2009 Header Info

09Jimmy · October 5, 2009

If you have a 2009 pickup, Denali, Escalade etc. you may have noticed that GM changed the exhaust on these trucks with a third cat the size of a gallon paint can. They also don't use a flange between the cat and your catback anymore, they use a flexible braided pipe and a slip fit connection. This means that the available headers and Y-pipe for GMT 900s will no longer bolt up to your factory or aftermarket cat-back exhaust. Who knows if, or when header manufacturers will come out with a 2009-up specific Y-pipe to fit these trucks. There are 2009 spec catback exhausts available that use the slip fit but if you get headers you'll have to fab up a connection to make them work together.

The solution is to use the currently available headers and a 2008 catback system. I just installed ARH stainless longtube headers with high flow cats and Y-pipe and a 2008 Magnaflow catback on my 2009 GMC RCSB 4X4 and it fit perfectly. All the muffler and pipe hanger locations etc. are the same. Absolutely no issues or fabrication involved.

I was, however, surprised by how loud it is now. The Magnaflows are a 3" in, dual 2 1/2" out system that are at least 3 times as loud as the Flowmaster system on my 2000 RCSB 4X4. The Flowmasters are also a 3" in, dual 2 1/2" out but the muffler is a 50 series. I certainly didn't expect the Magnaflow to be louder than the Flowmasters, let alone 3 times as loud. Oh well, my neighbors are going to have to learn to live with it.

I have a GMPP cold air intake that really improved throttle response (I'm serious, before I installed it I couldn't spin the tires, after, I could) but this exhaust really woke the truck up. I can now literally melt the rear tires (285/55R20 BFGs). I have 4.10 gears and it will smoke the tires for as long as I keep my foot in it. I found some new pavement and left at least 100 feet of rubber before my wallet said stop.

No codes yet but I'm going to get a Wester's dyno tune, hopefully next week. They assured me they could find a lot more power yet, while turning off torque management, raising the rev limiter, transmission upgrades etc. I can't wait. So, bottom line, if you think $1,200 is too much for headers, think again. I'm sure the less expensive headers like Pacesetters and OBX will deliver significant gains as well, I just wanted stainless so they'll last forever in the winter salt.

uh6tdrvr · October 6, 2009

Good write up. I was wondering how this would work with the 3rd cat on there now. Do you have any pics of the ARH system installed? I really REALLY want to get these, just was really wanting to hear about how much better it runs with them. Can you tell a noticable differance without the tune and just the bolt ons? Let me know how you like it after too!

Daryl LBZ · October 6, 2009

I had Headers and custom cat back exaust on my 05 without a tune and I noticed a difference with just that.

09Jimmy · October 6, 2009

Here are some pics from another forum.

http://www.performancetrucks.net/forums/sh...ad.php?t=433468

http://www.performancetrucks.net/forums/sh...ad.php?t=430345

I bought one of the sets that Allgonoshow had for sale. His installed pics look cruddy because he had spray-on rustproofing applied the day before. Rest assured, the headers and Y-pipe are actually nice and shiny, what looks like rust is baked on rustproofing.

Nice to have a side by side comparison of the Dynatechs and the ARHs. The ARHs have longer tubes and spun cats and fit like a glove.

I hope to get some pics of my setup soon. Big performance difference even before the tune but it kind of burbles in V4 mode.