the duke35

Have a 2009 GMC sierra all terrain with 6.2L. I would like to add (bolt on) ARH long tube headers to the factory exhaust set up. Would there be any out right (back pressure) problems and/or would the increased flow be restricted resulting in limited gains? I have a volant CAI installed. It has a nice muffled growl now and I think the LT's with factory muffler would make it sound just right. Additionally I like the stealth apperance of the factory tip.
Thanks in advance for your replys/recommendations.

supercharged680

iTrader: (1)

im nt really sure to be honest.. the flow will be restricted due to the stock muffler and cats.. just add a muffler instead of the stock one if u want the tip to stay the same.. or remove cats..

Coban

iTrader: (14)

I wouldn't hesistate to use the stock system. Isn't it 3.5"? The muffler shouldn't be too restrictive. I prefer stock mufflers though. No resonance.

XLR8NSS

iTrader: (4)

I agree with Coban! Headers are a worthwhile mod even with the stock exhaust.

BuyAmericanIron

Check my posts. I have done exactly what you are considering. There is virtually no restriction in the OE exhaust. I have checked it with a back pressure guage and at WOT there is less than 1 lb of backpressure. You can easily get that much from staight pipe when it is 15' long. There is no performance to gain in the muffler, only sound and bragging rights. Using ARH w/cats bolted to stock exhaust, it is quiet on the road with a mild rumble. During acceleration such as stop lights or on-ramps, it has some bark and a nice sound. When you get on it, it is loud enough to attract attention. To me, it sounds just like a Z06 with headers. I am a person that is very picky about the way my truck sounds, and I am very pleased with this setup.

I have a question for you. How do you like your Volant CAI? I have considered one, but most guys on here say there is little to no gain to be had with a CAI. Thanks

the duke35

buyamericaniron, thanks for the info. Very helpful. How much improvement do you think the headers produce?
I don't know how much hp the Volant adds but it is definately louder with it installed. Wish it came that way from the factory. Honestly I bought it because my buddy ordered the kit for his truck twice because he thought the first co. couldn't supply it. I am happly with it.
I had a '04 c5 vert and right now my 6.2L sounds better. I love remote starting it. Anxious to hear what it will sound like with addition of the headers. Do the headers bolt on to the factory exhaust with no modification?

supercharged680

iTrader: (1)

BuyAmericanIron, which headers do u have 1 3/4 or 1 7/8? how much rwhp did u gain?

BuyAmericanIron

Gentlemen, I will answer your questions the best I can. HP improvement, I don't know. I can't find a four wheel dyno in the midwest. ARH tells me 25-35 hp from headers alone. I would like to guess I got 30 hp with the headers and another 10-15 with the tune. That should put the truck around 440-445 hp. I am sure I will get flamed, but my butt dyno tells me this is fairly accurate. I also had a C5 with headers and Z06 mufflers. The truck sounds amazingly similar to the Vette. The headers and tune are pricey, but to me well worth it. Yes, the headers bolt directly to the factory exhaust without modification. ARH uses what appears to me to be the OE connector on their "Y" pipe. It is truely a bolt on system with no clearance issues, rattles or leaks. Best set of headers I have ever had the pleasure to install. I would recommend MSD wires with the adjustable ends. There are a couple of OE plug boots that touch the pipes, and that won't work for long. I have pictures I can email if you are interested. Send me a PM with your address and I will forward them. I also like to remote start, especially when guys are standing around after work. It really growls when you start it cold, especially if you are behind it! I bought the 1 3/4" headers. For a daily driver on a stock engine, they are plenty big enough. If this engine was FI and running 6 grand all day long, I would opt for the 1 7/8. Remember, this engine is only about 380 cu in, and too big of a header will cost you on the bottom and give very little payback at high RPM. Enjoy!

viciousknid

iTrader: (8)

Long Tube Headers are Typically 30-35 rwhp with tune on a 5.3. Probably more so with that 6.2.
you WILL have an improvement.

Mang213

iTrader: (1)

Btw a cai is definitely worth getting, just dont buy the big name types. I got a Spectre kit for about 120 bucks, where as all the others were $200+ (usually $300+). The cai is a good upgrade to help support other mods, but will only give you about a 10-15 hp improvement by itself. Dont judge the value of a cai without accounting for it's worth combined with other mods, because thats where it really matters