4Sep18 76,281mi
So my one regret in all of these mods has been the URD Mk3 Stainless Cat-back exhaust. It's been a royal PITA. I've had several issues with it leaking from different places. It also renders the rear window unusable while in motion. The fumes flow in through the window and into the cabin strong enough to be of concern even with just me in the truck and all the windows down. If I had to do again, I wouldn't even look at it twice, just go with some other company. Somehow I had completely forgotten that I wanted a side exit when I was doing my research and purchasing. Ironically that desire would probably have lead me down the Magnaflow or Gibson road instead.
I fixed the leaks around the muffler by changing out the clamps to a different style,
TorcTite 3" Stainless Lap Joint Clamp. In fairness, I probably caused the one between the muffler & mid-pipe by cutting the mid-pipe a little too short (1/4-3/8") This worked well to quiet it down some. I was happier, though still not satisfied.
The exhaust seemed louder than it should have, I just figured that it was the more aggressive sounding profile of the supercharger in combination with headers, bigger y-pipe, and cat-back. I was talking with a shop about adding a resonance tube to try to fix it, but couldn't narrow the loudness to an rpm range as much as to any throttle setting under load. Then last week it got even louder.
So now I have another exhaust leak somewhere. Except now I'm working 6 day weeks, and don't have time to mow the lawn let alone tinker with the truck. I took it back to the shop where I had the supercharger installed (Moorespeed Performance in Columbus OH).
URD had a different truck shear one of the bolts on the belt tensioner. They sent out some upgraded bolts that were to replace the original. While the shop had the truck doing that, I had them check for exhaust leaks, of course they found one. I've probably had it since I installed the exhaust and has only been getting worse since. Thankfully this isn't one I thought I already fixed as it's at the junction of the after the pipe goes over the axle and before the resonator. Shop said that the pipes weren't sized correctly, and band clamp was loose. I did check that band clamp and re-tighten it when I was swapping out the other clamps. The shop resized the pipes, and cranked the band clamp down. I was also informed that even a small leak at that junction would be directing exhaust and noise upwards towards the cabin, so it would seem even louder than just leaking near the muffler.
In addition to fixing the leak, I also had them fix my rear window problem with a side exit. They cut the pipe just after the resonator, ditched the tip, and put on a 90 degree bend. Since I don't exactly go for flashy and don't see a need/want for a tip, they just just used a square cut, and some high-temp rattle-can satin black. I debated about this, but figure it's best for two reasons: regular pipe would be easier to bend back than some tip should it ever get crushed, and the rattle can should help protect the pipe from the extra salt spray exposure that comes from being behind the tire. The rattle-can could have come out better, but there's only so much you can do when it's 95% humidity and 90 degrees inside the shop.
I think I'm finally happy with the Mk3 exhaust as modified, hoping this will be the last issue. For now it's not far off of the stock quiet when idling or coasting, and only aggressive when under acceleration and load. It's finally at an acceptable level for a daily driver!
EDIT 6Sep18: Didn't even get a round trip to work before it got loud again. Pretty sure I'm just going to have the shop weld that joint.
EDIT 11Sep18: Left truck at the shop with the understanding they were going to find, and weld up whatever exhaust leak I had. They tightened everything up instead, although mentioned that nothing was loose. Test drove the vehicle <500ft and turned right back around. Leak is near impossible to hear at idle, but obvious under moderate acceleration or load. Had to repeatedly rev the engine while the shop owner rolled around under the truck feeling and listening at every joint/connection. Turns out the leak was from the driver's side header to y-pipe. Since this connection was tight, we checked the gasket and found it had been misaligned when tightened, hence asymmetrically crushed and causing the leak. Of course he didn't have any gaskets around (performance shop not a Toyota dealer), so I'll be dropping it back tomorrow for resolution.
I'm still working with the techs on the UCON-EMS crew to resolve the reoccurring P0420 (occasionally P0430) codes and CEL that are the result of deleting the cats between the O2 sensors with the long tube headers. I have a backup solution provided by the performance shop, but it's more money I'd have to spend on fixing something that I was specifically told wouldn't be an issue!
I finally get a break from work early next month and get to load up some guns, my dog, and head down to the mountains of Tennessee again. There's sure to be some fire roads, and maybe a trail or two. Hopefully not as challenging (or damaging) as back in May! Look for more info on the supercharger results and difference after that trip. I'm sure I'll be going uphill better this time around. I might even be dragging an empty boat trailer back with me if the welding shop is done with it.
