as far as quality and performance gains? Also most importantly I want to know why they all say "for off road use only" Every add or magazine I have looked at that sells them says "off road use only" I plan on putting a Magnoflow with X-Pipe on my car as well. Will it be too loud with the headers? Is it not street legal? Sorry if this has already been posted. Thanks.

 

Off Road Use Only" is referencing to the lack of Cats. IMO Cats rob performance, and just don't sound as good as an X Pipe without them. LSX motors are sort of iffy on the lack of backpressure without running a catted setup.

It'll be louder,yet most of the time unless your running like a Bullet style muffler (B*B Bullets) it'll b raspy, or drone during a drive. it'll definietly sound better, deeper toned. If you get a "off road use" style header, just get 2 O2 extensions, plug in, and no codes should be given off.

 

I've got American Racing headers with their high flow cats on my '05 & have been absolutely pleased with both the quality of the product & performance improvement. Install was done by East Coast Supercharging in Central Jersey & I have to say that those guys did a perfect job with the install. Mated up to Corsa Sports mufflers that I had installed couple of years ago. I can highly recommend the AR headers & they are street legal.

 

i just installed American racing headers, cat's and x pipe on my 09 yesterday (there is a thread in general discusion) Really easy to do and the gains so far are seat of the pants,,,,but i gotta believe there is a HP gain.

 

come with the particular brand, and I add a Magnaflow Axel Back Exaust System am I gonna be droned out?, will i have to have anything tuned?, or is it just a bolt on operation? Will I notice an increase in HP? Sorry if these questions sound stupid, I am not a mechanic. Thanks for the help. Any links to quality header systems you guys can suggest?

 

In a nutshell, none of the long tube headers on the market for the C6 are emissions legal. Even if you get a model that has cats, they are still not legal because the location of the cat has been altered. So no, they will not be street legal. In California (and other states with similar testing), any C6 with headers will fail the visual part of the SMOG inspection, even if it has cats and passes the 'sniffer' portion of the test. The headers need a CARB approval # to be legal, and there are currently none on the market for our cars.

If you want to be 100% emissions legal, you need to keep the exhaust stock until after the cats. Some emissions test techs will look the other way on some modifications as long as it runs clean, others will fail you reguardless. Hope this makes your decision easier,

Andy

 

I think the 'drone' will really depend on the muffler design/brand more than anything. Headers and high-flow cats will definitely make the exhaust louder, but I don't really think them by themselves will create any resonance.

If you want to avoid any resonance (or drone), Corsa is a very good exhaust to look into. My Corsa Sport system has zero interior resonance that I can hear, and sounds great. If you do a search on this site, you will find a zillion other people saying the exact same thing. This is because it is very true. Exhaust sound can be very subjective though, and some people prefer a certain tone over another. I'd suggest hearing some other cars to see what you like.

As far as headers go, the leading brands tend to be (in no particular order) : American Racing (ARH), LG and Kooks. Can't go wrong with any of these. Even on a stock engine you will see solid gains with headers and full exhaust. You will gain even more when it is properly tuned, but it is not required.

Andy

 

Whats the difference between 1 3/4 and the 1 7/8 ?
I have an 07 LS2 and my next mod will be headers (w/cats) and a tune.
Kooks, ARH and maybe Texas Speed's version (CF Vendor) Illbe considering.

 

Smog inspection is the only reason I never got the L/T headers for my Coupe. Has anyone tried the Z06 factory headers/full exhaust on an LS2?? Im really considering this. Any power gains?? This way I can have it emission legal.

 

I have LGs and LOVE them

 

More header info.....

http://forums.corvetteforum.com/c6-t...st-for-c6.html

 

Still not legal. Z06 cats aren't stock on an LS2 or LS3. Z06 manifolds/cats/mid pipe/axle back is a bolt on (to M6 C6's) with a performance gain but you could still get caught since you don't have "original" cats in the "original" location per the Federal Emissions laws. A low chance of getting caught since even a rabid Inspector probably wouldn't know part numbers but still is illegal. Is a little bit illegal like a little bit pregnant?

 

I think it depends on what your future plans for the car/engine are. If you are just going to be doing bolt-ons or maybe even a small cam, the 1 3/4" would be probably ideal. If you have plans for a stroker motor or blower in the near future, then the 1 7/8" would probably be the way to go.

I don't have any real data to back this up on the LS2, but usually going with an overly large primary tube header tends to hurt low-end torque. I've seen guys swap from 1 3/4" to 1 7/8" and gain nothing on the dyno, which is no surprise to me since a 1 3/4" header is plenty large for even a potent small block. The thing you don't see is the potential torque that is lost at low RPM, since most chassis dyno tests don't start until 2500-3000 RPM.

I will be choosing a set of headers for my LS3 soon, and am leaning towards 1 7/8". This is because I have a blower and 600+ RWHP planned.

 

, but it is very unlikely that any emissions inspector is going to know the Z06 parts are not stock. Technically not legal, but you will not get hassled by anybody. Only a real Corvette nut is going to know the difference, and I doubt they will care. I am considering going this route myself since I am in California.

My main concern with long tubes is getting snagged by a cop that hears my car and wants to see if it is modified. Then again, I'm not sure if most cops can tell the difference between some factory manifolds and a set of raw stainless headers. The factory manifolds on my V8 M3 could have easily been mistaken for headers by someone not familiar with the car. I will not be going with any ceramic coating on my headers for this reason; to keep it more OEM looking.

Andy

 

Ok, I live in Mississippi and Smog Concern is non existant, so are emissions inspections. I think I am going to get some headers and the cats that come with them and either a Magnaflow, Corsa or Borla... I want a throaty sound at idle, but I don't want to be droned to death on the Hwy. Which system will give me a hearty sound but not drone me out? Thanks

 

I had Stainless Works Headers and Hi-Flow Cats installed on my 2008 C6. Excellent product and quality. Check out on their website - http://www.stainlessworks.net/cart/index.php

 

A former owner installed Melrose Long Tube Headers on my car. Just a warning. DO NOT TIE THE O2 SENSORS UP WITH ZIP TIES!!! Cost me $800 to replace all the sensors and remove the melted wiring harness from them and the headers and install proper hangers for the harnesses. What a mess!!!

BTW, they are nice headers.

 

I have several criteria for the corvette forum regarding headers for the C6.
When you a recommend headers for insurancepi, lets also consider:

(1) Ease of installation, especially important to the DIY hobbyist.

(2) Which brand offers the most ground clearance?

(3) Heat dissipation - Is the brand you're recommending a stainless steel or is it ceramic coated, and why did you choose yours?

 

Bump for the weekend crew.

 

As noted there are several decent brands. My personal opinion is that LG Pro long tube headers are the best! I would also recommend you spend the extra money and have the headers coated. As you're now aware, long tube headers are not CARB compliant and are not legal for street use. Any alteration (removal/relocation/replacement, etc.) of OEM cats is in violation of federal statute.

Many long tube headers with after market (2-stage) high-flow cats will pass a sniffer test (but not a visual inspection). The pollution 'problem' with long tube headers and after market cats is that the after market cats are located much further from the engine and accordingly they take longer to heat-up and fire. It's during this extended heating period that the after market cats pollute more than OEM cats.

FWIW there is a 'shorty' header available which is CARB compliant and legal for street use. That said the shorty headers are virutally worthless and don't produce any significant power gains.


If you have after market long tube headers and your OEM cats were removed and replaced with relocated 2-stage high-flow cats I'm confident that's in violation of federal law. It's not "street legal."