vet55

Getting a tune soon and looking at Kook's 1 7/8" headers possibly at the same time.
I need some teaching. I get the concept of single tube per cylinder and breathing. What I don't get is how this really changes HP much. Is a 4:1 OEM exhaust that much more bogged down than a 1:1 header?

Will this worsen or improve MPG?
Can I use these with the stock NPP
system for now with the headers?

Thx ahead!

b0xm0ns73r

I've got LG 1 3/4" headers bolted up to the stock NPP on my 08'. Not a GS but an LS3 none the less. The sound alone is worth the headers in my opinion. I have folks holler at me in the grocery store and tell me how good my car sounds.

The headers seemed quite a but lighter than the stock manifolds.

Technically I think the headers could increase gas mileage, but unfortunately I will probably never know. It sounds too good to keep my foot out of it

Having the headers bolted up to the stock NPP is nice. If we are on a road trip and I want super quiet I just hit the mild to wild controller and everything is quite just as it was before the headers.
I also have a great tune....thanks to DiabLew

Maybe someone else will chime in and explain how the headers help with the exhaust flow. That's above my paygrade

vet55

Thanks. Great answer. That gives me options and I get it about the MPG. Not looking to make it better really, just not worse. Thanks.

mikeCsix

Headers will lean out your air/fuel ratio so a tune will be helpful and you should see a slight increase in mileage. Plan on about a 10% increase in hp.

vet55

Thanks. Starting to learn more with this.
So with adding the headers I guess I am forced to change the X pipe due to the collector size, yes?

87SAM

1 7/8" over 1 3/4" may not necessarily be the best choice. Kind of depends on what your future mod plans are.

vet55

Thx. If 1 3/4 won't dump any power or torque by itself now I would do that instead but cams would be a long way off for now. That could be far off though and not sure how 1 3/4 will act without cams now. Any input is appreciated.

What got me started was cams and headers with a tune on my 2015 Harley Road Glide, what a difference before and after and really no downside to the motor itself.

Guard Dad

Headers are smoother and less restrictive plus they are actually tuned, not altogether unlike a musical instrument, to create a resonance in the primary tubes that helps extract the exhaust gases. They are a wonderful addition to almost any engine. Apart from the cost the big issue with street use is they require the relocation and/or removal of the catalytic converters which puts you in violation (in a lot of places) of emissions laws.

vet55

Thanks. I like your description and I get it about the price. About $2000.00 parts only. Per "Zip", Kooks makes a custom one for the GS apparently $300.00 more. Looks like it will work on a lot of cars. Will probably do it before Texas adopts a Carbon Law like LA.
Really learning a lot from you all. Thanks!

NMMike2012GS

I ordered a set of Kooks headers for my 2012 GS and there was no difference in price. Part numbers for a GS with an LS3 is the same as the one for a non GS.

vet55

Thanks. Would really like to hear your opinion and an audioclip once installed if possible.

NMMike2012GS

I'm currently checking on places to get them installed along with a tune. I hope to find someone I'm confident with by weeks end with an install date ASAP and will try to post results.

Garry in AZ

Changing the OEM exhaust manifolds for a set of equal length tube headers improves performance by increasing the volumetric efficiency of the engine. At it's most basic form, an internal combustion engine is simply an air pump. If we make improvements in how the air can enter and exit the engine, we can increase power and torque, as well as potentially improve economy.
The basic differences between your OEM manifolds and a good set of tubular headers is that the headers are designed to reduce exhaust back pressure, and create equal flow for all cylinders.
Headers can be constructed to alter the torque curve of the motor, or to create peak horsepower at different RPM's.
If you have no plans to alter the intake or overall airflow inside your engine, (intake manifold, camshaft swap, head work, or forced induction) and the car is a street driven vehicle, then (generally speaking) you are best served by going with smaller diameter header tubes. An otherwise stock LS3 works well with 1.75 inch diameter tubes, relatively long primary tubes and 3 inch collectors. The car will further benefit by using an X-pipe or crossover tube to connect the left and right cylinder banks together which aids in scavenging.
The above is a very general statement, and does not cover any of the myriad of tuning possibilities that headers can contribute to.
I hope this helps.
Garry

vet55

Thanks Garry and to NM. Great write up! Learning a lot.

0JDP Tech

Headers are an great upgrade on these cars. Generally on the LS3, we suggest 1-7/8" headers, as it leaves room for future upgrades, but if you will be stopping with bolt-ons, go with 1-3/4".

Gas Mileage is generally improved as long as you can keep your foot out of it, but chances are it will get worse since you'll want to hear and feel your new headers!

The Kooks long tube system will connect right up to your OEM NPP exhaust system.

We do have some killer specials going as well as hands on knowledge to be sure you're getting set up properly. Feel free to call, PM or email me anytime with questions.

Best regards,

Tyler
888-308-6007

CMY SIX

dollar for dollar your better off spending your $ else where, $3000 for headers and install don't get you much, the days off uncorking a 350{mamifold/headers} and getting big gains are over, if you were to look at the stock manifolds from behind you'd see a perfect set off "cast shorty headers" how does one think GM deliverd these HP#'s to us.

vet55

So why do they advertise 436 HP and it Dyno's 369 HP?

Vito.A

436 is at the flywheel, 369 is at the rear wheel. Auto trans cars dyno less than a manual because of higher loses.


With good shopping you can buy a set of Kooks or American Racing headers with high flow cats for $1800.
You can install a set in your driveway on jack stands. It really is easy. These cars come with the OEM catalytic converter up next to the oil pan, so when you remove the OEM cast iron manifolds and cats there is lots of room to install headers. It helps to have a friend that has done it before, but you can just follow the DIY Header install on this forum and do the install in one afternoon. And save big bucks. The only hard part is breaking loose the original exhaust bolts. Spray some PB Blaster on them the night before and you will not have any trouble. Depending on where you live, Autozone will loan you an O2 sensor tool. Other than that, it's just basic hand tools.

vet55

Great post, thanks!

greatgonzer

Did you ever get this done? I have some great references and know some great quality shops here in Albuquerque that I recommend.