Getting ready to order soon, probably going to add in an electric cutout and 3.5” cat if it fits before the main hanger.
Have you had to tighten bolts or add any heat protection around the 8 speed/wiring components? Coating holding up?
Thanks!
Coating still looks new on the headers, and have not needed any additional heat protection. Headers are very compact so there is good clearance between components. I did have to re-tighten the O2 sensors but that probably has more to do with me not having a big enough line wrench or a selection of short stubby wrenches in the first place. Using a crescent wrench can be a little clunky. Header flange bolts all appear to be tight and I'm sure remflex gaskets help.
The two piece Y-pipe bolts onto the headers fine but did have some leaking on the middle connection of the Y pipe and where it slips into the main pipe. I ended up using the another u-bolt clamp on the main pipe in addition to the factory u bolt so it seems to finally have sealed. Also ended up using the the 2.5 U-bolt in the kit to get a better connection but still had a small leak. Messed with orientating it a different direction and actually twisted the bolt off. Ended up buying this which seems to have finally sealed the middle of the Y pipe:
https://www.amazon.com/Dynomax-3643...Clamp+Band&qid=1579575511&s=automotive&sr=1-3
Permatex 81878 Ultra Copper Maximum Temperature RTV Silicone Gasket Maker, 3 oz. Tube
I'm using the solo mach 44 as a muffler by itself but have noticed that the truck sounds off in cold weather so I think I will add a CAT. Don't know if the muffler is breaking in or if drone is just more present during cold weather. I have to do some research on what type of CAT to add. It seems CATs have to be sized for the size of the engine so as not to plug and do you get ceramic or metallic, 200 cell, 400 cell? Does the tuner account for a single CAT after the O2 ports?
Overall, I still think these headers are great in terms of quality and value. In addition they have some great attributes that even the expensive 4/1 set-ups just don't have.
The Y-pipe could use some refinement. The good thing about the Y-pipe is that it is 14 gauge, the bad thing about the Y-pipe is that it is 14 gauge so it's hard get a good mechanical connection with the hardware they give you. Either look at welding it which could affect the coating or upgrade clamps and use some type of sealant.
Performance wise, the pickup just gets to speed with much less effort, less downshifts, passing is effortless with unintentional acceleration to 90+. Mileage seems a little improved. I'll eventually get some 0 to 60 times to compare.
Mileage wise, I remember getting 16.5 bone stock on the interstate at 75, now it's 18.5 going 77 to 80ish. I'd say a good tune is worth an MPG and headers probably add another mpg.
I'm running an unoptimized Jay Greene tune, meaning I haven't sent any logs yet as I may add a CAT. So who knows, there might be more gains to be had.