Decatted a 2017 header.

An observation - the honeycomb on the cat of a 2017 is approximately 5% heavier compared to a 2013 cat.

How do you like the power difference compared to stock?

I tried a 2017 decatted header and ultimately swapped back to my gruppe-s after trying different header/catback setups.

Suspension refresh, new springs, added some fluid film black to anything stamped steel, and hit all the rubbers with some silicone lubricant.

https://i.imgur.com/vXgicsT.jpg

I've not installed it yet - am still on a decatted 2013 header. But between that and a stock header with a tune is a very appreciable difference after 4K rev.

I'll have to retune for the 2017 headers to get the most out of it, but I would assume there would be a slight reduction at the low end due to the larger pipe diameters.

Im pretty sure decatting has been proven on this cars to cause a loss or minimal gain of HP due to the distortion of air created.

WHAT DID YOU DO TO YOUR FRS TODAY?
 

Lol no. PM rice_classic. For SCCA T4 they have to run the stock manifold but are allowed to decat it. They are making numbers comparable to most headers on the market.

Edit: you also don’t just punch the cat out. You cut that section out and replace it with a piece of tube. So what distortion?

It does make additional torque and power when paired with a tune.

Yes if you replace with pipe its fine, most just drill out the honeycomb leaving a chamber of distortion

Most? I’m all my years I’ve never seen or spoken to anyone who has drilled out a cat. I’ve heard of people knocking loose cores out with a pipe. But drilling, no. I’d be far easier to cut it out. The disruption in flow and resonance would be minor, no worse then a UEL and people have hard ons for those.

Are the LEDs plug and play? I've been thinking about this too. So the Vlands only give you the boomerang and turn signals, no high beam/low beam bulbs?

Yes they are! You can get H11 bulbs from anywhere and they’ll fit the low beams. I forgot which bulbs are the high beams, but they are also plug and play. The Vlands don’t give you bulbs, you have to order them! However, if you get the OLM headlights from FTSpeed (the ones on my car), they come with an HID projector, bulbs, and ballast, all with it for not too much more. Definitely the way to go in my opinion!

I forgot to ask. Would like to hear on why you preferred the Gruppe-S and the difference over the decatted header.

took a side profile shot of my ride, these cars are so beautiful Attachment 212150

The powerband with the gruppe-s feels better to me.
Power from 3500-5500 felt smoother and stronger. I also like the sound of UEL with stock catback over stock setup.

Tuning with both headers was done by @tomm.brz

I went from gruppe-s to decatted back to gruppe-s. It was an experiment to see if a different header would make the greddy SP catback I purchased useable for my ears.