Stock downpipe size comparison

Just wanted to show a few pics of the stock downpipe size and layout for anybody wondering. The second picture is of the Stainless Works downpipes for comparison. There is a significant difference in size between a 3'' aftermarket downpipe vs the stocks.

The stock pipes start just under 2.25" ID at the turbo and gradually increase to just over 2.5" ID at the end. I put in a piece of 3" piping in a few pics for comparison.

The stock turbo adapters are just over 2" ID at the narrowest point. That's a big chokepoint.

The rest of the stock exhaust is around the 2.75" mark. Aftermarket exhausts I've seen are 3".

To me the most restrictive part of the exhaust is without a doubt the downpipes. I don't know the measurement for the stock cats, but I've heard that Stainless Works uses 200cel cats and SPD performance uses 400cel, hence why SW throws check engine lights and SPD's pipes don't.

Are you doing this yourself? If so how difficult? My last DP I changed was a bitch but on a different vehicle.

I've already done it. Took over 6 hours. It was a PITA because i put in the SPD adapters too. You have to get a stud extractor tool and a torch or else they will likely break. Then you have to remove the trans crossmember/mount and support the trans. There are a bunch of heatshields and pieces to remove too. It's time consuming but you can do it in your garage without jacking up the truck.

any idea how many cel the stock downpipes have out of curiosity?

Awesome thanks for tge great info. Did you change adapters on the turbos to get them in a bigger size? Did you get a chance to dybo truck before the downpipe install?

This is great info, @k-rub!

Agreed thanks for posting!

I have no idea how much cel the stock cats are. I'm running the SPD downpipes right now and haven't had a check engine light in the few hundred miles I've been running them.

I did do the SPD adapters. I didn't measure them but they are a lot bigger. SPD's site has dyno graphs showing they make some power. I haven't done any dyno runs, but there is a noticeable increase in seat of the pants power after all my mods (intake, full exhaust, downpipes, and intercooler).

Thanks for sharing.

There are a bunch of options now for down pipes that will make a big difference like Kooks, SW, etc...