG 1-3/4" LG Pro, long tube headers..LG 3" X pipe.. no cats
Varraram cold air intake
Tune
Mustang Dyno...390 RWHP
1/4 mile with drag radials...11.90

Sigforty

What year ls6 are you working with 2001 or a 2002+? You will need everything to try an hit 400 rwhp without a cam. That would include the following:

Headers
Underdrive pulley
Ported TB
Fast intake manifold
Aftermarket air cleaner
Custom dyno tuning
Electric water pump

As for the LG headers if you get the pro series, you will get the x-pipe, headers, cats/off road pipes. The stock TI exhaust with the LG setup sounds good, not too loud either.

To give you an idea of possible gains, my car put down 340ish rwhp with just an air cleaner. Headers gave it a 12-18 boost rwhp, and after dyno tuning I was up to 372 rwhp. It took me a cam, ported TB and underdrive pulley before I broke 400 with 408 rwhp.

JetMechZ16

I'm at 388 RWHP with the mods in my sig.

jhopper408

I got 384/372 tq with Vararam, Kooks 1/3/4 headers and I kept the titanium exhaust. It was tuned on a Dynojet. And the car is a 2003 Z06 with 55000 miles on it.

Hib Halverson

2001 Z06es had four cats. Two "pup cats" near the exhaust manifold outlets and two main cats under the floor at the front of the tunnel.

2002-2004 Z06es had two cats under the floor at the front of the tunnel.

400 at the wheels SAE-corrected might be tough without a camshaft change or ported heads but you could get really close with these items:

Halltech KB2 CAI conversion
Hi ratio rockers and dual valve springs
Headers
02-04 Cat system
aftermarket x-pipe
Stock Ti exhaust
Calibration to match the above

Hib Halverson

Is that SAE or std. corrected?

H. Halverson
Z16 #8

JetMechZ16

I Dont remember, the dyno sheet is at home and I'm at work. It was on the portable Dyno that accompanied HotRod Power Tour in 2013.

They ran a Stock Challenger rated at 470 hp at the crank right after my car and he had nearly identical numbers.

Cheesecake 07

04z

Halltech Venom intake
Kooks 1 7/8 LTs
Kooks 3" OR X
OEM Ti's

393rwhp/375tq SAE on a dynojet

Went 12.2@116 @3600ft on street tires.(backs up power to weight)

You can get pretty close to 400 w/o cracking a valve cover. Some have on a "loose" dyno

Kins13y

If you want to save some money I made 391/384 with a blackwing intake, TSP 1 3/4 Longtubes, xpipe with no cats and stock axle back. Sounds great without being too loud. This was before my heads/cam.

ssrallyred

Seems the LS6 is very consistant. Kooks LT's, Ebay CAI and stock cat back here : 390/370

RedZMonte

Stock Hpipe:


Stock LS6 Manifolds vs LT Headers (ARH)


LT Headers installed: +20-30HP
Will NOT bolt up to stock Hpipe.. If you modify the Hpipe and remove the cats you could make it work but better off getting a correct X pipe for the headers esp if you want/need to keep cats.



B&B Shorty headers mated to stock LS6 Hpipe: +10HP


LS7 Manfiolds/Downpipes/Hpipe: +20-30HP (less TQ then LT headers)




S