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Cat bypass/ Sport Cat install - the non-fairy tale version
I had squirreled away a few choice parts while waiting for my TTS to finally arrive. One area in particular was exhaust mods. I got some Kline cat bypasses and Sharkwerks straight pipes off the marketplace and had them ceramic coated for heat isolation.
After watching the available install vids I felt pretty confident to be able to knock this out without too much trouble and without removing the rear bumper.
First I put the car up on a lift but it could likely be done just jacking up the rear end
Other install videos show removal of the O2 sensors first. Well the space is very tight and it is hard to get a 22mm crows foot to seat because of the heat shields. So I removed the cat heat shields. They;re held on by 3 T15 or 20 bolts
After removing the shields the O2 sensors can actually be removed with an adjustable crescent wrench - don't even need a fancy O2 sensor tool
Loosening the cat to muffler clamps is easy. 13mm socket. Loosening the exhaust valves is easy as well. The hard clamp to loosen is the V-band clamp holding the cat to the turbine housings. The band clamp has a 6mm socket head so you need to use a 6mm hex key or tool but there is not enough room for a traditional allen wrench. My bolt head was facing directly up.
I put together an adjustable 1/4 drive ratchet with a 1/4 drive 6mm allen key socket. 3/8 drive won't work as its too bulky. The key is to fit the socket on then fold the ratchet 180 degrees down. Then you use a long screwdriver to leverage it against itself to make it turn.
It's not easy but it's not impossible once you feel how to leverage the tool against itself to loosen the bolt. Reassembly is the reverse and be sure to move the V-band clamp so the bolt is more easily accessible. Finished and now enjoy louder snaps and burbles and a more aggressive sound!
I have the Soul non Cat race exhaust sitting waiting Soul removes the valves completely and puts them into a little jig that holds them so they can flap away.
1. Do you get a check engine light error?
2. Does the garage smell like raw fuel/gas after a drive and park?
Got the check engine light after about 50 miles. I have the M Engineering tune coming tomorrow.
The smell is really nothing. I don't notice it at all. Much less than my 993TT with cat bypasses. My 2001 Z71 truck with 6L and long tubes is 100x worse. As a matter of fact I would say its a non-issue for anyone leaning on the fence about bypasses.
Ok so a tune is necessary to code out the CE light. Not the case with 200 cell cats, but people should know they must get a tune to remove the CE light using straight pipes.
I had 100 cell cats on my 991 and the fuel smell in my closed garage was unbearable. I have my kids bikes and scooters in there and I thought I was causing them brain damage
You are the first to say it’s a non issue on 992’s. I would like to hear from anyone else with straight pipes to hear if they have the same opinion. Seems impossible as the purpose of the cats is to burn off excess raw fuel and by deleting them there is nothing to do that, but if you say there is no fuel smell
I have to believe you.
sounds like a lawnmower lol, thanks for posting .. how much percent would u say it’s louder than stock?
At idle and without the exhaust valves activated maybe 10-15%. When the valve is activated more than twice as loud - almost sounds like straight pipes.
Great write-up. This will be helpful when I install mine. Regarding the smell, I don't recall the smell being so bad way back then before cats were required.
Ok so a tune is necessary to code out the CE light. Not the case with 200 cell cats, but people should know they must get a tune to remove the CE light using straight pipes.
I had 100 cell cats on my 991 and the fuel smell in my closed garage was unbearable. I have my kids bikes and scooters in there and I thought I was causing them brain damage
You are the first to say it’s a non issue on 992’s. I would like to hear from anyone else with straight pipes to hear if they have the same opinion. Seems impossible as the purpose of the cats is to burn off excess raw fuel and by deleting them there is nothing to do that, but if you say there is no fuel smell
I have to believe you.
While I don't have straight pipes, I do have FabSpeed 200 cel cats, and after a drive my garage does smell a bit like fuel. And I love it.....
While I don't have straight pipes, I do have FabSpeed 200 cel cats, and after a drive my garage does smell a bit like fuel. And I love it.....
Well then that goes to my point, if 200 cell cats still cause raw fuel smell in a garage, then how can straight pipes which have nothing to help burn off and scrub the fuel smell not cause any?
I have 200 cell cats and I smell nothing in my garage. When I had straight pipes on my previous car you couldn't go into the garage without getting a headache. The raw fuel combined with a small garage structure and no open air ventilation caused the fuel smell to permeate everything and it was bad. Thats why I choose 200 cell cats, to avoid a CE light error and the smell. I have been told 200 cell flow 95% as well and straight pipes and 100 cell flow 97% as well as straight pipes. Anything flows better than the stock cats, so its all an improvement over OEM
04-15-2023, 10:26 PM
Cat bypass/ Sport Cat install - the non-fairy tale version
Soul removes the valves completely and puts them into a little jig that holds them so they can flap away.
