skibuggy

I think it involves gutting one of the cats, is that correct? Is it easier to just buy something already gutted from a vendor like VAST, and can the swap be done easily enough for a regular DIY guy?

I currently have neuspeed cat back and no chip. what kind of improvements can be expected?

thanks

gragravar

the piggy pipe mod guts the precats and leaves the main cats in place. FWIW, I am still able to pass Colorado's dyno based emissions test while running piggy pipes.

it also involves relocating the oxygen sensors that were behind the precats to a new location behind the main cats.

yes it is easier to buy them from vast (that is piggy who invented this downpipe) then to do them yourself. that said, they are still a PITA to get to for pulling the old ones and installing the new ones.

without a chip I am not sure what kind of gains I'd expect with piggys.

skibuggy

of stock turbos? It prob would with the lower heat and restriction, right? I am thinking about doing the MTM chip and piggies.

How bad of a PITA, compared to cam tensioner seals for example?

DocWyte

Takes about a day, so figure 6-8 hours to R&R the downpipes, then a few hours to gut the pre-cats. Then you have to take them to a welder to have the O2 bungs welded.

Don't know about the longevity, it'll help with power tho...

Trango

Access to either a hammer drill or an electrical demolition hammer can greatly speed gutting the cats. I did one with a demo hammer that took like 15 minutes, tops.

Wrinkledpants

It will certainly help reduce the amount of heat the oil in the turbo is exposed to after shutdown. It's probably not one of those things where piggies will absolutely lengthen the turbo life, but maybe one day you are driving hard, don't have time for a cool down, and the threshold for oil coking is nearly crossed. Maybe having pre-cats adds just enough heat to coke the oil, and maybe not having them limits the oils exposure enough that it doesn't coke.

It's added security I guess..... on top of improving sound and power

nord1899

had a CEL for O2 sensors for 18 months. Did piggies, along with relocating the sensors, and CEL went away.

Also did the trick of using anti-foulers to lift the O2 sensors out of the exhaust stream, but that alone did not resolve the CEL.

DougGo

nord1899, great tip on the O2 sensor issue, I just had my first CEL from the front O2 sensors this week and have learned they are quite expensive to replace, another reason to consider the piggy pipes. I've seen lots of commentary on the piggy pipes but no real dyno data. Has anyone actually dyno'ed before and after, or is there any other data to back the additional 20HP(or so) claims?

DocWyte

Piggy pipes don't do anything to the O2 sensors. You can get the O2 sensors for less from Vast Performance. It's something you can do yourself with some simple tools and about an hour of your time.

DougGo

Thanks for the clarification, sounded too good to be true. Will pursue the vast option and install them myself!