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What are the advantages & disadvantages of going catless?
My friend owns a BMW M6 & claims that without his cats he gained 30+HP.
Will removing the cats of an 08 C6 Auto be just as advantageous?
30+ HP? Dont know much about the M6 but pretty sure they couldnt get that much without cats. The Vette sure as hell doesnt. You may gain 1-2 hp or so but not much. I wouldnt go catless personally because of the smell. I have hi flow cats with LTs and it sounds good enough although there is still an exhaust smell that comes into the car.
Ill stand corrected. There are a few sites that claim 30-50 HP after a tune with catless downpipes. The downpipes may be the equivalent of long tubes for Vettes. Still seems a little steep but sure others can chime in. And thinking about it more, I would bet the HP comes mostly from the tune and not the cat removal. He probably just got both at the same time. A tune will definitely help out if not already done.
Last edited by schizcat; May 24, 2022 at 04:33 PM.
What are the advantages & disadvantages of going catless?
My friend owns a BMW M6 & claims that without his cats he gained 30+HP.
Will removing the cats of an 08 C6 Auto be just as advantageous?
I doubt there will be much in the way of HP increase, but more important, if this is street driven & living in CA, you'll never get past smog.
I doubt there will be much in the way of HP increase, but more important, if this is street driven & living in CA, you'll never get past smog.
Passing smog is the least of my worries, I’m more concerned if it will damage the engine or computers without a tune. I’m sure it’ll sound great paired with my exhaust but if it’ll bring more problems than good then I’ll avoid it.
Passing smog is the least of my worries, I’m more concerned if it will damage the engine or computers without a tune. I’m sure it’ll sound great paired with my exhaust but if it’ll bring more problems than good then I’ll avoid it.
it won't do anything bad to the engine although probably not advisable. I ran my vette with no cats (longtube headers & offroad midpipe(xpipe) w/ no mufflers (slp loudmouth II) without a tune for a couple of months until I got it tuned. Here is the difference between those mods without tune and with tune.
Again, keep in mind this isn't stock and then mods and tune. It's mods without tune and then mods with tune. Basically longtube headers and no mufflers is all.
This tuner is about 1½ hours away from you. Church's Automotive
Texas Speed LT Headers w/offroad midpipe ($700) & SLP Loudmouth II mufflerless axleback exhaust ($700). Dyno Tune was $500
Last edited by Jaime-Corvette; Jun 2, 2022 at 05:37 AM.
BMW M6 has a twin turbo V8 so going catless or high flow cats could definitely allow increase in power by lowering back pressure. In a turbo engine, car ideally you would want zero restriction in the exhaust and cats are a restriction.
In a naturally aspirated LS V8, no cats would likely give a little bump in power but not much. And no cats would likely increase the amount of drone when cruising and the exhaust would smell. It won't damage anything but will set a CEL if you are not tuned but it will just be an emissions code.
Best way to go would be to add long tube headers with cats and get a tune.
it won't do anything bad to the engine although probably not advisable. I ran my vette with no cats (longtube headers & offroad midpipe(xpipe) w/ no mufflers (slp loudmouth II) without a tune for a couple of months until I got it tuned. Here is the difference between those mods without tune and with tune.
Again, keep in mind this isn't stock and then mods and tune. It's mods without tune and then mods with tune. Basically longtube headers and no mufflers is all.
This tuner is about 1½ hours away from you. Church's Automotive
Thank you very much, I’ve been meaning to find a trust worthy tuner near me!
Originally Posted by Spaceme1117
BMW M6 has a twin turbo V8 so going catless or high flow cats could definitely allow increase in power by lowering back pressure. In a turbo engine, car ideally you would want zero restriction in the exhaust and cats are a restriction.
In a naturally aspirated LS V8, no cats would likely give a little bump in power but not much. And no cats would likely increase the amount of drone when cruising and the exhaust would smell. It won't damage anything but will set a CEL if you are not tuned but it will just be an emissions code.
Best way to go would be to add long tube headers with cats and get a tune.
How much more drone with LT headers & Hi Flo cats bring? My B&B Bullets alone bring a decent amount of cabin noise/squeaks
You are going to want to get rid of those bullets when you start doing mods it's gonna get too loud. I recently replaced my LG gt4 exhaust for the magnaflow street series and it quiet down the car significantly definitely in a good way. After heads/cam it was too loud for me. I even added flowmaster high flow cats into my xpipe it didn't quiet done the car at all but the exhaust smell was gone.
Thank you very much, I’ve been meaning to find a trust worthy tuner near me!
How much more drone with LT headers & Hi Flo cats bring? My B&B Bullets alone bring a decent amount of cabin noise/squeaks
I am running Kooks long tube headers and hi-flow cats threw the stock NPP on my 2011 Grand Sport. No drone at all. I also run the same exhaust on my 2017 Camaro SS; Kooks long tube with hi-flow cats into the stock NPP exhaust and again no drone.
Am I understanding this correctly? In order to go catless I’ll just simply need to install LT headers. Will I need to get a tune as well?
yea man. cats are on the short stock headers. Get rid of those with any longtube headers and you are catless. It's up to you for sound after that with either midpipes (like offroad x pipes), mufflers from different brands, or mufflerless (from different brands) for a true straight pipe.
As for me I am true straight pipe. My mods listed above. all cost me $1400 for lt headers, offroad xpipe and slp mufflerless axleback. As for sound. It's a bit dronie but not too bad. Depends on your foot. Highway speeds 70-80 mph is doable for me
Am I understanding this correctly? In order to go catless I’ll just simply need to install LT headers. Will I need to get a tune as well?
Most long tube headers that are sold can be purchased with or without cats (or at least they used to be). Typically, long tube header systems (Kooks, ARH, Stainless Works), consist of the headers and an intermediate connection pipe that goes between the headers and the muffler system. The intermediate or connection pipe is where the cats would be located or if catless, it would have a straight section of pipe in place of the cats.
The major brands of headers because of the garbage, environmental **** activists at the EPA, now do not have a catless intermediate pipe option and only offer the catted option.
Now you don't have to get a tune with LT's but you will likely get a CEL for emissions and you won't really take full advantage of the performance increase that headers have. So I highly, highly recommend getting your car tuned.
I do have a few header and exhaust options available from Kooks, ARH, Corsa and more if you want quality parts on your Vette. One of the first things folks do on Corvette is to add a header + x pipe kit + tune to give it more volume and power. Axleback exhaust from Corsa will tune out the added drone from headers and will add volume at the same time.
Catless
