I know the Borla has pretty good ratings, but was shocked to see that it only has dual 2-in tailpipes coming out of the muffler. Every chart I can find detailing engine displacement and horsepower recommends minimum 2.25 in dual pipes with 2.5s recommended.

Any thoughts on this from existing Borla owners? The math says it would choke the engine at higher RPM, but I spoke with Borla and they insisted they tune their exhausts on a dyno.

Looking for some real world experience....

Right now the H2 has an AFE Cat-Back system that was probably installed 15 years ago. Looks like it's held up rather well, just way too loud for the wife at cruising speed with a horrendous drone. It has the Dual 2.5 in pipes coming out of the muffler.

 

My Borla has been on since 2009, no issues, no drone.

 

That's exactly what I wanted to hear. I suspect the exhaust sizing charts available online are geared more towards people making maximum top-end horsepower.

 

To maximize flow, take a look at the dual exhaust options. Both Magnaflow and Borla offer dual exhaust cat backs for the H2 and they look great.

For the 08/09 H2s :

• Magnaflow 16772 is 3.5" from the muffler into dual 2.5"
• Borla 140258 is 3" from the muffler into dual 2.25"

The Magnaflow offers less resistance, and sounds great. That is what I went with and It is very wife and neighbor friendly, and sounds great.

The Borla exhaust has received very good reviews and there are a couple YouTube videos where you can hear it. Too bad it just is not available anywhere. In talking to Borla, they said they are still available to manufacture but they only ship to distributors who buy in large quantities, and none have made a recent order. Guessing too few 08/09s out there. You may have better luck with the 03-07 versions if you want the Borla.

 

So I'm guessing the 2007 and 2008 had the 6.2? I spoke to borla yesterday because it seemed odd that my 2003 has the Dual 2.5 going in the muffler and they only offer the 2 in duals coming out. That seems rather restrictive for a 6 later engine. But then I noticed the exhaust systems that have a single exhaust pipe coming out the muffler or only 2.5 in for the 2003. I am keeping the engine stock and don't drive it hard..

 

Ah right... yes, the 08/09 has the larger engine... you should be good with 2" dual out... that is effectively a 4" exhaust from the muffler...

 

The GMPP (GM Performance Parts) stainless touring cat-back one that used to be available was actually made by Borla and is what I had on my 2003. Sounded great and combined with long tube headers gave a decent boost in performance.

 

My AFE cap back system that was probably installed by the previous owner 15 years ago or more, was as loud as straight pipes and had to go according to the wife

I was leery of a deal that was too good to be true on the OBX system that has the Dual in and dual out Muffler, plus two sets of twin pipes coming out the back. All stainless steel. When I talk to OBX they said the retail price depending on the vendors between 1100 and 1200. Yet I found it readily available on Walmart.com as well as on eBay for $209. I think shipping was about $60. So I took a Gamble and ordered it and it showed up looking really good. No flaws in the welds. The muffler is the stock 24-in long, the AFE that I removed was 16 in Long. And the hanger brackets welded onto the OBX system lined up perfectly with the Factory location. They give you a bracket to bolt on the driver side rear for the other set of tail pipes, using an existing hole on the rear body mount bracket. Only involves relocating the ground and inch lower. The OBX muffler has two straight through pipes with perforations down them. The AFE pipe I removed look like it made an X inside open in the middle also with perforations. Started it up and it sounds like stock. For the first time I could actually hear the engine fan sucking air through the radiator at idle. No instructions included, but none were necessary. Went together really easy. Full Throttle is a little bit louder than stock, slightly louder than our 2014 Escalade. I tested the fuel mileage on a 40 mile round trip at 60 MPH which I ran last week with the AFE system at 13.7 miles per gallon. With the OBX I ended up 14.3 miles per gallon. Quite pleased. The preformed pipes were worth well more than the $200 price tag, in the event the muffler turned out to be crap. But everything's just fine.

 

Note: the clamps for the pipes I used were aftermarket from Summit Racing. Evil energy brand. The ones provided we're not very desirable, being the u-bolt type.

 

Looks good, the price is dirt cheap.