Quote:
Originally Posted by Goldy4R
I'm definitely interested to see how this turns out. It seems pretty simple for a shop to splice the cats into the DT Y pipe. Quite a bit simpler than trying to attach them to the Shorties and get things to fit properly and mate to the y pipe(which it sounds like was an issue for you).
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Yup it was. I think the flange that was welded to the collector on the header wasn't welded on very square, and as such kicked the cats all outta line... The Flange that was welded onto the top of the cat to mate to the collector flange was dead nuts on, so it only leaves the collector flange to be outta whack. I wish the installer would have welded them up in a jig that they built off the OEM manifold they took off, but that didn't happen and they made it right by not charging me for their fab time.
Still not 100% happy with the results as one of the exhaust pipes is pretty close to the front driveshaft slip yoke, so I have to keep it pumped full of grease as it cooks out pretty quickly.
Quote:
Originally Posted by Goldy4R
I'm not sure I care about the O2 sensors enough to move the bungs. I think I'd just do the simulator and trust the new cats are doing the job.
I also like this approach, as it I may be able to do this in stages. Stage 1 - long tubes and simulator. Stage 2 - y pipe with cats.
Also - How does that Vibrant Ultra Quiet resonator work for you? I have a 20" dirty deeds and added the vibrant bottle resonator to tone it down a bit. I'm sure with the headers, I'll need a bit more...
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Someone has already done roughly this configuration on a GX already which is where I got the idea.
The only difference is they had 100% custom exhaust done from the headers back with the GESi cats, a j-pipe (1/4 wave resonator), and I forget what muffler. There's a post in the GXOR facebook group where Dan goes through his build and even posts some dyno results too.
Not sure if he relocated the rear O2s or not, but I figured I would because I have emissions to worry about here, so I figured I'd give it a shot first. If that doesn't work out, move to the O2 Simulator.
But, I actually found that after the shorties, it actually is a touch quieter than the OEM manifold was. I like the Ultra Quiet Resonator, though. Really helped with the drone of the Magnaflow muffler. It's still there, but not nearly as bad as it was prior.
If I were to do it again, I'd go straight to a 1/4 wave resonator/j pipe and target it for 2100-2200ish RPM.
Quote:
Originally Posted by Clarkson!
For anyone who has done this with an 2005+, what magnaflow cats should I order? Little hesitant to have the old cats welded on. Thanks
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I'd recommend the Gesi cats I have linked in my signature. They're a bit pricey, but will outlast the truck. With how expensive that job is, buy once, cry once.
I also noticed it SIGNIFICANTLY improved/reduced the "rotten egg" smell under hard acceleration that I had with the OEM cats.
rrcats.com to sell your old cats, and if you sell all 4, you'll get close to recouping the cost for 2 of the 2.5" Gesi cats.
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'09 V8 Limited | Dobinsons Lift | Front: 3" - C59-302 + GS59-220 | Rear: 2.5" - C59-675V + GS59-701 | Tires | Ridge Grappler 275/65/18XL | Wheels | Method Standard Machined Finish 18x9 -12 offset | SPC UCAs | DT Long Tubes |
GSport 2.5" Cats | DT Y-Pipe |
Magnaflow Cat Back |
2.5" Vibrant Ultra Quiet Resonator