I'm another guy with leaking stock exhaust manifolds, and I just hate to miss out on the chance to upgrade something, so I'm researching the things I will need to bolt up a set of OBX longtubes.

Since I live in an area where there currently is no smog testing, and I'll never sell my truck to anyone, I was planning to buy the OBX kit with the resonators, and Y pipe.I understand I will need to extend the O2 sensor wires, to accommodate the headers, but will running with no cats trip the "check engine" light? How can I fix this?

I want to run this set-up with my existing single exhaust and Borla XR-1 Oval, which is dumped, before the rear axle. Is this a good idea? I used to have a dual exit package, but I don't care to see all that crap hanging off the back of my truck anymore. I like the cleaner look of what I have now, but if it would suck, I'd change it.

I also want to ditch the crappy studs and nuts stock fasteners, and go with a bolt kit, preferably a locking kit. Does anyone have any recommendations on these? And what is the absolute best gasket I could possibly get?

And will I need to have a custom tune? I am currently running an Edge programmer, set on Level 2?

I live way, way, way, out in the sticks, and there is no muffler shop, or otherwise, for a couple of hours drive, so it is very important that I get all the things I will need, and for this kit to be truly, bolt-on. I haven't got access to a welder, plasma torch,etc.

Anything else I missed?

 

Youll be fine with your single borla Xr1, but it would be the best if it was 3". If not, no worries. All the header piping and Y pipe will be 2.5", so if you have 2.5", youll be chillin. No cats you will get a CEL, and you can turn it off with either a custom tune, or install MIL eliminators. A custom tune designed strictly for the LTs will yield you a 30hp/35tq gain

 

Thanks for the info,migdaddy. My pipes right now are 2.5", so I'm good there. Any recommendations on MIL eliminators? Could I expect to lose MPG's with no cats? How about the Longtubes?(I'm guessing a bit)

And I was also wondering if anyone might know what size tap I would use to clean out or repair the threads, when I get to this project?

 

OP, your doing long tubes. Tune it! No cel, and you will get the most out of your headers.

 

I'd love to have it tuned, but I can't wait 6 months for a custom tune, or be without my EDGE programmer for months, while it's upgraded to PHP. Is there another way to get a custom tune quickly?

 

No loss in mpg with the long tubes when your taking it easy. I could still average 15 in my truck with a 50/50 mix city highway. 21 before gear swap with long tubes and 35s. Everything was flowing much more efficiently and I ran it with my gryphon tuner without issues.

I didn't have check engine light codes either. I extended all four o2 sensors, the rear two also had the gotts 02 mod. With cats, the sound of my exhaust setup volume wise during cruising was much more bearable and about 50% quieter but at WOT only 10-20% quieter.

 

Yes. Though if you custom tune, the added low end performance might almost accommodate for the velocity loss.

x2. Try SCT if you can not wait for PHP, or consider buying an entire new Gryphon programmer from them, tuned, and sell your Edge programmer used.

 

Thanks for the input,BLFX4K.If I read your post correctly, you are running the resonators from OBX in place of your cats, and at cruising speeds, it is 50% louder in the truck. Would you say that it's too loud, or annoying?

Did you use any type of locking bolt set-up? Or did you go with the stock set-up?
Also, what gaskets did you use?

 

You will only need to run o2 extenders on the front/upstream sensors. Stage 8 locking header bolts is what you are after. I am using SCE copper gaskets on mine and they work well.

 

Thanks for the info Gotts, Can I ask what OBX set-up you are running?ie:resonators, OBX cats, or Maggie Cats?
Was it a bolt-on setup, or did you need a muffler shop?

 

Different year truck then me but I used the OBX gaskets and they sealed up perfect for me. I reused my studs for the exhaust manifolds too. I used Gotts 02 mod (search it) for the rear Oxygen sensors and have gotten zero CELs.

Also, I've used dual 14" mufflers, 18" di/do muffler and they all were to loud. If you plan no cats I would look into a 22" muffler for a good sound that isnt overly loud.

 

Sorry, to clarify, the truck was 50% quieter running high flow cats and long tubes vs. resonators.

My original setup was with resonators and swapped them out and welded in some high flow cats and significantly reduced the sound. I preferred the setup with the high flows, wished it could have been a tad louder but was great for long drives, short trips etc.

Re-used the stock bolts, used the obx gaskets but you can't go wrong reusing your stockers depending on mileage. I torqued everything down again after about a week of driving. Didn't lose a bolt or anything after a full year of driving and didn't have to torque them again. Sold the truck and hope to see someone here with it in the near future

 

I'm running resonators

 

I'm using stock studs and nuts on my obx lt never had a problem with them backing off or leaking, used obx gaskets! As for resonators much to loud for me and my mileage did drop, so I put on high flow cats to get better mpg's!
Headers was a breeze to put on!

 

Delta force tuning. Call them.