Great job. Nice shop. I bet it sounds awesome.

 

Part deux....... Scored a new old stock GMPP (Borla) stainless cat-back setup for $125. Now the entire exhaust system will be brand new and all stainless. This will finish it out nicely.

 

Well its installed. Its a LOT quieter than it was with the stock cat back piping with the Flowmaster 50 series muffler. Louder than stock for sure and the combination of the headers with the rest of the exhaust does give a definite and noticeable performance improvement.

I almost wish it were a tiny bit louder now. lol I'm pretty sure the GMPP kit is a "touring" exhaust. With the headers and the Flowmaster muffler with the stock rear piping it was too loud though and was droning bad. Could not even talk to someone at low speeds if you were more than 20% throttle and it would give you a headache on the interstate. All that being said - it did sound downright nasty and badass and was damn fun for a week. My neighbors probably did not much care for it though.

I really did like the sound with the stock manifolds and just the Flowmaster though but things were hacked together and the cast iron manifolds were cracking and bolts snapping off.

So in the end I'm happy. It does have a nice low rumble now and has the distinct metallic sound of the bare stainless headers too and no drone at all. From behind when you get on it, it sounds killer too. Last bit to add for the exhaust will be the Borla made GM dual wall slant cut tips which Borla happens to have in their closeout section on their website. Had to buy two - one thing I had no idea of with this GMPP exhaust is that it brings duals out the back. Like the stock exhaust (on 03-04 models) its true duals until after the muffler. The stock went into a Y after the muffle to a single downturned outlet. The GMPP one goes from dual to single in the muffler itself, then a y after it goes over the rear axle.

 

Couple of obligatory pics.... Will post again on this once the tips come in from Borla.

By the way - Borla has the GMPP cat back setup in their closeout section for the 07-08 6.0 H2 for $339.75! They also have the GMPP Hummer H2 and H3 tips there too. If you try to buy from the Borla closeout corner it seems that the graphic for the add to cart button is missing - the text is there but its the same color as the page. Just click right under crossed out MSRP price and you will see your mouse change - thats the add to cart button text. You can drag select to see the text too.

I think the tips will help the look a good bit too. The GMPP kit narrows down to rather puny looking 2.25" pipes. The factory tips flare that out to 4" rolled tips. Also if you are curious - they have 3 different tips for the H2. NONE will fit on stock exhaust. They all are for 2.25" pipe. The difference between the three, one is a slant cut single wall tip (might get hot enough to burn your leg), the other two are double walled - one straight cut, one slant cut.

 

Looking good. Great price on the borla... i made a lot more for mine!
I know what you mean about it sounding quiet.. i went from stock to borla/headers and thought it would sound way louder. That being said, it got louder as time went on, but now am really pleased with it.

Time for the remap ?

 

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